Saving file on Android 11+

I want to save cache pdf file from my app-specific directory to Android shared storage for Android 11+ devices. How can I do this

I tried to understand concept of scoped storage but unable to implement. I'm developing application in java

In Android 11 and above, the concept of scoped storage was introduced, which provides more secure and controlled access to app-specific files and directories. To save a PDF file from your app-specific directory to Android shared storage, you need to follow these steps:

1. Request the necessary permissions: Add the following permission to your AndroidManifest.xml file:

   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

2. Check for the runtime permission: Request the WRITE_EXTERNAL_STORAGE permission from the user at runtime. You can use the checkSelfPermission() method to check if the permission is already granted, and if not, request it using the requestPermissions() method.

3. Use the MediaStore API to copy the file: Android 11 introduced the MediaStore API, which allows you to interact with shared media files. You can use this API to copy the PDF file from your app-specific directory to a location in shared storage.

Here's an example code snippet that demonstrates how to save a PDF file from your app-specific directory to shared storage:

import android.content.ContentResolver;
import android.content.ContentValues;
import android.net.Uri;
import android.os.Build;
import android.provider.MediaStore;
// Get the PDF file from your app-specific directory
File pdfFile = new File(getFilesDir(), "example.pdf");
// Prepare the content values for the new file
ContentValues values = new ContentValues();
values.put(MediaStore.MediaColumns.DISPLAY_NAME, "example.pdf");
values.put(MediaStore.MediaColumns.MIME_TYPE, "application/pdf");
// Determine the appropriate content URI based on the device's API level
Uri uri;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
// For Android 10 and above, use MediaStore API with MediaStore.Downloads
values.put(MediaStore.MediaColumns.RELATIVE_PATH, Environment.DIRECTORY_DOWNLOADS);
uri = MediaStore.Downloads.EXTERNAL_CONTENT_URI;
} else {
// For Android 9 and below, use the deprecated MediaStore API with MediaStore.Files
uri = MediaStore.Files.getContentUri("external");
}
// Insert the file into the media store
ContentResolver resolver = getContentResolver();
Uri newUri = resolver.insert(uri, values);
// Copy the file content from the app-specific directory to the shared storage
try {
OutputStream outputStream = resolver.openOutputStream(newUri);
FileInputStream inputStream = new FileInputStream(pdfFile);
byte[] buffer = new byte[4096];
int bytesRead;
while ((bytesRead = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
}
outputStream.close();
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}

In this code snippet, the example.pdf file is retrieved from the app-specific directory using getFilesDir(). Then, ContentValues are created to store the metadata of the new file, including its display name and MIME type. The appropriate content URI is determined based on the device's API level, and the file is inserted into the media store using insert().

Finally, the file content is copied from the app-specific directory to the shared storage by opening an output stream to the newUri and reading the content from the input stream obtained from the app-specific file.