iOS添加自动更新的代码

- (void)versionUpdate{

    //获得当前发布的版本
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

        //耗时的操作－－获取某个应用在AppStore上的信息,更改id就行
        __weak LoginViewController *weakSelf = self;
        NSString *string = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://itunes.apple.com/cn/lookup?id=1108288793"] encoding:NSUTF8StringEncoding error:nil];
        NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
        NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];
        NSString *version = [[[dic objectForKey:@"results"]firstObject]objectForKey:@"version"];

        NSString *updateInfo = [[[dic objectForKey:@"results"]firstObject]objectForKey:@"releaseNotes"];
        //NSString *updateURL = [[[dic valueForKey:@"results"] firstObject] objectForKey:@""];

        //获得当前版本
        NSString *currentVersion = [[[NSBundle mainBundle]infoDictionary]objectForKey:@"CFBundleShortVersionString"];

        dispatch_async(dispatch_get_main_queue(), ^{
            //更新界面
            if ( version &&![version isEqualToString:currentVersion]) {
                //有新版本
                NSString *message = [NSString stringWithFormat:@"有新版本发布啦!\n%@",updateInfo];
                UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"温馨提示" message:message preferredStyle:UIAlertControllerStyleAlert];
                UIAlertAction *action1 = [UIAlertAction actionWithTitle:@"忽略" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {

                }];
                UIAlertAction *action2 = [UIAlertAction actionWithTitle:@"前往更新" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
                    NSString *url = @"https://itunes.apple.com/cn/app/rich-products/id1108288793?mt=8&uo=4";

                    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:url]];
                }];

                [alertController addAction:action1];
                [alertController addAction:action2];

                [weakSelf presentViewController:alertController animated:YES completion:nil];
            }else{
                //已是最高版本
                NSLog(@"已是最高版本");
            }

        });

    });

}

记得http://itunes.apple.com/cn/lookup?id=1108288793，这中间的这个CN不能掉了，不然返回的JSON数组为空。