无涯教程-OC - Alerts函数

Alert用于向用户提供重要信息。只有在Alert视图中选择了选项，我们才能进一步使用该应用程序。

Alerts - 重要属性

• alertViewStyle
• cancelButtonIndex
• delegate
• message
• numberOfButtons
• title

Alerts - 重要方法

- (NSInteger)addButtonWithTitle:(NSString *)title
- (NSString *)buttonTitleAtIndex:(NSInteger)buttonIndex
- (void)dismissWithClickedButtonIndex:
   (NSInteger)buttonIndex animated:(BOOL)animated
- (id)initWithTitle:(NSString *)title message:
   (NSString *)message delegate:(id)delegate
   cancelButtonTitle:(NSString *)cancelButtonTitle
   otherButtonTitles:(NSString*)otherButtonTitles， ...
- (void)show

如下更新ViewController.h-

通过添加<UIAlertViewDelegate>来使您的类符合警报视图委托协议，如ViewController.h中所示。

#import <UIKit/UIKit.h>
@interface ViewController : UIViewController<UIAlertViewDelegate> {
}
@end

Alerts - 自定义方法

-(void)addAlertView {
   UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:
   @"Title" message:@"This is a test alert" delegate:self 
   cancelButtonTitle:@"Cancel" otherButtonTitles:@"Ok"， nil];
   [alertView show];
}

Alerts - 委托方法

#pragma mark - Alert view delegate
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:
   (NSInteger)buttonIndex {
      switch (buttonIndex) {
         case 0:
            NSLog(@"Cancel button clicked");
         break;
     </span><span class="kwd">case</span><span class="pln"> </span><span class="lit">1</span><span class="pun">:</span><span class="pln">
        </span><span class="typ">NSLog</span><span class="pun">(@</span><span class="str">"OK button clicked"</span><span class="pun">);</span><span class="pln">
     </span><span class="kwd">break</span><span class="pun">;</span><span class="pln">
    
     </span><span class="kwd">default</span><span class="pun">:</span><span class="pln">
     </span><span class="kwd">break</span><span class="pun">;</span><span class="pln">
  </span><span class="pun">}</span><span class="pln">

}
}

更新ViewController.m中的viewDidLoad，如下所示:

(void)viewDidLoad {
   [super viewDidLoad];
   [self addAlertView];
}

运行应用程序时，将获得以下输出-

参考链接

www.learnfk.com/ios/ios-ui-…