iOS UIAlertController

在Xcode的iOS9.0 SDK中，UIAlertView和UIActionSheet都被UIAlertController取代。

在iOS 9中，UIAlertController在功能上是和UIAlertView以及UIActionSheet相同的，UIAlertController以一种模块化替换的方式来代替这两货的功能和作用。是使用对话框(alert)还是使用上拉菜单(action sheet)，就取决于在创建控制器时，您是如何设置首选样式的。

1、对话框

  UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"标题"message:@"这个是UIAlertController的默认样式"preferredStyle:UIAlertControllerStyleAlert];    [self presentViewController:alertController animated:YES completion:nil];

同创建UIAlertView相比，我们无需指定代理，也无需在初始化过程中指定按钮。不过要特别注意第三个参数，要确定您选择的是对话框样式还是上拉菜单样式。

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2、将动作按钮添加到控制器

通过创建UIAlertAction的实例，您可以将动作按钮添加到控制器上。UIAlertAction由标题字符串、样式以及当用户选中该动作时运行的代码块组成。通过UIAlertActionStyle，您可以选择如下三种动作样式：常规(default)、取消(cancel)以及警示(destruective)。为了实现原来我们在创建UIAlertView时创建的按钮效果，我们只需创建这两个动作按钮并将它们添加到控制器上即可。

  UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"标题"message:@"这个是UIAlertController的默认样式"preferredStyle:UIAlertControllerStyleAlert];  UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];  UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"好的" style:UIAlertActionStyleDefault handler:nil];  [alertController addAction:cancelAction];  [alertController addAction:okAction];  [self presentViewController:alertController animated:YES completion:nil];

3、“警示”样式

  UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"标题"message:@"这个是UIAlertController的默认样式"preferredStyle:UIAlertControllerStyleAlert];  UIAlertAction *resetAction = [UIAlertAction actionWithTitle:@"重置" style:UIAlertActionStyleDestructive handler:nil];  UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];    //添加顺序和显示顺序相同  [alertController addAction:cancelAction];  [alertController addAction:resetAction];  [self presentViewController:alertController animated:YES completion:nil];

4、文本对话框

设置输入框，并且设置通知，检测输入字符长度少于3时，不能点击“好的”

  UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"文本对话框" message:@"登录和密码对话框示例" preferredStyle:UIAlertControllerStyleAlert];  [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField){    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(alertTextFieldDidChange:) name:UITextFieldTextDidChangeNotification object:textField];    textField.placeholder = @"登录";  }];    [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(alertTextFieldDidChange:) name:UITextFieldTextDidChangeNotification object:textField];    textField.placeholder = @"密码";    textField.secureTextEntry = YES;  }];      UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"好的" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {    UITextField *login = alertController.textFields.firstObject;    UITextField *password = alertController.textFields.lastObject;    NSLog(@"%@",login.text);    NSLog(@"%@",password.text);  }];    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];  [alertController addAction:cancelAction];  [alertController addAction:okAction];      [self presentViewController:alertController animated:YES completion:nil];

- (void)alertTextFieldDidChange:(NSNotification *)notification{  UIAlertController *alertController = (UIAlertController *)self.presentedViewController;  if (alertController) {        UITextField *login = alertController.textFields.firstObject;    UIAlertAction *okAction = alertController.actions.lastObject;    okAction.enabled = login.text.length > 2;  }}

5、上拉菜单

  UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"保存或删除数据" message:@"删除数据将不可恢复" preferredStyle: UIAlertControllerStyleActionSheet];    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * action) {    NSLog(@"点击了取消");  }];    UIAlertAction *deleteAction = [UIAlertAction actionWithTitle:@"删除" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * action) {    NSLog(@"点击了删除");  }];  UIAlertAction *archiveAction = [UIAlertAction actionWithTitle:@"保存" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action) {    NSLog(@"点击了保存");  }];      [alertController addAction:cancelAction];  [alertController addAction:deleteAction];  [alertController addAction:archiveAction];    [self presentViewController:alertController animated:YES completion:nil];

原标题：iOS UIAlertController

关键词：IOS