关于App版本判断 与 AppStore比对

关于App做版本升级的判断

        NSDictionary *infoDict = [[NSBundle mainBundle] infoDictionary];

        NSString *nowVersion = [infoDict objectForKey:@"CFBundleShortVersionString"];

        //xxxxxxxx AppStore的应用ID

        NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"http://itunes.apple.com/lookup?id=%@",xxxxxxxx]];

        NSString *file =  [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];

        

        NSRange substr = [file rangeOfString:@"\"version\":\""];

        NSRange range1 = NSMakeRange(substr.location + substr.length, 10);

        NSRange substr2 = [file rangeOfString:@"\"" options:NSCaseInsensitiveSearch range:range1];

        NSRange range2 = NSMakeRange(substr.location + substr.length, substr2.location - substr.location - substr.length);
        NSString *newVersion = [file substringWithRange:range2];

       //  新老版本的判断

        if(![nowVersion isEqualToString:newVersion]) {

        }