Optimasi Event Listener untuk mencegah Over 65K Methods.

Optimasi Event Listener selain berdampak terhadap alokasi memori seperti yg pernah dibahas oleh Om Jane Velger di sini, ternyata juga berdampak pada jumlah method.

Mari perhatikan perbandingan berikut ini:

1. Tanpa memanggil object new OnClickListener().

btnFirst = (Button) findViewById(R.id.btnFirst);
btnSecond = (Button) findViewById(R.id.btnSecond);
btnThird = (Button) findViewById(R.id.btnThird);

Total methods count: 15594

2. Memanggil 1 object new OnClickListener().

btnFirst = (Button) findViewById(R.id.btnFirst);
btnFirst.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    	Toast.makeText(MainActivity.this, "Click", Toast.LENGTH_SHORT).show();
    }
});
btnSecond = (Button) findViewById(R.id.btnSecond);
btnThird = (Button) findViewById(R.id.btnThird);

Total methods count: 15596

2. Memanggil 2 object new OnClickListener().

btnFirst = (Button) findViewById(R.id.btnFirst);
btnFirst.setOnClickListener(new View.OnClickListener() {
	@Override
    public void onClick(View v) {
    	Toast.makeText(MainActivity.this, "Click", Toast.LENGTH_SHORT).show();
    }
});
btnSecond = (Button) findViewById(R.id.btnSecond);
btnSecond.setOnClickListener(new View.OnClickListener() {
	@Override
    public void onClick(View v) {
    	Toast.makeText(MainActivity.this, "Click 2", Toast.LENGTH_SHORT).show();
	}
});
btnThird = (Button) findViewById(R.id.btnThird);

Total methods count: 15598

3. Setiap Button memanggil satu object onClicklistener dengan pengkondisian

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btnFirst = (Button) findViewById(R.id.btnFirst);
        btnFirst.setOnClickListener(onClickListener);
        btnSecond = (Button) findViewById(R.id.btnSecond);
        btnSecond.setOnClickListener(onClickListener);
        btnThird = (Button) findViewById(R.id.btnThird);
        btnThird.setOnClickListener(onClickListener);

    }

    View.OnClickListener onClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            switch (v.getId()){
                case R.id.btnFirst :
                    Toast.makeText(MainActivity.this, getString(R.string.btn_first), Toast.LENGTH_SHORT).show();
                    break;

                case R.id.btnSecond :
                    Toast.makeText(MainActivity.this, getString(R.string.btn_second), Toast.LENGTH_SHORT).show();
                    break;

                case R.id.btnThird :
                    Toast.makeText(MainActivity.this, getString(R.string.btn_third), Toast.LENGTH_SHORT).show();
                    break;
            }
        }
    };