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这篇文章主要讲解了Android自定义圆弧进度条加数字动态变化的方法，内容清晰明了，对此有兴趣的小伙伴可以学习一下，相信大家阅读完之后会有帮助。
效果如下:
思路:一个内环圆弧和一个外环圆弧,因为有一个圆圈是在圆弧上做圆周运动,所以在画圆的时候必须要得到圆弧上的各个点的坐标,这里其实就用到了PathMeasure这个类,可以帮我们拿到这些点,在画圆弧的时候也理所应当的要使用path,然后根据外界动态的传值进行重绘就能达到动态的效果
代码如下:
public class ProgressPathRainbow extends View {
private Paint outPaint;
private Paint innerPaint;
private Paint mTextPaint;
private Paint mRmbTextPaint;
private int mBorderWidth = 40;
private int mCircleRadius = 40;
private int mCurrentProgress = 0;
private int mMaxProgress = 0;
private int startAngle = 180;
private int sweepAngels = 180;
private Paint mCirclePaint;
private String rmb = "¥";
private String currentText = "0.0";
public void setCurrentText(String currentText) {
this.currentText = currentText;
}
//储存位置点
private float[] pos =new float[2];
public ProgressPathRainbow(Context context) {
super(context);
initPaint();
}
public ProgressPathRainbow(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
initPaint();
}
public ProgressPathRainbow(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
initPaint();
}
private void initPaint(){
outPaint = new Paint();
outPaint.setColor(0xFFECECEC);
outPaint.setAntiAlias(true);
outPaint.setStyle(Paint.Style.STROKE);
outPaint.setStrokeCap(Paint.Cap.ROUND);
outPaint.setStrokeWidth(mBorderWidth);
//
innerPaint = new Paint();
innerPaint.setColor(0xffFBA123);
innerPaint.setAntiAlias(true);
innerPaint.setStyle(Paint.Style.STROKE);
innerPaint.setStrokeCap(Paint.Cap.ROUND);
innerPaint.setStrokeWidth(mBorderWidth);
mCirclePaint = new Paint();
mCirclePaint.setColor(Color.WHITE);
mCirclePaint.setStyle(Paint.Style.FILL);
mTextPaint = new Paint();
mTextPaint.setAntiAlias(true);
mTextPaint.setColor(0xffE5423D);
mTextPaint.setFakeBoldText(true);
mTextPaint.setTextSize(SizeUtils.sp2px(42));
mRmbTextPaint = new Paint();
mRmbTextPaint.setAntiAlias(true);
mRmbTextPaint.setColor(0xffE5423D);
mRmbTextPaint.setTextSize(SizeUtils.sp2px(18));
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int width = MeasureSpec.getSize(widthMeasureSpec);
int height = MeasureSpec.getSize(heightMeasureSpec);
if (width >= height){
setMeasuredDimension(height,height);
}else {
setMeasuredDimension(width,width);
}
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
RectF rectF = new RectF(mBorderWidth,mBorderWidth,getWidth()-mBorderWidth,getHeight()-mBorderWidth);
//画内环圆弧
Path outerPath = new Path();
outerPath.arcTo(rectF,startAngle,sweepAngels);
canvas.drawPath(outerPath,outPaint);
//画外环圆弧
Path innerPah = new Path();
float percent = (float)mCurrentProgress/mMaxProgress;
innerPah.arcTo(rectF,startAngle,percent*sweepAngels);
canvas.drawPath(innerPah,innerPaint);
//画金额
String tempText = new BigDecimal(currentText).multiply(new BigDecimal(percent)).setScale(1, RoundingMode.HALF_UP).toString();
Rect textBounds = new Rect();
mTextPaint.getTextBounds(tempText, 0, tempText.length(), textBounds);
int dx = getWidth()/2 - textBounds.width()/2;
// 基线 baseLine
Paint.FontMetricsInt fontMetrics = mTextPaint.getFontMetricsInt();
int dy = (fontMetrics.bottom - fontMetrics.top)/2 - fontMetrics.bottom;
int baseLine = getHeight()/3 + dy;
canvas.drawText(tempText,dx,baseLine,mTextPaint);
//画人民币符号
Rect textBoundRmbs = new Rect();
mTextPaint.getTextBounds(rmb, 0, rmb.length(), textBoundRmbs);
int dxRmb = dx-50;
// 基线 baseLine
Paint.FontMetricsInt fontMetricsRmb = mTextPaint.getFontMetricsInt();
int dyRmb = (fontMetricsRmb.bottom - fontMetricsRmb.top)/2 - fontMetricsRmb.bottom;
int baseLineRmb = getHeight()/3 + dyRmb;
canvas.drawText(rmb,dxRmb,baseLineRmb,mRmbTextPaint);
//获取圆弧上点的位置(坐标,画一个圆)
PathMeasure pathMeasure = new PathMeasure(outerPath,false);
boolean posTan = pathMeasure.getPosTan(pathMeasure.getLength() * percent, pos, null);
canvas.drawCircle(pos[0],pos[1],mCircleRadius,mCirclePaint);
}
public synchronized void setmCurrentProgress(int mCurrentProgress) {
this.mCurrentProgress = mCurrentProgress;
invalidate();
}
public synchronized void setmMaxProgress(int mMaxProgress) {
this.mMaxProgress = mMaxProgress;
}
} 
