在iOS8中如何使用UIAlertController来替换UIAlertView和UIActionsheet

在iOS8中UIAlertController已经取代UIActionsheet UIAlertView。
可以创建一个AlertController“标题”和“消息”来作为警告框。

UIAlertController的两种设置格式：

• UIAlertControllerStyleActionSheet
  用于配置UIAlertController ActionSheet
• UIAlertControllerStyleAlert
  用于配置UIAlertController警报。

1.创建一个alert对象和一个actionsheet对象，请看以下code：

• 创建AlertController对象：

UIAlertController *alertView = [UIAlertController alertControllerWithTitle:@"title"
                                                                                                                             message:@"Select a title"
                                                                                                                  preferredStyle:UIAlertControllerStyleAlert];

• 添加action:

  [alertView addAction:[UIAlertAction actionWithTitle:@"ok"
                                                                                       style:UIAlertActionStyleDefault
                                                                                   handler:^(UIAlertAction *action) {
                                                                                                    //要做的事情
                                                                                           }]];

在你点击‘ok’的时候会回调handler这个block

• 显示alertController

[self presentViewController:alertView animated:YES completion:{
BJLog("show the alertView");
}];

2.创建一个简单的提醒OK按钮和消息

下面的这个方法将创建一个简单的AlertController在iOS8警报

- (void)showAlertView
{
//创建alertcontroller对象
   UIAlertController *alertView = [UIAlertController alertControllerWithTitle:@"simple" message:@"This is an simple AlertView" perferredStyle:UIAlertControllerAlert];
   //添加action
   [alertView addAction:[UIAlertAction actionWithTitle:@"ok" style:UIAlertActionStyleDefault
   handler:^(UIAlertAction *action) {                                                                                                       //要做的事情
   BJLog(@"action - %@", action.title);  
                                                                                                                              }]];   
     //显示alertView
     [self presentViewController:alertView animated:YES completion:^{
    NSLog(@"alertView shown!");
}];                                                                                                                                                                                                                                              
}

3.创建一个警告文本框:

- (void)showAlertWithTextField {

UIAlertController *alertView = [UIAlertController alertControllerWithTitle:@"Menu"
                                                                   message:@"Select a menu"
                                                            preferredStyle:UIAlertControllerStyleAlert];

[alertView addTextFieldWithConfigurationHandler:^(UITextField *textField) {
    //Customize the textField
    textField.placeholder = @"User name";
    textField.textColor = [UIColor whiteColor];
    textField.borderStyle = UITextBorderStyleRoundedRect;
    textField.backgroundColor = [UIColor colorWithRed:171/255 green:182/255 blue:255/255 alpha:0.5];
}];

[alertView addAction:[UIAlertAction actionWithTitle:@"ok"
                                              style:UIAlertActionStyleDefault
                                            handler:^(UIAlertAction *action) {
                                                BJLog(@"action - %@", action.title);//callback
                                            }]];

[self presentViewController:alertView animated:YES completion:^{
    BJLog(@"completed");
}];

}

4.给AlertController添加两个文本框：

- (void)showActionSheetWithTwoButtons {

UIAlertController *alertView = [UIAlertController alertControllerWithTitle:@"ActionSheet!"
                                                                   message:@"This is an ActionSheet."
                                                      preferredStyle:UIAlertControllerStyleActionSheet];

[alertView addAction:[UIAlertAction actionWithTitle:@"ok"
                                              style:UIAlertActionStyleDefault
                                            handler:^(UIAlertAction *action) {
                                                NSLog(@"action - %@", action.title);
                                            }]];

[alertView addAction:[UIAlertAction actionWithTitle:@"Cancel"
                                              style:UIAlertActionStyleDefault
                                            handler:^(UIAlertAction *action) {
                                                NSLog(@"action - %@", action.title);
                                            }]];

[self presentViewController:alertView animated:YES completion:^{
    NSLog(@"alertView shown!");
}];

}

代码比较简单，就不让代码君出来玩了！