SwipeBackLayout.java 文件源码

/**
 * 绘制侧滑时, 左边的渐变线
 */
protected void drawSwipeLine(Canvas canvas) {
    if (mTargetView != null && mTargetView.getLeft() != getMeasuredWidth()) {
        mDimRect.set(mTargetView.getLeft() - dimWidth, 0, mTargetView.getLeft(), getMeasuredHeight());
        mPaint.setAlpha((int) (255 * (1 - (mTargetView.getLeft() * 1f / getMeasuredWidth()))));
        mPaint.setShader(new LinearGradient(mDimRect.left, 0, mDimRect.right, 0,
                new int[]{Color.TRANSPARENT, Color.parseColor("#40000000")}, null, Shader.TileMode.CLAMP));
        canvas.drawRect(mDimRect, mPaint);
    }
}