SetupStartIndicatorView.java 文件源码

@Override
protected void onDraw(final Canvas canvas) {
    super.onDraw(canvas);
    final int layoutDirection = ViewCompat.getLayoutDirection(this);
    final int width = getWidth();
    final int height = getHeight();
    final float halfHeight = height / 2.0f;
    final Path path = mIndicatorPath;
    path.rewind();
    if (layoutDirection == ViewCompat.LAYOUT_DIRECTION_RTL) {
        // Left arrow
        path.moveTo(width, 0.0f);
        path.lineTo(0.0f, halfHeight);
        path.lineTo(width, height);
    } else { // LAYOUT_DIRECTION_LTR
        // Right arrow
        path.moveTo(0.0f, 0.0f);
        path.lineTo(width, halfHeight);
        path.lineTo(0.0f, height);
    }
    path.close();
    final int[] stateSet = getDrawableState();
    final int color = mIndicatorColor.getColorForState(stateSet, 0);
    mIndicatorPaint.setColor(color);
    canvas.drawPath(path, mIndicatorPaint);
}