How to kill background processes in Android 6.0 and newest?

Question

I use that code fragment for cleaning RAM memory:

public void onClear(){
    ActivityManager am = (ActivityManager) getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE);
    for (ActivityManager.RunningAppProcessInfo pid : am.getRunningAppProcesses()) {
        am.killBackgroundProcesses(pid.processName);
        android.os.Process.killProcess(pid.uid);
    }   
}

It works correct on my phone with Android 5.1, but doesn not works on the same phone with 7.1 firmware, also does not works on other phone with Android 6.0.

I have a <uses-permission android:name="android.permission.KILL_BACKGROUND_PROCESSES" /> in the AndrodManifest.xml. In the build.gradle targetSdkVersion = 22.

Answer 1

Starting from Android M, system doesn't grant dangerous permissions automatically. android.permission.KILL_BACKGROUND_PROCESSES falls in dangerous permission category. You have to request permission at runtime. Tutorial to implement can be found here