<declare-styleable name="CountDownProgressBar">
    <attr name="countDown_circleWidth" format="dimension" />
    <attr name="countDown_centerTextSize" format="dimension" />
    <attr name="countDown_betaAngle" format="integer" />
    <attr name="countDown_firstColor" format="color" />
    <attr name="countDown_secondColor" format="color" />
    <attr name="countDown_centerTextColor" format="color" />
    <attr name="countDown_isShowGradient" format="boolean" />
</declare-styleable>

import android.animation.ValueAnimator;
import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.LinearGradient;
import android.graphics.Paint;
import android.graphics.Paint.FontMetricsInt;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Shader;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.View;
import android.view.animation.LinearInterpolator;
 
import com.daodaojk.myapplication.R;
 
public class CountDownProgressBar extends View {
  /**
   * 進度條最大值
   */
  private int maxValue = 200;
 
  /**
   * 當前進度值
   */
  private int currentValue ;
 
  /**
   * 每次掃過的角度，用來設(shè)置進度條圓弧所對應(yīng)的圓心角，alphaAngle=(currentValue/maxValue)*360
   */
  private float alphaAngle;
 
  /**
   * 底部圓弧的顏色，默認為Color.LTGRAY
   */
  private int firstColor;
 
  /**
   * 進度條圓弧塊的顏色
   */
  private int secondColor;
  /**
   * 中間文字顏色(默認藍色)
   */
  private int centerTextColor = Color.BLUE;
  /**
   * 中間文字的字體大小(默認40dp)
   */
  private int centerTextSize;
 
  /**
   * 圓環(huán)的寬度
   */
  private int circleWidth;
 
  /**
   * 畫圓弧的畫筆
   */
  private Paint circlePaint;
 
  /**
   * 畫文字的畫筆
   */
  private Paint textPaint;
  /**
   * 是否使用漸變色
   */
  private boolean isShowGradient = false;
 
  /**
   * 漸變圓周顏色數(shù)組
   */
  private int[] colorArray = new int[]{Color.parseColor("#2773FF"),
      Color.parseColor("#27C0D2"), Color.parseColor("#40C66E")};
  private int duration;
  private OnFinishListener listener;
  private ValueAnimator animator;
 
  public CountDownProgressBar(Context context) {
    this(context, null);
  }
 
 
  public CountDownProgressBar(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
  }
 
 
  public CountDownProgressBar(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
 
    TypedArray ta = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CountDownProgressBar,
        defStyleAttr, 0);
    int n = ta.getIndexCount();
 
    for (int i = 0; i < n; i++) {
      int attr = ta.getIndex(i);
      switch (attr) {
        case R.styleable.CountDownProgressBar_countDown_firstColor:
          firstColor = ta.getColor(attr, Color.LTGRAY); // 默認底色為亮灰色
          break;
        case R.styleable.CountDownProgressBar_countDown_secondColor:
          secondColor = ta.getColor(attr, Color.BLUE); // 默認進度條顏色為藍色
          break;
        case R.styleable.CountDownProgressBar_countDown_centerTextSize:
          centerTextSize = ta.getDimensionPixelSize(attr, (int) dip2px(40)); // 默認中間文字字體大小為40dp
          break;
        case R.styleable.CountDownProgressBar_countDown_circleWidth:
          circleWidth = ta.getDimensionPixelSize(attr, (int) dip2px(6f)); // 默認圓弧寬度為6dp
          break;
        case R.styleable.CountDownProgressBar_countDown_centerTextColor:
          centerTextColor = ta.getColor(attr, Color.BLUE); // 默認中間文字顏色為藍色
          break;
        case R.styleable.CountDownProgressBar_countDown_isShowGradient:
          isShowGradient = ta.getBoolean(attr, false); // 默認不適用漸變色
          break;
        default:
          break;
      }
    }
    ta.recycle();
 
    circlePaint = new Paint();
    circlePaint.setAntiAlias(true); // 抗鋸齒
    circlePaint.setDither(true); // 防抖動
    circlePaint.setStrokeWidth(circleWidth);//畫筆寬度
 
    textPaint = new Paint();
    textPaint.setAntiAlias(true);
    textPaint.setDither(true);
  }
 
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    // 分別獲取期望的寬度和高度，并取其中較小的尺寸作為該控件的寬和高,并且不超過屏幕寬高
    int widthPixels = this.getResources().getDisplayMetrics().widthPixels;//獲取屏幕寬
    int heightPixels = this.getResources().getDisplayMetrics().heightPixels;//獲取屏幕高
    int width = MeasureSpec.getSize(widthMeasureSpec);
    int hedight = MeasureSpec.getSize(heightMeasureSpec);
    int minWidth = Math.min(widthPixels, width);
    int minHedight = Math.min(heightPixels, hedight);
    setMeasuredDimension(Math.min(minWidth, minHedight), Math.min(minWidth, minHedight));
  }
 
  @Override
  protected void onDraw(Canvas canvas) {
    int center = this.getWidth() / 2;
    int radius = center - circleWidth / 2;
 
    drawCircle(canvas, center, radius); // 繪制進度圓弧
    drawText(canvas, center);
  }
 
  /**
   * 繪制進度圓弧
   *
   * @param canvas 畫布對象
   * @param center 圓心的x和y坐標
   * @param radius 圓的半徑
   */
  private void drawCircle(Canvas canvas, int center, int radius) {
    circlePaint.setShader(null); // 清除上一次的shader
    circlePaint.setColor(firstColor); // 設(shè)置底部圓環(huán)的顏色，這里使用第一種顏色
    circlePaint.setStyle(Paint.Style.STROKE); // 設(shè)置繪制的圓為空心
    canvas.drawCircle(center, center, radius, circlePaint); // 畫底部的空心圓
    RectF oval = new RectF(center - radius, center - radius, center + radius, center + radius); // 圓的外接正方形
    if (isShowGradient) {
      // 繪制顏色漸變圓環(huán)
      // shader類是Android在圖形變換中非常重要的一個類。Shader在三維軟件中我們稱之為著色器，其作用是來給圖像著色。
      LinearGradient linearGradient = new LinearGradient(circleWidth, circleWidth, getMeasuredWidth()
          - circleWidth, getMeasuredHeight() - circleWidth, colorArray, null, Shader.TileMode.MIRROR);
      circlePaint.setShader(linearGradient);
    }
    circlePaint.setShadowLayer(10, 10, 10, Color.BLUE);
    circlePaint.setColor(secondColor); // 設(shè)置圓弧的顏色
    circlePaint.setStrokeCap(Paint.Cap.ROUND); // 把每段圓弧改成圓角的
 
    alphaAngle = currentValue * 360.0f / maxValue * 1.0f; // 計算每次畫圓弧時掃過的角度，這里計算要注意分母要轉(zhuǎn)為float類型，否則alphaAngle永遠為0
    canvas.drawArc(oval, -90, alphaAngle, false, circlePaint);
  }
 
  /**
   * 繪制文字
   *
   * @param canvas 畫布對象
   * @param center 圓心的x和y坐標
   */
  private void drawText(Canvas canvas, int center) {
    int result = ((maxValue - currentValue) * (duration / 1000) / maxValue); // 計算進度
    String percent;
    if (maxValue == currentValue) {
      percent = "完成";
      textPaint.setTextSize(centerTextSize); // 設(shè)置要繪制的文字大小
    } else {
      percent = (result / 60 < 10 ? "0" + result / 60 : result / 60) + ":" + (result % 60 < 10 ? "0" + result % 60 : result % 60);
//      percent = result+"秒";
      textPaint.setTextSize(centerTextSize+centerTextSize/3); // 設(shè)置要繪制的文字大小
    }
    textPaint.setTextAlign(Paint.Align.CENTER); // 設(shè)置文字居中，文字的x坐標要注意
    textPaint.setColor(centerTextColor); // 設(shè)置文字顏色
 
    textPaint.setStrokeWidth(0); // 注意此處一定要重新設(shè)置寬度為0,否則繪制的文字會重疊
    Rect bounds = new Rect(); // 文字邊框
    textPaint.getTextBounds(percent, 0, percent.length(), bounds); // 獲得繪制文字的邊界矩形 
    FontMetricsInt fontMetrics = textPaint.getFontMetricsInt(); // 獲取繪制Text時的四條線 
    int baseline = center + (fontMetrics.bottom - fontMetrics.top) / 2 - fontMetrics.bottom; // 計算文字的基線    canvas.drawText(percent, center, baseline, textPaint); // 繪制表示進度的文字
  
  }
 
  /**
   * 設(shè)置圓環(huán)的寬度
   *
   * @param width
   */
  public void setCircleWidth(int width) {
    this.circleWidth = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, width, getResources()
        .getDisplayMetrics());
    circlePaint.setStrokeWidth(circleWidth);
    //一般只是希望在View發(fā)生改變時對UI進行重繪。invalidate()方法系統(tǒng)會自動調(diào)用 View的onDraw()方法。
    invalidate();
  }
 
  /**
   * 設(shè)置圓環(huán)的底色，默認為亮灰色LTGRAY
   *
   * @param color
   */
  public void setFirstColor(int color) {
    this.firstColor = color;
    circlePaint.setColor(firstColor);
    //一般只是希望在View發(fā)生改變時對UI進行重繪。invalidate()方法系統(tǒng)會自動調(diào)用 View的onDraw()方法。
    invalidate();
  }
 
  /**
   * 設(shè)置進度條的顏色，默認為藍色<br>
   *
   * @param color
   */
  public void setSecondColor(int color) {
    this.secondColor = color;
    circlePaint.setColor(secondColor);
    //一般只是希望在View發(fā)生改變時對UI進行重繪。invalidate()方法系統(tǒng)會自動調(diào)用 View的onDraw()方法。
    invalidate();
  }
 
  /**
   * 設(shè)置進度條漸變色顏色數(shù)組
   *
   * @param colors 顏色數(shù)組，類型為int[]
   */
  public void setColorArray(int[] colors) {
    this.colorArray = colors;
    //一般只是希望在View發(fā)生改變時對UI進行重繪。invalidate()方法系統(tǒng)會自動調(diào)用 View的onDraw()方法。
    invalidate();
  }
 
 
  /**
   * 按進度顯示百分比，可選擇是否啟用數(shù)字動畫
   *
   * @param duration 動畫時長
   */
  public void setDuration(int duration, OnFinishListener listener) {
     this.listener = listener;
    this.duration = duration + 1000;
    if (animator != null) {
      animator.cancel();
    } else {
      animator = ValueAnimator.ofInt(0, maxValue);
      animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
          currentValue = (int) animation.getAnimatedValue();
          //一般只是希望在View發(fā)生改變時對UI進行重繪。invalidate()方法系統(tǒng)會自動調(diào)用 View的onDraw()方法。
          invalidate();
          if (maxValue == currentValue && CountDownProgressBar.this.listener != null) {
            CountDownProgressBar.this.listener.onFinish();
          }
        }
      });
      animator.setInterpolator(new LinearInterpolator());
    }
    animator.setDuration(duration);
    animator.start();
  }
 
  public interface OnFinishListener {
    void onFinish();
  }
 
  public void setOnFinishListener(OnFinishListener listener) {
    this.listener = listener;
  }
 
  public static int px2dip(int pxValue) {
    final float scale = Resources.getSystem().getDisplayMetrics().density;
    return (int) (pxValue / scale + 0.5f);
  }
 
 
  public static float dip2px(float dipValue) {
    final float scale = Resources.getSystem().getDisplayMetrics().density;
    return (dipValue * scale + 0.5f);
  }
} 

<?xml version="1.0" encoding="utf-8"?>
<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:layout_width="match_parent"
  android:text="開始"
  android:id="@+id/btn_start"
  android:layout_height="wrap_content" />
  <com.daodaojk.myapplication.view.CountDownProgressBar
    android:id="@+id/cpb_countdown"
    android:layout_width="200dp"
    android:layout_marginTop="100dp"
    android:layout_gravity="center_horizontal"
    app:countDown_centerTextSize="25dp"
    app:countDown_circleWidth="4dp"
    app:countDown_firstColor="@color/text_gray_ccc"
    app:countDown_secondColor="@color/text_blue"
    app:countDown_isShowGradient="true"
    app:countDown_centerTextColor="#2395FF"
    android:layout_height="200dp" />
</LinearLayout>

package com.daodaojk.myapplication.ui;
 
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
 
import com.daodaojk.myapplication.R;
import com.daodaojk.myapplication.view.CountDownProgressBar;
 
public class CountDownActivity extends AppCompatActivity {
 
  private CountDownProgressBar cpb_countdown;
 
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_count_down);
    Button btn_start = findViewById(R.id.btn_start);
    cpb_countdown = (CountDownProgressBar) findViewById(R.id.cpb_countdown);
    btn_start.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        cpb_countdown.setDuration(10000, new CountDownProgressBar.OnFinishListener() {
          @Override
          public void onFinish() {
            Toast.makeText(CountDownActivity.this, "完成了", Toast.LENGTH_SHORT).show();
          }
        });
      }
    });
  }
}