我有一个主UIViewcontroller
(vcMain),其中有两个UIViewControllers
子类。子类UIViewcontrollers
(vcSub1 / vcSub2)只显示图像和更多控件。 vcSub1和vcSub2显示在UITabBarController
中。
我已经像这样实施了didReceiveMemoryWarning
:
vcMain:
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
if ([self isViewLoaded] == NO) {
// release the model, will be recreated in viewDidLoad
[_brain release], self.brain = nil;
}
}
vcSub1:
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
if ([self isViewLoaded] == NO) {
// will be recreated in viewDidLoad, only exists in vcSub1
[self.zoomBrain release], [self setZoomBrain:nil];
_button = nil; // autoreleased, created programmatically
}
}
vcSub2:
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
if ([self isViewLoaded] == NO) {
// nothing in here (yet)
}
}
当我第一次模拟内存警告时,一切似乎都能正常工作。
Received simulated memory warning.
-[AppDelegate applicationDidReceiveMemoryWarning:] [Line 81]
-[vcSub2 didReceiveMemoryWarning] [Line 102]
-[vcMain didReceiveMemoryWarning] [Line 73]
-[vcSub2 viewDidUnload] [Line 112]
-[vcMain viewDidUnload] [Line 65]
-[vcSub1 didReceiveMemoryWarning] [Line 150]
-[vcMain didReceiveMemoryWarning] [Line 73]
-[vcSub1 viewDidUnload] [Line 143]
-[vcMain viewDidUnload] [Line 65]
我可以一次又一次地做到这一点而没有问题。但是,如果我切换标签(从而重新加载视图)并再次模拟内存警告,我会得到这个:
Received simulated memory warning.
-[AppDelegate applicationDidReceiveMemoryWarning:] [Line 81]
-[vcSub2 didReceiveMemoryWarning] [Line 102]
-[vcMain didReceiveMemoryWarning] [Line 73]
-[vcSub1 didReceiveMemoryWarning] [Line 150]
-[vcMain didReceiveMemoryWarning] [Line 73]
-[vcSub1 viewDidUnload] [Line 143]
-[vcMain viewDidUnload] [Line 65]
*** -[vcSub1 isViewLoaded]: message sent to deallocated instance 0x614de80
info malloc-history 0x614de80
显示该实例是vcSub1 viewcontroller。
Alloc: Block address: 0x0614de80 length: 192
Stack - pthread: 0xa0425540 number of frames: 21
0: 0x93f7f0a3 in malloc_zone_calloc
1: 0x93f7effa in calloc
2: 0x154a2d4 in class_createInstance
3: 0x13165d8 in +[NSObject(NSObject) allocWithZone:]
4: 0x13163da in +[NSObject(NSObject) alloc]
5: 0x2bf0 in -[AppDelegate application:didFinishLaunchingWithOptions:] at AppDelegate.m:47
6: 0x8dec89 in -[UIApplication _callInitializationDelegatesForURL:payload:suspended:]
7: 0x8e0d88 in -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:]
8: 0x8eb617 in -[UIApplication handleEvent:withNewEvent:]
9: 0x8e3abf in -[UIApplication sendEvent:]
10: 0x8e8f2e in _UIApplicationHandleEvent
11: 0x30b9992 in PurpleEventCallback
12: 0x13d3944 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__
13: 0x1333cf7 in __CFRunLoopDoSource1
14: 0x1330f83 in __CFRunLoopRun
15: 0x1330840 in CFRunLoopRunSpecific
16: 0x1330761 in CFRunLoopRunInMode
17: 0x8e07d2 in -[UIApplication _run]
18: 0x8ecc93 in UIApplicationMain
19: 0x28f9 in main at main.m:14
20: 0x2875 in start
为什么和 是如何取消分配我的vcSub1 viewcontroller?
答案 0 :(得分:1)
我认为你发布的对象太多次了。假设你的财产是(保留)那么你在这里有一个错误:
[self.zoomBrain release]
[self setZoomBrain:nil];
第一行将释放zoomBrain。
第二行将释放zoomBrain ,然后将其设置为nil。
你要发布两次 - 你只需要第二行。如果您使用setter方法(即setZoomBrain :),它会自动为您释放以前的zoomBrain。
同样如此:
[_brain release];
self.brain = nil;
对self.brain
的调用是另一种写[self setBrain:nil];
的方式 - 再次,释放将被调用两次。
在每种情况下你只需要第二行:
self.brain = nil;