2016.04.19 添加在上面在下面

[self.view bringSubviewToFront:pickview]; 

- (void)removeFromSuperview;

- (void)insertSubview:(UIView *)view atIndex:(NSInteger)index;

- (void)exchangeSubviewAtIndex:(NSInteger)index1 withSubviewAtIndex:(NSInteger)index2;

 

- (void)addSubview:(UIView *)view;

- (void)insertSubview:(UIView *)view belowSubview:(UIView *)siblingSubview;

- (void)insertSubview:(UIView *)view aboveSubview:(UIView *)siblingSubview;

 

- (void)bringSubviewToFront:(UIView *)view;

- (void)sendSubviewToBack:(UIView *)view;

 

- (void)didAddSubview:(UIView *)subview;

- (void)willRemoveSubview:(UIView *)subview;

 

- (void)willMoveToSuperview:(nullable UIView *)newSuperview;

- (void)didMoveToSuperview;

- (void)willMoveToWindow:(nullable UIWindow *)newWindow;

- (void)didMoveToWindow;

 

- (BOOL)isDescendantOfView:(UIView *)view;  // returns YES for self.

- (nullable __kindof UIView *)viewWithTag:(NSInteger)tag; // recursive search. includes self

 

// Allows you to perform layout before the drawing cycle happens. -layoutIfNeeded forces layout early

- (void)setNeedsLayout;

- (void)layoutIfNeeded;

 

- (void)layoutSubviews