Option to delete albums from storage in Phimpme Android Application

In the Phimpme Android application, users can perform various operations on the albums available such as creating a zip file of the album, hiding an album and many more. However, one another useful functionality that has been added to the Phimpme Android application is the option to delete unwanted albums permanently from the storage. So in this post, I will be discussing how we implemented the functionality to delete albums.

Step 1

First, we need to provide an option in the overflow menu to delete album/albums when the user long-selects album/albums or the user is viewing photos inside a particular album. The option in the overflow menu can be added by integrating following lines of code in the menu_albums.xml file(this file contains the XML code for overflow menu options provided for albums).

 <item
android:id=”@+id/delete_action”
android:title=”@string/delete”
app:showAsAction=”ifRoom” />

Step 2

Now when the user opts to delete some selected albums, we need to retrieve user’s choice of albums to delete and store it in an ArrayList<Album> to keep track of the albums and for further use. We would here also keep track of all the albums displayed currently to the user through another ArrayList<Album> named displayAlbums. Thereafter deleteSelectedAlbums method of class HandlingAlbums will be invoked passing in the activity context as the parameter. Now in this method we’d iterate through the ArrayList<Album>(ArrayList used to store user’s choice of albums to delete) and in turn invoke another method deleteAlbum with each iteration, passing in the album and context as the parameters. The deleteAlbum method would return a boolean value that will indicate whether or not the particular album was successfully deleted. If the boolean value returned is true, indicating that the particular album and its contents have been permanently deleted from the device storage, then we would delete that particular album object from the displayAlbums list and the AlbumsAdapter would be notified to display the remaining set of albums by passing in the modified displayAlbums list. The code snippet used to implement the method deleteSelectedAlbums and deleteAlbum is provided below.

public boolean deleteSelectedAlbums(Context context) {
boolean success = true;

for (Album selectedAlbum : selectedAlbums) {
  int index = dispAlbums.indexOf(selectedAlbum);
  if(deleteAlbum(selectedAlbum, context))
    dispAlbums.remove(index);
  else success = false;
}
return success;
}
public boolean deleteAlbum(Album album, Context context) {
return ContentHelper.deleteFilesInFolder(context, new File(album.getPath()));
}

Step 3

In the previous step, we were invoking a function deleteAlbum which would return a boolean variable denoting whether the album was deleted permanently or not. Therefore in this step, I’d be discussing the working of the deleteAlbum method. So the deleteAlbum method was being invoked passing in the album to delete and the context as the parameters. This method, in turn invokes the deleteFilesInFolder method of the ContentHelper class passing in the context and a File object created from the album path(to be deleted). This method returns a boolean variable indicating the success or failure of the operation and this variable is in turn returned by the deleteAlbum method. The code representing the function invoke has been provided above. The code snippet representing the deleteFilesInFolder method is provided below.

public static boolean deleteFilesInFolder(Context context, @NonNull final File folder) {
 boolean totalSuccess = true;

 String[] children = folder.list();
 if (children != null) {
    for (String child : children) {
       File file = new File(folder, child);
       if (!file.isDirectory()) {
          boolean success = deleteFile(context, file);
          if (!success) {
             Log.w(TAG, “Failed to delete file” + child);
             totalSuccess = false;
          }
       }
    }
 }
 return totalSuccess;
}

Now inside the deleteFilesInFolder method first all the contents of the file are stored in a String[] array child. Thereafter by iterating through the child array, every time a method deleteFile is invoked passing in an item from the child array(an image path) and the context as parameters, which returns a boolean variable indicating if the particular image content is deleted or not.

Now depending on which Android version the device is running, there are two methods used to delete the image file permanently from the storage.

If the device is running on version LOLLIPOP and above, the Android Storage Access Framework has been used to delete the image file, and if the device is running version KITKAT, the MediaStore content provider is used to delete the file from device’s storage. The code snippet implementing the deleteFile method is provided below.

public static boolean deleteFile(Context context, @NonNull final File file) {
 boolean success = file.delete();

 // Try with Storage Access Framework.
 if (!success && Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
    DocumentFile document = getDocumentFile(context, file, false, false);
    success = document != null && document.delete();
 }

 // Try the Kitkat workaround.
 if (!success && Build.VERSION.SDK_INT == Build.VERSION_CODES.KITKAT) {
    ContentResolver resolver = context.getContentResolver();

    try {
       Uri uri = null;//MediaStoreUtil.getUriFromFile(file.getAbsolutePath());
       if (uri != null) {
          resolver.delete(uri, null, null);
       }
       success = !file.exists();
    }
    catch (Exception e) {
       Log.e(TAG, “Error when deleting file “ + file.getAbsolutePath(), e);
       return false;
    }
 }

 if(success) scanFile(context, new String[]{ file.getPath() });
 return success;
}

This is how we achieved the functionality to delete album/albums from the storage in the Phimpme Android application. To get the full source code, please refer to the Phimpme Android Github repository listed in the resource section below.

Resources

1.Android Developer Guide – https://developer.android.com/guide/topics/providers/document-provider#delete

2.Github-Phimpme Android Repository – https://github.com/fossasia/phimpme-android/

3.MediaStore class – https://developer.android.com/reference/android/provider/MediaStore

4.Deleting files via Android media content provider – https://stackoverflow.com/questions/10925196/deleting-files-via-a-contentresolver-as-opposed-to-deleting-them-via-file-del