I have a file transfer app that needs to save the files it received in the Download folder.
On Android >= 10, MediaStore makes this extremely easy, since it provides a direct method for creating entries in the download folder, without any special permission.
However, on Android < 10, the download URI is not avaiable in the MediaStore API, and I have to rely on the old method for saving files, which requires the WRITE_EXTERNAL_STORAGE permission with consequent popup for asking it.
Is there any way around this? Maybe some kind of support library that brings the Download URI back to older versions of Android?
Related
I have an android application already available on playstore. It is a file transfer app between PC to Android using localhost. I'm using following java function within it:
To create directory/file/show list of files and many other file functions(append, byte read/write etc):
file.mkdir
directory.listFiles();
file.createNewFile()
I had also put
requestLegacyExternalStorage="true"
And it is working fine on android 10 after giving sufficient read/write external storage permission.
But the problem is that these will not work on android 11 as requestLegacyExternalStorage will not work. I have used MANAGE_EXTERNAL_STORAGE and the app works perfect but the problem is that playstore is not allowing it. (Don't know why they rejected the update)
I have also used getExternalFilesDir and it works perfect but don't like data to be in android folder and remove if app is deleted.
I have also tried to use download location and it works but the problem is getExternalStorageDirectory is deprecated:
File file = new File(Environment.getExternalStorageDirectory()+"/"+Environment.DIRECTORY_DOWNLOADS,"FileChat");
So what I wanted to ask how can I manage/use file library for android 11 to read/write/create/delete files and directory. It should not be in android folder as this will be deleted after app is deleted. Can I used public directory like downloads? If I can, what is the alternative to getExternalStorageDirectory()?
I don't need to read user data. Just want to have a directory in which app can store files. The read function is working as file is picked by user using intent.
Thanks in advance.
Top-level directory write access of shared storage is not available in Android 11, however you can use the existing File APIs to access the media and download collection folders like /Pictures, /Downloads, /DICM etc. It won't be possible to create your app's own folder as top level directory but it is possible to create a dedicated sub-directory in the default collection folders.
To keep your app running as expected on Android 10, requestLegacyExternalStorage flag will also be required since access to shared storage on Android 10 was restricted via MediaStore APIs only.
If transfer is only for your apps own files then put them in
File file = new File(Environment.getExternalStoragePublicDirectory(DIRECTORY_DOCUMENTS),"FileChat");
Or use Storage Access Framework to let the user choose and or create a directory on external storage inclusive removable micro sd card.
I want to list all files .txt in the Download folder and then allow the user to pick one and read its content. My minSdkVersion is 16, but I came across this problem because my Android is Q (29).
What I tried:
Apparently Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) would solve it for SDK <= 29. However, I didn't test it because I would first like to check out a solution for Android Q.
getExternalStoragePublicDirectory says:
When an app targets Build.VERSION_CODES.Q, the path returned from this method is no longer directly accessible to apps. Apps can continue to access content stored on shared/external storage by migrating to alternatives such as Context#getExternalFilesDir(String), MediaStore, or Intent#ACTION_OPEN_DOCUMENT.
So:
getExternalFilesDir returns /storage/emulated/0/Android/data/com.mypackage/files/Download. This path is not useful, I expected it to return /storage/emulated/0/Download, which is where the downloaded files are.
I didn't manage to do something with MediaStore.Downloads. I checked the documentation and it says "In particular, if your app wants to access a file within the MediaStore.Downloads collection that your app didn't create, you must use the Storage Access Framework.". So, I assume it won't work for me.
In my concept, Intent and Storage Access Framework would need the user to navigate through directories and files using a File Manager, which is not what I want here.
In short:
Is it possible to list the .txt downloaded files programmatically in Android Q (SDK >= 29)? If so, how?
Is it possible to list the .txt downloaded files programmatically in Android Q (SDK >= 29)?
Not ones created by other apps, which would appear to be your intention.
The closest is if you use ACTION_OPEN_DOCUMENT_TREE and ask the user to open the Downloads/ tree on external storage... and you cannot do that on Android R (at least through DP1).
Android Api 29 has big changes regarding files and folders.
I have not found a way so far to create a folder in the internal storage that is public visible.
Every folder I create can be seen by my app only.
I write an app that creates data files that shall be picked up by other apps, for instance the Total Commander to copy them to a destination.
Everything worked fine until I activated Api 29. Some of my clients DO use pixel phones and they use Android 10.
How can I create a folder and files in Android 10 that are public?
This has been deprecated:
Environment.getExternalStorageDirectory();
Environment.getExternalStoragePublicDirectory(type);
and when I use
File root = context.getExternalFilesDir(null);
The created files can only be seen by my app.
How can I achieve the behavior that was valid before Android 10?
Thanks in advance.
when I use File root = context.getExternalFilesDir(null); The created files can only be seen by my app
They can be seen by any app that uses the Storage Access Framework (e.g., ACTION_OPEN_DOCUMENT), if the user chooses the document that you place in that directory.
I write an app that creates data files that shall be picked up by other apps
Other apps have no access to external or removable storage on Android 10, except in the limited directories like getExternalFilesDir() or via non-filesystem means (ACTION_OPEN_DOCUMENT, MediaStore).
How can I create a folder and files in Android 10 that are public?
Use getExternalFilesDir() and related methods on Context. Or, use ACTION_CREATE_DOCUMENT or ACTION_OPEN_DOCUMENT_TREE and use the Storage Access Framework. In either case, the resulting documents can be used by other apps that also use the Storage Access Framework.
Starting from Android 10, you should use SAF, and let user choose the directory using ACTION_OPEN_DOCUMENT_TREE.
If you need a simple example. You can find it here
Alternatively, you could use requestLegacyExternalStorage = true in manifest when your app is not newly released. But, this is something that should not be used for future release, as this is a short-term solution provided by Google.
Note: In future releases of Android, user will not be able to pick the whole external file directory and Downloads directory, so unfortunately, keep in mind that we are not going to have access to these as well! For more information you can click here
I have been looking at a few different tutorials, however am really struggling to see exactly how the Expansion Files can be firstly copied to a location that the user cannot access adn the how to use them in my actual app.
I will have a lot of key images within the Expansion file and therefore would also need to prevent users from playing the game until everything is downloaded.
Finally, I would have to also access a density based section for a lot of the images, along with a handful of raw files such as videos, this is what I currently have to work out which folder to open within the extension files.
String ExpansionFolder = "";
switch (getResources().getDisplayMetrics().densityDpi)
{
case DisplayMetrics.DENSITY_MEDIUM:
ExpansionFolder = "mdpi";
break;
case DisplayMetrics.DENSITY_HIGH:
ExpansionFolder = "hdpi";
break;
default: // This cover XHDPI, XXHDPI, TVDPI
ExpansionFolder = "xhdpi";
break;
}
Some sample code that i can use would be much appreciated.
I don't have sample code, because i haven't used expansion files myself, but specific answers to your questions do seem to be available at Android Developer APK Expansion Files page.
how the Expansion Files can be firstly copied to a location that the user cannot access adn the how to use them in my actual app.
from the "Storag Location" section of the Android developer page on expansion files (APK Expansion Files):
When Google Play downloads your expansion files to a device, it saves them to the system's shared storage location. To ensure proper behavior, you must not delete, move, or rename the expansion files. In the event that your application must perform the download from Google Play itself, you must save the files to the exact same location.
The specific location for your expansion files is:
[shared-storage]/Android/obb//
[shared-storage] is the path to the shared storage space, available from getExternalStorageDirectory().
[package-name] is your application's Java-style package name, available from getPackageName().
For each application, there are never more than two expansion files in this directory. One is the main expansion file and the other is the patch expansion file (if necessary). Previous versions are overwritten when you update your application with new expansion files.
If you must unpack the contents of your expansion files, do not delete the .obb expansion files afterwards and do not save the unpacked data in the same directory. You should save your unpacked files in the directory specified by getExternalFilesDir(). However, if possible, it's best if you use an expansion file format that allows you to read directly from the file instead of requiring you to unpack the data. For example, we've provided a library project called the APK Expansion Zip Library that reads your data directly from the ZIP file.
Note: Unlike APK files, any files saved on the shared storage can be read by the user and other applications.
From http://developer.android.com/reference/android/content/Context.html#getExternalFilesDir(java.lang.String):
getExternalFilesDir
Returns the absolute path to the directory on the primary external filesystem (that is somewhere on Environment.getExternalStorageDirectory()) where the application can place persistent files it owns. These files are internal to the applications, and not typically visible to the user as media.
I will have a lot of key images within the Expansion file and therefore would also need to prevent users from playing the game until everything is downloaded.
From the "Downloading the Expansion Files" section of APK Expansion Files:
In most cases, Google Play downloads and saves your expansion files to the device at the same time it installs or updates the APK. This way, the expansion files are available when your application launches for the first time. However, in some cases your app must download the expansion files itself by requesting them from a URL provided to you in a response from Google Play's Application Licensing service.
The basic logic you need to download your expansion files is the following:
When your application starts, look for the expansion files on the shared storage location (in the Android/obb/[package-name]/ directory).
If the expansion files are there, you're all set and your application can continue.
If the expansion files are not there:
a. Perform a request using Google Play's Application Licensing to get your app's expansion file names, sizes, and URLs.
b. Use the URLs provided by Google Play to download the expansion files and save the expansion files. You must save the files to the shared storage location (Android/obb/[package-name]/) and use the exact file name provided by Google Play's response.
Note: The URL that Google Play provides for your expansion files is unique for every download and each one expires shortly after it is given to your application.
In addition to the LVL, you need a set of code that downloads the expansion files over an HTTP connection and saves them to the proper location on the device's shared storage. As you build this procedure into your application, there are several issues you should take into consideration:
The device might not have enough space for the expansion files, so you should check before beginning the download and warn the user if there's not enough space.
File downloads should occur in a background service in order to avoid blocking the user interaction and allow the user to leave your app while the download completes.
A variety of errors might occur during the request and download that you must gracefully handle.
Network connectivity can change during the download, so you should handle such changes and if interrupted, resume the download when possible.
While the download occurs in the background, you should provide a notification that indicates the download progress, notifies the user when it's done, and takes the user back to your application when selected.
To simplify this work for you, we've built the Downloader Library, which requests the expansion file URLs through the licensing service, downloads the expansion files, performs all of the tasks listed above, and even allows your activity to pause and resume the download. By adding the Downloader Library and a few code hooks to your application, almost all the work to download the expansion files is already coded for you. As such, in order to provide the best user experience with minimal effort on your behalf, we recommend you use the Downloader Library to download your expansion files. The information in the following sections explain how to integrate the library into your application.
You may also find Steps to create APK expansion file useful, if you haven't already seen it, though I don't know if Google has changed anything regarding expansion files since that question and its answers were posted.
I understand that ExternalFiles is to be used on API 8 and up and getExternalStorageDirectory is for 7 and down. However I am a little confused between the use. For example I wanted to check that a folder that exists and previously you would use something like:
File ChildFolder = new File(Environment.getExternalStorageDirectory() + "/ParentFolder/Child");
However every example I see says to use getExternalFilesDir (null), File.ext. Since I am above API 8 I want to use this method but how do I just check for a folder? I will check for a files existence at another point but for now just want to see if the folders exist??
getExternalFilesDir()
It returns the path to files folder inside Android/data/data/your_package/ on your SD card. It is used to store any required files for your app (e.g. images downloaded from web or cache files). Once the app is uninstalled, any data stored in this folder is gone too.
getExternalStorageDirectory()
It returns the root path to your SD card (e.g mnt/sdcard/). If you save data on this path and uninstall the app, that data won't be lost.
First of all, we need to understand what is difference between Internal Storage, External Storage (aka primary external storage), and Secondary External Storage?
Internal Storage: is storage that is not accessible by the user, except via installed apps (or by rooting their device). Example: data/data/app_packageName
Primary External Storage: In built shared storage which is "accessible by the user by plugging in a USB cable and mounting it as a drive on a host computer". Example: When we say Nexus 5 32 GB.
Secondary External Storage: Removable storage. Example: SD Card.
getExternalFilesDir (String type)
It returns the path to files folder inside Android/data/data/your_package/ on primary external storage. Which is inbuilt storage.
Environment.getExternalStorageDirectory()
It will return the path of the secondary external storage directory
! IMPORTANT UPDATE ! for whoever comes across this question.
As this is a somewhat old question just wanted to provide some additional information. Since KitKat even apps that have WRITE_EXTERNAL_STORAGE permission are only allowed to write to Android/data/data/your_package/ on external storage, a.k.a getExternalFilesDir()
If you will try to write to getExternalStorageDirectory() + "/somefolder/anotherfolder/" you will get a SecurityException on most devices
!! IMPORTANT !!
Environment.getExternalStorageDirectory() is deprecated and Context#getExternalFilesDir(String), MediaStore, or Intent#ACTION_OPEN_DOCUMENT, should be used instead.
This method was deprecated in API level 29.
To improve user privacy, direct access to shared/external storage devices is deprecated. When an app targets Build.VERSION_CODES.Q, the path returned from this method is no longer directly accessible to apps. Apps can continue to access content stored on shared/external storage by migrating to alternatives such as Context#getExternalFilesDir(String), MediaStore, or Intent#ACTION_OPEN_DOCUMENT.
https://developer.android.com/reference/android/os/Environment.html#getExternalStorageDirectory()
Also beginning from Android.M developers need to ask for permissions at run time.
See more details in documentation here and this question
Environment.getExternalStorageDirectory() deprecated in API level 29 java