Explain the use of below function with meaning in iphone

I m confused to use following methods and i want the cl开发者_如何学JAVAear meaning of all so that i can use that perfectly in my project

1. -(void)viewWillAppear
2. -(void)viewWillDisappear
3. -(void)viewDidLoad
4. -(void)viewDidUnload
5. -(void)viewDidAppear
6. -(void)viewDidDisappear

Please can any body who knows these very well then please help me.

Thanks in Advance

Have you looked at the iPhone Developer Documentation for UIViewController? It explains it well I think.

This is from the top of my head. Here is some more info: Custom View Controllers

-(void)viewWillAppear
Fired just before the uiview appears on the screen.

-(void)viewWillDisappear
Fired just before the uiview disappears from the screen.

-(void)viewDidLoad
Fired after the uview loaded into memory and after the IBOutlets are hooked up (if any)

-(void)viewDidUnload
Fired after the uview unloaded from memory.

-(void)viewDidAppear
Fired after the view appeared on the screen.

-(void)viewDidDisappear
Fired after view disappeared from the screen.