UIAlertController 实现kvo实现mes文字设置

 1 UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"更新提示" message:[NSString stringWithFormat:@"%@",self.model.groups.update_content]  preferredStyle: UIAlertControllerStyleAlert];
 2             
 3             UIView *subView1 = alert.view.subviews[0];
 4             UIView *subView2 = subView1.subviews[0];
 5             UIView *subView3 = subView2.subviews[0];
 6             UIView *subView4 = subView3.subviews[0];
 7             UIView *subView5 = subView4.subviews[0];
 8             NSLog(@"%@",subView5.subviews);
 9             //取title和message：
10             //UILabel *title = subView5.subviews[0];
11             UILabel *message = subView5.subviews[1];
12             message.textAlignment = NSTextAlignmentLeft;
13           
14             
15             
16             [alert addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
17                 
18             }]];
19             
20             [alert addAction:[UIAlertAction actionWithTitle:@"去更新" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
21                 //点击按钮的响应事件；
22                 NSURL *url = [NSURL URLWithString:@"http://itunes.apple.com/cn/app/id1198896188?mt=8"];
23                 
24                 [[UIApplication sharedApplication]openURL:url];
25             }]];
26             
27             //弹出提示框；
28             [self presentViewController:alert animated:true completion:nil];