xcode IOS 5 消息通过 alloc 命令发送到解除分配的实例
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IOS 5 message sent to deallocated instance on alloc command
提问by Patrik
I have the following error on a Ios 5 application using ARC:
我在使用 ARC 的 Ios 5 应用程序上出现以下错误：
*** -[ViewDettaglio respondsToSelector:]: message sent to deallocated instance 0x12193300
on console i write command:
在控制台上我写命令：
info malloc-history 0x12193300
and i get the following stack-trace:
我得到以下堆栈跟踪：
Alloc: Block address: 0x12193300 length: 192
Stack - pthread: 0xa08a3540 number of frames: 31
0: 0x96bdab03 in malloc_zone_calloc
1: 0x96bdaa5a in calloc
2: 0x16f8c93 in class_createInstance
3: 0x170388b in _objc_rootAllocWithZone
4: 0x21af661 in +[NSObject allocWithZone:]
5: 0x17038b9 in _objc_rootAlloc
6: 0x2c4c8 in -[ViewElenco CaricaViewDettaglio:] at /Users/.../ViewElenco.m:186
7: 0x2e550 in -[ViewElenco mapView:annotationView:calloutAccessoryControlTapped:] at /Users/.../ViewElenco.m:337
8: 0x3fa99c
9: 0x405faa in MKLongHash
10: 0x21aeec9 in -[NSObject performSelector:withObject:withObject:]
11: 0x60d5c2 in -[UIApplication sendAction:to:from:forEvent:]
12: 0x60d55a in -[UIApplication sendAction:toTarget:fromSender:forEvent:]
13: 0x6b2b76 in -[UIControl sendAction:to:forEvent:]
14: 0x6b303f in -[UIControl(Internal) _sendActionsForEvents:withEvent:]
15: 0x6b22fe in -[UIControl touchesEnded:withEvent:]
16: 0x632a30 in -[UIWindow _sendTouchesForEvent:]
17: 0x632c56 in -[UIWindow sendEvent:]
18: 0x619384 in -[UIApplication sendEvent:]
19: 0x60caa9 in _UIApplicationHandleEvent
20: 0x1a95fa9 in PurpleEventCallback
21: 0x21811c5 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__
22: 0x20e6022 in __CFRunLoopDoSource1
23: 0x20e490a in __CFRunLoopRun
24: 0x20e3db4 in CFRunLoopRunSpecific
25: 0x20e3ccb in CFRunLoopRunInMode
26: 0x1a94879 in GSEventRunModal
27: 0x1a9493e in GSEventRun
28: 0x60aa9b in UIApplicationMain
29: 0x20bb in main at /Users/.../main.m:14
30: 0x2065 in start
The code at line 186 of ViewElenco.m is the following:
ViewElenco.m 第 186 行的代码如下：
ViewDettaglio *viewq=[[ViewDettaglio alloc] initWithNibName:@"ViewDettaglio" bundle:nil];
How can this happen? I'm using a UINavigationController to navigate from ViewElenco and ViewDettaglio.
这怎么会发生？我正在使用 UINavigationController 从 ViewElenco 和 ViewDettaglio 进行导航。
EDIT
编辑
Is it possibile that in the following code:
是否有可能在以下代码中：
ViewDettaglio* viewDettaglio=[[ViewDettaglio alloc] initWithNibName:@"ViewDettaglio" bundle:nil];
viewDettaglio.idObject=idObj;
[self.navigationController pushViewController:viewDettaglio animated:YES];
alloc returns a deallocated object?
alloc 返回一个释放的对象？
回答by Patrik
The problem has been solved: in ViewDettaglio and ViewElenco there was a MKMapView, and the delegate was set to the container ViewController. When pushing a new ViewController in the UINavigationController, probably some thread created by MapView was still running and calling map delegate, even if it was not visible.
问题已经解决了：在ViewDettaglio和ViewElenco中有一个MKMapView，并且委托被设置到了容器ViewController。在 UINavigationController 中推送新的 ViewController 时，可能某些由 MapView 创建的线程仍在运行并调用地图委托，即使它不可见。
The solution was to set delegate to null when view will disapper, and set it again before view will appear:
解决方案是在视图消失时将委托设置为空，并在视图出现之前再次设置它：
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
self.mapView.delegate=nil;
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
self.mapView.delegate=self;
}
