UIAlertController的使用

在iOS 8中,苹果废弃了UIAlertView，UIActionSheet类,但仍然可用。你应该避免使用它,iOS的未来版本可能不支持它。
原文链接：UIAlertController Example in iOS
接下来我将交大家如何使用UIAlertController。
UIAlertController支持2中类型。使用UIAlertController你可以创建一个警告对话框(UIAlerview)或行动表(UIActionSheet).
<pre>
typedef NS_ENUM(NSInteger, UIAlertControllerStyle) {
UIAlertControllerStyleActionSheet = 0,
UIAlertControllerStyleAlert
} NS_ENUM_AVAILABLE_IOS(8_0);
</pre>

一下是在UIAlertController中非常有用的方法
<pre>
//Create UIAlertController

• (instancetype)actionWithTitle:(NSString *)title style:(UIAlertActionStyle)style
  handler:(void (^)(UIAlertAction *action))handler;

//Adding an action

• (void)addAction:(UIAlertAction *)action;

//Adding text filed to UIAlertController.This method is supported only for UIAlertControllerStyleAlert

• (void)addTextFieldWithConfigurationHandler:(void (^)(UITextField *textField))configurationHandler;
  </pre>

• 创建一个简单的Alert Dialog

  
  
  

  <pre>
  UIAlertController * alert= [UIAlertController
  alertControllerWithTitle:@"My Title"
  message:@"Enter User Credentials"
  preferredStyle:UIAlertControllerStyleAlert];

  [self presentViewController:alert animated:YES completion:nil];
  </pre>

• 2创建一个alert Dialog with action

  
  
  

  <pre>
  UIAlertController * alert= [UIAlertController
  alertControllerWithTitle:@"Info"
  message:@"You are using UIAlertController"
  preferredStyle:UIAlertControllerStyleAlert];

  UIAlertAction* ok = [UIAlertAction
  actionWithTitle:@"OK"
  style:UIAlertActionStyleDefault
  handler:^(UIAlertAction * action)
  {
  [alert dismissViewControllerAnimated:YES completion:nil];

                    }];
  

  UIAlertAction* cancel = [UIAlertAction
  actionWithTitle:@"Cancel"
  style:UIAlertActionStyleDefault
  handler:^(UIAlertAction * action)
  {
  [alert dismissViewControllerAnimated:YES completion:nil];

                       }];
  

  [alert addAction:ok];
  [alert addAction:cancel];

  [self presentViewController:alert animated:YES completion:nil];
  </pre>

• 3 创建一个actionSheet with action

  
  
  

  <pre>
  UIAlertController * view= [UIAlertController
  alertControllerWithTitle:@"My Title"
  message:@"Select you Choice"
  preferredStyle:UIAlertControllerStyleActionSheet];

  UIAlertAction* ok = [UIAlertAction
  actionWithTitle:@"OK"
  style:UIAlertActionStyleDefault
  handler:^(UIAlertAction * action)
  {
  //Do some thing here
  [view dismissViewControllerAnimated:YES completion:nil];

                    }];
  

  UIAlertAction* cancel = [UIAlertAction
  actionWithTitle:@"Cancel"
  style:UIAlertActionStyleDefault
  handler:^(UIAlertAction * action)
  {
  [view dismissViewControllerAnimated:YES completion:nil];
  }];
  [view addAction:ok];
  [view addAction:cancel];
  [self presentViewController:view animated:YES completion:nil];
  </pre>

• 4. Create an Alert dialog with username and password fields.

     
     
     

     <pre>
     UIAlertController * alert= [UIAlertController
     alertControllerWithTitle:@"My Title"
     message:@"Enter User Credentials"
     preferredStyle:UIAlertControllerStyleAlert];

  UIAlertAction* ok = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault
  handler:^(UIAlertAction * action) {
  //Do Some action here

                                          }];
  

  UIAlertAction* cancel = [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleDefault
  handler:^(UIAlertAction * action) {
  [alert dismissViewControllerAnimated:YES completion:nil];
  }];

  [alert addAction:ok];
  [alert addAction:cancel];

  [alert addTextFieldWithConfigurationHandler:^(UITextField *textField) {
  textField.placeholder = @"Username";
  }];
  [alert addTextFieldWithConfigurationHandler:^(UITextField *textField) {
  textField.placeholder = @"Password";
  textField.secureTextEntry = YES;
  }];

  [self presentViewController:alert animated:YES completion:nil];
  </pre>