Android studio圆形进度条 百分数跟随变化

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{
 private Gua mGua1;
 private Button play;
 private Button resele;
 private Button dao;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  mGua1 = (Gua) findViewById(R.id.Circle);
  mGua1.setTargetPercent(0);
  play=(Button)findViewById(R.id.play);
  resele=(Button)findViewById(R.id.resele);
  dao=(Button)findViewById(R.id.dao);

  play.setOnClickListener(this);
  resele.setOnClickListener(this);
  dao.setOnClickListener(this);
 }

 @Override
 public void onClick(View view) {
  switch (view.getId()){
   case R.id.play:
    //设置目标百分比为100
    mGua1.setTargetPercent(100);
    mGua1.invalidate();
    break;
   case R.id.resele:
    //设置目标百分比为0
    mGua1.setTargetPercent(0);
    mGua1.invalidate();
    break;
   case R.id.dao:
    //设置目标百分比为100
    mGua1.setTargetPercent(0);
    mGua1.invalidate();
    break;
  }
 }
}

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.Align;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.View;

public class Gua extends View{
 private Paint mCirclePaint;
 private Paint mTextPaint;
 private Paint mArcPaint;
 private int mCircleX;
 private int mCircleY;
 private float mCurrentAngle;
 private RectF mArcRectF;
 private float mStartSweepValue;
 private float mTargetPercent;
 private float mCurrentPercent;

 private int mRadius;
 private int mCircleBackground;
 private int mRingColor;
 private int mTextSize;
 private int mTextColor;


 public Gua(Context context,AttributeSet attrs,int defStyle) {
  super(context,attrs,defStyle);
  init(context);
 }

 public Gua(Context context,AttributeSet attrs) {
  super(context,attrs);
  //自定义属性 values/attr
  TypedArray typedArray = context.obtainStyledAttributes(attrs,R.styleable.PercentageRing);
  //中间圆的背景颜色 默认为浅紫色
  mCircleBackground = typedArray.getColor(R.styleable.PercentageRing_circleBackground,0xffafb4db);
  //外圆环的颜色 默认为深紫色
  mRingColor = typedArray.getColor(R.styleable.PercentageRing_ringColor,0xff6950a1);
  //中间圆的半径 默认为60
  mRadius = typedArray.getInt(R.styleable.PercentageRing_radius,60);
  //字体颜色 默认为白色
  mTextColor = typedArray.getColor(R.styleable.PercentageRing_textColor,0xffffffff);
  //最后一定要调用这个 释放掉TypedArray
  typedArray.recycle();
  //初始化数据
  init(context);
 }

 public Gua(Context context) {
  super(context);
  init(context);
 }

 private void init(Context context){
  //圆环开始角度 -90° 正北方向
  mStartSweepValue = -90;
  //当前角度
  mCurrentAngle = 0;
  //当前百分比
  mCurrentPercent = 0;
  //设置中心园的画笔
  mCirclePaint = new Paint();
  mCirclePaint.setAntiAlias(true);
  mCirclePaint.setColor(mCircleBackground);
  mCirclePaint.setStyle(Paint.Style.FILL);
  //设置文字的画笔
  mTextPaint = new Paint();
  mTextPaint.setColor(mTextColor);
  mTextPaint.setAntiAlias(true);
  mTextPaint.setStyle(Paint.Style.FILL);
  mTextPaint.setStrokeWidth((float) (0.025*mRadius));
  mTextPaint.setTextSize(mRadius/2);
  mTextPaint.setTextAlign(Align.CENTER);
  //设置外圆环的画笔
  mArcPaint = new Paint();
  mArcPaint.setAntiAlias(true);
  mArcPaint.setColor(mRingColor);
  mArcPaint.setStyle(Paint.Style.STROKE);
  mArcPaint.setStrokeWidth((float) (0.075*mRadius));
  //获得文字的字号 因为要设置文字在圆的中心位置
  mTextSize = (int) mTextPaint.getTextSize();


 }

 //主要是测量wrap_content时候的宽和高，因为宽高一样，只需要测量一次宽即可，高等于宽
 @Override
 protected void onMeasure(int widthMeasureSpec,int heightMeasureSpec) {
  setMeasuredDimension(measure(widthMeasureSpec),measure(widthMeasureSpec));
  //设置圆心坐标
  mCircleX = getMeasuredWidth()/2;
  mCircleY = getMeasuredHeight()/2;
  //如果半径大于圆心横坐标，需要手动缩小半径的值，否则就画到外面去了
  if (mRadius>mCircleX) {
   //设置半径大小为圆心横坐标到原点的距离
   mRadius = mCircleX;
   mRadius = (int) (mCircleX-0.075*mRadius);
   //因为半径改变了，所以要重新设置一下字体宽度
   mTextPaint.setStrokeWidth((float) (0.025*mRadius));
   //重新设置字号
   mTextPaint.setTextSize(mRadius/2);
   //重新设置外圆环宽度
   mArcPaint.setStrokeWidth((float) (0.075*mRadius));
   //重新获得字号大小
   mTextSize = (int) mTextPaint.getTextSize();
  }
  //画中心园的外接矩形，用来画圆环用
  mArcRectF = new RectF(mCircleX-mRadius,mCircleY-mRadius,mCircleX+mRadius,mCircleY+mRadius);
 }

 //当wrap_content的时候，view的大小根据半径大小改变，但最大不会超过屏幕
 private int measure(int measureSpec){
  int result=0;
  int specMode = MeasureSpec.getMode(measureSpec);
  int specSize = MeasureSpec.getSize(measureSpec);
  if (specMode == MeasureSpec.EXACTLY) {
   result = specSize;
  }else {
   result =(int) (1.075*mRadius*2);
   if (specMode == MeasureSpec.AT_MOST) {
    result = Math.min(result,specSize);
   }
  }
  return result;

 }
 //开始画中间圆、文字和外圆环
 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  //画中间圆
  canvas.drawCircle(mCircleX,mCircleY,mRadius,mCirclePaint);
  //画圆环
  canvas.drawArc(mArcRectF,mStartSweepValue,mCurrentAngle,false,mArcPaint);
  //画文字
  canvas.drawText(String.valueOf(mCurrentPercent)+"%",mCircleX,mCircleY+mTextSize/4,mTextPaint);
  //判断当前百分比是否小于设置目标的百分比
  if (mCurrentPercent<mTargetPercent) {
   //当前百分比+1
   mCurrentPercent+=1;
   //当前角度+360
   mCurrentAngle+=3.6;
   //每10ms重画一次
   postInvalidateDelayed(10);
  }/*else if(mCurrentPercent==mTargetPercent){
   //当前百分比-1
   mCurrentPercent=0;
   //当前角度+360
   mCurrentAngle=0;
   //每10ms重画一次
   postInvalidateDelayed(10);
  }*/else if(mCurrentPercent>mTargetPercent){
   //当前百分比-1
   mCurrentPercent-=1;
   //当前角度+360
   mCurrentAngle-=3.6;
   //每10ms重画一次
   postInvalidateDelayed(10);
  }

 }
 //设置目标的百分比
 public void setTargetPercent(int percent){
  this.mTargetPercent = percent;
 }
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 android:orientation="vertical">
 <Button
  android:id="@+id/but1"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:text="改变外层圆环颜色"
  />
 <com.bwie.test.wuxiaorui1508a20171009.Gua
  android:id="@+id/Circle"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  app:radius="90"
  app:textColor="#ffffffff"
  />
 <LinearLayout
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:orientation="horizontal"
  android:gravity="center"
  >
  <Button
   android:id="@+id/play"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text="开始"
   />
  <Button
   android:id="@+id/resele"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text="重置"
   />
  <Button
   android:id="@+id/dao"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text="暂停"
   />
 </LinearLayout>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <declare-styleable name="PercentageRing">
  <attr name="radius" format="integer"/>
  <attr name="circleBackground" format="color"/>
  <attr name="ringColor" format="color"/>
  <attr name="textColor" format = "color"/>

 </declare-styleable>
</resources>