@Override
    protected void drawForeground(Canvas canvas, Paint foregroundPaint) {
        canvas.drawLine(mForegroundLeft, mCenterY, mForegroundRight, mCenterY, foregroundPaint);
    }
A drawable to draw loading form Line Type
caprice/ui/src/main/java/net/qiujuer/genius/ui/drawable/LoadingLineDrawable.java