我在 UIViews 和手动内存管理方面遇到了一个奇怪的问题。
我有一个 View (contentView)，它是 View Controller 的主视图。
在 contentView 上长按后，另一个 View 应该淡入(在它的顶部)。
当手势结束时，附加 View 淡出。
问题是:
当 contentView 收到长按时，我创建辅助 View ，将其添加到 contentView，然后释放它，这是/以前的常见做法在 ARC 之前的日子里。
它在 iPhone 上运行正常，但在 iPad 上崩溃了!
崩溃的行是:
[ZPNowPlayingItemInfoView dealloc]
...当我从 contentView 中删除辅助 View 时触发。
关于为什么会发生这种情况的任何线索？
如果我注释掉 release 行(请参阅我在代码中的注释)，它在两种设备上都能完美运行，但感觉很糟糕。
代码如下:
-(void)longPressDetected:(UILongPressGestureRecognizer*)longPressGR
{
//Content view of the view controller I'm in
UIView *contentView = MSHookIvar<UIView*>(self, "_contentView");
if (longPressGR.state == UIGestureRecognizerStateBegan) {
id item = MSHookIvar<MPAVItem*>(self, "_item");
ZPNowPlayingItemInfoView *infoView =
[[ZPNowPlayingItemInfoView alloc] initWithFrame:
CGRectMake(0,0,contentView.frame.size.width,contentView.frame.size.height)
item:item];
//infoView retain count: 1
[infoView setAlpha:0.f];
[contentView addSubview:infoView];
//infoView retain count: 3 (???)
//iPad goes berserk on this line
//Commented - Works both on iPhone and iPad
//Uncommented - Works only on iPhone
//[infoView release];
//infoView retain count: 2 (if release is uncommented)
[UIView animateWithDuration:0.35f animations:^{
[infoView setAlpha:1.0f];
} completion:^(BOOL finished) {
//infoView retain count: 3
}];
} else if (longPressGR.state == UIGestureRecognizerStateEnded) {
ZPNowPlayingItemInfoView* infoView = nil;
for (UIView *subview in contentView.subviews) {
if ([subview isKindOfClass:[ZPNowPlayingItemInfoView class]]) {
infoView = (ZPNowPlayingItemInfoView*)subview;
break;
}
}
[UIView animateWithDuration:0.35f animations:^{
[infoView setAlpha:0.f];
} completion: ^(BOOL finished){
[infoView removeFromSuperview];
}];
}
附言我需要使用手动内存管理。这是对越狱设备的调整。
堆栈跟踪:
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0 libobjc.A.dylib 0x195287bdc 0x19526c000 + 0x1bbdc // objc_msgSend + 0x1c
1 + Musix.dylib 0x10015b19c 0x100154000 + 0x719c // -[ZPNowPlayingItemInfoView dealloc] + 0x48
2 libsystem_blocks.dylib 0x19590d90c 0x19590c000 + 0x190c // _Block_release + 0xfc
3 UIKit 0x188ef8590 0x188eb0000 + 0x48590 // -[UIViewAnimationBlockDelegate dealloc] + 0x44
4 CoreFoundation 0x1845f1374 0x1845ec000 + 0x5374 // CFRelease + 0x208
5 CoreFoundation 0x184601004 0x1845ec000 + 0x15004 // -[__NSDictionaryI dealloc] + 0x8c
6 libobjc.A.dylib 0x19528d720 0x19526c000 + 0x21720 // (anonymous namespace)::AutoreleasePoolPage::pop(void*) + 0x230
7 CoreFoundation 0x1845f4f90 0x1845ec000 + 0x8f90 // _CFAutoreleasePoolPop + 0x18
8 CoreFoundation 0x1846c774c 0x1845ec000 + 0xdb74c // __CFRunLoopRun + 0x5d8
9 CoreFoundation 0x1845f51f0 0x1845ec000 + 0x91f0 // CFRunLoopRunSpecific + 0x188
10 GraphicsServices 0x18d7575a0 0x18d74c000 + 0xb5a0 // GSEventRunModal + 0xa4
11 UIKit 0x188f26780 0x188eb0000 + 0x76780 // UIApplicationMain + 0x5cc
12 Music (*) 0x10006ee28 0x100064000 + 0xae28 // 0x0000adac + 0x7c
13 libdyld.dylib 0x1958e2a04 0x1958e0000 + 0x2a04 // start + 0x0
ZPNowPlayingItemInfoView:
@interface ZPNowPlayingItemInfoView()
@property (nonatomic, retain) MPAVItem* item;
@property (nonatomic, retain) MPUSlantedTextPlaceholderArtworkView *artworkView;
@property (nonatomic, retain) UILabel *artistLabel;
@property (nonatomic, retain) UILabel *albumLabel;
@property (nonatomic, retain) UILabel *songLabel;
@end
ZPNowPlayingItemInfoView 释放:
-(void)dealloc
{
[super dealloc];
[self.item release];
[self.artworkView release];
[self.artistLabel release];
[self.songLabel release];
}
最佳答案
您在 ZPNowPlayingItemInfoView 类中遇到了一些问题。这个问题什么时候出现？仅当对象被释放时。当您注释掉 [infoView release] 时，您的对象永远不会被释放并且问题不会出现 - 但是您会发生内存泄漏。
检查 ZPNowPlayingItemInfoView 做了什么，尤其是它的 dealloc 方法。你确定你正在正确构建它吗？ item 是否始终是有效对象？
在看到ZPNowPlayingItemInfoView dealloc 方法后，问题就很清楚了——[super dealloc] 必须始终是最后一次调用，而不是第一次调用。释放对象后，访问其属性是未定义的操作。
关于ios - removeFromSuperview 导致崩溃(非 ARC)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/28399210/