自定义 View：文字的测量与绘制

public class SportView extends View {
    Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);    Paint paintText = new Paint();
    private static final float RADIUS = Util.dp2px(150);    private static final float STROKE_WIDTH = Util.dp2px(20);    private static final int CIRCLE_COLOR = Color.GRAY;    private static final int ARC_COLOR = Color.RED;    private static final int START_ANGLE = 270;    private static final int SWEEP_ANGLE = 280;
    public SportView(Context context, @Nullable AttributeSet attrs) {        super(context, attrs);    }
    @Override    protected void onSizeChanged(int w, int h, int oldw, int oldh) {        super.onSizeChanged(w, h, oldw, oldh);    }
    Rect rect = new Rect();    private Paint.FontMetrics fontMetrics = new Paint.FontMetrics();
    {        paint.setTextSize(Util.dp2px(90));//        paint.setTypeface(Typeface.createFromAsset(getContext().getAssets(), "Quicksand-Regular.ttf"));        paint.setTextAlign(Paint.Align.CENTER);
        paint.getFontMetrics(fontMetrics);    }
    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);
        // 绘制圆环        paint.setColor(CIRCLE_COLOR);        paint.setStrokeWidth(STROKE_WIDTH);        paint.setStyle(Paint.Style.STROKE);        canvas.drawCircle(getWidth()/2, getHeight()/2, RADIUS, paint);
        // 绘制进度条        paint.setColor(ARC_COLOR);        paint.setStyle(Paint.Style.STROKE);        paint.setStrokeCap(Paint.Cap.ROUND);        canvas.drawArc(getWidth()/2-RADIUS, getHeight()/2-RADIUS, getWidth()/2+RADIUS, getHeight()/2+RADIUS,                START_ANGLE, SWEEP_ANGLE, false, paint);
        // 绘制文字        paint.setStyle(Paint.Style.FILL);
        String value = "ggghhh";//        方式一//        paint.getTextBounds(value, 0, value.length(), rect);//        float offset = (rect.bottom-rect.top)/2.0f;
//        方式二        float offset = (fontMetrics.ascent+fontMetrics.descent)/2.0f;
        canvas.drawText(value, getWidth()/2, getHeight()/2 + offset, paint);
//        StaticLayout    }}