UIAlertController 与 NSObject 重用更多次

Question

在我的应用程序中，UIAlertController 使用了很多 time.So，我创建了 NSObject Helper.

这里是Helper.h

#import <Foundation/Foundation.h>
#import "PrefixHeader.pch"
#import "LectureViewController.h"

@interface Helper : NSObject
+(void) showNotice:(NSString *) message;
+(void) showNoticeWithAction;
@end

这里是Helper.m

#import "Helper.h"
#import "AppDelegate.h"
@implementation Helper


+(void) showNotice:(NSString *) message{
    NSArray *versionArray = [[[UIDevice currentDevice] systemVersion] componentsSeparatedByString:@"."];
    if ([[versionArray objectAtIndex:0] intValue] >= 9) {

        //ver.IOS >= 9
        UIAlertController* alert = [UIAlertController alertControllerWithTitle:nil
                                                                       message:message
                                                                preferredStyle:UIAlertControllerStyleAlert];

        alert.view.backgroundColor = [UIColor grayColor];
//        [self presentViewController:alert animated:YES completion:nil];
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

            [alert dismissViewControllerAnimated:YES completion:^{

            }];

        });

    } else {
        //ver.IOS < 9
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil message:message delegate:nil cancelButtonTitle:nil otherButtonTitles:nil, nil];
        [alert performSelector:@selector(show) withObject:nil afterDelay:5];
    }

}

@end

由于 presentViewController，此行不能运行在助手中：[self presentViewController:alert animated:YES completion:nil];。请帮助我

Answer 1

您收到此错误是因为基础 class 是 NSObject 并且 self 表示该 class 的对象，而 NSObject 没有任何名为 presentViewController 的方法。

要解决它，您需要在该方法中传递一个 UIViewController 对象，并在该对象上像这样使用 presentViewController

+(void) showNotice:(NSString *) message andViewController : (UIViewController *) controller;

然后像这样使用它

 [controller presentViewController:alert animated:YES completion:nil];

Answer 2

在您的控制器被按下并显示时尝试此操作。

 UIViewController *vc = [[[[UIApplication sharedApplication] delegate] window] rootViewController];
 [[vc presentedViewController] ? vc.presentedViewController : vc presentViewController:alert animated:YES completion:nil];

Answer 3

在 class nsobject

的@end 中创建 c 函数的击球手方式

void showAlertView( NSString *title,NSString *message) {
    [[[UIAlertController alloc]initWithTitle:title message:message delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles: nil] show];
}

并像这样调用任何 class

showAlertView(@"Done", [NSString stringWithFormat:@"%@",responseObject[@"message"]]);

UIAlertController 与 NSObject 重用更多次

UIAlertController reuse more times with NSObject

objective-c

nsobject

ios