我觉得UIView.window返回的是当前view所在的那个window，未必是keywindow

self.view.window 只是当前view的window,可能是keywindow
@property(nonatomic, readonly) UIWindow *window
Description	
The receiver’s window object, or nil if it has none. (read-only)
This property is nil if the view has not yet been added to a window.

[[UIApplication sharedApplication] keyWindow]
@property(nonatomic, readonly) UIWindow *keyWindow
This property holds the UIWindow object in the windows array that is most recently sent the makeKeyAndVisible message.

[[UIApplication sharedApplication] windows]
@property(nonatomic, readonly) NSArray *windows
This property returns an array of the application's visible and hidden windows. The windows are ordered back to front.

万一view是键盘上的某一块，view.window就是键盘的window。

不一定是。

可通过view.window.keyWindow判断。