在Objective-C

Question

提取从self.window视图在我：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions: 

我设置以下scrollView：

UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:screenRect]; 
[self.window addSubview:scrollView]; 

在以后的方法，我怎么会那么毁了这个观点，也就是从self.window中删除它。

Answer 1

通常我不会在application:didFinishLaunchingWithOptions:中添加scrollView。相反，请在视图控制器中创建UIScrollView，或者在viewDidLoad方法中或在故事板中创建UIScrollView。

无论哪种方式，删除scrollView将看起来像这样。首先创建一个属性来存储参考UIScrollView：

@property (nonatomic, weak) UIScrollView *scrollView; // Use a weak reference to the scrollview, that way once its removed from the superview (which keeps a strong reference to its subviews), the scrollview will be deallocated. 

然后初始化属性，并将其添加为子视图：

self.scrollView = [[UIScrollView alloc] initWithFrame:screenRect]; 
[self.window addSubview:scrollView]; 

之后，你可以将其删除：

[self.scrollView removeFromSuperview];