I'm attempting to set the device wallpaper from an Imageview. My code works perfectly on devices running Android 5.0 and up but for some reason, it doesn't work on 4.4.4 or below.
I'm setting the wallpaper from a menu item. Here is the code:
else if (id == R.id.action_quick_set) {
wallpaper_img_menu = (ImageView) findViewById(R.id.wallpaper_image);
wallpaper_img_menu.setDrawingCacheEnabled(true);
// this is the important code :)
// Without it the view will have a dimension of 0,0 and the bitmap will be null
wallpaper_img_menu.measure(View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
wallpaper_img_menu.layout(0, 0,
wallpaper_img_menu.getMeasuredWidth(),
wallpaper_img_menu.getMeasuredHeight());
wallpaper_img_menu.buildDrawingCache(true);
// This is what's null (line 807); everything else works fine
Bitmap b = Bitmap.createBitmap(wallpaper_img_menu.getDrawingCache());
wallpaper_img_menu.setDrawingCacheEnabled(false); // clear drawing cache
try {
WallpaperManager.getInstance(getBaseContext()).setBitmap(b);
Toast.makeText(getBaseContext(), "Done!", Toast.LENGTH_SHORT).show();
finish();
} catch (IOException | NullPointerException e) {
e.printStackTrace();
}
}
Here's the logcat output:
08-29 19:34:57.025 25668-25668/com.hidden.hidden E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at android.graphics.Bitmap.createBitmap(Bitmap.java:505)
at com.hidden.hidden.viewer.WallpaperViewer.onOptionsItemSelected(WallpaperViewer.java:807)
at android.app.Activity.onMenuItemSelected(Activity.java:2566)
at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:325)
at android.support.v7.app.AppCompatActivity.onMenuItemSelected(AppCompatActivity.java:147)
at android.support.v7.internal.view.WindowCallbackWrapper.onMenuItemSelected(WindowCallbackWrapper.java:100)
at android.support.v7.app.AppCompatDelegateImplV7.onMenuItemSelected(AppCompatDelegateImplV7.java:583)
at android.support.v7.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:811)
at android.support.v7.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:153)
at android.support.v7.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:958)
at android.support.v7.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:948)
at android.support.v7.internal.view.menu.MenuPopupHelper.onItemClick(MenuPopupHelper.java:191)
at android.widget.AdapterView.performItemClick(AdapterView.java:298)
at android.widget.AbsListView.performItemClick(AbsListView.java:1100)
at android.widget.AbsListView$PerformClick.run(AbsListView.java:2788)
at android.widget.AbsListView$1.run(AbsListView.java:3463)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
The code is from here.
What I don't understand is why it works for Android 5.0 and up but nothing below.
Help appreciated!
