ios - 为什么 retainCount = 2 - 发布后？

Question

我使用这个代码。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.

    view = [[UIView alloc] init];

    [_window addSubview:view];

    [view release];

    NSLog(@"count - %d", [view retainCount]);

    [self.window makeKeyAndVisible];

    return YES;

}


- (IBAction)click{

    NSLog(@"count - %d", [view retainCount]); 

}

当我点击 uibutton - 我的 View 保留计数 = 2。为什么会这样？

Answer 1

请不要依赖于 retainCount。启动仪器，看看是否有泄漏。 Apple 不鼓励将 retainCount 用于调试目的:

Important: This method is typically of no value in debugging memory management issues. Because any number of framework objects may have retained an object in order to hold references to it, while at the same time autorelease pools may be holding any number of deferred releases on an object, it is very unlikely that you can get useful information from this method.

看看 NSObjectProtocol and the retainCount文档。阅读 Memory Management Programming Guide以便更深入地了解保留计数。