UIImageView問題通過OperationQueue加載

Question

我使用NSOperationQueue加載UIImageView。

負載從Internet獲取圖像，然後將其添加到圖像視圖。我的問題是，該方法結束，但它需要約3秒後的圖像視圖實際上任一顯示圖像，或從上海華移除圖像視圖...

- (void)viewDidLoad { NSLog(@"AirportDetailView: viewDidLoad"); 
    [super viewDidLoad]; 
    [self.activity startAnimating]; 
    self.queue = [NSOperationQueue new]; 
    NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(loadImage) object:NULL]; 
    [self.queue addOperation:operation]; 
    [operation release]; 
} 

-(void)loadImage { 
     [myAp ImageForAp]; 

     NSLog(@"ImageFor Ap Ended, %@",myAp.ApDiagram); 

     [self.activity stopAnimating]; 

     if (myAp.ApDiagram==NULL) { 
      NSLog(@"Finally Gets Here"); 
      [self.Diagram removeFromSuperview]; 
     } 
     else { 
      NSLog(@"Finally Gets Here with Diag"); 
      [self.Diagram setBackgroundImage:myAp.ApDiagram forState:UIControlStateNormal]; 
     } 

    } 

所述的NSLog顯示之間的延遲約3秒前兩個日誌語句不明白爲什麼....

更新了我的最新的代碼......

-(void)loadImage { 

    [myAp ImageForAp]; 

    NSLog(@"ImageFor Ap Ended, %@",myAp.ApDiagram); 

    [self performSelectorOnMainThread:@selector(UpdateUI) withObject:nil waitUntilDone:NO]; 
} 

-(void)UpdateUI { 

    [self.activity stopAnimating]; 

    if (myAp.ApDiagram==NULL) { 
     NSLog(@"Finally Gets Here"); 
     [self.Diagram removeFromSuperview]; 
    } 
    else { 
     NSLog(@"Finally Gets Here with Diag"); 
     [self.Diagram setBackgroundImage:myAp.ApDiagram forState:UIControlStateNormal]; 
    } 
} 

Answer 1

確保loadImage方法正在運行主線程。所有UI操作都需要在主線程上按預期工作。您的代碼需要與此類似。

-(void)loadImage { 
    [myAp ImageForAp]; 
    [self performSelectorOnMainThread:@selector(UpdateUI) withObject:nil waitUntilDone:NO]; 
} 

-(void)UpdateUI { 
    [self.activity stopAnimating]; 

    if (myAp.ApDiagram==NULL) { 
     [self.Diagram removeFromSuperview]; 
    } 
    else { 
     [self.Diagram setBackgroundImage:myAp.ApDiagram forState:UIControlStateNormal]; 
    } 
} 

viewDidLoad中還有可能的內存泄漏。

self.queue = [NSOperationQueue new];應改爲

self.queue = [[[NSOperationQueue alloc] init] autorelease];