[UIApplication sharedApplication].keyWindow和[UIApplication sharedApplication].delegate.window

突然遇到了一个小问题 ， 然后发现了这俩的区别：
[UIApplication sharedApplication].keyWindow 一般可以获取到你想要的window 但是如果有键盘或者AlertView 出现的时候 window就被这两个所掌控了，接下咱们直接 看代码的打印

- (void)viewDidLoad {    [super viewDidLoad];    NSLog(@"keyWindow --------> %@",[UIApplication sharedApplication].keyWindow.rootViewController);    NSLog(@"delegate.window --> %@",[UIApplication sharedApplication].delegate.window.rootViewController);    NSLog(@"self.view.window -> %@\n \n",self.view.window.rootViewController);}- (void)viewDidAppear:(BOOL)animated {    [super viewDidAppear:animated];    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"title" message:@"message" delegate:self cancelButtonTitle:@"cancel" otherButtonTitles:nil];    [alert show];    NSLog(@"keyWindow --------> %@",[UIApplication sharedApplication].keyWindow.rootViewController);    NSLog(@"delegate.window --> %@",[UIApplication sharedApplication].delegate.window.rootViewController);    NSLog(@"self.view.window -> %@",self.view.window.rootViewController);}

看到 打印我们能看出来 不同之处了。