Question

我有一个UIView，当我初始化它已经保留计数2，我不明白为什么，因此我无法删除它与removefromsuperview

ViewController.h

  @property (nonatomic, retain)FinalAlgView * drawView;

ViewController.m

  self.drawView =[[FinalAlgView alloc]init];

 NSLog(@"the retain count 1 of drawView is %d", [self.drawView retainCount]);
 //the retain count 1 of drawView is 2

 [self.bookReader addSubview:self.drawView];

 NSLog(@"the retain count 2 of drawView is %d", [self.drawView retainCount]);
 //the retain count 2 of drawView is 3

 [self.drawView release];

 NSLog(@"the retain count 3 of drawView is %d", [self.drawView retainCount]);
 //the retain count 3 of drawView is 2

 [UIView animateWithDuration:0.2
                 animations:^{self.drawView.alpha = 0.0;}
                 completion:^(BOOL finished){ [self.drawView removeFromSuperview];
                 }]; 
 //do not remove

我不使用ARC

Answer 1

你不能指望retainCount你会得到令人困惑的结果，最好不要使用它。

来自Apple：

...您不太可能从此方法中获得有用的信息。

Answer 2

正如null所说，你不能依赖retainCount。假设您正在使用ARC，您的代码实际上正在编译为：

FinalAlgView *dv = [[FinalAlgView alloc] init]; // Starts with retainCount of 1
self.drawView = dv; // Increments the retainCount

 NSLog(@"the retain count 1 of drawView is %d", [self.drawView retainCount]);
 //the retain count 1 of drawView is 2

...
// do not remove
...
[dv release];

如果您不使用ARC，则需要将第一行代码更改为：

self.drawView =[[[FinalAlgView alloc]init]autorelease];

retainCount仍将从2开始，直到自动释放池在runloop结束时耗尽。

保留计数并删除SuperSuperview

2 个答案: