Android自定义弧型View

Posted 2021-05-10 AnalyzeSystem

好久没动手玩View自定义，有点生疏了。效果如下

思路很简单，onDraw绘制弧线、绘制Text

canvas.drawArc(oval, startAngle, sweepAngle, false, paint);
 
canvas.drawText(integralValue, rectF.centerX(), baseline, textPaint);

draw 动画效果实现：invalidate

canvas.drawArc(oval, startAngle, i, false, paint);

        if(i<sweepAngle){
            i = i+10;//sweepAngle ：240，所以这里+10没问题，具体细节具体修改
            getHandler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    invalidate();
                }
            },50);
        }

绘制的效果差别有点大不理想，先给画笔添加抗锯齿和画笔圆角

textPaint.setAntiAlias(true);
textPaint.setTypeface(Typeface.DEFAULT_BOLD);

drawText让文字居中对齐，一定要算好边界和baseLine

RectF rectF = new RectF(borderWidth * 2 + arcMargin, borderWidth * 2 + arcMargin, getMeasuredWidth() - arcMargin - borderWidth * 2, getMeasuredHeight() - arcMargin - borderWidth * 2);

 //计算baseline
 Paint.FontMetrics fontMetrics = textPaint.getFontMetrics();
 float distance = (fontMetrics.bottom - fontMetrics.top) / 2 - fontMetrics.bottom;
 float baseline = rectF.centerY() + distance;
 canvas.drawText(integralValue, rectF.centerX(), baseline, textPaint);

积分商城文本背景可以用shape绘制，这里直接代码搞一个drawable

   /**
     * 设置圆角背景
     *
     * @param
     * @param radiiValue     设置图片四个角圆形半径
     * @return
     */
    @SuppressLint("WrongConstant")
    public static GradientDrawable getBackgroundShapeDrawable(int color, float radiiValue) {
        float[] radii = new float[] { radiiValue, radiiValue, radiiValue, radiiValue, radiiValue, radiiValue, radiiValue,radiiValue };
        GradientDrawable drawable = new GradientDrawable();
        drawable.setShape(GradientDrawable.RECTANGLE);
        drawable.setGradientType(GradientDrawable.RECTANGLE);
        drawable.setCornerRadii(radii);
        drawable.setColor(color);
        return drawable;
    }

居中文字大小不能固定值，防止超出弧型，要跟据文字长度动态调整

textPaint.setTextSize(getIntegralTextSize(integralValue));

 protected int getIntegralTextSize(String text) {
        int flag = 80;
        if (text.length() == 8) {
            flag = 70;
        } else if (text.length() == 9) {
            flag = 60;
        } else if (text.length() >= 10) {
            flag = 50;
        }

        return flag;
    }

源码就不上传了，实现起来还是不难用了十几分钟，等下班咯