切换活动后，Android Studio Soundboard按钮将无法播放声音，我只能按它们7次才能停止

Question

In Android studios i made Soundboard in which i have 4 activities when i'm on first activity i can press sounds all day and they play but right after i click next for second activity when i try to play them they won't play sound. I can click like 7 times and they stop.

I look everywhere but nothing works i even changed whole code again still same thing happens.

Button button1; Button theuniverserequired, iusedthestones, etc more sounds....

    iaminevitable = (Button) findViewById(R.id.iaminevitable);
    final MediaPlayer mp = MediaPlayer.create(this, R.raw.iaminevitable);
    iaminevitable.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            mp.start();
        }
    });
    iusedthestones = (Button) findViewById(R.id.iusedthestones);
    final MediaPlayer mp2 = MediaPlayer.create(this, 
    R.raw.iusedthestones);
    iusedthestones.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            mp2.start();
        }
    });               etc....


    button1 = findViewById(R.id.button_1);
    button1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent int1 = new Intent(MainActivity.this, Activity2.class);
            startActivity(int1);
        }
    });

there is nothing in error messages for why is this happening

Answer 1

First off: Declare your MPs outside your onCreate to prevent it from garbage collected when activity is paused

private MediaPlayer mp,mp2;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mp = new MediaPlayer.create(...
    mp2 = new MediaPlayer.create(...

Further more: Drop off resources used by MPs when activity stops to avoid memory leaks which may force your app to crash on continuous usage.

@Override
protected void onStop() {
    super.onStop();
    if (mp != null) {
     mp.reset();
     mp.release();
     mp = null;
    }
    if (mp2 != null) {
     mp2.reset();
     mp2.release();
     mp2 = null;
    }
}