Question

我有一个自定义的ImageView，它覆盖onDraw方法，使用Path来裁剪角落给出给定半径的圆角。我有一个RecyclerView，我在所有4个项目中都有这些自定义ImageView。现在问题是这个自定义ImageView第一次出现在列表中时呈现正常。一次只能容纳2个屏幕。当我向下滚动时，所有视图中的一切都很好。我可以在所有这些中看到圆角。但是当我向上滚动到上一个项目时。现在这些角落在角落里失去了它们的透明度，并且除了列表中的第三项之外都变成了黑色。 onDraw中的画布也有isOpaque = true。我尝试了很多东西，但似乎没有任何工作。这是代码

public class RoundedImageView extends ImageView
{
    private Paint mPaint;
    private int mCornerRadius = 0;
    private boolean mRoundedTopLeft = true, mRoundedBottomLeft = true, mRoundedTopRight = true, mRoundedBottomRight = true;

    public void setCornerRadius(int mCornerRadius)
    {
        this.mCornerRadius = mCornerRadius;
    }

    public void RoundCorners(boolean isRoundedTopLeft, boolean isRoundedTopRight, boolean isRoundedBottomLeft, boolean isRoundedBottomRight)
    {
        mRoundedTopLeft = isRoundedTopLeft;
        mRoundedBottomLeft = isRoundedBottomLeft;
        mRoundedBottomRight = isRoundedBottomRight;
        mRoundedTopRight = isRoundedTopRight;
    }

    public RoundedImageView(Context context)
    {
        super(context);
        if (Build.VERSION.SDK_INT >= 11)
            setLayerType(View.LAYER_TYPE_SOFTWARE, null);
        setupPaint();
    }

    public RoundedImageView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        if (Build.VERSION.SDK_INT >= 11)
            setLayerType(View.LAYER_TYPE_SOFTWARE, null);
        setupPaint();
    }

    public RoundedImageView(Context context, AttributeSet attrs, int defStyleAttr)
    {
        super(context, attrs, defStyleAttr);
        if (Build.VERSION.SDK_INT >= 11)
            setLayerType(View.LAYER_TYPE_SOFTWARE, null);
        setupPaint();
    }

    @TargetApi(21)
    public RoundedImageView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)
    {
        super(context, attrs, defStyleAttr, defStyleRes);
        if (Build.VERSION.SDK_INT >= 11)
            setLayerType(View.LAYER_TYPE_SOFTWARE, null);
        setupPaint();

    }

    private Paint setupPaint()
    {
        mPaint = new Paint();
        mPaint.setColor(Color.TRANSPARENT);
        mPaint.setStyle(Paint.Style.FILL_AND_STROKE);
        mPaint.setAntiAlias(true);
        mPaint.setDither(true);
        mPaint.setStrokeWidth(1);
        mPaint.setStrokeJoin(Paint.Join.ROUND);
        mPaint.setStrokeCap(Paint.Cap.ROUND);
        mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
        return mPaint;
    }

    @Override
    protected void onDraw(Canvas canvas)
    {
        super.onDraw(canvas);

        Path path = RoundedRect(0, 0, getWidth(), getHeight(), mCornerRadius, mCornerRadius,
                mRoundedTopLeft, mRoundedTopRight, mRoundedBottomRight, mRoundedBottomLeft);
        canvas.drawPath(path, mPaint);
    }

    public static Path RoundedRect(
            float left, float top, float right, float bottom, float rx, float ry,
            boolean tl, boolean tr, boolean br, boolean bl)
    {
        Path path = new Path();
        if (rx < 0) rx = 0;
        if (ry < 0) ry = 0;
        float width = right - left;
        float height = bottom - top;
        if (rx > width / 2) rx = width / 2;
        if (ry > height / 2) ry = height / 2;
        float widthMinusCorners = (width - (2 * rx));
        float heightMinusCorners = (height - (2 * ry));

        path.moveTo(right, top + ry);
        if (tr)
            path.rQuadTo(0, -ry, -rx, -ry);//top-right corner
        else
        {
            path.rLineTo(0, -ry);
            path.rLineTo(-rx, 0);
        }
        path.rLineTo(-widthMinusCorners, 0);
        if (tl)
            path.rQuadTo(-rx, 0, -rx, ry); //top-left corner
        else
        {
            path.rLineTo(-rx, 0);
            path.rLineTo(0, ry);
        }
        path.rLineTo(0, heightMinusCorners);

        if (bl)
            path.rQuadTo(0, ry, rx, ry);//bottom-left corner
        else
        {
            path.rLineTo(0, ry);
            path.rLineTo(rx, 0);
        }

        path.rLineTo(widthMinusCorners, 0);
        if (br)
            path.rQuadTo(rx, 0, rx, -ry); //bottom-right corner
        else
        {
            path.rLineTo(rx, 0);
            path.rLineTo(0, -ry);
        }

        path.rLineTo(0, -heightMinusCorners);

        path.close();//Given close, last lineto can be removed.

        path.setFillType(Path.FillType.INVERSE_EVEN_ODD);
        return path;
    }
}

我已经尝试过： - 在ViewHolder中设置isRecyclable false

在绘画中设置不同的PorterDuff模式
此视图的LAYER_TYPE_HARDWARE（硬件加速）
setDrawingCacheBackgroundColor(0x00000000);
setLayerType(View.LAYER_TYPE_SOFTWARE, paint);在此函数中传递绘画
尝试在super.onDraw()

更新：

经过大量的摆弄后，我得出的结论是每当我的viewHolder视图出现在屏幕外时。它的所有alpha通道都变黑了。我觉得必须对setLayerType(View.LAYER_TYPE_SOFTWARE, null);

做些什么

Answer 1

通过使父软件加速来实现。

我把它解决了

if (Build.VERSION.SDK_INT >= 11)
                view.setLayerType(View.LAYER_TYPE_SOFTWARE, null);

在我的ViewHolder的构造函数中。即使我为任何父容器视图启用了软件加速，它也能正常工作。

现在我不知道为什么会这样。

自定义ImageView在recycleView

1 个答案: