iOS APP如何实现检测更新

第一种是直接从AppStore上获取APP的版本号，然后已安装的App版本号比较判断是否需要更新，另一种是从服务器上获取APP的版本号，然后与已安装的App版本号比较判断是否需要更新。
第一种方法检测更新方法的优点是：检测版本号是实时同步的；缺点是：苹果网络不稳定，检测更新有点延时，部分App获取不到任何参数。第二种检测更新方法的优点是：检测更新速度快、检测稳定；缺点是：和App Store上的应用版本号不同步（App上架需要审核时间，不确定什么时候成功更新到App Store上）。

那么，我先来说一下第一种方法吧，先从AppStore上获取版本号，代码如下：

//获取版本号
-(void)Postpath
{
    NSString *appId = @"0123456789";//这是随便写的，你可以在查看APP信息里找到AppleId
NSString *urlStr = [[NSString alloc] initWithFormat:@"http://itunes.apple.com/lookup?id=%@",appId];
    NSURL *url = [NSURL URLWithString: urlStr];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url
                                                           cachePolicy:NSURLRequestReloadIgnoringCacheData
                                                       timeoutInterval:10];
    
    [request setHTTPMethod:@"POST"];
    
    
    NSOperationQueue *queue = [NSOperationQueue new];
    
    [NSURLConnection sendAsynchronousRequest:request queue:queue completionHandler:^(NSURLResponse *response,NSData *data,NSError *error){
        NSMutableDictionary *receiveStatusDic=[[NSMutableDictionary alloc]init];
        if (data) {
            
            NSDictionary *receiveDic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];
            if ([[receiveDic valueForKey:@"resultCount"] intValue]>0) {
                
                [receiveStatusDic setValue:@"1" forKey:@"status"];
                [receiveStatusDic setValue:[[[receiveDic valueForKey:@"results"] objectAtIndex:0] valueForKey:@"version"]   forKey:@"version"];
            }else{
                
                [receiveStatusDic setValue:@"-1" forKey:@"status"];
            }
        }else{
            [receiveStatusDic setValue:@"-1" forKey:@"status"];
        }
        
        [self performSelectorOnMainThread:@selector(receiveData:) withObject:receiveStatusDic waitUntilDone:NO];
    }];
    
}

在这个方法里可以输出获取的版本号：

-(void)receiveData:(id)sender
{
    NSLog(@"receiveData=%@",sender);
    [self compareVersion:sender[@"version"]];
   
}

在这个方法里比较新旧版本号的大小：

- (BOOL)compareVersion:(NSString *)serverVersion{
    
    //获取应用当前版本号
    NSDictionary *infoDic = [[NSBundle mainBundle] infoDictionary];
    NSString *appVersion = [infoDic objectForKey:@"CFBundleShortVersionString"];
    
    /*
     typedef NS_ENUM(NSInteger, NSComparisonResult)
     {
     NSOrderedAscending = -1L,//升序
     NSOrderedSame,   //等于
     NSOrderedDescending  //降序
     };
     */
    
    //比较当前版本和新版本号的大小
    if ([appVersion compare:serverVersion options:NSNumericSearch] == NSOrderedAscending) {
        NSLog(@"发现新版本： %@",serverVersion);
        return YES;
    }else{
        NSLog(@"没有新版本");
        return NO;
    }
    
}

第二种方法，是从服务器上获取版本号进行判断的，代码如下：

-(void)reloadData{

 NSString *BaseUrl = @"";
    NSDictionary *dic = [NSDictionary dictionary];
    dic = @{@"FunName":@"Get_App_Version",@"Params":@{@"DATA":@"2"}};
    HttpRequest *respont = [HttpRequest share];
    [respont sendRequestWithUrlNSString:BaseUrl withDic:dic withCompletion:^(NSDictionary *responseData, id status, NSError *error) {
        
        //判断版本
        NSLog(@"%@",responseData);
        if ([[responseData objectForKey:@"FAG"]isEqualToString:@"1"]) {

//获取当前应用版本号
            NSDictionary *infoDict=[[NSBundle mainBundle] infoDictionary]; 
            NSString *version=[infoDict objectForKey:@"CFBundleShortVersionString"];
            //            NSLog(@"%@",version);
            NSDictionary *VersionDic = [responseData objectForKey:@"RET"];
//获取到服务器上最后的版本号
            NSString *backVersion = [VersionDic objectForKey:@"IOS_VERSION"];
            
            if(backVersion==nil)
            {
              return;
            }
//VersionDic  objectForKey:@"IOS_Index"]判断是否在审核期间，如果在审核期间为1，没在审核期间为0,后台给的
            if([version isEqualToString:backVersion] == NO&&[[VersionDic  objectForKey:@"IOS_Index"] isEqualToString:@"0"])
            {
                dispatch_async(dispatch_get_main_queue(), ^{
                    
                    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"软件有新版本，是否下载" message:nil preferredStyle:UIAlertControllerStyleAlert];

                    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
                            NSLog(@"取消更新");          
                    }];
                    UIAlertAction *otherAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
                        NSString *updateUrl = [VersionDic objectForKey:@"IOS_URL"];//后台给的
                        [[UIApplication sharedApplication]openURL:[NSURL URLWithString:updateUrl]];
                    }];
                    [alertController addAction:cancelAction];
                    [alertController addAction:otherAction];
                    
                    [self presentViewController:alertController animated:YES completion:nil];
                    
                });
                
                
            }else{
                dispatch_async(dispatch_get_main_queue(), ^{

                });
            }
        }
    }];

}