IOS 中弹框的实现方法整理

#define iOS8Later ([UIDevice currentDevice].systemVersion.doubleValue >= 8.0)

@interface RootViewController ()<UIAlertViewDelegate>  @end 

UIAlertView * alert = [[UIAlertView alloc] initWithTitle:@"登陆失败" message:@"请重新输入用户名和密码" delegate:self cancelButtonTitle:@"取消" otherButtonTitles:@"确定", nil];       [alert show]; 

#pragma mark - UIAlertView Delegate Methods - - (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {   if(buttonIndex == 0)   {     NSLog(@"点击取消按钮后，想要的操作,可以加此处");   }   else if(buttonIndex == 1)   {     NSLog(@"点击确定按钮后，想要的操作，可以加此处");   } } 

      UIAlertController *_alertVC = [UIAlertController alertControllerWithTitle:@"登陆失败" message:@"请重新输入用户名和密码" preferredStyle:UIAlertControllerStyleAlert];              //警告类型，红色字体 UIAlertActionStyleDestructive //      UIAlertAction *_doAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDestructive handler:nil]; //      [_alertVC addAction:_doAction];              UIAlertAction *_doAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action)       {         NSLog(@"点击确定按钮后，想要的操作，可以加此处");       }];       [_alertVC addAction:_doAction];  //      UIAlertAction *_cancleAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil]; //      [_alertVC addAction:_cancleAction];              UIAlertAction *_cancleAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action)       {         NSLog(@"点击取消按钮后，想要的操作");       }];       [_alertVC addAction:_cancleAction];              [self presentViewController:_alertVC animated:YES completion:nil]; 

//警告类型，红色字体 UIAlertActionStyleDestructive，如下图所示的效果      UIAlertAction *_doAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDestructive handler:nil];      [_alertVC addAction:_doAction];