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...

Answer 2

You could set the property:

android:onClick="buttonClicked" 

in the xml file for each of those buttons, and use this in the java code:

public void buttonClicked(View view) {      if (view.getId() == R.id.button1) {         // button1 action     } else if (view.getId() == R.id.button2) {         //button2 action     } else if (view.getId() == R.id.button3) {         //button3 action     }  }