iOS-UI控件之UIButton

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UIButton

• 既可以显示图片，又可以显示文字，还能随时调整内部位置
• 系统自带尺寸

storyboard内部调整UIButton属性

状态

监听按钮点击事件

• 凡是继承自UIControl的控件，都可以通过addTarget:...方法来监听事件

  addTarget:(id) action:(SEL) forControlEvents:(UIControlEvents) 

//UIControlEvents 的取值 typedef NS_OPTIONS(NSUInteger, UIControlEvents) { UIControlEventTouchDown = 1 << 0, // on all touch downs UIControlEventTouchDownRepeat = 1 << 1, // on multiple touchdowns (tap count > 1) UIControlEventTouchDragInside = 1 << 2, UIControlEventTouchDragOutside = 1 << 3, UIControlEventTouchDragEnter = 1 << 4, UIControlEventTouchDragExit = 1 << 5, UIControlEventTouchUpInside = 1 << 6, UIControlEventTouchUpOutside = 1 << 7, UIControlEventTouchCancel = 1 << 8, UIControlEventValueChanged = 1 << 12, // sliders, etc. UIControlEventEditingDidBegin = 1 << 16, // UITextField UIControlEventEditingChanged = 1 << 17, UIControlEventEditingDidEnd = 1 << 18, UIControlEventEditingDidEndOnExit = 1 << 19, // 'return key' ending editing UIControlEventAllTouchEvents = 0x00000FFF, // for touch events UIControlEventAllEditingEvents = 0x000F0000, // for UITextField UIControlEventApplicationReserved = 0x0F000000, // range available for application use UIControlEventSystemReserved = 0xF0000000, // range reserved for internal framework use UIControlEventAllEvents = 0xFFFFFFFF }; 

设置button内部文字和图片的方法

- (void)setTitle:(NSString *)title forState:(UIControlState)state; - (void)setTitleColor:(UIColor *)color forState:(UIControlState)state UI_APPEARANCE_SELECTOR; - (void)setImage:(UIImage *)image forState:(UIControlState)state; - (void)setBackgroundImage:(UIImage *)image forState:(UIControlState)state UI_APPEARANCE_SELECTOR; 

自定义UIButton

UIButton内部有两个子控件 UILabel和UIImageView

调整控件内部子控件的frame（两种方式）

• 实现 titleRectForContentRect 和 imageRectForContentRect方法分别返回子控件的 frame

- (CGRect)titleRectForContentRect:(CGRect)contentRect; - (CGRect)imageRectForContentRect:(CGRect)contentRect; 

• 在另一方法中设置子控件的frame

/** * 当前控件的frame发生改变的时候就会调用 * 这个方法专门用来布局子控件，设置子控件的frame */ - (void)layoutSubviews; 

内边距

// 设置按钮内容的内边距（影响到imageView和titleLabel） @property(nonatomic) UIEdgeInsets contentEdgeInsets; // 设置titleLabel的内边距（影响到titleLabel） @property(nonatomic) UIEdgeInsets titleEdgeInsets; // 设置imageView的内边距（影响到imageView） @property(nonatomic) UIEdgeInsets imageEdgeInsets; 

图片拉伸

• UIButton 图片的拉伸，大小改变

• iOS5之前

// 只拉伸中间的1x1区域 //传入左上的距离的区域 - (UIImage *)stretchableImageWithLeftCapWidth:(NSInteger)leftCapWidth topCapHeight:(NSInteger)topCapHeight; 

• iOS5开始

//传入左上右下不拉伸的区域，默认方式是平铺 - (UIImage *)resizableImageWithCapInsets:(UIEdgeInsets)capInsets; //resizingMode 拉伸方式的参数 - (UIImage *)resizableImageWithCapInsets:(UIEdgeInsets)capInsets resizingMode:(UIImageResizingMode)resizingMode; 

• 另一种改变图片拉伸方式
  • 在Images.xcassets中选择图片
  • 在slicing属性中选择拉伸范围 
  • 自动计算拉伸范围
  •