Cocoa touch（八）：UIAlertView

 @interface UIAlertView : UIView 

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

 

@property(nonatomic,assign) id/*<UIAlertViewDelegate>*/ delegate;    // weak reference

@property(nonatomic,copy) NSString *title;

@property(nonatomic,copy) NSString *message;   // secondary explanation text

- (NSInteger)addButtonWithTitle:(NSString *)title;    // returns index of button. 0 based.

- (NSString *)buttonTitleAtIndex:(NSInteger)buttonIndex;

@property(nonatomic,readonly) NSInteger numberOfButtons;

@property(nonatomic) NSInteger cancelButtonIndex;      // if the delegate does not implement -alertViewCancel:, we pretend this button was clicked on. default is -1

 

@property(nonatomic,readonly) NSInteger firstOtherButtonIndex;// -1 if no otherButtonTitles or initWithTitle:... not used

@property(nonatomic,readonly,getter=isVisible) BOOL visible; 

// shows popup alert animated.

- (void)show;

 

// hides alert sheet or popup. use this method when you need to explicitly dismiss the alert.

// it does not need to be called if the user presses on a button

- (void)dismissWithClickedButtonIndex:(NSInteger)buttonIndex animated:(BOOL)animated;

 

// Alert view style - defaults to UIAlertViewStyleDefault

@property(nonatomic,assign) UIAlertViewStyle alertViewStyle NS_AVAILABLE_IOS(5_0);
 

/* Retrieve a text field at an index - raises NSRangeException when textFieldIndex is out-of-bounds. 

   The field at index 0 will be the first text field (the single field or the login field), the field at index 1 will be the password field. */

- (UITextField *)textFieldAtIndex:(NSInteger)textFieldIndex NS_AVAILABLE_IOS(5_0); 

@end

@protocol UIAlertViewDelegate <NSObject>
@optional

// Called when a button is clicked. The view will be automatically dismissed after this call returns
- (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;

@end

UIAlertView *alertView = [UIAlertView alloc] initWithTitle: @"Hello world"
message: @"Do you agree"
delete: self
cacelButtonTitle: @"Cancel"
otherButtonTitles: @"NO", @"YES", nil];
alertView.alertViewStyle = NSAlertViewStyleDefault;
[alertView show];

typedef NS_ENUM(NSInteger, UIAlertViewStyle) {
    UIAlertViewStyleDefault = 0,
    UIAlertViewStyleSecureTextInput,
    UIAlertViewStylePlainTextInput,
    UIAlertViewStyleLoginAndPasswordInput
};