TasksCompletedView.java 程式碼如下

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 {

        // 畫實心圓的畫筆
        private Paint mCirclePaint;
        // 畫圓環的畫筆
        private Paint mRingPaint;
        // 畫字型的畫筆
        private Paint mTextPaint;
        // 圓形顏色
        private int mCircleColor;
        // 圓環顏色
        private int mRingColor;
        // 半徑
        private float mRadius;
        // 圓環半徑
        private float mRingRadius;
        // 圓環寬度
        private float mStrokeWidth;
        // 圓心x座標
        private int mXCenter;
        // 圓心y座標
        private int mYCenter;
        // 字的長度
        private float mTxtWidth;
        // 字的高度
        private float mTxtHeight;
        // 總進度
        private int mTotalProgress = 100;
        // 當前進度
        private int mProgress;

        public TasksCompletedView(Context context, AttributeSet attrs) {
                super(context, attrs);
                // 獲取自定義的屬性
                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>