I am new in Android development, and I wanna build some apps for myself. I have installed Android SDK last version, NetBeans IDE 7.4 and also the plugin for this. I wrote a simple code for Android to see if it works:
package com.app;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class MainActivity extends Activity
{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
TextView tv = new TextView(this);
tv.setText("HelloWorld");
setContentView(tv);
}
}
When I try to build and run with an emulator, I get this error: [path] \AndroidApplication1\build.xml:1: Premature end of file.
When I go to the file (build.xml) I see that is empty. I should write to it? What should I do? Thanks in advance.
Related
Hello im coding with java in android and i have this code:
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
**setSupportActionBar(toolbar);
if(getSupportActionBar() != null){
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeAsUpEnabled(true);**
}
the code inside the ** requires this library to be imported but first the suggestion to import the libary wont show and when i import it myself it says Unused import statement
this is the import code:
import android.support.v7.app.AppCompatActivity;
the weird part is that the same method is been used in the same project but only in this class wont work.
I also tried to do this method but makes error when its on run time
AppCompatActivity app = new AppCompatActivity();
app.setSupportActionBar(toolbar); //error here when execute
Thanks in advance!
I fixed it the solution was add AppCompatActivity on
public class X extends AppCompatActivity ....
For reference I am using Android Studio 3.1.4. My problem is that android studio isn't recognizing any of my java objects aka all of the objects names are underlined in red. Here is the code for my main activity:
package com.example.t00587599.unitconverter;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.AdapterView;
public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Spinner spinner = findViewById(R.id.spinner);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(context: this, R.array.temptypes, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(this);
}
}
I donot know much about the issues that you are facing as there can be multiple reasons why that is happening. There are two things that you could be happening
- if your package is compiled then you should check if the files are in the project. Or the project where the package is included is added in the build.gradle. I do this by adding
compile ":unitconverter"
- if you are including this as a compiled dependency then you can add the following line in your build.grade for the project
compile "com.example.t00587599.unitconverter"
After that you should do a gradle sync. If after doing all this you still get the red lines then you should do a "File/Sync Project with Gradle Files" from the file menu.
All of these class of problems disappear after these steps for me.
If it still appears then you should give us the error that come when you highlight it.
When I run my first app, I got error.
Code of the activity:
package com.pradeep.ulc;
import android.app.Activity;
import android.os.Bundle;
public class New1Activity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}
Error:
R cannot be resolved to a variable New1Activity.java /new1/src/com/pradeep/ulc line 11 Java Problem
How can I fix it?
1) Make sure the package name is correctly set everywhere
2) Try doing a clean build to regenerate R.java.
If you must use a different package, import the R.java from the package specified in the manifest.
It means that you have problem in your resources, so R file cannot be generated.
What do you have in res/layout/main.xml file?
I did clean project and now i cannot run any of my code. Any files that has to do with R, just says cannot be resolved as a field. I've looked at so many other stackoverflow posts with similar problems but none seems to actually help. Help please!!
I have about 15 classes but here is an example
package com.Class;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceActivity;
import android.preference.PreferenceManager;
public class NewAccount extends PreferenceActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.preferences);
SharedPreferences sp = PreferenceManager
.getDefaultSharedPreferences(this);
}
}
If R.java is not being generated, chances are there are some other errors in your code than the ones referring to the R file. Find these errors, solve them, and then R will be regenerated.
Did you import the R file?
import com.example.myapp.R;
This may be useful too: R cannot be resolved - Android error
i m new to this platform, please help me to find what is the error...
setContentView(R.layout.main); // this line shows the error.
Code:
package com.example.helloandroid;
import android.R;
import android.app.Activity;
import android.os.Bundle;
public class HelloAndroidActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}
Try deleting the line import android.R then clean your project.
Just adding more details on why the error is coming.
As there is an import of android.R so setContentView() is looking for a layout file 'android.R.layout.main' and there is no main.xml in the layout files that come along with SDK. So, using the correct R.java import will work.
clean Project then try To Run because i faced same problem before a month and remember layout/main.xml must be their and it must not contains any error.
you can Also Do this
import android.R;
or
import your.application.packagename.R; Now Clear Project and Run it.
You must have to simply change the
setContentView(R.layout.main);
... to:
setContentView(R.layout.activity_main);
... because Layout contains this .xml file.
I hope your problem will be solved.
First remove import android.R;
After any change on xml fiels you must clean project.
Build > Clean Project
after that every things corrects.