canvas上的Android Center文本

我试图使用下面的代码显示一个文本。问题是文本没有水平居中。当我为drawText设置坐标时，它将文本的底部设置在这个位置。我想要的文本被绘制，使文本也是水平居中。

这是一张进一步展示我的问题的图片:

@Override
protected void onDraw(Canvas canvas) {
    // TODO Auto-generated method stub
    super.onDraw(canvas);
    //canvas.drawRGB(2, 2, 200);
    Paint textPaint = new Paint();
    textPaint.setARGB(200, 254, 0, 0);
    textPaint.setTextAlign(Align.CENTER);
    textPaint.setTypeface(font);
    textPaint.setTextSize(300);
    canvas.drawText("Hello", canvas.getWidth()/2, canvas.getHeight()/2  , textPaint);
}

当前回答

在我的例子中，我不需要把文本放在画布的中间，而是放在一个旋转的轮子上。尽管我必须使用以下代码才能成功:

fun getTextRect(textSize: Float, textPaint: TextPaint, string: String) : PointF {
    val rect = RectF(left, top, right, bottom)
    val rectHeight = Rect()
    val cx = rect.centerX()
    val cy = rect.centerY()

    textPaint.getTextBounds(string, 0, string.length, rectHeight)
    val y = cy + rectHeight.height()/2
    val x = cx - textPaint.measureText(string)/2

    return PointF(x, y)
}

然后我从View类调用这个方法:

private fun drawText(canvas: Canvas, paint: TextPaint, text: String, string: String) {
    val pointF = getTextRect(paint.textSize, textPaint, string)
    canvas.drawText(text, pointF!!.x, pointF.y, paint)
}

2020-03-05 11:40:09

其他回答

试试下面的方法:

 Paint textPaint = new Paint();
 textPaint.setTextAlign(Paint.Align.CENTER);

 int xPos = (canvas.getWidth() / 2);
 int yPos = (int) ((canvas.getHeight() / 2) - ((textPaint.descent() + textPaint.ascent()) / 2)) ; 
 //((textPaint.descent() + textPaint.ascent()) / 2) is the distance from the baseline to the center.

 canvas.drawText("Hello", xPos, yPos, textPaint);

2012-06-20 14:31:44

在你的油漆属性中使用这个:

 textPaint.setTextAlign(Paint.Align.CENTER);

2020-10-01 07:21:42

这招对我很管用:

 paint.setTextAlign(Paint.Align.CENTER);
        int xPos = (newWidth / 2);
        int yPos = (newHeight / 2);
        canvas.drawText("Hello", xPos, yPos, paint);

如果有人发现任何问题，请告诉我

2018-10-02 08:22:37

在我的例子中，我不需要把文本放在画布的中间，而是放在一个旋转的轮子上。尽管我必须使用以下代码才能成功:

fun getTextRect(textSize: Float, textPaint: TextPaint, string: String) : PointF {
    val rect = RectF(left, top, right, bottom)
    val rectHeight = Rect()
    val cx = rect.centerX()
    val cy = rect.centerY()

    textPaint.getTextBounds(string, 0, string.length, rectHeight)
    val y = cy + rectHeight.height()/2
    val x = cx - textPaint.measureText(string)/2

    return PointF(x, y)
}

然后我从View类调用这个方法:

private fun drawText(canvas: Canvas, paint: TextPaint, text: String, string: String) {
    val pointF = getTextRect(paint.textSize, textPaint, string)
    canvas.drawText(text, pointF!!.x, pointF.y, paint)
}

2020-03-05 11:40:09

适用于我使用: textPaint。textAlign = Paint.Align.CENTER使用textPaint.getTextBounds

private fun drawNumber(i: Int, canvas: Canvas, translate: Float) {
            val text = "$i"
            textPaint.textAlign = Paint.Align.CENTER
            textPaint.getTextBounds(text, 0, text.length, textBound)

            canvas.drawText(
                    "$i",
                    translate + circleRadius,
                    (height / 2 + textBound.height() / 2).toFloat(),
                    textPaint
            )
        }

结果是:

2019-03-19 11:57:38

canvas上的Android Center文本

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