<?xml version="1.0" encoding="utf-8"?>
<resources>
 
  <declare-styleable name="circleProgressBar">
    <attr name="circleWidth" format="dimension" />
    <attr name="betaAngle" format="integer" />
    <attr name="firstColor" format="color" />
    <attr name="secondColor" format="color" />
  </declare-styleable>
 
</resources>

package com.ctgu.circleprogressbar;
 
import android.animation.ValueAnimator;
import android.content.Context;
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.OvershootInterpolator;
 
public class CircleProgressBar extends View
{
 /**
 * 進(jìn)度條最大值，默認(rèn)為100
 */
 private int maxValue = 100;
 
 /**
 * 當(dāng)前進(jìn)度值
 */
 private int currentValue = 0;
 
 /**
 * 每次掃過的角度，用來設(shè)置進(jìn)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(rèn)為Color.LTGRAY
 */
 private int firstColor;
 
 /**
 * 進(jìn)度條圓弧塊的顏色
 */
 private int secondColor;
 
 /**
 * 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;
 
 /**
 * 漸變圓周顏色數(shù)組
 */
 private int[] colorArray = new int[] { Color.parseColor("#27B197"), Color.parseColor("#00A6D5") };//
 
 /**
 * 通過代碼創(chuàng)建時才使用
 * 
 * @param context
 */
 public CircleProgressBar(Context context)
 {
 this(context, null);
 }
 
 /**
 * 當(dāng)從xml中加載view的時候，這個構(gòu)造器才會被調(diào)用。其第二個參數(shù)中就包含自定義的屬性。
 * 
 * @param context
 *      上下文
 * @param attrs
 *      自定義屬性
 */
 public CircleProgressBar(Context context, AttributeSet attrs)
 {
 this(context, attrs, 0);
 }
 
 /**
 * 從xml加載時執(zhí)行和應(yīng)用一個特定的風(fēng)格。這里有兩種方式，一是從theme中獲得，二是從style中獲得。    
 * 第三個參數(shù)官方有這樣的說明： defStyle - The default style to apply to this view. If 0,
 * no style will be applied (beyond what is included in the theme). This may
 * either be an attribute resource, whose value will be retrieved from the
 * current theme, or an explicit style resource.
 * 默認(rèn)的風(fēng)格會被應(yīng)用到這個view上。如果是0，沒有風(fēng)格將會被應(yīng)用
 * （除了被包含在主題中）。這個也許是一個屬性的資源，它的值是從當(dāng)前的主題中檢索，或者是一個明確的風(fēng)格資源。
 * 
 * @param context
 *      上下文
 * @param attrs
 *      自定義的屬性
 * @param defStyleAttr
 *      自定義風(fēng)格
 */
 public CircleProgressBar(Context context, AttributeSet attrs, int defStyleAttr)
 {
 super(context, attrs, defStyleAttr);
 
 TypedArray ta = context.getTheme().obtainStyledAttributes(attrs, R.styleable.circleProgressBar,
  defStyleAttr, 0);
 int n = ta.getIndexCount();
 
 for (int i = 0; i < n; i++)
 {
  int attr = ta.getIndex(i);
  switch (attr)
  {
  case R.styleable.circleProgressBar_firstColor:
   firstColor = ta.getColor(attr, Color.LTGRAY); // 默認(rèn)底色為亮灰色
   break;
  case R.styleable.circleProgressBar_secondColor:
   secondColor = ta.getColor(attr, Color.BLUE); // 默認(rèn)進(jìn)度條顏色為藍(lán)色
   break;
  case R.styleable.circleProgressBar_circleWidth:
   circleWidth = ta.getDimensionPixelSize(attr, (int) TypedValue.applyDimension(
    TypedValue.COMPLEX_UNIT_DIP, 6, getResources().getDisplayMetrics())); // 默認(rèn)圓弧寬度為6dp
   break;
  default:
   break;
  }
 }
 ta.recycle();
 
 circlePaint = new Paint();
 circlePaint.setAntiAlias(true); // 抗鋸齒
 circlePaint.setDither(true); // 防抖動
 circlePaint.setStrokeWidth(circleWidth);
 
 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
 int measureWidth = MeasureSpec.getSize(widthMeasureSpec);
 int measureHeight = MeasureSpec.getSize(heightMeasureSpec);
 setMeasuredDimension(Math.min(measureWidth, measureHeight), Math.min(measureWidth, measureHeight));
 }
 
 @Override
 protected void onDraw(Canvas canvas)
 {
 int center = this.getWidth() / 2;
 int radius = center - circleWidth / 2;
 
 drawCircle(canvas, center, radius); // 繪制進(jìn)度圓弧
 drawText(canvas, center, radius);
 }
 
 /**
 * 繪制進(jìn)度圓弧
 * 
 * @param canvas
 *      畫布對象
 * @param center
 *      圓心的x和y坐標(biāo)
 * @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
 
 // 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.RED);
 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(yuǎn)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(biāo)
 * @param radius
 *      圓的半徑
 */
 private void drawText(Canvas canvas, int center, int radius)
 {
 float result = (currentValue * 100.0f / maxValue * 1.0f); // 計算進(jìn)度
 String percent = String.format("%.1f", result) + "%";
 
 textPaint.setTextAlign(Paint.Align.CENTER); // 設(shè)置文字居中，文字的x坐標(biāo)要注意
 textPaint.setColor(Color.BLACK); // 設(shè)置文字顏色
 textPaint.setTextSize(40); // 設(shè)置要繪制的文字大小
 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,方法見http://blog.csdn.net/harvic880925/article/details/50423762
 canvas.drawText(percent, center, baseline, textPaint); // 繪制表示進(jìn)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);
 invalidate();
 }
 
 /**
 * 設(shè)置圓環(huán)的底色，默認(rèn)為亮灰色LTGRAY
 * 
 * @param color
 */
 public void setFirstColor(int color)
 {
 this.firstColor = color;
 circlePaint.setColor(firstColor);
 invalidate();
 }
 
 /**
 * 設(shè)置進(jìn)度條的顏色，默認(rèn)為藍(lán)色<br>
 * 
 * @param color
 */
 public void setSecondColor(int color)
 {
 this.secondColor = color;
 circlePaint.setColor(secondColor);
 invalidate();
 }
 
 /**
 * 設(shè)置進(jìn)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;
 invalidate();
 }
 
 /**
 * 按進(jìn)度顯示百分比
 * 
 * @param progress
 *      進(jìn)度，值通常為0到100
 */
 public void setProgress(int progress)
 {
 int percent = progress * maxValue / 100;
 if (percent < 0)
 {
  percent = 0;
 }
 if (percent > 100)
 {
  percent = 100;
 }
 this.currentValue = percent;
 invalidate();
 }
 
 /**
 * 按進(jìn)度顯示百分比，可選擇是否啟用數(shù)字動畫
 * 
 * @param progress
 *      進(jìn)度，值通常為0到100
 * @param useAnimation
 *      是否啟用動畫，true為啟用
 */
 public void setProgress(int progress, boolean useAnimation)
 {
 int percent = progress * maxValue / 100;
 if (percent < 0)
 {
  percent = 0;
 }
 if (percent > 100)
 {
  percent = 100;
 }
 if (useAnimation) // 使用動畫
 {
  ValueAnimator animator = ValueAnimator.ofInt(0, percent);
  animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener()
  {
  @Override
  public void onAnimationUpdate(ValueAnimator animation)
  {
   currentValue = (int) animation.getAnimatedValue();
   invalidate();
  }
  });
  animator.setInterpolator(new OvershootInterpolator());
  animator.setDuration(1000);
  animator.start();
 }
 else
 {
  setProgress(progress);
 }
 }
}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  xmlns:lh2="http://schemas.android.com/apk/res/com.ctgu.circleprogressbar"
  android:layout_width="match_parent"
  android:layout_height="match_parent" >
 
  <com.ctgu.circleprogressbar.CircleProgressBar
    android:id="@+id/circleProgressBar"
    android:layout_width="150dp"
    android:layout_height="150dp"
    android:layout_centerHorizontal="true"
    android:layout_gravity="center"
    android:layout_marginTop="20dp"
    lh2:circleWidth="6dp"
    lh2:firstColor="#d3d3d3"
    lh2:secondColor="#3B95C8" />
 
  <SeekBar
    android:id="@+id/seekbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_marginBottom="40dp"
    android:layout_marginLeft="10dp"
    android:layout_marginRight="10dp"
    android:background="#778899" />
 
</RelativeLayout>

package com.ctgu.circleprogressbar;
 
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.os.Handler;
import android.widget.SeekBar;
 
public class MainActivity extends Activity
{
 private CircleProgressBar circleProgressBar; // 自定義的進(jìn)度條
 private SeekBar seekbar; // 拖動條
 
 private int[] colors = new int[] { Color.parseColor("#27B197"), Color.parseColor("#00A6D5") };
 
 @Override
 protected void onCreate(Bundle savedInstanceState)
 {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 
 circleProgressBar = (CircleProgressBar) findViewById(R.id.circleProgressBar);
// circleProgressBar.setFirstColor(Color.LTGRAY);
// circleProgressBar.setColorArray(colors); //覺得進(jìn)度條顏色丑的，這里可以自行傳入一個顏色漸變數(shù)組。
// circleProgressBar.setCircleWidth(6);
 
 seekbar = (SeekBar) findViewById(R.id.seekbar);
 seekbar.setMax(100);
 seekbar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener()
 {
  @Override
  public void onStopTrackingTouch(SeekBar seekBar)
  {
 
  }
 
  @Override
  public void onStartTrackingTouch(SeekBar seekBar)
  {
 
  }
 
  @Override
  public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser)
  {
  if (fromUser)
  {
   // circleProgressBar.setProgress(progress); //不使用動畫
   circleProgressBar.setProgress(progress, true); // 使用數(shù)字過渡動畫
  }
  }
 });
 }
}