运行时绑定属性的一个小分类，可以设定UIView子类两种状态的边框颜色，背景色，UIButton,UILabel的文字颜色
默认边框宽度1.0
self.button.normalBorderColor = [UIColor grayColor];
self.button.selectBorderColor = [UIColor blueColor];
self.button.normalTextColor = [UIColor lightGrayColor];
self.button.selectTextColor = [UIColor cyanColor];
self.button.normalBackColor = [UIColor whiteColor];
self.button.selectBackColor = [UIColor grayColor];
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(IBAction)onButtonClick:(UIButton *)sender {
sender.mixSelected = !sender.mixSelected; }