如果您在閱讀我的文章時(shí)有疑問 , 請(qǐng)點(diǎn)擊這里

UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"錯(cuò)誤" message:@"請(qǐng)先安裝微信客戶端" preferredStyle:UIAlertControllerStyleAlert];

UIAlertAction *actionConfirm = [UIAlertAction actionWithTitle:@"好的" style:UIAlertActionStyleDefault handler:nil];
 [alert addAction:actionConfirm];
 [self presentViewController:alert animated:YES completion:nil];

UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"已經(jīng)登錄" message:@"您已經(jīng)登錄" preferredStyle:UIAlertControllerStyleAlert];
        [alert addAction:[UIAlertAction actionWithTitle:@"確定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
            NSLog(@"點(diǎn)擊確認(rèn)");
            [self.navigationController pushViewController:[UserViewController new] animated:YES];
        }]];
        
        [self presentViewController:alert animated:YES completion:nil];

只顯示幾秒

    UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"已推出" message:nil preferredStyle:UIAlertControllerStyleAlert];
    [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(), ^{
        [self.presentedViewController dismissViewControllerAnimated:YES completion:nil];
    });