How to manage setOnClickListener on a array of but

Question

I have a dynamic array of buttons and I would like to know how to handle the onclick on every button?

Thanks

Answer 1

The same way you would on a single button...

Set an on click listener, if you have an Array it would look something like this:

btns[0].setOnClickListener(new OnClickListener() {
    public void onClick(View v){
        //do something
    }
});

btns[1].setOnClickListener(new OnClickListener() {
    public void onClick(View v){
        //do something
    }
});
//etc.

If you want all of them to do the same thing you could use a for loop to loop over the array like this:

for(int i = 0; i< btns.length; i++){
    btns[i].setOnClickListener(new OnClickListener() {
        public void onClick(View v){
            //do something
        }
    });
}

I don't know exactly what you are doing but if you have an Array of Buttons it is likely that you should probably be using an Adapter with a ListView or something instead of how every you are doing it now.

Answer 2

Without seeing some code or more of an explanation, it's hard to really answer your question, but here are some tips:

Before we get to the listeners, we have to make sure that each of the dynamically created buttons knows how to respond to a click event. You can use the setTag method on a button to attach an arbitrary Object to it. This Object will represent how the Button acts when clicked. You can just use Integers as this Object (perhaps some constant values) or if each button needs some unique data, create a class that maintains both how the button needs to act when clicked AND the data you need (or at least a reference to it).

Then, you can initialize one single listener that handles all of your button clicks. In the onClick method of this listener place a conditional that branches to handle all of your click cases. Set this listener on all of your dynamic buttons as you create them. At the start of your onClick, get the Tag from the View parameter of the onClick method (this view will be the button that was clicked), and use that to decide which branch of the conditional to take.

Hope this helps. If you make your question more specific, we'll be able to offer some more detailed assistance.

Answer 3

I don't see a need to create a new OnClickListener for each button -- all the buttons could share a single listener.

private OnClickListener myListener = new OnClickListener() {
  public void onClick(View v) {
    Object tag = v.getTag();
    // Do something depending on the value of the tag
  }
};

...

for (int i=0; i < btns.length; ++i) {
  btns[i].setOnClickListener(myListener);
  btns[i].setTag(some_identifying_information);
}

Of course, you could create a unique OnClickListener for each button, and take advantage this way:

for (int i=0; i < btns.length; ++i) {
  final Button btn = btns[i];
  btn.setOnClickListener(new OnClickListener() {
    public void onClick(View v) {
      // do something depending on the value of btn, which you're allowed
      // to reference here because it was declared final above.
    }
  });
}