如何在Android中添加圆角到画布画？

Question

我正在使用@Override ReplacementSpan方法创建一个矩形。如何向其添加RoundCorner和padding？

代码：

@Override
public void draw(Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom, Paint paint) {
    RectF rect = new RectF(x, top, x + measureText(paint, text, start, end), bottom);
    paint.setColor(mBackgroundColor);
    canvas.drawRect(rect, paint);
    paint.setColor(mForegroundColor);
    canvas.drawText(text, start, end, x, y, paint);
}

修改-1

我正在使用MeasureText：

private float measureText(Paint paint, CharSequence text, int start, int end) { return paint.measureText(text, start, end); }

修改-2

在提出一些建议后，我做了这些更改，我可以看到Rounded上的Rectangle角落

@Override
public void draw(Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom, Paint paint) {
    RectF rect = new RectF(x, top, x + measureText(paint, text, start, end), bottom);
    paint.setColor(mBackgroundColor);
    canvas.drawRoundRect(rect, 15,15,paint);
    paint.setColor(mForegroundColor);
    canvas.drawText(text, start, end, x, y, paint);

}

以下是截图：

我从以下代码调用draw方法：

int currentIndex = 0;
for (int i = 0; i < words.length - 1; i++) {
            s.setSpan(new CustomDrawble(Color.GRAY, Color.WHITE), currentIndex, currentIndex + words[i].length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
            currentIndex += words[i].length() + 1;
        }

Answer 1

Canvas的方法为drawRoundRect。您必须提供要绘制的RectF，Paint和drawRect以及两个代表x和rx和ry的参数y圆角的半径。 E.g。

canvas.drawRoundRect(rect, 5, 5, paint);

将绘制一个圆角为5像素的矩形

EDIT2：

免责声明：使用dip代替像素

@Override
public void draw(Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom, Paint paint) {
   RectF rect = new RectF(x, top, x + measureText(paint, text, start, end) + 10, bottom);
   paint.setColor(mBackgroundColor);
   canvas.drawRoundRect(rect, 15,15,paint);
   paint.setColor(mForegroundColor);
   canvas.drawText(text, start, end, x + 5, y, paint); 
 }

Answer 2

这对我有用：

 public static int cnvToDip(Context context,
                            int     pixels)
 {

  return ((int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, pixels, context.getResources().getDisplayMetrics()));
 }

public static float[] getRoundRectangleShape(Context context,
                                              int     radius)
 {

  Display display = ((WindowManager) context.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();

  Point point = new Point();
  display.getSize(point);

  return new float[]{point.x / cnvToDip(context, radius),
                     point.x / cnvToDip(context, radius),
                     point.x / cnvToDip(context, radius),
                     point.x / cnvToDip(context, radius),
                     point.x / cnvToDip(context, radius),
                     point.x / cnvToDip(context, radius),
                     point.x / cnvToDip(context, radius),
                     point.x / cnvToDip(context, radius)};
 }

ShapeDrawable shapeDrawable = new ShapeDrawable(new RoundRectShape(getRoundRectangleShape(context, 20), null, null));
    shapeDrawable.getPaint().setColor(Color.BLUE);

   @Override
   public void draw(Canvas canvas)
   {

    super.draw(canvas);

    shapeDrawable.draw(canvas);