UIButton.h

//
//  UIButton.h
//  UIKit
//
//  Copyright (c) 2005-2013, Apple Inc. All rights reserved.
//

@class UIImage, UIFont, UIColor, UIImageView, UILabel;

typedef NS_ENUM(NSInteger, UIButtonType) {
    UIButtonTypeCustom = 0,                         // 无样式，用户调整
    UIButtonTypeSystem NS_ENUM_AVAILABLE_IOS(7_0),  // 系统标准样式

    UIButtonTypeDetailDisclosure, // 圈圈 i 样式
    UIButtonTypeInfoLight,        // 圈圈 i 样式
    UIButtonTypeInfoDark,         // 圈圈 i 样式
    UIButtonTypeContactAdd,       // 圈圈 + 样式
    
    UIButtonTypeRoundedRect = UIButtonTypeSystem,   // 淘汰，用 UIButtonTypeSystem 替代
};

NS_CLASS_AVAILABLE_IOS(2_0) @interface UIButton : UIControl <NSCoding> {
  @private // 私有的
    CFMutableDictionaryRef _contentLookup;
    UIEdgeInsets           _contentEdgeInsets;  // 内容的内边距
    UIEdgeInsets           _titleEdgeInsets;    // 标题的内边距
    UIEdgeInsets           _imageEdgeInsets;    // 图片的内边距
    
    UIImageView           *_backgroundView;      // 内部的背景图片控件
    UIImageView           *_imageView;           // 内部的图片控件
    UILabel               *_titleView;           // 内部的标题
    
    BOOL                   _initialized;
    UIControlState         _lastDrawingControlState;
    struct {
        unsigned int reversesTitleShadowWhenHighlighted:1;
        unsigned int adjustsImageWhenHighlighted:1;
        unsigned int adjustsImageWhenDisabled:1;
        unsigned int autosizeToFit:1;
        unsigned int disabledDimsImage:1;
        unsigned int showsTouchWhenHighlighted:1;
        unsigned int buttonType:8;
        unsigned int shouldHandleScrollerMouseEvent:1;
        unsigned int titleFrozen:1;
    } _buttonFlags;
}

+ (id)buttonWithType:(UIButtonType)buttonType;

@property(nonatomic)          UIEdgeInsets contentEdgeInsets UI_APPEARANCE_SELECTOR; // 内容缩进
@property(nonatomic)          UIEdgeInsets titleEdgeInsets;                // 文字标题缩进
@property(nonatomic)          BOOL         reversesTitleShadowWhenHighlighted; // 默认 NO. 高亮时，阴影反转
@property(nonatomic)          UIEdgeInsets imageEdgeInsets;                // 图片缩进

@property(nonatomic)          BOOL         adjustsImageWhenHighlighted;    // default is YES. if YES, image is drawn darker when highlighted(pressed)
@property(nonatomic)          BOOL         adjustsImageWhenDisabled;       // default is YES. if YES, image is drawn lighter when disabled
@property(nonatomic)          BOOL         showsTouchWhenHighlighted;      // 点击时按钮中间现实白色的高亮
@property(nonatomic,retain)   UIColor     *tintColor NS_AVAILABLE_IOS(5_0); // The tintColor is inherited through the superview hierarchy. See UIView for more information.
@property(nonatomic,readonly) UIButtonType buttonType;

# 设置内部子控件的属性
- (void)setTitle:(NSString *)title forState:(UIControlState)state; # 字体
- (void)setTitleColor:(UIColor *)color forState:(UIControlState)state UI_APPEARANCE_SELECTOR; #字体颜色
- (void)setTitleShadowColor:(UIColor *)color forState:(UIControlState)state UI_APPEARANCE_SELECTOR; # 阴影
- (void)setImage:(UIImage *)image forState:(UIControlState)state;
- (void)setBackgroundImage:(UIImage *)image forState:(UIControlState)state UI_APPEARANCE_SELECTOR;
- (void)setAttributedTitle:(NSAttributedString *)title forState:(UIControlState)state NS_AVAILABLE_IOS(6_0);

# 这些 getters 方法只返回一种状态的值
- (NSString *)titleForState:(UIControlState)state;
- (UIColor *)titleColorForState:(UIControlState)state;
- (UIColor *)titleShadowColorForState:(UIControlState)state;
- (UIImage *)imageForState:(UIControlState)state;
- (UIImage *)backgroundImageForState:(UIControlState)state;
- (NSAttributedString *)attributedTitleForState:(UIControlState)state NS_AVAILABLE_IOS(6_0);

# 当按钮的状态改变时，这些值会自动改变，只有get方法，只读的
@property(nonatomic,readonly,retain) NSString *currentTitle;             // 可以为空
@property(nonatomic,readonly,retain) UIColor  *currentTitleColor;        // 默认是white(1,1) ，不能为空
@property(nonatomic,readonly,retain) UIColor  *currentTitleShadowColor;  // default is white(0,0.5).
@property(nonatomic,readonly,retain) UIImage  *currentImage;             // 可以为空
@property(nonatomic,readonly,retain) UIImage  *currentBackgroundImage;   // 可以为空
@property(nonatomic,readonly,retain) NSAttributedString *currentAttributedTitle NS_AVAILABLE_IOS(6_0); # 可以为空

# return title and image views. will always create them if necessary. always returns nil for system buttons
@property(nonatomic,readonly,retain) UILabel     *titleLabel NS_AVAILABLE_IOS(3_0);
@property(nonatomic,readonly,retain) UIImageView *imageView  NS_AVAILABLE_IOS(3_0);


#pragma - mark 自定义按钮，重写这些方法调整按钮内部子控件的尺寸
- (CGRect)backgroundRectForBounds:(CGRect)bounds;
- (CGRect)contentRectForBounds:(CGRect)bounds;
- (CGRect)titleRectForContentRect:(CGRect)contentRect;
- (CGRect)imageRectForContentRect:(CGRect)contentRect;

@end

# 已经失效
@interface UIButton(UIButtonDeprecated)

@property(nonatomic,retain) UIFont         *font              NS_DEPRECATED_IOS(2_0, 3_0); // 字体
@property(nonatomic)        NSLineBreakMode lineBreakMode     NS_DEPRECATED_IOS(2_0, 3_0); //
@property(nonatomic)        CGSize          titleShadowOffset NS_DEPRECATED_IOS(2_0, 3_0);

@end