Question

How can it be:

final Button okButton = (Button)findViewById(R.id.okButton);

This is very clear that it is a variable declaration + assignment, absolutely not an object !
If so, how can I do the following, and actually operate a methods on it ?:

okButton.setOnClickListener(this);
okButton.setOnLongClickListener(this);

??

It makes confusion…

Thanks…

Answer 1

A variable can be an Object

If you look at the documentation for findViewById it takes a parameter of type int and returns a View.

You have prefixed findViewById with (Button) to tell the system that you are expecting that passing R.id.okButton to findViewById will return a View which is actually an instance of Button (a sub-class of View).

That instruction (Button) casts the View returned by findViewById to the Type Button and assigns it to your variable okButton.

So

• R.id.okButton is an int which is passed as a parameter to
• findViewById which is a method (probably of an Activity I guess)
• which returns an Object of type View which can be cast to an object
• of type Button which is assigned to your Button variable