UIAlertView是在屏幕中央弹出一个消息框，该消息框可以用来做消息提示，也可以让用户选择不同选项。

UIActionSheet是在屏幕底端弹出一个消息框，功能类似UIAlertView，不过两者除了位置不一样外，其外观也有出入。为了能够响应UIAlertView和UIActionSheet，需要设定其代理，而对应的代理需要实现对应的协议（UIAlertViewDelegate，UIActionSheetDelegate）。实现以下两个函数

// 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 a button is clicked. The view will be automatically dismissed after this call returns
- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex;

示例代码

• 代理实现协议

  @interface ViewController : UIViewController <UIAlertViewDelegate, UIActionSheetDelegate>

  
  
• 主要功能代码

  -(IBAction)onTextFieldEnd:(id)sender
  {
      [_textTime resignFirstResponder];
      
  // 显示对话框
  #if 0
      UIAlertView* alert = [[UIAlertView alloc] initWithTitle:@"TextContend" message:_textTime.text delegate:self cancelButtonTitle:@"OK" otherButtonTitles:@"Good", @"Thanks", nil];
      
      [alert show];
      [alert release];
  #else
      // 底部弹出对话框
      UIActionSheet* sheet = [[UIActionSheet alloc] initWithTitle:@"ActionSheet" delegate:self cancelButtonTitle:@"cancelButtonTitle" destructiveButtonTitle:@"destructiveButtonTitle" otherButtonTitles:@"OtherButton1", @"OtherButton2", nil];
      
      [sheet showInView:self.view];
      [sheet release];
  #endif
  }
  
  // 按钮按下时响应函数
  - (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
  {
      NSString* strInfo = nil;
      
      strInfo = [[NSString alloc] initWithFormat:@"你按下了【%@】按钮，第%d个按钮", [alertView buttonTitleAtIndex:buttonIndex], buttonIndex];
      UIAlertView* alert = [[UIAlertView alloc]initWithTitle:@"按钮响应代理函数" message:strInfo delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil];
      
      [alert show];
      [alert release];
      [strInfo release];
  }
  
  // 按钮按下时响应函数
  - (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
  {
      NSString* strInfo = nil;
      
      strInfo = [[NSString alloc] initWithFormat:@"你按下了【%@】按钮，第%d个按钮", [actionSheet buttonTitleAtIndex:buttonIndex], buttonIndex];
      UIAlertView* alert = [[UIAlertView alloc]initWithTitle:@"按钮响应代理函数" message:strInfo delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil];
      
      [alert show];
      [alert release];
      [strInfo release];
  }