4 Ways To Implement OnClickListener On Android

AwesomeButtonActivity_1.java

public class AwesomeButtonActivity extends AppCompatActivity {

    private Button awesomeButton;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        awesomeButton = new Button(this);

        awesomeButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                awesomeButtonClicked();
            }
        });
    }

    private void awesomeButtonClicked() {
        awesomeButton.setText("AWESOME!");
    }
}

AwesomeButtonActivity_2.java

public class AwesomeButtonActivity extends AppCompatActivity {

    private Button awesomeButton;
    
    private View.OnClickListener awesomeOnClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            awesomeButtonClicked();
        }
    };

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        awesomeButton = new Button(this);

        awesomeButton.setOnClickListener(awesomeOnClickListener);
    }

    private void awesomeButtonClicked() {
        awesomeButton.setText("AWESOME!");
    }
}

AwesomeButtonActivity_3.java

public class AwesomeButtonActivity extends AppCompatActivity {

    private Button awesomeButton;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        awesomeButton = new Button(this);

        awesomeButton.setOnClickListener(new AwesomeButtonClick());
    }

    private void awesomeButtonClicked() {
        awesomeButton.setText("AWESOME!");
    }
    
    class AwesomeButtonClick implements View.OnClickListener {
        @Override
        public void onClick(View v) {
            awesomeButtonClicked();
        }
    }
}

AwesomeButtonActivity_4.java

public class AwesomeButtonActivity extends AppCompatActivity implements View.OnClickListener {

    private Button awesomeButton;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        awesomeButton = new Button(this);

        awesomeButton.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        awesomeButtonClicked();
    }

    private void awesomeButtonClicked() {
        awesomeButton.setText("AWESOME!");
    }
    
}