Android 如何在画布内部的中心显示TextView？

我有一个

文本视图

，我使用

布局将它放在
画布
中。
我的第一个问题是如何将其居中？
因为每次我做
width/2
和
height/2
都会给它一个偏移量

其次，为什么我的
angleTextView.setGravity（Gravity.CENTER）是不工作

下面是我在做什么来绘制我的
TextView
有什么建议吗

昂德劳：

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


        if (pathsArray.size() == 0) { // initlizes the init
            init();
        }

        // draws the first circle
        canvas.drawCircle(width / 2f, height / 2f, OUTER_RING_DIAMETER, firstCirclePaint);

        //go through the array and paints the corisponding cells
        for (int i = 0; i < pathsArray.size(); i++) {

            if (pathsArray.get(i).state == 1) { // scanned
                canvas.drawPath(pathsArray.get(i), fillColorForSlicesNoHbs);
                canvas.drawPath(pathsArray.get(i), circleOutlinesPaint);

            } else if (pathsArray.get(i).state == 2) { // found hbs
                canvas.drawPath(pathsArray.get(i), fillColorForSlicesWithHbs);
                canvas.drawPath(pathsArray.get(i), circleOutlinesPaint);

            } else {
                canvas.drawPath(pathsArray.get(i), mainPaintForSlices);
                canvas.drawPath(pathsArray.get(i), circleOutlinesPaint);
            }
        }


        //paint the outer circles
        canvas.drawCircle(width / 2f, height / 2f, OUTER_RING_DIAMETER, outSideCirclePaint);

        canvas.drawCircle(width / 2f, height / 2f, (OUTER_RING_DIAMETER - (RINGS_STEP)), circleOutlinesPaint);

        canvas.drawCircle(width / 2f, height / 2f, (OUTER_RING_DIAMETER - (RINGS_STEP * 2)), circleOutlinesPaint);

        canvas.drawCircle(width / 2f, height / 2f, (OUTER_RING_DIAMETER - (RINGS_STEP * 3)), firstCirclePaint);


        canvas.drawPath(highlightedPath, highlitedCirclePaint);

        for (int i = 0; i < pathsArray.size(); i++) {

            if (pathsArray.get(i).elvation == highlightedPath.elvation) {

                if (pathsArray.get(i).state == 1) { // scanned
                    canvas.drawPath(pathsArray.get(i), fillColorForSlicesNoHbs);
                    canvas.drawPath(pathsArray.get(i), circleOutlinesPaint);

                } else if (pathsArray.get(i).state == 2) { // found hbs
                    canvas.drawPath(pathsArray.get(i), fillColorForSlicesWithHbs);
                    canvas.drawPath(pathsArray.get(i), circleOutlinesPaint);

                } else {
                    canvas.drawPath(pathsArray.get(i), circleOutlinesPaint);
                }

            }
        }


        //draws the dark opacity on top of everything else
        canvas.drawPath(lowlightedPathOuter, lowlitedCirclePaint);
        canvas.drawPath(lowlightedPathInner, lowlitedCirclePaint);


        // draw the needle
        // draw the circle of the current elevantion.
        alignmentSlice staticNeedle = getSlicesPaths(width / 2f, height / 2f, (OUTER_RING_DIAMETER - (RINGS_STEP * 3)), OUTER_RING_DIAMETER + 100, 0, 0.6f, 0);
        alignmentSlice mainNeedle = getSlicesPaths(width / 2f, height / 2f, (OUTER_RING_DIAMETER - (RINGS_STEP * 3)), OUTER_RING_DIAMETER + 100, needleAngle, 0.6f, 0);

        canvas.drawPath(staticNeedle, paintSecondaryNeedle);
        canvas.drawPath(mainNeedle, paintMainNeedle);


        //puts a text view
        RelativeLayout layout = new RelativeLayout(getContext());

        angleTextView = new TextView(getContext());
        angleTextView.setVisibility(View.VISIBLE);
        angleTextView.setTextSize(width/35);
        angleTextView.setGravity(Gravity.CENTER);
        angleTextView.setTextColor(Color.WHITE);
        angleTextView.setText(angleText);

        layout.addView(angleTextView);

        layout.measure(canvas.getWidth(), canvas.getHeight());
        layout.layout(0, 0, canvas.getWidth(), canvas.getHeight());

        // To place the text view somewhere specific:
        canvas.translate((width/2)-(width/15), (height/2)-(height/27));


        layout.draw(canvas);

    }

@覆盖
受保护的void onDraw（画布）{
super.onDraw（帆布）；
if（pathsArray.size（）==0）{//初始化初始化
init（）；
}
//画第一个圆
帆布画圈（宽/2f，高/2f，外圈直径，第一圈漆）；
//遍历数组并绘制相应的单元格
对于（int i=0；i
如果要使用
重力
，则需要在父项上设置重力。在这种情况下，
layout.setGravity（Gravity.CENTER）
。如果要在
textview
上进行设置，必须使用
布局参数

LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.FILL_PARENT);
params.gravity = Gravity.CENTER;

angleTextView.setLayoutParams(params);

将
textview
更改为：

Paint textPaint = new Paint();
        textPaint.setColor(getResources().getColor(R.color.alignementWhite));
        textPaint.setTextAlign(Paint.Align.CENTER);
        textPaint.setTextSize(width/10);

        int xPos = (canvas.getWidth() / 2);
        int yPos = (int) ((canvas.getHeight() / 2) - ((textPaint.descent() + textPaint.ascent()) / 2)) ;

        canvas.drawText(angleText, xPos, yPos, textPaint);

什么样的补偿？你试过
（width+textview.getMeasuredWidth（））/2
和
（height+textview.getMeasuredHeight（））/2
？是的，我试过了，它真的会将它偏移到右下角。你正在创建一个新的
RelativeLayout
并在
onDraw
中调用它的
addView
方法？？？你知道调用
onDraw
的频率吗？这是我读到的唯一一种在画布中放置文本视图的方法，你有更好的方法吗？愚蠢的问题-当你打印
textview.getX（）
和
textview.getY（）
时，它们是否在所需的位置（画布的宽度/2和高度/2？）我应该导入什么layoutparams？是吗，线性布局，布局公园？或者RelativeLayout.layoutparmas？实际上我不确定它在这种情况下是否重要，但我会使用RelativeLayout使其与父级匹配。它仍然没有修复它，仍然是相同的问题