介绍两个Android不常用的Drawable：GradientDrawable和 StateListDrawable

//---------------------------------------------------------------------------------------------------------------------------------  
          /*--------------- normalDrawable begin ---------------*/
            GradientDrawable normalDrawable = new GradientDrawable();
            // 得到随机颜色
            Random random = new Random();
            int alpha = 255;
            int green = random.nextInt(190) + 30; // 30-220
            int red = random.nextInt(190) + 30;// 30-220
            int blue = random.nextInt(190) + 30;// 30-220
            int argb = Color.argb(alpha, red, green, blue);
            // 设置填充颜色
            normalDrawable.setColor(argb);

            // 设置圆角半径
            normalDrawable.setCornerRadius(UIUtils.dip2Px(6));
            /*--------------- normalDrawable end ---------------*/
//-----------------------------------------------------------------------------------------------------------------------------------------------
            /*--------------- pressedDrawable begin ---------------*/
            GradientDrawable pressedDrawable = new GradientDrawable();
            pressedDrawable.setColor(Color.DKGRAY);
            pressedDrawable.setCornerRadius(UIUtils.dip2Px(6));
            /*--------------- pressedDrawable end ---------------*/
//-------------------------------------------------------------------------------------------------------------------------------------------
            // 设置一个状态图片
            StateListDrawable stateListDrawable = new StateListDrawable();
            // @attr ref android.R.styleable#DrawableStates_state_pressed
            stateListDrawable.addState(new int[] { android.R.attr.state_pressed }, pressedDrawable);
            stateListDrawable.addState(new int[] {}, normalDrawable);

需求说明：这两个类GradientDrawable和StateListDrawable；

GradientDrawable：可以自定义颜色，圆角。

StateListDrawable：就是一个状态选择器。