Android自定义漂亮的圆形进度条

import android.content.Context; 
import android.content.res.TypedArray; 
import android.graphics.Canvas; 
import android.graphics.Paint; 
import android.graphics.RectF; 
import android.graphics.Paint.FontMetrics; 
import android.util.AttributeSet; 
import android.view.View; 
 
import com.snailws.taskscompleted.R; 
 
/** 
* @author naiyu(http://snailws.com) 
* @version 1.0 
*/ 
public class TasksCompletedView extends View { 
 
    // 画实心圆的画笔 
    private Paint mCirclePaint; 
    // 画圆环的画笔 
    private Paint mRingPaint; 
    // 画字体的画笔 
    private Paint mTextPaint; 
    // 圆形颜色 
    private int mCircleColor; 
    // 圆环颜色 
    private int mRingColor; 
    // 半径 
    private float mRadius; 
    // 圆环半径 
    private float mRingRadius; 
    // 圆环宽度 
    private float mStrokeWidth; 
    // 圆心x坐标 
    private int mXCenter; 
    // 圆心y坐标 
    private int mYCenter; 
    // 字的长度 
    private float mTxtWidth; 
    // 字的高度 
    private float mTxtHeight; 
    // 总进度 
    private int mTotalProgress = 100; 
    // 当前进度 
    private int mProgress; 
 
    public TasksCompletedView(Context context, AttributeSet attrs) { 
        super(context, attrs); 
        // 获取自定义的属性 
        initAttrs(context, attrs); 
        initVariable(); 
    } 
 
    private void initAttrs(Context context, AttributeSet attrs) { 
        TypedArray typeArray = context.getTheme().obtainStyledAttributes(attrs, 
                R.styleable.TasksCompletedView, 0, 0); 
        mRadius = typeArray.getDimension(R.styleable.TasksCompletedView_radius, 80); 
        mStrokeWidth = typeArray.getDimension(R.styleable.TasksCompletedView_strokeWidth, 10); 
        mCircleColor = typeArray.getColor(R.styleable.TasksCompletedView_circleColor, 0xFFFFFFFF); 
        mRingColor = typeArray.getColor(R.styleable.TasksCompletedView_ringColor, 0xFFFFFFFF); 
         
        mRingRadius = mRadius + mStrokeWidth / 2; 
    } 
 
    private void initVariable() { 
        mCirclePaint = new Paint(); 
        mCirclePaint.setAntiAlias(true); 
        mCirclePaint.setColor(mCircleColor); 
        mCirclePaint.setStyle(Paint.Style.FILL); 
         
        mRingPaint = new Paint(); 
        mRingPaint.setAntiAlias(true); 
        mRingPaint.setColor(mRingColor); 
        mRingPaint.setStyle(Paint.Style.STROKE); 
        mRingPaint.setStrokeWidth(mStrokeWidth); 
         
        mTextPaint = new Paint(); 
        mTextPaint.setAntiAlias(true); 
        mTextPaint.setStyle(Paint.Style.FILL); 
        mTextPaint.setARGB(255, 255, 255, 255); 
        mTextPaint.setTextSize(mRadius / 2); 
         
        FontMetrics fm = mTextPaint.getFontMetrics(); 
        mTxtHeight = (int) Math.ceil(fm.descent - fm.ascent); 
         
    } 
 
    @Override 
    protected void onDraw(Canvas canvas) { 
 
        mXCenter = getWidth() / 2; 
        mYCenter = getHeight() / 2; 
         
        canvas.drawCircle(mXCenter, mYCenter, mRadius, mCirclePaint); 
         
        if (mProgress > 0 ) { 
            RectF oval = new RectF(); 
            oval.left = (mXCenter - mRingRadius); 
            oval.top = (mYCenter - mRingRadius); 
            oval.right = mRingRadius * 2 + (mXCenter - mRingRadius); 
            oval.bottom = mRingRadius * 2 + (mYCenter - mRingRadius); 
            canvas.drawArc(oval, -90, ((float)mProgress / mTotalProgress) * 360, false, mRingPaint); // 
//            canvas.drawCircle(mXCenter, mYCenter, mRadius + mStrokeWidth / 2, mRingPaint); 
            String txt = mProgress + "%"; 
            mTxtWidth = mTextPaint.measureText(txt, 0, txt.length()); 
            canvas.drawText(txt, mXCenter - mTxtWidth / 2, mYCenter + mTxtHeight / 4, mTextPaint); 
        } 
    } 
     
    public void setProgress(int progress) { 
        mProgress = progress; 
//        invalidate(); 
        postInvalidate(); 
    } 
 
} 

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