detachNewThreadSelector隨機崩潰應用程序

Question

我正在開發一個iphone應用程序，我在其中提取RSS提要然后解析它們。我的代碼如下：

 - (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
    NSLog(@"in view did appear");

    if ([stories count] == 0) {
        NSString * path = @"http://www.shire.com/shireplc/rss.jsp";

        //[self parseXMLFileAtURL:path];
        //[self performSelectorInBackground:@selector(parseXMLFileAtURL:) withObject:path];
        NSLog(@"internet is %d",[self checkInternet]);
        if([self checkInternet]==1)
        [NSThread detachNewThreadSelector:@selector(parseXMLFileAtURL:) 
                              toTarget:self withObject:path];

}
}

 - (void)parseXMLFileAtURL:(NSString *)URL
  { 
  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
  stories = [[NSMutableArray alloc] init];

  //you must then convert the path to a proper NSURL or it won't work
  NSURL *xmlURL = [NSURL URLWithString:URL];

  // here, for some reason you have to use NSClassFromString when trying to alloc NSXMLParser, otherwise you will get an object not found error
  // this may be necessary only for the toolchain
  rssParser = [[NSXMLParser alloc] initWithContentsOfURL:xmlURL];

  // Set self as the delegate of the parser so that it will receive the parser delegate methods callbacks.
[rssParser setDelegate:self];

// Depending on the XML document you're parsing, you may want to enable these features of NSXMLParser.
[rssParser setShouldProcessNamespaces:NO];
[rssParser setShouldReportNamespacePrefixes:NO];
[rssParser setShouldResolveExternalEntities:NO];

[rssParser parse];

 [pool release];

}

誰能告訴我哪里出錯了？ 我的日志如下：log：[切換到線程12803] [切換到線程12035] 2011-05-10 11：31：30。9。9年度報告[454：490b]找到文件並開始解析[切換到線程14339] 2011- 05-10 11：32：04。73年度報告[454：640b]找到文件並開始解析[切換到線程13827] [切換到線程13827]程序接收信號：“EXC_BAD_ACCESS”。

gdb stack trace at 'putpkt: write failed':
0   gdb-arm-apple-darwin                0x0019026b remote_backtrace_self + 54

Answer 1

//您可以使用該方法，如果您不必更新UserInterface，則更安全

 [self performSelectorInBackground:@selector(parseXMLFileAtURL:) withObject:path];

如果UserInterface也需要更新，你可以先在后台解析數據，然后用方法更新ui。

[self performSelectorOnMainThread:@selector(myUpdateUI) withObject:nil waitUntilDone:YES];

Answer 2

我不確定，但我猜這個方法的參數在某些時候被釋放。 您能否確保該方法parseXMLFileAtURL存在該URL

Answer 3

最后，我使用一個標志來檢查視圖是否出現（通過在viewdidAppear中使標志為true）並且如果視圖沒有出現，則不要運行線程函數。這解決了問題！