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
  •