@Override
    public void setColorFilter(ColorFilter cf) {
        mPaint.setColorFilter(cf);
    }
Subclasses should implement this method to do the actual drawing

@param canvas The current {@link Canvas} to draw into
@param paint  The {@link Paint} preconfigurred with the current
              {@link ColorStateList} color
app/src/main/java/com/duan/musicoco/view/discreteseekbar/internal/drawable/StateDrawable.java