FreeDTouch.OnForceTouchListener onForceTouchListener = new FreeDTouch.OnForceTouchListener() {
    @Override
    public void onPeek(View popup, View v, MotionEvent e) {
        Log.d(TAG, "onPeek");
        Toast.makeText(MainActivity.this, "PEEK", Toast.LENGTH_SHORT).show();
        ((Vibrator) getSystemService(VIBRATOR_SERVICE)).vibrate(20);
        
        // To find views inside your popup, use popup.findViewById(...).
        // E.g. -> TextView textView = (TextView) popup.findViewById(R.id.textview);
    }
    
    @Override
    public void onPop(View popup, View v, MotionEvent e) {
        Log.d(TAG, "onPop");
        Toast.makeText(MainActivity.this, "POP", Toast.LENGTH_SHORT).show();
        ((Vibrator) getSystemService(VIBRATOR_SERVICE)).vibrate(20);
    }
    
    @Override
    public void onClick(View popup, View v, MotionEvent e) {
        Log.d(TAG, "onClick");
        Toast.makeText(MainActivity.this, "Click", Toast.LENGTH_SHORT).show();
    }
    
    @Override
    public void onCancel(View popup, View v, MotionEvent e) {
        Log.d(TAG, "onCancel");
        Toast.makeText(MainActivity.this, "Cancel", Toast.LENGTH_SHORT).show();
    }
};

Button button = (Button) findViewById(R.id.button);
View popupContainer = findViewById(R.id.popup_container);

FreeDTouch.setup(button, onForceTouchListner)
        .addPopup(popupContainer, R.layout.popup_example)
        .start();