Full image not displayed

I make an application with wallpaper, BUT there was a problem with the display of the picture, the picture appears only after I click on the "Set wallpaper" button

I would appreciate the help

my code

public class FullImageActivity extends Activity { public ImageView mImageView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.full_image); } public void tempbitMap(View view){ // get intent data Intent i = getIntent(); // Selected image id int position = i.getExtras().getInt("id"); ImageAdapter imageAdapter = new ImageAdapter(this); mImageView = (ImageView) findViewById(R.id.full_image_view); mImageView.setImageBitmap(BitmapFactory.decodeResource(getResources(), imageAdapter.mThumbIds[position])); DisplayMetrics metrics = new DisplayMetrics(); getWindowManager().getDefaultDisplay().getMetrics(metrics); int height = metrics.heightPixels; int width = metrics.widthPixels; Bitmap tempbitMap = (BitmapFactory.decodeResource(getResources(), imageAdapter.mThumbIds[position])); Bitmap bitmap = Bitmap.createScaledBitmap(tempbitMap, width, height, true); WallpaperManager wallpaperManager = WallpaperManager.getInstance(FullImageActivity.this); wallpaperManager.setWallpaperOffsetSteps(1, 1); wallpaperManager.suggestDesiredDimensions(width, height); try { wallpaperManager.setBitmap(bitmap); } catch (IOException e) { e.printStackTrace(); } } }