<?xml version="1.0" encoding="utf-8"?>
<resources>
 <declare-styleable name="CountDownView">
  <!--顏色-->
  <attr name="ringColor" format="color" />
  <!-- 進(jìn)度文本的字體大小 -->
  <attr name="progressTextSize" format="dimension" />
  <!-- 圓環(huán)寬度 -->
  <attr name="ringWidth" format="float" />
  <!--進(jìn)度文本顏色-->
  <attr name="progressTextColor" format="color"/>
  <!--倒計(jì)時(shí)-->
  <attr name="countdownTime" format="integer"/>
 </declare-styleable>
</resources>

import android.content.Context;

/**
 * Created by 王 on 2017/10/21.
 */

public class DisplayUtil {
 /**
  * 將px裝換成dp，保證尺寸不變
  * @param context
  * @param pxValue
  * @return
  */
 public static int px2dp(Context context, float pxValue){
  float density = context.getResources().getDisplayMetrics().density;//得到設(shè)備的密度
  return (int) (pxValue/density+0.5f);
 }
 public static int dp2px(Context context,float dpValue){
  float density = context.getResources().getDisplayMetrics().density;
  return (int) (dpValue*density+0.5f);
 }
 public static int px2sp(Context context,float pxValue){
  float scaleDensity = context.getResources().getDisplayMetrics().scaledDensity;//縮放密度
  return (int) (pxValue/scaleDensity+0.5f);
 }
 public static int sp2px(Context context,float spValue) {
  float scaleDensity = context.getResources().getDisplayMetrics().scaledDensity;
  return (int) (spValue*scaleDensity+0.5f);
 }
}

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ValueAnimator;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.LinearInterpolator;

/**
 * Created by 王 on 2017/10/21.
 */

public class CountDownView extends View{
 //圓輪顏色
 private int mRingColor;
 //圓輪寬度
 private float mRingWidth;
 //圓輪進(jìn)度值文本大小
 private int mRingProgessTextSize;
 //寬度
 private int mWidth;
 //高度
 private int mHeight;
 private Paint mPaint;
 //圓環(huán)的矩形區(qū)域
 private RectF mRectF;
 //
 private int mProgessTextColor;
 private int mCountdownTime;
 private float mCurrentProgress;
 private OnCountDownFinishListener mListener;

 public CountDownView(Context context) {
  this(context, null);
 }

 public CountDownView(Context context, AttributeSet attrs) {
  this(context, attrs, 0);
 }

 public CountDownView(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CountDownView);
  mRingColor = a.getColor(R.styleable.CountDownView_ringColor, context.getResources().getColor(R.color.colorAccent));
  mRingWidth = a.getFloat(R.styleable.CountDownView_ringWidth, 40);
  mRingProgessTextSize = a.getDimensionPixelSize(R.styleable.CountDownView_progressTextSize, DisplayUtil.sp2px(context, 20));
  mProgessTextColor = a.getColor(R.styleable.CountDownView_progressTextColor, context.getResources().getColor(R.color.colorAccent));
  mCountdownTime = a.getInteger(R.styleable.CountDownView_countdownTime, 10);
  a.recycle();
  mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
  mPaint.setAntiAlias(true);
  this.setWillNotDraw(false);
 }

 public void setCountdownTime(int mCountdownTime) {
  this.mCountdownTime = mCountdownTime;
 }

 @Override
 protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
  super.onLayout(changed, left, top, right, bottom);
  mWidth = getMeasuredWidth();
  mHeight = getMeasuredHeight();
  mRectF = new RectF(0 + mRingWidth / 2, 0 + mRingWidth / 2,
    mWidth - mRingWidth / 2, mHeight - mRingWidth / 2);
 }

 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  /**
   *圓環(huán)
   */
  //顏色
  mPaint.setColor(mRingColor);
  //空心
  mPaint.setStyle(Paint.Style.STROKE);
  //寬度
  mPaint.setStrokeWidth(mRingWidth);
  canvas.drawArc(mRectF, -90, mCurrentProgress - 360, false, mPaint);
  //繪制文本
  Paint textPaint = new Paint();
  textPaint.setAntiAlias(true);
  textPaint.setTextAlign(Paint.Align.CENTER);
  String text = mCountdownTime - (int) (mCurrentProgress / 360f * mCountdownTime) + "";
  textPaint.setTextSize(mRingProgessTextSize);
  textPaint.setColor(mProgessTextColor);

  //文字居中顯示
  Paint.FontMetricsInt fontMetrics = textPaint.getFontMetricsInt();
  int baseline = (int) ((mRectF.bottom + mRectF.top - fontMetrics.bottom - fontMetrics.top) / 2);
  canvas.drawText(text, mRectF.centerX(), baseline, textPaint);
 }

 private ValueAnimator getValA(long countdownTime) {
  ValueAnimator valueAnimator = ValueAnimator.ofFloat(0, 100);
  valueAnimator.setDuration(countdownTime);
  valueAnimator.setInterpolator(new LinearInterpolator());
  valueAnimator.setRepeatCount(0);
  return valueAnimator;
 }
 /**
  * 開始倒計(jì)時(shí)
  */
 public void startCountDown() {
  setClickable(false);
  ValueAnimator valueAnimator = getValA(mCountdownTime * 1000);
  valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
   @Override
   public void onAnimationUpdate(ValueAnimator animation) {
    float i = Float.valueOf(String.valueOf(animation.getAnimatedValue()));
    mCurrentProgress = (int) (360 * (i / 100f));
    invalidate();
   }
  });
  valueAnimator.start();
  valueAnimator.addListener(new AnimatorListenerAdapter() {
   @Override
   public void onAnimationEnd(Animator animation) {
    super.onAnimationEnd(animation);
    //倒計(jì)時(shí)結(jié)束回調(diào)
    if (mListener != null) {
     mListener.countDownFinished();
    }
    setClickable(true);
   }

  });
 }
 public void setAddCountDownListener(OnCountDownFinishListener mListener) {
  this.mListener = mListener;
 }
 public interface OnCountDownFinishListener {
  void countDownFinished();
 }

}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 tools:context="com.example.circulardemo.MainActivity">

 <com.example.circulardemo.CountDownView
  android:id="@+id/cdv"
  android:layout_width="50dp"
  android:layout_height="50dp"
  android:layout_centerVertical="true"
  android:layout_centerHorizontal="true" />

</RelativeLayout>

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  CountDownView countDownView = (CountDownView) findViewById(R.id.cdv);
  //啟動(dòng)
  countDownView.startCountDown();

  countDownView.setAddCountDownListener(new CountDownView.OnCountDownFinishListener() {
   @Override
   public void countDownFinished() {
    Toast.makeText(MainActivity.this, "倒計(jì)時(shí)結(jié)束", Toast.LENGTH_SHORT).show();
   }
  });
 }


}