I want to set my app's background to be the same as my home screen's wallpaper. How can I get the home screen wallpaper in activity.xml? Can I do that?
Use
final WallpaperManager wallpaperManager = WallpaperManager.getInstance(this);
final Drawable wallpaperDrawable = wallpaperManager.getDrawable();
to get the current wallpaper. Then set it as your own app's background:
LinearLayout ll = (LinearLayout) findViewById(R.id.myLinearLayout);//Substitute with your layout
ll.setBackground(wallpaperDrawable);
All this should happen in the onCreate() if you wish to have it as the initial background.