Question: I'm a new android programmer, and recently I found some problem when programming.
In the main activity, there are three functions, `a()`, `b()`, `c()`, for example. So what can I do to make sure that `c()` will run after `a()` and `b()` are finished? 

Like this: 

```
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    a();//get view
    b();//do sth for view like set text in text view

    //trigger.setOnClickListener(new OnClickListener() {
        //@Override
        //public void onClick(View v) {
        //  c();
        //}
    //});
    //this is using a button to call the function, but I want it run automatically after a() and b() finish
}

```

Answer: 
Functions return values.
Like Fygo wrote, when you put `:` at the end of a function signature in AS3, it expects you to put the type of the return value of the function there there.

Given that the function in question is an event listener, it should be `void`, meaning that "nothing" gets returned, so to speak.

So you either write what Fygo posted in the first half of his answer, or you write

```
function ADFclicked(event:MouseEvet):void

```

Please take a look at the [Documentation](http://www.adobe.com/devnet/actionscript/learning/as3-fundamentals/functions.html)
To use `navigateToURL` we do like this : 

```
navigateToURL(new URLRequest(your_url_here)) 

```

For more details, take a look here : [navigateToURL()](http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/net/package.html#navigateToURL())