android - 自定义 View 屏幕截图以编程方式在 android 中不起作用

Question

我有这样的自定义 View ，

public class RoundedCornerLayout extends FrameLayout
{
    private final static float CORNER_RADIUS = 100.0f;

    private Bitmap maskBitmap;
    private Paint paint, maskPaint;
    private float cornerRadius;

    public RoundedCornerLayout(Context context)
    {
        super(context);
        init(context, null, 0);
    }

    public RoundedCornerLayout(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        init(context, attrs, 0);
    }

    public RoundedCornerLayout(Context context, AttributeSet attrs, int defStyle)
    {
        super(context, attrs, defStyle);
        init(context, attrs, defStyle);
    }

    private void init(Context context, AttributeSet attrs, int defStyle)
    {
        p = new Paint();
        p.setFlags(Paint.ANTI_ALIAS_FLAG);
        p.setColor(Color.WHITE);
        p.setStyle(android.graphics.Paint.Style.STROKE);
        p.setStrokeWidth(6);

        pp = new Paint();
        pp.setColor(Color.parseColor("#686868"));

        DisplayMetrics metrics = context.getResources().getDisplayMetrics();
        cornerRadius = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, CORNER_RADIUS, metrics);

        paint = new Paint(Paint.ANTI_ALIAS_FLAG);

        maskPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG);
        maskPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));

        setWillNotDraw(false);
    }

    Paint p;
    Paint pp;

    @Override
    public void draw(Canvas canvas)
    {

        android.util.Log.e("MAYUR", "draw");

        canvas.drawCircle(canvas.getWidth() / 2, canvas.getHeight() / 2, canvas.getWidth() / 2, pp);

        Bitmap offscreenBitmap = Bitmap.createBitmap(canvas.getWidth(), canvas.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas offscreenCanvas = new Canvas(offscreenBitmap);

        super.draw(offscreenCanvas);

        if (maskBitmap == null)
        {
            maskBitmap = createMask(canvas.getWidth(), canvas.getHeight());
        }

        offscreenCanvas.drawBitmap(maskBitmap, 0f, 0f, maskPaint);
        canvas.drawBitmap(offscreenBitmap, 0f, 0f, paint);

        canvas.drawCircle(canvas.getWidth() / 2, canvas.getHeight() / 2, (canvas.getWidth() - 6) / 2, p);
    }

    private Bitmap createMask(int width, int height)
    {
        Bitmap mask = Bitmap.createBitmap(width, height, Bitmap.Config.ALPHA_8);
        Canvas canvas = new Canvas(mask);

        Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setColor(Color.WHITE);

        canvas.drawRect(0, 0, width, height, paint);

        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
        canvas.drawRoundRect(new RectF(0, 0, width, height), cornerRadius, cornerRadius, paint);

        return mask;
    }
}

我正在截屏，

View v1 = ll_contain;
v1.setDrawingCacheEnabled(true);
v1.buildDrawingCache(true);
Bitmap bitmap = Bitmap.createBitmap(v1.getDrawingCache());
v1.setDrawingCacheEnabled(false);

并将位图保存到 sdcard，但保存结果与屏幕上显示的不同。为什么？我哪里错了？

请给我解决这个问题的方向，我试图搜索问题，但我没有找到任何人遇到此类问题。

屏幕上的 View 显示，

截屏时，保存为

Answer 1

我遇到了类似的问题(对于 Drawable)，问题本质上在于使用 canvas.getHeight() 和 canvas.getWidth() 位置和大小的方法，同时进行 drawCircle 调用。在实际绘制 View 时，这些方法返回与 View 尺寸相同的值，一切顺利。在绘制屏幕截图时，这些将返回整个屏幕截图的高度和宽度，而不是 View 的尺寸。

解决方案是计算变量 canvasHeight 和 canvasWidth 作为如下:

• 对于可绘制对象:canvasWidth = getBounds().width();
• 对于 View :canvasWidth = getRight() - getLeft();