Objective C在定時器上加載圖標

Question

我爲我的應用程序創建了一個加載圖標。在應用程序正在加載地圖並放置標記時，我在屏幕上顯示一個正在旋轉的加載圖標。用我當前的代碼顯示加載圖標，但只有在標記全部放置在地圖上並且所有內容都已完成加載時纔會旋轉。我已經嘗試了一切，任何人都可以幫忙嗎？

我會附上下面的代碼，我明白這不是最好的方式來做到這一點，我打算一旦找到我在做什麼錯了，讓它在地圖加載時旋轉時，將它整理好。

謝謝。

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 
    loading=@"0"; 

    rotateTimer = [NSTimer scheduledTimerWithTimeInterval:0.3 
                target:self 
               selector:@selector(rotateMove) 
               userInfo:nil 
                repeats:YES]; 
} 

-(void)rotateMove 
{ 
    if([loading isEqual:@"1"]) 
    { 
     [rotateTimer invalidate]; 
     rotateTimer = nil; 
    } 
    if([loading isEqual:@"0"]) 
    { 
     NSLog(@"move"); 
     [UIView animateWithDuration:1.0f delay:0 options:UIViewAnimationOptionCurveLinear animations:^{ 
      [self.rotate setTransform:CGAffineTransformRotate(self.rotate.transform, M_PI_2)]; 
     } completion:^(BOOL finished){ 
      if (finished) { 
      } 
     }]; 
    } 
} 

編輯：將地圖下面的代碼

-(void)mapload 
{ 

[self.mapView clear]; 


NSString *lat = [[NSString alloc] initWithFormat:@"%g", latitude]; 
NSString *lng = [[NSString alloc] initWithFormat:@"%g", longitude]; 
NSURL *blogURL = 
NSLog(@"URL = %@", blogURL); 
NSData *jsonData = [NSData dataWithContentsOfURL:blogURL]; 
if(jsonData == nil) 
{ 
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Connection Error" message:@"Please check your internet connection and try again." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
    [alert show]; 
    return; 
} 
else{ 



    NSError *error = nil; 
    NSDictionary *dataDictionary = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:&error]; 
    NSArray *test = [dataDictionary objectForKey:@"test"]; 

    self.bottombutton.hidden=FALSE; 
    self.time.hidden=FALSE; 
    self.mins.hidden=FALSE; 
    self.rotate.hidden=TRUE; 
    int tes = [[test[0] valueForKey:@"time"] intValue]; 


    } 

    for (int i = 0; i < [test count]; i++) { 
     for(NSDictionary *coordinates in test){ 

      double la=[coordinates[@"lat"] doubleValue]; 
      double lo=[coordinates[@"long"] doubleValue]; 

      CLLocation * loca=[[CLLocation alloc]initWithLatitude:la longitude:lo]; 
      CLLocationCoordinate2D coordi=loca.coordinate; 

      GMSMarker *marker= [[GMSMarker alloc] init]; 
      marker=[GMSMarker markerWithPosition:coordi]; 
      marker.snippet = coordinates[@"name"]; 
      marker.map = self.mapView; 
      marker.appearAnimation = kGMSMarkerAnimationPop; 

      UIImage * image = [UIImage imageNamed:@"mapiconlarge"]; 
      CGSize sacleSize = CGSizeMake(45, 45); 
      UIGraphicsBeginImageContextWithOptions(sacleSize, NO, 0.0); 
      [image drawInRect:CGRectMake(0, 0, sacleSize.width, sacleSize.height)]; 
      UIImage * resizedImage = UIGraphicsGetImageFromCurrentImageContext(); 
      UIGraphicsEndImageContext(); 

      NSLog(@"markeradded"); 
      marker.icon = resizedImage; 
      NSLog(loading); 


     } 
     } 


} 



} 

Answer 1

我們需要梳理出你的代碼應該在後臺完成的部分 - 至少是，網絡請求 - 和必須在主做的代碼 - 任何改變UI ...

// here, everything you do to prepare for the network request 

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ 
    // make the network request 
    NSData *jsonData = [NSData dataWithContentsOfURL:blogURL]; 
    dispatch_async(dispatch_get_main_queue(), ^{ 
     // here everything you do after with the json data result 
    }); 
}); 

所以你不要自己開車瘋狂的語法，構建兩個方法，第一個產生blogURL關於使用網絡請求，第二，採取NSData結果，並做一切。通過這種方式，嵌套在內部調度中的只有一行方法調用。