In my Android app, I always get VerifyErrors! And I cannot figure out why. Whenever I include a external JAR, I always get VerifyErrors when I try to launch my app (except for once, when I included Apache Log4j.)
I usually get around this by taking the source of the library and adding it to my project, but I am trying to put the GData client library.
I can get this in source, but it's dependencies (mail.jar, activation.jar, servlet-api.jar) I cannot, so I get verify errors. I would like to get to the root of this problem once and for all. I looked on the internet, but they all seem to talk about incomplete class files? which I do not know of.
Look at LogCat and see what's causing the verifyerror. It's probably some method in a java.lang class that is not supported on the android SDK level you are using (for instance, String.isEmpty()).
From android-developers:
The output from "adb logcat" indicates the class that could not be
found as well as the class that has the bad reference. The location
is identified down to the specific Dalvik instruction. The trick is
to look in the logs above the exception.
Android uses a different class file format. Are you running the 3rd party JAR files through the "dx" tool that ships with the Android SDK?
To make it work you need to add jar of the library to one of the source folders (even if you have already added it as eclipse library, you still need to add it as source).
Create a directory in your project
(e.x. "libs") and put library jar
there.
Add the directory to the build class
path by (click right button on the
folder and select "Build path"->"Use
as source folder").
Rebuild your project.
It happened to me right now.
The error was caused because I was using methods from a newer SDK that my device had.
Android 1.5 device installed an apk using this:
<uses-sdk android:minSdkVersion="3" android:targetSdkVersion="4"/>
I found an interesting case. I use:
<uses-sdk
android:minSdkVersion="9"
android:targetSdkVersion="18" />
So some of new Android 4 capabilities are not implenented in Android 2.3 like ImageView.setLayerType. To avoid runtime error simply:
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
setLayerType(View.LAYER_TYPE_SOFTWARE, null);
}
This approach should be used also with exceptions handling:
} catch (NetworkOnMainThreadException nomte) {
// log this exception
} catch (SocketTimeoutException socketTimeoutException) {
// log this exception
}
NetworkOnMainThreadException is not implemented in Android 2.3 so when the class is loaded (and not before!) the exception java.lang.VerifyError occurs.
If you're using Retrolambda you might have added a static method to an interface (which is only allowed in Java 8).
This can also occur because of referencing limit error on Lollypop below versions, where it is limited upto max 65K size
Possible solution for above issue
Step1: Add android-support-multidex.jar to your project. The jar can be found in your Android SDK folder /sdk/extras/android/support/multidex/library/libs
Step2: Extend your application with MultiDexApplication, for e.g.
public class MyApplication extends MultiDexApplication
Step3: Override attachBaseContext
protected void attachBaseContext(Context base) {
super.attachBaseContext(base);
MultiDex.install(this);
}
Step4:
The next step is to add the following to the android part of your apps build.gradle
dexOptions {
preDexLibraries = false
}
Step5:
Lastly, following to the general part of your apps build.gradle
afterEvaluate {
tasks.matching {
it.name.startsWith('dex')
}.each { dx ->
if (dx.additionalParameters == null) {
dx.additionalParameters = ['--multi-dex']
} else {
dx.additionalParameters += '--multi-dex'
}
}
}
For details, please checkout
https://developer.android.com/tools/building/multidex.html
In my case, it happened when I updated from Eclipse Indigo to Eclipse Juno: I'm not sure what is the true reason, but, my Android project that I'm working on for a long time stopped work because of that exception.
After many hours of trying to fix that, I found the solution for me.
In my Android project, I use other project (say, "MyUtils") that is in the same workspace. So, I needed to do the following:
Right click on Android project -> Build path -> Configure build path
Now, go to tab "Order and Export" and make "MyUtils" checked. That's it: I got rid of this annoying exception.
I downgrade gradle version from 2.0.0-alpha2 to 1.5.0 that solved this problem.
The problem could also be caused by a mismatch between two androids projects. For example if you have developed an android library using the package "com.yourcompany", Then you have the main application's project using the same package as base package. Then let say you want to change the version of your main app, so you change the manifest file's values: Version Code and Version name. If you run your app without changing those values for the library, you would get a verify error on any call of a method on a object from the library.
I had the same issue. I was building with 2.1 r1 and updated to 2.1 r3 with the new adt 17. I had verify errors on javamail's mail.jar and it was driving me crazy. Here is how i solved the issue:
created a libs/ folder and added the jars.
right click > add as source folder
i tried a rebuild and it failed. I removed the libs/ directory as a source folder and removed refs to the 3 jar files in the build path. Then i added the libs/ folder again, and added each jar in the libs/ folder to the build path. Now it works as expected. This is a weird workaround but it worked for me.
In Eclipse 4.x, if you encounter this problem, try below:
migrate all included 3th-party jars into the User-Libaray
move up the user lib before the android lib and check it in the Order and Export tab
clean and rebuild to run
I have this issue after a SDK update. The compiler had problems with my external librarys. I did this: right click on project, then "android Tools > add suport library..." this install on my project library "android-support-v4.jar".
java.lang.VerifyError means your compiled bytecode is referring to something that Android cannot find at runtime. This verifyError Issues me only with kitkat4.4 and lesser version not in above version of that even I ran the same build in both Devices. when I used jackson json parser of older version it shows java.lang.VerifyError
compile 'com.fasterxml.jackson.core:jackson-databind:2.2.+'
compile 'com.fasterxml.jackson.core:jackson-core:2.2.+'
compile 'com.fasterxml.jackson.core:jackson-annotations:2.2.+'
Then I have changed the Dependancy to the latest version 2.2 to 2.7 without the core library(when I include core2.7 it gives the verifyError), then it works. which means the Methods and other contents of core is migrated to the latest version of Databind2.7. This fix my Issues.
compile 'com.fasterxml.jackson.core:jackson-annotations:2.7.0-rc3'
compile 'com.fasterxml.jackson.core:jackson-databind:2.7.0-rc3'
I get the VerfiyError as well... can't find a real reason. It helps to wrap the new lines of code into a method (Eclipse, 'Extract Method...'). So in my case the reason is not an unsupported method.
I had very similar problem. I had added Apache POI jars and problem appeared when I updated to android SDK 22.3.
I had Android Private Libraries checked so this was not the common problem with android SDK. I unchecked all Apache POI jars and added one by one. I found that poi-3.9-20121203.jar should be before poi-ooxml-3.9-20121203.jar. Otherwise it will not work.
If you have tests, try commenting out this line from your build.grade file:
testCoverageEnabled = true
For me this caused VerifyError exceptions on classes which use Java 1.7 features, particularly string switch statements.
I had the same problem after making a git pull.
Solution: Build -> Clean Project.
Hope this helps.
I have found another case.
Conditions:
Use Retrolambda (not sure if it's necessary);
Make a static method in an interface.
And the result is boom! java.lang.VerifyError when trying to access the class that uses that interface. Looks like Android (4.4.* in my case) doesn't like static methods in interfaces. Removing the static method from interface makes VerifyError go away.
I also had this problem, as had my jars in a user library...
The way I solved this was to add them to the lib folder and then add them in the build properties in eclipse...
The first time i did this it did not work, but then i removed them and readded them again and it started working...
bit of a strange one! but now working all the time.
Good Luck
I have coded Android API methods/class that are in SDK 2.1, and was trying to run it on Android 1.6 emulator. So i got that error.
SOLUTION:
Changed it to correct emulator version.
THIS WORKED FOR ME.. Thanks.
For posterity, I just got this error because I was using Arrays.copyOf() which is not a method supported by Java 1.5 which corresponds to Android Level 4. Because I was running including libraries developed under 1.6 they compiled fine. I only saw the problems when I moved the class in question over to my Android project -- then the error was highlighted.
Uncaught handler: thread main exiting due to uncaught exception
java.lang.VerifyError: com.j256.ormlite.dao.BaseDaoImpl$DaoConfigArray
at com.j256.ormlite.dao.BaseDaoImpl$1.initialValue(BaseDaoImpl.java:71)
at com.j256.ormlite.dao.BaseDaoImpl$1.initialValue(BaseDaoImpl.java:1)
at java.lang.ThreadLocal$Values.getAfterMiss(ThreadLocal.java:429)
at java.lang.ThreadLocal.get(ThreadLocal.java:66)
On that line I was trying to do a new DaoConfigArray and that class had the following line:
// copyOf is only supported in Java >= 1.6
doArray = Arrays.copyOf(daoArray, newLength);
What made it even more complicated is that line 71 was pointing to a ThreadLocal initialization which I thought was the reason for the problem initially.
private static final ThreadLocal<DaoConfigArray> daoConfigLevelLocal
= new ThreadLocal<DaoConfigArray>() {
#Override
protected DaoConfigArray initialValue() {
return new DaoConfigArray();
}
};
I had to remove dependent projects and instead compile dependent projects are jar's and include them in the libs folder.
I'm sure that my cause was different than yours, but since this is one of the top hits when searching for "Android java.lang.VerifyError", I thought I'd record it here for posterity.
I had some classes along the lines of:
public class A { ... }
public class B extends A { ... }
public class C extends A { ... }
And a method that did:
A[] result = null;
if (something)
result = new B[cursor.getCount()];
else
result = new C[cursor.getCount()];
// Fill result
...
As long as this code was present in the file, I would get a VerifyError the first time the class containing this method was loaded. Splitting it out into two separate methods (one that dealt only with B's, and one that dealt only with C's) fixed the problem.
In my case, this error occur because my google-play-service is not the newest.
If your project does not support some class in the .jar, this error occurs(ex. ImageView.setLayerType, AdvertisingIdClient, etc.).
I just identified another situation that it occurs, not only due to libs not dx'ed.
I have a AsyncTask with a very long doInBackground mehtod. For some reason this method with more than 145 lines started to break.
It happened on a 2.3 app.
When I just encapsulated some parts into methods, it worked fine.
So for those that could not find the class that was not correctly dx'ed, try reducing the length of your method.
For me, the issue ended up actually being that I was using multi-catch clause somewhere in the class which is a Java 7 feature (and API 19+). So it would crash with VerifyError on all pre-19 devices.
For me it was in correlation between compileSdkVersion and buildToolsVersion. I had:
compileSdkVersion 21
buildToolsVersion '19.1.0'
I changed it to:
compileSdkVersion 21
buildToolsVersion '21.1.2'
For me, it is the problem of compileSdkVersion. When I used the API level 21 in a specific android application (https://github.com/android10/Android-AOPExample):
compileSdkVersion 21
the java.lang.verifyerror happened. So I changed the compileSdkVersion to 19
compileSdkVersion 19
It worked well. I think that it might be the problem of SDK buildTools, and it seems OK when API level < 21.
Related
I am new to kotlin, i have converted some code from java but it seems like there's something wrong, The R in findViewById(R.id.my_id) is highlighted in red and it shows this message : "Unresolved reference: R".. I've been looking for a solution but i seem not to figure it out, So what should i do?
Here's a screenshot :
The issue can be caused by many factors,
as mentioned by martomstom in this Answer the issue is sometimes caused by com.android.tools.build:gradle version, changing it's version to a more stable one would solve the problem: for example: com.android.tools.build:gradle:3.4.0-alpha02 with com.android.tools.build:gradle:3.2.1
Also, having libraries from the same group, but with different versions may cause the problem or even more runtime errors. use the exclude group method like the following : implementation('com.squareup.picasso:picasso:2.71828') { exclude(group: 'com.android.support') } in this case, picasso library uses android.support components, the android library version used in picasso is different than the one you're currently using in your app, so in order to solve this issue, we have to exclude it completely from its sub library and class groups.
It can also happen by the mismatch of resources and code, including this importation line in your activity may solve the problem too : import com.package.name.R
Sometimes it can happen because of the IDE, performances or memory.. Cleaning the project from time to time may save you some time, on Android Studio it would be something like this : Build -> Clean Project / Rebuild Project - Cleaning IDE cash also helps with performance and memory, on Android Studio it would look like this : File-> Invalidate Chases/ Restart -> Invalidate Cashes and Restart
I noticed that this problem happens to me the most of the time when importing new resources, Using prohibited characters in their names would fire the error, such as . , , - , UpperCase or special Letters
And as a suggestion , if you're using Kotlin, i really recommend using Kotlin extensions in your activity such as : import kotlinx.android.synthetic.main.activity_page.* or if you're using a custom view : kotlinx.android.synthetic.main.view_layout.view.*
after that, in onCreat() method of an activity , you'll only have to call the id, for example : my_edit_text_ID.text = "Kotlin Dbest!", or from a custom view : mCostumView.my_edit_text_ID.text = "Kotlin Dbest!"
EDIT :
I have faced this issue againe and the problem was the '' R '' library was imported from 2 different sources :
com.android.R
com.example.package.R
You must only import the '' R '' library with your application package name,
in this case com.example.package.R
Sometimes the library is not imported at all, to import it, click on the
unresolved reference R and press Alt + Enter
EDIT:
As tobltobs mentioned in the comments section: " Most of the time the problem is caused by another error which prevents the build system from creating generated sources. To find the root cause look at the gradle log (the "toggle view" icon below of the green hammer in the Build output) and look for errors unrelated to R or BuildConfig (also generated). If there is no other error left and the problem with R persists then maybe something of this list might help. "
EDIT:
As Patrick Beagan mentioned, Kotlin extensions are now deprecated - I'd advise using ViewBinding instead
I used com.android.tools.build:gradle:3.3.0-alpha13 and had the same issue. Changing to stable Version 3.2.1 solved this problem for me.
So this is a misleading error.
The fastest way to get to the root cause is to run:
bash gradlew assembleDebug --debug
then scroll up and look for the real error happening.
However, if it still doesn't seem like you have the answer you are looking for, then read on.
I'm going to explain the 30,000 foot view of what is happening. This is not EXACT order or EXACT flow, it is just pretty damn close ;) so if you know more then I do of the exact order and care to make corrections with links, feel free I won't stop ya :).
The Process
The R file is generated code.
There is an order to the generation.
Gradle will do it's magic, pull it's dependencies and kick off it's
warning and error tree first,
then Android converts all Kotlin to Java behind the scenes. Yup that's
right, our beloved Kotlin still has to be Java to compile for our
beloved ART virtual machine.
Then it runs through and does the adapters that you have created for
JVM Statics and a few other tasks.
Next up it compiles all the xml databinding files first to create the
generated databinding files.
If everything succeeds it moves on to processing the assets and
resources. Which creates pointers or IDs for each resource that you
reference in code. Next it will run through and begin compiling the
code and packaging process after that.
Pretty straight forward process, but here in lies the problem.
The misleading Error
If any step fails before the R generation is complete, then the R does not get generated. Sometimes a simple rebuild is all you need to do, sometimes a simple File->Invalidate Cache and Restart is all you need. However, more often than not you have a code issue in your gradle, your xml, your databinding or your adapters that are preventing the compiler from even reaching the R generation stage.
So the next question is
"Well shoot, how do we troubleshoot it if the errors are worthless or
non-existent".
Well first let's talk about the many ways these errors present themselves.
Duplicate Databinding class found
xml Binding Error at line #
Couldn't find matching signature of bind:customAdapterMethod
Can't find R file of the correct project, only shows import options for sub modules or incorrect namespace R files.
Couldn't find DataBindingUtility or DataBinding for activity/fragment
And many other various ways as well, too many to list them all
Next, let's talk about potential candidates causing the problem. As there are sooo many lol.
Gradle Syncing issues
Bad versions of Gradle or Tools, you may have gone too far forward in your last gradle file modification. Try stepping back one version and "invalidate cache and restart" if that fixed it, great, if not, read on.
Caching Issues (File->Restart and Invalidate Cache)
xml elements with wrong namespace
xml elements with bad IDs or references IDs out of order (i.e. you say align to right of an element that is lower in the xml document then the sibling element that is trying to reference it)
xml data binding issues referencing namespace or member that doesn't exist or is not typed correctly
xml data binding issues in non-auto-filled spots like custom attributes using adapters as those are harder to spot. i.e. bind:myCustomMethod=#"myObject.mistypedProperty()"
JVM Static adapters with issues or duplicated signatures
Duplicated or bad character in the Strings or Dimens file or any other xml file for that matter
Private variable marked for #Binding without properties to access it
Member variable marked for #Binding that matches a parent class method causing duplications that manifests itself in almost impossible errors
Mismatch of types like using an adapter that takes (Int) but you are passing (Int?) via data binding and it isn't recognized with JVM Statics until compile time
You selected IMPORT on a popup to import R file of a sub module instead of the application file
Having bindable members in a child or parent class, but not giving fully qualified namespace to class cast in the XML usage of the parent or child class. As the databinding compiler is not smart enough to realize the variable provided for class Foo is also parentFoo baseclass, so you have to qualify it as android:text="#((com.path.parentFoo)foo).parentMethod"
Having a method name in a class, that matches a "generated property from #Binding member variable" i.e. firstName as a variable, but then having a method called getFirstName in a parent or child class, because you are now matching a method name that will get auto generated, thus causing dataBindingUtility duplication class errors.
There are more causes, but this should give you a series of places to look, but the list can go on and on seriously.
Unfortunately this happens a lot in bleeding edge technologies where the UI tools are not up to speed with the terminal based tools yet. So I suggest you run from the project root in a terminal with
bash gradlew assembleDebug --debug
When it fails, and it will. Start scrolling up through the logs until you find the red where you see what is actually failing and preventing the next stage from occurring.
You will find this especially useful when you start dealing with databinding.
TIP:
When you start dealing with databinding, make sure you compile and run often because the goal is to recognize right away before doing other files to make sure you didn't break generation and make your life MUCH easier to know code you just added caused the issue before getting too far.
Times to compile and run to confirm no issues before moving on.
If you add a few JVM statics compile and run
If you add variables to your XML to use
If you bind to properties of your model in 1 file
If you add a binding to a JVMStatic
If you add bindable members or properties to an model
If you refactor moving observable member variables or properties into children or base classes
Any other xml or binding related elements that can effect the generated code.
Like I mentioned above, the reason is to avoid getting so many changes, that it becomes a troubleshooting nightmare to find a generic vague, horrible error related to generated databinding code. I'm sure the tools will improve, but for now, do yourself a favor and compile and run often when changing Databinding related items.
Happy Coding
Use gradle commands.
In Android Studio, on the right menu:
Gradle -> :app -> Tasks -> build -> clean.
After that, Gradle -> :app -> Tasks -> build -> build
I had wrong import statement import android.R instead of import my.project.package.R. Fixing it solved the problem
I had the same problem, and I tried not to downgrade from gradle version 3.3 to gradle version 3.2.1. Instead I updated Android Studio to version 3.3, which made the trick for me ;-)
This worked for me. How much work it is depends on how big your project is. I started a new project, created the required modules (XML, Kotlin, colors, strings, etc.), then copied the code into the modules in the new project from the modules in the old project. Copying XML saves a lot of time compared to recreating the UI. All in all, it take a little while, but I have spent much more time tring to fix the unresolved reference error without it.
TRY THIS
Go to the content_main.xml file and there you need to change the
android:id="#+id/??????"> line of code to whatever id you have given to your file.
Replace question mark ?????? with the related file id name.(IF you dont know the id go to the design tab on the bottom and click on the related Asset.
On the right side below attributes, you can find the ID you have given to it.
If it is blank you can freshly name it and Android Studio will write the code.
Then restart Android Studio. Hope this will help. Happy coding.
I believe that I came across the real answer (though by accident).
I also, as the OP had my KT file fail to location R. as well as other classes that happen to be in java. What I noticed was that there was a case difference I the filenames. Once I corrected the import statements to match the case of the package (aka, folder) the errors resolved.
I had the same problem with R reference too.
Finally Android Studio 3.3 has been released and using 'com.android.tools.build:gradle:3.3.0' the problem has been fixed!
I update Android Studio to version 3.3.1 and solved this problem.
Downgrading gradle version worked for me.
I changed :
Gradle version from : 4.10.4 to 4.4.1
and Gradle Plugin version from : 3.3.1 to 3.1.3
If your are experiencing this issue in Kotlin because you cannot reference the elements of the xml layout by ids. (e.g. R.id.adView) then try removing the line import android.R from your kotlin file.
For me it was because I had created a new package and R wasn't available until I imported it from the package above
I faced the same issue. I restarted my Android Studio, invalidate caches, Sync Gradle but nothing was working. Then I looked into my file and there are 2 imports of my R. 1 import was related to my application package and the other was related to Android.
import com.example.myApp.R
import android.R // This import was added accidentally during the build.
Removing second import related to android solved this issue.
I had an issue because of this import:
import android.os.Build.VERSION_CODES.*
In the latest version it contains R
I had same problem while using auto-manifest plugin. Adding AndroidManifest.xml explicitly solved the problem to me.
I used to File --> Invalidate Caches... and issue resolved.
Just restarting Android Studio solved it for me.
I also had this problem, Gradle Sync, and Invalidate Cache, and Restarting Android Studio Didn't help. Upgrading and Downgrading Gradle were also not helpful.
What worked for me is: Make Project (Ctrl + F9) and then try to run the project.
I solved this error by following Android Studio's lint tools to upgrade the version of a dependency in the project-level gradle file. In this case, I upgraded androidx.navigation:navigation-safe-args-gradle-plugin from 2.3.2 to 2.5.2 (latest version), then synced the project.
Here is the solution,
File->Project Structure->Project, select Android Gradle Plugin Version as 3.2.1 from the drop-down. then click apply.
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In every instance in all of my classes where I reference R.id.something, the R is in red and it says "cannot resolve symbol R". Also every time there is R.layout.something it is underlined in red and says "cannot resolve method setContentView(?)". The project always builds fine. It is annoying to see this all the time. I have read many other questions on here about something similar but most involved importing projects from Eclipse. I am using what I believe to be the most recent version of Android Studio and the project was created with Android Studio and worked without any "cannot resolve R" problems. I would like to know what causes this if anyone knows.
I had this this issue too. A simple 'gradlew clean' and 'gradlew build' did the trick.
Click on Build->Clean Project and that will perform a gradle clean
In the latest versions of Android Studio, at least for me, the following works:
"Tools" -> "Android" -> "Sync Project with Gradle Files"
In latest Android Studio 3.1.3 (July 2018), "Sync Project with Gradle Files" is available in main menu bar.
I was using gradle 3.3.0. It was the main culprit. Wasted 6.50 hours from my life. Gradle 3.2.1 removed the error.
classpath 'com.android.tools.build:gradle:3.2.1'
Problem resolved after changing the gradle version. Details history can be found here.
I have a similar problem and here is what I did:
Clean Project and Sync Project with Gradle ,
check buildTools version in my sdk
From build gradle (module ) change minSdkVersion from 8 to 9
defaultConfig {
applicationId "PackageName"
minSdkVersion 9
targetSdkVersion 22
versionCode 1
versionName "1.0"
}
But all this didn't help.
Finally I found the answer (this worked in my case)
Change from build.gradle(module:app)
android {
compileSdkVersion 21
buildToolsVersion '21.0.1'
......
....
}
Or
Select File | Project Structure change Build Tools Version to 21.1.1
Check your xml files.
Clean Project.
This is it.
For example I had an entry in my strings.xml:
<string name="A">Some text</string>
And in activity_main.xml I used this string entry
<TextView
android:id="#+id/textViewA"
android:text="#string/A"/>
While'd been working with project, I deleted that
<string name="A">Some text</string>
And consequently activity_main.xml became not valid. As the result: cannot resolve R.
So, check your *.xml files and clean project.
If you see this error after moving java files or directories to other locations, then you can guarantee that Android Studio has gotten confused. And guess what? undo-ing those actions doesn't fix the problem.
So you try a clean, but that doesn't work.
And restarting doesn't work either.
But try File -> Invalidate Caches / Restart... -> Invalidate and Restart
Android Studio maintains information about which files are dependent on which other files. And since moving files around is not implemented correctly, moving files causes errors. And that's not all: caches of these dependencies are used in an attempt to speed up the build.
This means you not only have to restart, but you need to invalidate those caches to restore (or more accurately, rebuild) sanity.
I think if you put your Activities files to another folder than the default one. You need to import the com.example.yourproject.R (this is your project R file NOT Android.R file) to ALL activities using R. For example, in MainActivity file insert this line:
import com.example.yourproject.R;
There seems to be many causes for this issue. Recently, I added an activity to test with called NewActivity. This created a file called res/menu/new.xml and gradle did not like that name because new is a reserved word.
gradlew clean
or
"Tools" -> "Android" -> "Sync Project with Gradle Files"
Those are definitely good things to try, but you may have some other issues you need to resolve before you run those commands.
You should do two things, first clean the project (in build menu) - it deletes the build directory which may be the culprit:
Next, Sync project with Gradle files (under file):
This is the placement for the items in Android Studio 3.6.1 on Windows 10.
If all else fails, Invalidate Caches and Restart (under file) usually does the trick. This closes down the whole program and takes the most amount of time, in my opinion.
To clarify, I am running this on windows 10, but it should work on MacOS and Linux as well.
R.java file contains the link between xml and java page. "R cannot be resolved" arise only if there is a problem with some of your resource files. So the best and effective way is delete the last done xml or drawable in res file. and then again start from there according to android coding norms. This is the only way. The effective and right way.
Also use Git for proper tracking of code. ..
Your code is just scrambled. The answer is fairly simple.
Just go to Build --> Clean Project.
That should do the trick.
Check also your version of Android Studio.
I'm currently using Android Studio 3.0.1.
Have you updated your SDK tools recently? Launch the android SDK manager and make sure you have the latest SDK tools, which is now separate from the platform tools. I had this same issue when I first updated my SDK manager, the SDK build tools package did not show up for install/update until I closed and reopened the SDK manager.
I had to import my R package in android studio. For ex: import com.example.<package name>.R
Just clean your project and Sync Project with Gradle File.
And the problem will be resolved.
I recently had this issue and the clean/build etc. didn't resolve it. I guessed I had an issue somewhere but wasn't sure where to look to find it (was it in the manifest, resource xml files etc?).
When something is wrong, you can find out what it is by doing a code analysis run.
From the menu at the top choose:
Analyze -> Inspect code, scan the whole project using the 'Default' profile.
Your inspection results will contain an element called 'Android'. In here you will get a list of anything that is causing issues in your resources and manifest file. The errors will open up the generated xml files from your build which will show any errors in red.
My exact issue was caused because I was using flavour based manifest files and I copied some permissions inside the <application> tag in the flavour by accident.
UPDATE: I did have an issue after where Android Studio still showed the error after the fix, even though I could now build and run perfectly fine while the error was still there. (I am running a canary build so putting it down to that for now)
I have had this with
An uppercase letter in my drawable resources.
Import Android.R being added by Android Studio (or Eclipse)
Error in xml file
I faced this issue when I manually renamed the domain folder of my app. To fix this issue, I had to
Set the proper package folder structure of <manifest> in AndroidManifest.xml.
Set the new package location for android:name of <activity> in AndroidManifest.xml.
Clear cache by
File Menu -> Invalidate Caches / Restart ...
The issue will be gone, once the Android studio restarts and builds the fresh index.
I had the same issue:
Android Studio 3.2
The project compiles and runs fine, but I am getting "Cannot resolve symbol "R" on-screen warnings
Does not help:
Build->Clean Project
Build->Rebuild Project
File->Invalidate Caches/Restart
Helps:
either
in build.gradle
dependencies {
classpath 'com.android.tools.build:gradle:3.3.0'
...
}
replace with
dependencies {
classpath 'com.android.tools.build:gradle:3.2.1'
...
}
or
Update Android Studio to 3.3
This is a very old question, but it still happens a lot and there is no truly comprehensive answer here.
I have had this problem more times than I want to admit. It can be caused by a wide variety of issues that mostly all have to do with your project structure not matching what's expected. Here's a list of all the problems I've had:
Importing from Eclipse to Android Studio does not always work smoothly, especially with older versions of Android Studio. Make sure you're using the correct directory tree. It should look like this for a moderately mature app:
AppName/ // AppName is your app's name, obviously
.gradle/ // This is a compiler created directory. You should normally leave it alone
.idea/ // Ditto
build/ // This too
gradle/ // And this
app/
build/
libs/
src/
androidTest/ // Tests based on the Android instrumentation runner should go here
main/
java/
fully/ // Typically com
qualified/ // the domain name. Longer package
// names may have deeper folder trees
AppName/ // All your java files go here
res/
drawable-*/ // One of these for each resolution you support
layout/ // All of your general layouts
menu/ // All of your menu layouts
values/ // All of your resource xml files
xml/ // PreferenceScreen layouts go here
AndroidManifest.xml
debug/
test/ // Pure jUnit tests should go here
.gitignore
app.iml
build.gradle // This is the gradle file you should be making most changes to
proguard-rules.pro
.gitignore
build.gradle // This gradle file should mostly be left alone
gradle.properties
gradlew
local.properties
AppName.iml
settings.gradle
It may not look like this in your IDE. There is a drop-down above the file tree that displays your files in different ways, and it defaults on my system to one called Android that breaks your files out into their different types. It's easier to fix this kind of problem from the one called Project, and even easier directly from your OS's file system, because Android Studio collapses folders that only contain another folder onto a single line.
Especially if you ever change the name of your app, you need to make sure that the source tree main/java/com/domain/AppName is updated. Also make sure that the package tag in your AndroidManifest.xml is correct.
If there are errors in either your Gradle files or your AndroidManifest.xml, this will prevent Android Studio from properly building your resource files. Gradle files can be broken by upgrading Android Studio sometimes, especially from the pre-1.0 versions. Sometimes this is because it stops supporting older versions of the Gradle plugin, so you need to update your version numbers. It can sometimes be hard to find what the current versions are. As of today, 7/17/15, my apps are compiling fine with com.android.tools.build:gradle:1.2.3. This is in the dependencies block in the outermost gradle file,
If your AndroidManifest references a non-existent drawable or string resource or activity, it will break and cause this error. Sometimes if anything references a nonexistent drawable or string resource you will get this error.
If you have a file in your resources that is corrupted, or an invalid xml file, you will get this error.
In my experience, sometimes Android Studio just hiccups for no reason, and you need to restart it and/or your PC. I don't know why, but sometimes it works.
If you have two xml resources with the same name, in directories that do not override each other, you can have this problem. For instance, you can have the same name in drawable-mhdpi and drawable-xhdpi because they override each other depending on the target device, but if you have the same name in layout and in menu, it will cause a problem. Rename or delete one of the files.
If only some resources are having this problem, those resources are most likely in the wrong directory.
In one case I had to completely reinstall Android Studio. I don't know what was wrong, but it worked.
In one case I moved my entire project to a different directory and re-imported it as a new project. I don't know what was wrong, but it worked.
Xml files with reserved words for names can cause this problem. Rename or delete them.
There are a few ways your Gradle file can end up referencing a version of the build-tools that you do not have installed. Correct this by changing Gradle or downloading the appropriate build-tools.
Finally, after you've fixed whatever is wrong, you need to clean your Gradle project. You do this by going to the Build menu at the top and selecting Clean Project.
Just go to Android Top menu list. click on Build Menu, in under Build click on Rebuild Project.
I have a special case for this problem.
In my project, every thing goes well, it can compile and build successfully, but in my Android Studio IDE(and I also tried Intelligent IDEA, they are in the same situation) the R.java file can not be resolved well and always be drop in red line.
Just like this:
This almost made me crazy, I can't bear the read color when I am programing.
At last I found this tricky problem is cause by my R.java's file size.
My project is very a huge one, it supports many multi-languages and multi screen sizes. There are so many resources that my R.java's file size is about 2.5M.
The max size of a file in Android Studio is 2.5M in default settings, so files bigger than this limit can't not be resolved well. And you can change the default settings in "AndroidStudio-root/bin/idea.properties".
change this line:
idea.max.intellisense.filesize=2500
to :
idea.max.intellisense.filesize=5000
Then restart Android studio, the red color dismissed, I can program happily again.
Build > Clean Project
This worked for me. Had the same problem a few times, and this seems to set it right. Unless you have changed something or called a variable R. This issue usually happens out of nowhere, when it happens to me, so I imagine its just Android studios freaking out. haha
Have a good one, and good luck with your projects.
Do: Build > Clean Project
IMPORTANT: Make sure you don't have any Errors after Clean Project in Message Pane (Alt+0). If you find any red circles with exclamation mark, than you must remove those errors in your code.
Mostly these errors are related to #string/ or #array/. Clean Project again and done!
I had the same problem and most times it is resolved by
Sync project with gradle files
Doing Build -> Clean Project
Doing File -> Invalidate Caches
But this time the error persisted even after doing all these things and at last i found the culprit.
The problem was in an xml file, where i have given ordinary string value for an android:id instead of an id resource type.
MISTAKE
android:id="username"
CORRECTION
android:id="#id/username"
Messing up things related to resources in xml files is a major
reason for this error.Beware of the fact that it may not be shown as an error in the xml layout file.
NOTE
In most cases the compiler shows you the source of error in the Message.
Try to check it first before attempting other solutions
I had the same problem, and it happens when I create a new project.
What I do is:
check for SDK updates
then android studio updates,
then reopen the project
open the andoridmanifest.xml
erase a space between a "_>" in the android:label and save.
That works for me.
I had a hard time fixing this myself.
Make sure you have no errors in your layout.xml files.
Go to Build > Clean project
It worked for me, hope it works for you too.
`I had same problem and it solved by :
1) Sync Project with gradle files
2) Build -> Clean Project
3) Build -> Rebuild Project
4) File -> Invalidate caches
//imp step
5) Check your xml files properly.`
This notation seems to work fine.
android:id="#+id/viewID"
Android Studio's design panel doesn't seem to work well.
Same problem. Started when I added a few images in my drawable folder and tried to access them. Also the images added were having the extension with capital letters. That seems to have crashed the build, since even if I renamed them, the message was the same and R was inaccessible. What I did is, in the .iml file I looked for the excludeFolder and removed them (like bellow):
<excludeFolder url="file://$MODULE_DIR$/build/apk" />
<excludeFolder url="file://$MODULE_DIR$/build/assets" />
<excludeFolder url="file://$MODULE_DIR$/build/bundles" />
<excludeFolder url="file://$MODULE_DIR$/build/classes" />
<excludeFolder url="file://$MODULE_DIR$/build/dependency-cache" />
<excludeFolder url="file://$MODULE_DIR$/build/incremental" />
<excludeFolder url="file://$MODULE_DIR$/build/libs" />
<excludeFolder url="file://$MODULE_DIR$/build/manifests" />
<excludeFolder url="file://$MODULE_DIR$/build/res" />
<excludeFolder url="file://$MODULE_DIR$/build/symbols" />
<excludeFolder url="file://$MODULE_DIR$/build/tmp" />
After that I rebuilt the project and R magically re-appeared.
There are many causes for this error.
Sometimes it occurs for replacing an image file keeping same name.
Suppose you deleted an item from your layout .xml say a <Button/> but it is still declared in any Activity or Fragment .java.
Many more.
Best way to track the error is Rebuild it rather clean or sync doing some intentional error.
If it doesn't solve your problem then there must have to be some flaw or runtime error or error occurred due to improper use of resources in may be both java or xml file in your code or design which is forcing gradle to stop because (R)esource file can't index your resources properly and you have to admit that.
If your project ran before you made the changes then comment out the changes you have made and try to rebuild the project.
It will surely work since there will be no changes.
To track down the exact error, check the changes by breaking the changes into smaller module.
For example - If you are making a list visible with a button click and inserting list values in the adapter, first check if you are able to make it visible or not then check for adapter errors.
Want to improve this post? Provide detailed answers to this question, including citations and an explanation of why your answer is correct. Answers without enough detail may be edited or deleted.
In every instance in all of my classes where I reference R.id.something, the R is in red and it says "cannot resolve symbol R". Also every time there is R.layout.something it is underlined in red and says "cannot resolve method setContentView(?)". The project always builds fine. It is annoying to see this all the time. I have read many other questions on here about something similar but most involved importing projects from Eclipse. I am using what I believe to be the most recent version of Android Studio and the project was created with Android Studio and worked without any "cannot resolve R" problems. I would like to know what causes this if anyone knows.
I had this this issue too. A simple 'gradlew clean' and 'gradlew build' did the trick.
Click on Build->Clean Project and that will perform a gradle clean
In the latest versions of Android Studio, at least for me, the following works:
"Tools" -> "Android" -> "Sync Project with Gradle Files"
In latest Android Studio 3.1.3 (July 2018), "Sync Project with Gradle Files" is available in main menu bar.
I was using gradle 3.3.0. It was the main culprit. Wasted 6.50 hours from my life. Gradle 3.2.1 removed the error.
classpath 'com.android.tools.build:gradle:3.2.1'
Problem resolved after changing the gradle version. Details history can be found here.
I have a similar problem and here is what I did:
Clean Project and Sync Project with Gradle ,
check buildTools version in my sdk
From build gradle (module ) change minSdkVersion from 8 to 9
defaultConfig {
applicationId "PackageName"
minSdkVersion 9
targetSdkVersion 22
versionCode 1
versionName "1.0"
}
But all this didn't help.
Finally I found the answer (this worked in my case)
Change from build.gradle(module:app)
android {
compileSdkVersion 21
buildToolsVersion '21.0.1'
......
....
}
Or
Select File | Project Structure change Build Tools Version to 21.1.1
Check your xml files.
Clean Project.
This is it.
For example I had an entry in my strings.xml:
<string name="A">Some text</string>
And in activity_main.xml I used this string entry
<TextView
android:id="#+id/textViewA"
android:text="#string/A"/>
While'd been working with project, I deleted that
<string name="A">Some text</string>
And consequently activity_main.xml became not valid. As the result: cannot resolve R.
So, check your *.xml files and clean project.
If you see this error after moving java files or directories to other locations, then you can guarantee that Android Studio has gotten confused. And guess what? undo-ing those actions doesn't fix the problem.
So you try a clean, but that doesn't work.
And restarting doesn't work either.
But try File -> Invalidate Caches / Restart... -> Invalidate and Restart
Android Studio maintains information about which files are dependent on which other files. And since moving files around is not implemented correctly, moving files causes errors. And that's not all: caches of these dependencies are used in an attempt to speed up the build.
This means you not only have to restart, but you need to invalidate those caches to restore (or more accurately, rebuild) sanity.
I think if you put your Activities files to another folder than the default one. You need to import the com.example.yourproject.R (this is your project R file NOT Android.R file) to ALL activities using R. For example, in MainActivity file insert this line:
import com.example.yourproject.R;
There seems to be many causes for this issue. Recently, I added an activity to test with called NewActivity. This created a file called res/menu/new.xml and gradle did not like that name because new is a reserved word.
gradlew clean
or
"Tools" -> "Android" -> "Sync Project with Gradle Files"
Those are definitely good things to try, but you may have some other issues you need to resolve before you run those commands.
You should do two things, first clean the project (in build menu) - it deletes the build directory which may be the culprit:
Next, Sync project with Gradle files (under file):
This is the placement for the items in Android Studio 3.6.1 on Windows 10.
If all else fails, Invalidate Caches and Restart (under file) usually does the trick. This closes down the whole program and takes the most amount of time, in my opinion.
To clarify, I am running this on windows 10, but it should work on MacOS and Linux as well.
R.java file contains the link between xml and java page. "R cannot be resolved" arise only if there is a problem with some of your resource files. So the best and effective way is delete the last done xml or drawable in res file. and then again start from there according to android coding norms. This is the only way. The effective and right way.
Also use Git for proper tracking of code. ..
Your code is just scrambled. The answer is fairly simple.
Just go to Build --> Clean Project.
That should do the trick.
Check also your version of Android Studio.
I'm currently using Android Studio 3.0.1.
Have you updated your SDK tools recently? Launch the android SDK manager and make sure you have the latest SDK tools, which is now separate from the platform tools. I had this same issue when I first updated my SDK manager, the SDK build tools package did not show up for install/update until I closed and reopened the SDK manager.
I had to import my R package in android studio. For ex: import com.example.<package name>.R
Just clean your project and Sync Project with Gradle File.
And the problem will be resolved.
I recently had this issue and the clean/build etc. didn't resolve it. I guessed I had an issue somewhere but wasn't sure where to look to find it (was it in the manifest, resource xml files etc?).
When something is wrong, you can find out what it is by doing a code analysis run.
From the menu at the top choose:
Analyze -> Inspect code, scan the whole project using the 'Default' profile.
Your inspection results will contain an element called 'Android'. In here you will get a list of anything that is causing issues in your resources and manifest file. The errors will open up the generated xml files from your build which will show any errors in red.
My exact issue was caused because I was using flavour based manifest files and I copied some permissions inside the <application> tag in the flavour by accident.
UPDATE: I did have an issue after where Android Studio still showed the error after the fix, even though I could now build and run perfectly fine while the error was still there. (I am running a canary build so putting it down to that for now)
I have had this with
An uppercase letter in my drawable resources.
Import Android.R being added by Android Studio (or Eclipse)
Error in xml file
I faced this issue when I manually renamed the domain folder of my app. To fix this issue, I had to
Set the proper package folder structure of <manifest> in AndroidManifest.xml.
Set the new package location for android:name of <activity> in AndroidManifest.xml.
Clear cache by
File Menu -> Invalidate Caches / Restart ...
The issue will be gone, once the Android studio restarts and builds the fresh index.
I had the same issue:
Android Studio 3.2
The project compiles and runs fine, but I am getting "Cannot resolve symbol "R" on-screen warnings
Does not help:
Build->Clean Project
Build->Rebuild Project
File->Invalidate Caches/Restart
Helps:
either
in build.gradle
dependencies {
classpath 'com.android.tools.build:gradle:3.3.0'
...
}
replace with
dependencies {
classpath 'com.android.tools.build:gradle:3.2.1'
...
}
or
Update Android Studio to 3.3
This is a very old question, but it still happens a lot and there is no truly comprehensive answer here.
I have had this problem more times than I want to admit. It can be caused by a wide variety of issues that mostly all have to do with your project structure not matching what's expected. Here's a list of all the problems I've had:
Importing from Eclipse to Android Studio does not always work smoothly, especially with older versions of Android Studio. Make sure you're using the correct directory tree. It should look like this for a moderately mature app:
AppName/ // AppName is your app's name, obviously
.gradle/ // This is a compiler created directory. You should normally leave it alone
.idea/ // Ditto
build/ // This too
gradle/ // And this
app/
build/
libs/
src/
androidTest/ // Tests based on the Android instrumentation runner should go here
main/
java/
fully/ // Typically com
qualified/ // the domain name. Longer package
// names may have deeper folder trees
AppName/ // All your java files go here
res/
drawable-*/ // One of these for each resolution you support
layout/ // All of your general layouts
menu/ // All of your menu layouts
values/ // All of your resource xml files
xml/ // PreferenceScreen layouts go here
AndroidManifest.xml
debug/
test/ // Pure jUnit tests should go here
.gitignore
app.iml
build.gradle // This is the gradle file you should be making most changes to
proguard-rules.pro
.gitignore
build.gradle // This gradle file should mostly be left alone
gradle.properties
gradlew
local.properties
AppName.iml
settings.gradle
It may not look like this in your IDE. There is a drop-down above the file tree that displays your files in different ways, and it defaults on my system to one called Android that breaks your files out into their different types. It's easier to fix this kind of problem from the one called Project, and even easier directly from your OS's file system, because Android Studio collapses folders that only contain another folder onto a single line.
Especially if you ever change the name of your app, you need to make sure that the source tree main/java/com/domain/AppName is updated. Also make sure that the package tag in your AndroidManifest.xml is correct.
If there are errors in either your Gradle files or your AndroidManifest.xml, this will prevent Android Studio from properly building your resource files. Gradle files can be broken by upgrading Android Studio sometimes, especially from the pre-1.0 versions. Sometimes this is because it stops supporting older versions of the Gradle plugin, so you need to update your version numbers. It can sometimes be hard to find what the current versions are. As of today, 7/17/15, my apps are compiling fine with com.android.tools.build:gradle:1.2.3. This is in the dependencies block in the outermost gradle file,
If your AndroidManifest references a non-existent drawable or string resource or activity, it will break and cause this error. Sometimes if anything references a nonexistent drawable or string resource you will get this error.
If you have a file in your resources that is corrupted, or an invalid xml file, you will get this error.
In my experience, sometimes Android Studio just hiccups for no reason, and you need to restart it and/or your PC. I don't know why, but sometimes it works.
If you have two xml resources with the same name, in directories that do not override each other, you can have this problem. For instance, you can have the same name in drawable-mhdpi and drawable-xhdpi because they override each other depending on the target device, but if you have the same name in layout and in menu, it will cause a problem. Rename or delete one of the files.
If only some resources are having this problem, those resources are most likely in the wrong directory.
In one case I had to completely reinstall Android Studio. I don't know what was wrong, but it worked.
In one case I moved my entire project to a different directory and re-imported it as a new project. I don't know what was wrong, but it worked.
Xml files with reserved words for names can cause this problem. Rename or delete them.
There are a few ways your Gradle file can end up referencing a version of the build-tools that you do not have installed. Correct this by changing Gradle or downloading the appropriate build-tools.
Finally, after you've fixed whatever is wrong, you need to clean your Gradle project. You do this by going to the Build menu at the top and selecting Clean Project.
Just go to Android Top menu list. click on Build Menu, in under Build click on Rebuild Project.
I have a special case for this problem.
In my project, every thing goes well, it can compile and build successfully, but in my Android Studio IDE(and I also tried Intelligent IDEA, they are in the same situation) the R.java file can not be resolved well and always be drop in red line.
Just like this:
This almost made me crazy, I can't bear the read color when I am programing.
At last I found this tricky problem is cause by my R.java's file size.
My project is very a huge one, it supports many multi-languages and multi screen sizes. There are so many resources that my R.java's file size is about 2.5M.
The max size of a file in Android Studio is 2.5M in default settings, so files bigger than this limit can't not be resolved well. And you can change the default settings in "AndroidStudio-root/bin/idea.properties".
change this line:
idea.max.intellisense.filesize=2500
to :
idea.max.intellisense.filesize=5000
Then restart Android studio, the red color dismissed, I can program happily again.
Build > Clean Project
This worked for me. Had the same problem a few times, and this seems to set it right. Unless you have changed something or called a variable R. This issue usually happens out of nowhere, when it happens to me, so I imagine its just Android studios freaking out. haha
Have a good one, and good luck with your projects.
Do: Build > Clean Project
IMPORTANT: Make sure you don't have any Errors after Clean Project in Message Pane (Alt+0). If you find any red circles with exclamation mark, than you must remove those errors in your code.
Mostly these errors are related to #string/ or #array/. Clean Project again and done!
I had the same problem and most times it is resolved by
Sync project with gradle files
Doing Build -> Clean Project
Doing File -> Invalidate Caches
But this time the error persisted even after doing all these things and at last i found the culprit.
The problem was in an xml file, where i have given ordinary string value for an android:id instead of an id resource type.
MISTAKE
android:id="username"
CORRECTION
android:id="#id/username"
Messing up things related to resources in xml files is a major
reason for this error.Beware of the fact that it may not be shown as an error in the xml layout file.
NOTE
In most cases the compiler shows you the source of error in the Message.
Try to check it first before attempting other solutions
I had the same problem, and it happens when I create a new project.
What I do is:
check for SDK updates
then android studio updates,
then reopen the project
open the andoridmanifest.xml
erase a space between a "_>" in the android:label and save.
That works for me.
I had a hard time fixing this myself.
Make sure you have no errors in your layout.xml files.
Go to Build > Clean project
It worked for me, hope it works for you too.
`I had same problem and it solved by :
1) Sync Project with gradle files
2) Build -> Clean Project
3) Build -> Rebuild Project
4) File -> Invalidate caches
//imp step
5) Check your xml files properly.`
This notation seems to work fine.
android:id="#+id/viewID"
Android Studio's design panel doesn't seem to work well.
Same problem. Started when I added a few images in my drawable folder and tried to access them. Also the images added were having the extension with capital letters. That seems to have crashed the build, since even if I renamed them, the message was the same and R was inaccessible. What I did is, in the .iml file I looked for the excludeFolder and removed them (like bellow):
<excludeFolder url="file://$MODULE_DIR$/build/apk" />
<excludeFolder url="file://$MODULE_DIR$/build/assets" />
<excludeFolder url="file://$MODULE_DIR$/build/bundles" />
<excludeFolder url="file://$MODULE_DIR$/build/classes" />
<excludeFolder url="file://$MODULE_DIR$/build/dependency-cache" />
<excludeFolder url="file://$MODULE_DIR$/build/incremental" />
<excludeFolder url="file://$MODULE_DIR$/build/libs" />
<excludeFolder url="file://$MODULE_DIR$/build/manifests" />
<excludeFolder url="file://$MODULE_DIR$/build/res" />
<excludeFolder url="file://$MODULE_DIR$/build/symbols" />
<excludeFolder url="file://$MODULE_DIR$/build/tmp" />
After that I rebuilt the project and R magically re-appeared.
There are many causes for this error.
Sometimes it occurs for replacing an image file keeping same name.
Suppose you deleted an item from your layout .xml say a <Button/> but it is still declared in any Activity or Fragment .java.
Many more.
Best way to track the error is Rebuild it rather clean or sync doing some intentional error.
If it doesn't solve your problem then there must have to be some flaw or runtime error or error occurred due to improper use of resources in may be both java or xml file in your code or design which is forcing gradle to stop because (R)esource file can't index your resources properly and you have to admit that.
If your project ran before you made the changes then comment out the changes you have made and try to rebuild the project.
It will surely work since there will be no changes.
To track down the exact error, check the changes by breaking the changes into smaller module.
For example - If you are making a list visible with a button click and inserting list values in the adapter, first check if you are able to make it visible or not then check for adapter errors.
I just upgraded to AS 2.0 Preview 8 and I'm trying to build my old project. I updated it to be
classpath 'com.android.tools.build:gradle-experimental:0.6.0-alpha8'
and updated the gradle-wrapper.properties to use gradle-2.10-all.zip, but when I try to build my project I get a Java stactrace saying:
Unable to load class com.android.build.gradle.managed.NdkConfig$Impl
I'm using Java 8 to start AS as well as having that set as the JDK for the project. I was also having the same problem with Java7. What am I missing?
The problem with my project was due to a change in the gradle-experimental plugin:
+= no longer works for collections. Adding items to the list can be done with the 'add' or 'addAll' method. e.g. CFlags +=
"-DCUSTOM_DEFINE" can be replaced with CFlags.add("-DCUSTOM_DEFINE")
Changed those occurrences and the build finished successfully.
Oddly enough, this was fixed by simply doing a Gradle clean. Hope this helps someone else as this was not intuitive
I'm trying to use JRuby in projects created in Android studio. I have built the latest (as of 9/10/2014) JRuby, and have completely updated Android Studio. I have a working app that I can use to test. I have a copy of jruby.jar in the MyApp/app/libs directory. Once there I right-clicked on jruby.jar and selected "Add as Library", which presumably did something (though what I am not certain), and have added the line "compile files('libs/jruby.jar')" to the build.gradle that is in MyApp/app/.
In one of the class files I have "import org.jruby.embed.ScriptingContainer;", which Android Studio says is fine (if I hadn't added jruby.jar as a library I couldn't include this without an error). Then in one of the working methods I say "ScriptingContainer container = new ScriptingContainer();". When I run this method the app will crash. I won't try to include the whole error message, but the important part seems to be:
Caused by: java.lang.ExceptionInInitializerError
at org.jruby.embed.internal.AbstractLocalContextProvider.<init>(AbstractLocalContextProvider.java:42)
at org.jruby.embed.internal.SingletonLocalContextProvider.<init>(SingletonLocalContextProvider.java:88)
at org.jruby.embed.ScriptingContainer.getProviderInstance(ScriptingContainer.java:248)
at org.jruby.embed.ScriptingContainer.<init>(ScriptingContainer.java:228)
at org.jruby.embed.ScriptingContainer.<init>(ScriptingContainer.java:185)
and
Caused by: java.lang.RuntimeException: unsupported Java version: 0.9
at org.jruby.RubyInstanceConfig.initGlobalJavaVersion(RubyInstanceConfig.java:1858)
at org.jruby.RubyInstanceConfig.<clinit>(RubyInstanceConfig.java:1608)
At least, those are the parts that make sense to me. I hav no idea why I would get the error "java.lang.RuntimeException: unsupported Java version: 0.9", since I am using 1.8.0_20. The rest of the errors I cannot follow. When I click on any of the files giving me an error (say AbstractLocalContextProvider.java:42) Android Studio will show the file but also say "Sources not found". That could be the problem, but I don't know why it can't find the sources.
Thanks for any help,
Brian
Uwe Kubosch (#donv70) was able to tell me the solution to this via Twitter, so credit to him, but I wanted to post the solution here in case anyone else needs it.
It was Java version that was causing the problem. In Ruboto the problem is solved here: https://github.com/ruboto/ruboto/blob/master/assets/src/org/ruboto/JRubyAdapter.java#L137
and for use in Android Studio it is necessary only to include the line: System.setProperty("jruby.bytecode.version", "1.6");
The number of course can be 1.6, 1.7, or 1.8, depending on your version of Java.
Looks like an interoperability problem between JRuby and the Dalvik VM (don't forget that you're running against Dalvik, not the Java VM).
There's a bug report at http://jira.codehaus.org/browse/JRUBY-5774 that may lead you in the right direction.
It's kind of old, and is marked 'fixed', but maybe it'll provide some clues?