介绍： 无需图片，自定义各种外观样式的按钮。包括加边框、渐变颜色、圆角、扁平化风格等等，也可以用图片填充按钮背景。支持Nib。-Descr iption: No pictures, customize various exterior style button. Including Canadian border, gradient colors, rounded, flat style, etc., can also be filled with a picture button backgr

不需要加载图片，只用代码实现按钮颜色的各种渐变效果。(You don't need to load the picture, and you use only code to implement various gradients of button colors.)