prefersStatusBarHidden
titleEdgeInsets
UIBarButtonItem appearanceWhenContainedIn:
UIBarButtonItem setTitleTextAttributes:<#(NSDictionary )#> forState:<#(UIControlState)#>
NSMutableAttributedString
uiview.contentmode=uiviewcontentmodecenter
nsclassformstring
layer.contentsGravity = kCAGravityBottom
[self performSelector:_cmd withObject:alayer afterDelay:0.1];(定时递归调用)
[[[UIApplication sharedApplication] keyWindow] endEditing:YES];UITapGestureRecognizer singleRecognizer;
singleRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:selfaction:@selector(SingleTap：)];
//点击的次数
singleTapRecognizer.numberOfTapsRequired = 1; // 单击
//给self.view添加一个手势监测；
[self.view addGestureRecognizer:singleRecognizer];
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
- (CGPoint)convertPoint:(CGPoint)point toView:(nullable UIView *)view;
- (CGPoint)convertPoint:(CGPoint)point fromView:(nullable UIView *)view;
- (CGRect)convertRect:(CGRect)rect toView:(nullable UIView *)view;
- (CGRect)convertRect:(CGRect)rect fromView:(nullable UIView *)view;
