UIAlertView,UIActionSheet都是系统的弹框

　　UIAlertView:创建方法

- (id)initWithTitle:(NSString *)title message:(NSString *)message delegate:(id /*<UIAlertViewDelegate>*/)delegate cancelButtonTitle:(NSString *)cancelButtonTitle otherButtonTitles:(NSString *)otherButtonTitles, ...

- (void)show;

　　UIAlertView:代理方法

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex;

 // Called when we cancel a view (eg. the user clicks the Home button). This is not called when the user clicks the cancel button.

// If not defined in the delegate, we simulate a click in the cancel button

- (void)alertViewCancel:(UIAlertView *)alertView;

- (void)willPresentAlertView:(UIAlertView *)alertView;  // before animation and showing view

- (void)didPresentAlertView:(UIAlertView *)alertView;  // after animation

- (void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex; // before animation and hiding view

- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex;  // after animation

// Called after edits in any of the default fields added by the style

- (BOOL)alertViewShouldEnableFirstOtherButton:(UIAlertView *)alertView;

　　UIActionSheet:使用

- (id)initWithTitle:(NSString *)title delegate:(id<UIActionSheetDelegate>)delegate cancelButtonTitle:(NSString *)cancelButtonTitle destructiveButtonTitle:(NSString *)destructiveButtonTitle otherButtonTitles:(NSString *)....

- (void)showInView:(UIView *)view;

　　UIActionSheet:代理方法

- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex;

// Called when we cancel a view (eg. the user clicks the Home button). This is not called when the user clicks the cancel button.

// If not defined in the delegate, we simulate a click in the cancel button

- (void)actionSheetCancel:(UIActionSheet *)actionSheet;

- (void)willPresentActionSheet:(UIActionSheet *)actionSheet;  // before animation and showing view

- (void)didPresentActionSheet:(UIActionSheet *)actionSheet;  // after animation

- (void)actionSheet:(UIActionSheet *)actionSheet willDismissWithButtonIndex:(NSInteger)buttonIndex; // before animation and hiding view

- (void)actionSheet:(UIActionSheet *)actionSheet didDismissWithButtonIndex:(NSInteger)buttonIndex;  // after animation