如何延迟某些行的执行

Question

我有按钮点击事件。在其中，我正在调用另一个 NSObject class 中的另一个方法。该方法在调度块中调用 Web 服务。我的按钮点击甚至是这样的

-(IBAction)Loging:(id)sender
{

NSString *strParam=[NSString stringWithFormat:@"userName=%@&password=%@&ipAddress=%@",@"admin",@"1234",@"127.0.0.1"];

NSString *str=[wb prepareURL:@"account/users?" :strParam :NO :YES :nil];
 NSLog(@"data array %@",dm.arrayData);
 NSLog(@"str========= %@",str);
}

我的问题是这样的。此 arrayData 和 str 打印为空，因为这两行在 prepareURL 完成执行之前执行。我想在完全完成 prepareURL 方法后执行后面的部分。解决这个问题的方法是什么？如果我应该使用块，我该如何为此编写块？请帮助我。

谢谢

已更新

-(NSString *)prepareURL :(NSString *)appendString :(NSString *)bindedParams :(BOOL)isauthorized :(BOOL)isGet :(NSMutableDictionary *)jsonBody

 {

dm=[Datamanager sharedManager];
NSString *strToken=dm.strAuthToken;
NSString *strServerURL=[[[NSBundle mainBundle]infoDictionary] objectForKey:@"BaseURL"];
NSString *strfullURL=[NSString stringWithFormat:@"%@%@%@",strServerURL,appendString,bindedParams];
NSURL *url=[NSURL URLWithString:strfullURL];
NSMutableURLRequest *request=[NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:30.0];

if (isauthorized) {

    [request addValue:[NSString stringWithFormat:@"Bearer %@", strToken] forHTTPHeaderField:@"Authorization"];
}

NSString *str=[self GetPostPreperation:request:isGet:jsonBody];

return str;



 }

这是我的GetPostPreperation方法

-(NSString *)GetPostPreperation :(NSMutableURLRequest *)request :(BOOL)isGet :(NSMutableDictionary *)jsonBody


 {


 NSError *error=nil;
 __block NSString *strReturn;

if (isGet) {
     [request setHTTPMethod:@"GET"];
}

else
{
    [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
     NSData* jsonData = [NSJSONSerialization dataWithJSONObject:jsonBody
                                                       options:NSJSONWritingPrettyPrinted error:&error];
    NSString *string = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
    NSLog(@"Json string %@",string);
    [request setHTTPMethod:@"POST"];
    [request setHTTPBody:jsonData];


}


dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

dispatch_async(queue, ^{
    NSError *error = nil;
    NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error: &error];
    NSString *string = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];


    NSLog(@"Response string %@",string);

    if (!error) {

        NSLog(@"No Error");

        NSError *jsonerror=nil;
        NSMutableArray *jsonArray = [NSJSONSerialization JSONObjectWithData: returnData options: NSJSONReadingAllowFragments error: &jsonerror];

        if (!jsonArray) {
            NSLog(@"Error parsing JSON: %@", jsonerror);
            strReturn=[[NSString alloc] initWithFormat:@"%@",jsonerror];
        } else {

            dm=[Datamanager sharedManager];
            [dm.arrayData addObjectsFromArray:jsonArray];


            }

    }
    else
    {
        NSLog(@"Error %@",error);
        strReturn=[NSString stringWithFormat:@"%@",error];

    }

});


return strReturn;




  }

Answer 1

目前 iOS 中 api 调用的最佳原生 class 是 NSURLSession。

使用这个 class:

-(NSString *)prepareURL :(NSString *)appendString :(NSString *)bindedParams :(BOOL)isauthorized :(BOOL)isGet :(NSMutableDictionary *)jsonBody completionHandler:(void(^)(NSData *data, NSURLResponse *response, NSError *error) ) completion{
   NSURLSession *session = [NSURLSession sharedSession];
   NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
    //request is your NSURLRequest object
    //use the data here to get your wanted result
    completion(data,response,error); //send data to calling class
    }];
    [task resume];
}

积木的使用方法可以参考this website

如何延迟某些行的执行

How to delay the execution of some lines

ios

objective-c-blocks