Question

I’m programming an Android calculator in Eclipse. I want to be able to set up the OnClickListener for several variables instead of having to code a listener for each one. Seems like overkill. Is there a way to do this using an array, maybe? Much help would be appreciated.

package rechee.cool;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class HelloAndroidActivity extends Activity {
    /** Called when the activity is first created. */

    int counter=0;
    //Just have two buttons so far, I'm going to have like 10 more
    Button one;
    Button two;

    EditText display;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        // Associate the button variable with the xml reference
        one= (Button) findViewById(R.id.bOne);

        display= (EditText) findViewById(R.id.editText1);

        //When button is clicked, display the text. How do I do this for the rest of my variables?
        one.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {

                //String string= Integer.toString(counter);
                display.setText("1");
            }
        });

    }
}

Answer 1

The way I’d do this is add the same onClick attribute in XML to every button, like this:

<Button android:onClick="onButtonClick"
        ... />

and then add the method that you used in that attribute to your activity, differentiating the buttons by id:

public void onButtonClick(View v) {

    switch(v.getId()) {

        case R.id.button1:
           // do something when button 1 is pressed
           break;

        case R.id.button2:
           // do something when button 2 is pressed
           break;

        // and so on ....
    }
}

Alternatively you can use findViewById() to get each button and assign the same listener to all the buttons. Then differentiate by id inside onClick()as shown above. This adds a few useless codelines though, so I think this example here is slightly more clean.