Iphone停止ASIFormDataRequest

Question

我有一個問題，當我有一個掛起的ASIFormDataRequest（作爲異步任務啓動），仍在執行和用戶按下後退按鈕（爲了彈出視圖）我的viewController。

有什麼辦法可以阻止異步任務嗎？

我讀過這是一個名爲「clearDelegatesAndCancel」的方法，但我不知道它是我在找什麼。

感謝

Answer 1

事情是，打電話給clearDelegatesAndCancel，你必須有一個處理異步運行的ASIFromDataRequest對象。這意味着你應該將其設置爲一個屬性，就像...

@interface MyViewController : UIViewController <ASIHTTPRequestDelegate> 
{ 
    ASIFormDataRequest *theRequest 
    ... 
} 

@property (nonatomic, retain) ASIFormDataRequest *theRequest; 

然後在您的m，不申報新的請求對象，只是你formdatarequest定義的類的實例變量：

@synthesize theRequest; 

-(void)viewDidLoad //or whatever 
{ 
    self.theRequest = [ASIFormDataRequest requestWithUrl:myUrl]; 
    // then configure and fire the request, being sure to set .delegate to self 
} 

-(void)viewWillDisappear:(BOOL)animated //or whatever 
{ 
    [self.theRequest clearDelegatesAndCancel]; 
} 

-(void)dealloc 
{ 
    [theRequest release]; //don't not do this. 
} 

需要指出的是，您需要設置自己，以便在異步運行時請求與對話。

順便說一下，這是非常好的做法。如果你的viewcontroller在你的請求返回之前消失了（比如通過彈出UINavController棧），它會嘗試調用一個釋放對象上的委託方法，並繁榮。

Answer 2

從ASI文檔（http://allseeing-i.com/ASIHTTPRequest/How-to-use）

 
    To cancel an asynchronous request (either a request that was started with 
    [request startAsynchronous] or a request running in a queue you created), 
    call [request cancel]. Note that you cannot cancel a synchronous request. 

    Note that when you cancel a request, the request will treat that as an error, 
    and will call your delegate and/or queue’s failure delegate method. If you do 
    not want this behaviour, set your delegate to nil before calling cancel, or 
    use the clearDelegatesAndCancel method instead.