What is the difference between setOnItemClickListener and only onItemClick

Question

I searched the internet and read out documents on Google Android Help Centre, But still now I am not clear what the difference between the two and when I will use it at what situation? I go through stack-overflow not found any detailed answer.

serviceListViewProviderPage.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                      //something to do
        }
    });

and

serviceListViewProviderPage.setOnItemClickListener(this);
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
//something to do
}

Thanks in Advance

Answer 1

Both are same but different declarations and uses. First, lets see what we are doing.

Here:

view.setOnItemClickListener(Listener);

You are setting a listener in your view.

After, you must override the method onItemClick of the OnItemClickListener interface in order to follow the contract provided and make an action on item click.

---

Now see your code examples:

FIRST CASE

// set a listener to your wiew                 
serviceListViewProviderPage.setOnItemClickListener(
      // create a new OnItemClickListener 
      new AdapterView.OnItemClickListener() {

    @Override
    // 
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                  //something to do
    }
});

Here you're declaring the listener as a anonymous inner class at time you set it to your view.

PROS:

• fast to code

CONS:

• if the logic inside the metod is too long or the interface has many methods you will loose readability
• you cannot reuse the logic inside the Listener
• can cause memory leaks (thanks to @Murat K)

---

SECOND CASE

To understand second one you must see the code MUST be inside a View that implements AdapterView.OnItemClickListener, that's why you can use this

// here you set the class itself as a listener
serviceListViewProviderPage.setOnItemClickListener(this);

But, as long as you must follow the contract of the interface, the class must implement the method:

public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    //something to do
}

PROS:

• readability
• reusability

CONS:

• make a View be also a Listener is not my prefered way, I like more to have a class that is only a Listener and another is only a View.