null pointer exception at getRingerMode()

Question

I wrote this app where users can toggle silent mode by clicking on an image button: package p.a;

import android.media.AudioManager;
import android.support.v7         


        

Answer 1

You can do it as Vamshi Krishna says, it's totally a good answer for this problem, but if you don't want to instantiate it for some reason you could change "Mode class" to a "Mode static class" as follows:

package p.a;

import android.media.AudioManager;

/**
 * Created by root on 9/19/17.
 */

public static class mode {
    public static boolean phonesilent(AudioManager audioManager){
        return audioManager.getRingerMode()==AudioManager.RINGER_MODE_SILENT;
    }
    public static void toggle(AudioManager audioManager){
        int mode = phonesilent(audioManager)?
                AudioManager.RINGER_MODE_NORMAL:
                AudioManager.RINGER_MODE_SILENT;
    }
}

Hope it helps!

Answer 2

Firstly create a Mode Object like this :

Mode mode = new Mode();