绘制阴影线

Question

现在我画线时没有阴影：

override fun onDraw(canvas: Canvas, parent: RecyclerView, state: RecyclerView.State) {
        val dividerStart = parent.paddingStart
        val dividerEnd = parent.width - parent.paddingEnd
        val endIndex = parent.adapter?.itemCount ?: 0
        for (index in 0 until endIndex) {
            val currentChild = parent.getChildAt(index)
            if (needDrawBottomDelimiter(parent, currentChild)) {
                val topOfCurrentView = currentChild.top
                val startX = dividerStart.toFloat()
                val topY = topOfCurrentView.toFloat() - rectHeight
                val endX = dividerEnd.toFloat()
                val bottomY = topOfCurrentView.toFloat()
                canvas.drawRect(startX, topY, endX, bottomY, spacePaint)
                canvas.drawLine(startX, bottomY, endX, bottomY, dividerPaint)
            }
        }
    }

我知道什么可以帮助我着色器，但是不知道我如何在这里使用它。

在这里让我知道如何使用shader。

Answer 1

在您的布局中，您可以执行以下操作：

    <View
    android:layout_width="match_parent"
    android:layout_height="0.5dp"
    android:elevation="5dp"
    android:background="@color/colorBlack" />

Answer 2

您只需尝试以下方法：

 Paint paint;

 paint = new Paint(Paint.ANTI_ALIAS_FLAG);
 paint.setShadowLayer(12, 0, 0, Color.YELLOW);

 // Important for certain APIs 
 setLayerType(LAYER_TYPE_SOFTWARE, paint);

    @Override
    protected void onDraw(Canvas canvas)
    {   
        canvas.drawRect(20, 20, 100, 100, paint);
    }

Answer 3

我用comment deepak kumar解决了问题>

dividerPaint.setShadowLayer(12F, 0F, 0F, Color.YELLOW)
setLayerType(parent, LAYER_TYPE_SOFTWARE, dividerPaint)