1、简单介绍UIButton
UIButton是继承于UIControl(UIControl继承于UIView)，UIButton具有点击功能，可以绑定事件。UIButton既能显示文字，又能显示图片，还能随时调整内部文字和图片的位置。
2、UIButton使用及常用属性
- (UIButton *)textButton
{
if (!_textButton) {
//1、初始化button
_textButton = [UIButton buttonWithType:UIButtonTypeCustom];
//2、设置frame
_textButton.frame = CGRectMake(100, 100, 200, 50);
//3、设置背景颜色
_textButton.backgroundColor = [UIColor blueColor];
//4、设置title
_textButton.titleLabel.font = [UIFont systemFontOfSize:14];
[_textButton setTitle:@"正常状态下的title" forState:UIControlStateNormal];
[_textButton setTitleColor:[UIColor greenColor] forState:UIControlStateNormal];
[_textButton setTitle:@"选中状态下的title" forState:UIControlStateSelected];
[_textButton setTitleColor:[UIColor redColor] forState:UIControlStateSelected];
//5、设置Image
[_textButton setImage:[UIImage imageNamed:@"Image-1"] forState:UIControlStateNormal];
[_textButton setImage:[UIImage imageNamed:@"Image-2"] forState:UIControlStateSelected];
//6、添加事件
[_textButton addTarget:self action:@selector(textButtonClick:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:_textButton];
}
return _textButton;
}
//常用属性
@property(nonatomic,readonly) UIButtonType buttonType; //按钮形状类型
@property(nullable, nonatomic,readonly,strong) NSString *currentTitle;
@property(nonatomic,readonly,strong) UIColor *currentTitleColor;
@property(nullable, nonatomic,readonly,strong) UIColor *currentTitleShadowColor;
@property(nullable, nonatomic,readonly,strong) UIImage *currentImage;
@property(nullable, nonatomic,readonly,strong) UIImage *currentBackgroundImage;
@property(nullable, nonatomic,readonly,strong) NSAttributedString *currentAttributedTitle ;
@property(nullable, nonatomic,readonly,strong) UILabel *titleLabel;
@property(nullable, nonatomic,readonly,strong) UIImageView *imageView ;
@property(nonatomic,readonly) UIControlState //按钮状态类型
/*
UIControlStateNormal = 0, 常规状态显现
UIControlStateHighlighted = 1 << 0, 高亮状态显现
UIControlStateDisabled = 1 << 1, 禁用的状态才会显现
UIControlStateSelected = 1 << 2, 选中状态
UIControlStateApplication = 0x00FF0000, 当应用程序标志时
UIControlStateReserved = 0xFF000000 为内部框架预留，可以不管他
*/
//特殊属性
@property(nonatomic) UIEdgeInsets titleEdgeInsets; //设置标题的边缘值
@property(nonatomic) UIEdgeInsets imageEdgeInsets; //设置图片的边缘值
@property(nonatomic) BOOL reversesTitleShadowWhenHighlighted; // 点击按钮是否使其发光
@property(nonatomic) BOOL adjustsImageWhenHighlighted;// 高亮时是否显示图像的变化。
@property(nonatomic) BOOL adjustsImageWhenDisabled; //禁用时是否显示图像的变化
@property(nonatomic) BOOL showsTouchWhenHighlighted; //点击按钮时是否发光
@property(nonatomic) UIControlContentVerticalAlignment contentVerticalAlignment; //按钮垂直放置方式
@property(nonatomic) UIControlContentHorizontalAlignment contentHorizontalAlignment; //按钮水平放置方式
3、UIButton内部文字和图片的位置调整
self.textButton.imageEdgeInsets = UIEdgeInsetsMake(0, 10, 0, 0);
self.textButton.titleEdgeInsets = UIEdgeInsetsMake(0, 20, 0, 0);
4、自定义Button内部文字和图片的位置调整
//重写下面方法 内部布局
- (CGRect)backgroundRectForBounds:(CGRect)bounds;
- (CGRect)contentRectForBounds:(CGRect)bounds;
- (CGRect)titleRectForContentRect:(CGRect)contentRect;
- (CGRect)imageRectForContentRect:(CGRect)contentRect;
