Android自定义圆形ProgressBar

闲来无事做了一个自定义的进度条，大致效果图如下：

progressbar.gif

废话不多说，下面直接上代码：
自定义控件代码CircleProgressBar.java：

public class CircleProgressBar extends View{
  // 画圆环的画笔
  private Paint ringPaint;
  // 画字体的画笔
  private Paint textPaint;
  // 圆环颜色
  private int ringColor;
  // 字体颜色
  private int textColor;
  // 半径
  private float radius;
  // 圆环宽度
  private float strokeWidth;
  // 字的长度
  private float txtWidth;
  // 字的高度
  private float txtHeight;
  // 总进度
  private int totalProgress = 100;
  // 当前进度
  private int currentProgress;
  // 透明度   private int alpha = 25;      

  public CircleProgressBar(Context context, AttributeSet attrs) {
    super(context, attrs);
    initAttrs(context, attrs);
    initVariable();
  }   

  private void initAttrs(Context context, AttributeSet attrs) {
    TypedArray typeArray = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CircleProgressbar, 0 , 0);
    radius = typeArray.getDimension(R.styleable.CircleProgressbar_radius, 80);
    strokeWidth = typeArray.getDimension(R.styleable.CircleProgressbar_strokeWidth, 10);
    ringColor = typeArray.getColor(R.styleable.CircleProgressbar_ringColor, 0xFF0000);
    textColor = typeArray.getColor(R.styleable.CircleProgressbar_textColor, 0xFFFFFF);
  }      

  private void initVariable() {
    ringPaint = new Paint();
    ringPaint.setAntiAlias(true);
    ringPaint.setDither(true);
    ringPaint.setColor(ringColor);
    ringPaint.setStyle(Paint.Style.STROKE);
    ringPaint.setStrokeCap(Cap.ROUND);
    ringPaint.setStrokeWidth(strokeWidth);
    textPaint = new Paint();
    textPaint.setAntiAlias(true);
    textPaint.setStyle(Paint.Style.FILL);
    textPaint.setColor(textColor);
    textPaint.setTextSize(radius/2);
    FontMetrics fm = textPaint.getFontMetrics();
    txtHeight = fm.descent + Math.abs(fm.ascent);
  }   

  @Override
  protected void onDraw(Canvas canvas) {
    if (currentProgress >= 0) {
      ringPaint.setAlpha((int) (alpha + ((float) currentProgress / totalProgress)*230));
      RectF oval = new RectF(getWidth() / 2 - radius, getHeight() / 2 - radius, getWidth() / 2 + radius, getHeight() / 2 + radius);
      canvas.drawArc(oval, 0, 0, false, ringPaint);
      canvas.drawArc(oval, -90, ((float) currentProgress / totalProgress) * 360, false, ringPaint);
      String txt = currentProgress + "%";
      txtWidth = textPaint.measureText(txt, 0, txt.length());
      canvas.drawText(txt, getWidth() / 2 - txtWidth / 2, getHeight() / 2 + txtHeight / 4, textPaint);
    }
  }      

  public void setProgress(int progress) {
    currentProgress = progress;
    postInvalidate();
  }
}

自定义控件的属性文件attrs.xml：

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <declare-styleable name="CircleProgressbar">
    <attr name="radius" format="dimension"/>
    <attr name="strokeWidth" format="dimension"/>
    <attr name="ringColor" format="color"/>
    <attr name="textColor" format="color"/>
  </declare-styleable>
</resources>

下面是主界面的布局文件和具体实现：
布局activity_main.xml：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:cp="http://schemas.android.com/apk/res-auto"
  android:layout_width="match_parent"
  android:layout_height="match_parent">
  <me.my.circleprogressbar.CircleProgressBar
    android:id="@+id/circleProgressbar"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    cp:radius="80dp"
    cp:strokeWidth="10dp"
    cp:ringColor="#ff0000"
    cp:textColor="#0000ff"/>
</RelativeLayout>

实现MainActivity.java：

public class MainActivity extends Activity {
  private CircleProgressBar circleProgressBar;
  private int totalProgress = 100;
  private int currentProgress;    

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    circleProgressBar = (CircleProgressBar) findViewById(R.id.circleProgressbar);
    new Thread(new ProgressRunable()).start();
  }    

  class ProgressRunable implements Runnable {
    @Override
    public void run() {
      while (currentProgress < totalProgress) {
        currentProgress += 1;
        circleProgressBar.setProgress(currentProgress);
        try {
          Thread.sleep(100);
        } catch (Exception e) {
          e.printStackTrace();
        }
      }
    }
  }
}

其实实现非常简单，就是通过进度画圆环，具体的我也就不多说了，代码中有不足之处希望大家批评指正，共同学习！