Best practice for defining button events in android

Question

I have a Layout defined in XML which consists of several Buttons.

Currently I am doing this in the OnCreate method to define the event handlers against the buttons:

public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    Button newPicButton = (Button)findViewById(R.id.new_button);
    newPicButton.setOnClickListener(btnListener);
    ..... similarly for other buttons too
    .....
}

Inside of the Button's onClick event, I launch a camera Intent to get a picture and inside the onActivityResult callback I am again setting the event handlers along with setting the View like this:

protected void onActivityResult(int requestCode, int resultCode, Intent data) 
{ 
    setContentView(R.layout.main);
    Button newPicButton = (Button)findViewById(R.id.new_button);
    newPicButton.setOnClickListener(btnListener);
    ...similarly for other buttons too
}

I am new to android and this approach of redefining an event every time seems quite dirty to me. I would like to know what is the best practice in terms of defining button event handlers in scenarios like this.

Edit: pasting my complete class

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

    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button newPicButton = (Button)findViewById(R.id.new_button);
        newPicButton.setOnClickListener(btnListener);
    }

    //---create an anonymous class to act as a button click listener---
    private OnClickListener btnListener = new OnClickListener()
    {

        public void onClick(View v)
        {   
             //Intent newPicIntent = new Intent(v.getContext(), NewPictureActivity.class);
             //startActivityForResult(newPicIntent, 0);
            Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
            startActivityForResult(cameraIntent, 999);
        } 

    };  

    protected void onActivityResult(int requestCode, int resultCode, Intent data) 
    {  

        setContentView(R.layout.main);
        Button newPicButton = (Button)findViewById(R.id.new_button);
        newPicButton.setOnClickListener(btnListener);

       //if I comment last two lines nothing happens when I click on button

    }

The main question is

setContentView(R.layout.main);
Button newPicButton = (Button)findViewById(R.id.new_button);
newPicButton.setOnClickListener(btnListener);

Re-registering events inside onActivityResult.. is it right approach? Or am I doing something wrong? Because If I don't re-register event nothing happens when I click the button.

user_523325 · Answer

this is the best approach

@Override
public void onCreate(Bundle savedInstanceState) {
        button1.setOnClickListener(onClickListener);
        button2.setOnClickListener(onClickListener);
        button3.setOnClickListener(onClickListener);
}

private OnClickListener onClickListener = new OnClickListener() {
     @Override
     public void onClick(final View v) {
         switch(v.getId()){
             case R.id.button1:
                  //DO something
             break;
             case R.id.button2:
                  //DO something
             break;
             case R.id.button3:
                  //DO something
             break;
         }

   }
};

Best practice for defining button events in android

10 Answers