<uses-permission android:name="android.permission.FORCE_STOP_PACKAGES"
    tools:ignore="ProtectedPermissions" />

public static void stopAppByPackage(Context context, String packageName) {
    try{
        ActivityManager m= (ActivityManager) context.getSystemService(ACTIVITY_SERVICE);
        Method method = m.getClass().getMethod("forceStopPackage", String.class);
        method.setAccessible(true);
        method.invoke(m, packageName);
    }catch(Exception e){
        e.printStackTrace();
    }
}