检测版本更新，iOS

检测版本更新的方法。

  //检查新版本 更新

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, ), ^{
        // 耗时的操作

        //获取本地版本号
        NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary];
        NSString *version = [infoDictionary objectForKey:@"CFBundleShortVersionString"];
        NSString *build = [infoDictionary objectForKey:@"CFBundleVersion"];
        NSString *nowVersion = [NSString stringWithFormat:@"%@.%@", version, build];

        //获取appStore网络版本号
        NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"http://itunes.apple.com/lookup?id=%@", @""]];
        NSString * file =  [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];

        NSRange substr = [file rangeOfString:@"\"version\":\""];
        NSRange range1 = NSMakeRange(substr.location+substr.length,);
        //    NSRange substr2 =[file rangeOfString:@"\"" options:nil range:range1];
        NSRange substr2 = [file rangeOfString:@"\"" options:NSCaseInsensitiveSearch  range:range1];
        NSRange range2 = NSMakeRange(substr.location+substr.length, substr2.location-substr.location-substr.length);
        NSString *appStoreVersion =[file substringWithRange:range2];

        dispatch_async(dispatch_get_main_queue(), ^{
            // 更新界面

            //如果不一样去更新
            if(![nowVersion isEqualToString:appStoreVersion])
            {

                [self showAlert];

            }

        });
    });

/**
 *  检查新版本更新
 */
-(void)showAlert
{
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil message:@"有新的版本啦~~" delegate:self cancelButtonTitle:@"取消" otherButtonTitles:@"前去更新",nil];
    [alert show];

}

- (void)alertView:(UIAlertView*)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    if(buttonIndex==)
    {
        // 此处加入应用在app store的地址，方便用户去更新，一种实现方式如下：
        NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"https://itunes.apple.com/us/app/id%@?ls=1&mt=8", @""]];
        [[UIApplication sharedApplication] openURL:url];
    }
}