Multiple Buttons' OnClickListener() android

Question

I'm currently making a simple calculator app on Android. Im trying to set up the code so that when a number button is pressed it updates the calculator screen with that number. Currently I'm doing it like this.

    Button one = (Button) findViewById(R.id.oneButton);
    one.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            TextView output = (TextView) findViewById(R.id.output);
            output.append("1");
        }
    });

It works but I'm writing this same code for every single button on the calculator. As you can imagine it is very redundant. Is there anyway I can write this code in a more efficient way? One that involves not writing this method for every single button?

Answer 1

You Just Simply have to Follow these steps for making it easy...

You don't have to write new onClickListener for Every Button... Just Implement View.OnClickLister to your Activity/Fragment.. it will implement new Method called onClick() for handling onClick Events for Button,TextView` etc.

1. Implement OnClickListener() in your Activity/Fragment

public class MainActivity extends Activity implements View.OnClickListener {

}

2. Implement onClick() method in your Activity/Fragment

public class MainActivity extends Activity implements View.OnClickListener {
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }
    
    @Override
    public void onClick(View v) {
      // default method for handling onClick Events..
    }
}

3. Implement OnClickListener() For Buttons

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    
    setContentView(R.layout.your_layout);
    
    Button one = (Button) findViewById(R.id.oneButton);
    one.setOnClickListener(this); // calling onClick() method
    Button two = (Button) findViewById(R.id.twoButton);
    two.setOnClickListener(this);
    Button three = (Button) findViewById(R.id.threeButton);
    three.setOnClickListener(this);
}

4. Find Buttons By Id and Implement Your Code..

@Override
public void onClick(View v) {
    switch (v.getId()) {
        case R.id.oneButton:
            // do your code
            break;
        case R.id.twoButton:
            // do your code
            break;
        case R.id.threeButton:
            // do your code
            break;
        default:
            break;
    }
}

Please refer to this link for more information :

https://androidacademic.blogspot.com/2016/12/multiple-buttons-onclicklistener-android.html (updated)

This will make easier to handle many buttons click events and makes it looks simple to manage it...