Android自定义View基础开发之图片加载进度条

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:custom="http://schemas.android.com/apk/res-auto"
 android:layout_width="match_parent"
 android:layout_height="match_parent">
 <ImageView
 android:id="@+id/img"
 android:layout_width="200dp"
 android:layout_height="200dp"
 android:scaleType="centerCrop"
 android:layout_centerInParent="true"/>
 <com.example.circleprogresstest.CircleProgressView
 android:id="@+id/progressView"
 android:layout_width="60dp"
 android:layout_height="60dp"
 android:layout_centerInParent="true"
 custom:isShowProgress="true" />
</RelativeLayout>

ImageLoader.getInstance().displayImage(url, imageView, options,
 new SimpleImageLoadingListener() ,
 new ImageLoadingProgressListener() {
  @Override
  public void onProgressUpdate(String imageUri, View view, int current, int total) {
  if(current==total){
   progressView.setVisibility(View.GONE);
  }else{
   progressView.setSweepAngle((int)(360*current*1.0f/total));
   progressView.postInvalidate();
  }
  }
 }
);

protected void onDraw(Canvas canvas) {
 mWidth=getMeasuredWidth();
 mHeight=getMeasuredHeight();
 radius=(float)(Math.min(mWidth,mHeight)*1.0/2)-strokeWidth/2;
 //绘制内圈圆
 mPaint.setColor(initColor);
 mPaint.setStyle(Paint.Style.STROKE);
 mPaint.setStrokeWidth(strokeWidth);
 canvas.drawCircle(mWidth/2,mHeight/2,radius,mPaint);
 //绘制覆盖的圆弧
 mPaint.setColor(coverColor);
 RectF rectF=new RectF(mWidth/2-radius,mHeight/2-radius,mWidth/2+radius,mHeight/2+radius);
 canvas.drawArc(rectF,-90,sweepAngle,false,mPaint);
 //绘制中间的文本
 if(isShowProgress){
 progressText=String.format(getResources().getString(R.string.progress_text),(int)(sweepAngle*100.0/360));
 mPaint.setTextSize(textSize);
 mPaint.setColor(textColor);
 if(mBound==null){
  mBound=new Rect();
 }
 mPaint.getTextBounds(progressText,0,progressText.length(),mBound);
 mPaint.setStyle(Paint.Style.FILL);
 canvas.drawText(progressText,mWidth/2-mBound.width()/2,mHeight/2+mBound.height()/2,mPaint);
 }
}

<resources>
 <declare-styleable name="CircleProgressView">
 <attr name="initColor" format="color"/>
 <attr name="coverColor" format="color"/>
 <attr name="strokeWidth" format="dimension"/>
 <attr name="progressTextSize" format="dimension"/>
 <attr name="progressTextColor" format="color"/>
 <attr name="isShowProgress" format="boolean"/>
 </declare-styleable>
</resources>

private void initValues(Context context, AttributeSet attrs, int defStyleAttr){
 TypedArray typedArray=context.getTheme().obtainStyledAttributes(attrs,R.styleable.CircleProgressView,defStyleAttr,0);
 int num=typedArray.getIndexCount();
 for(int i=0;i<num;i++){
 int attr=typedArray.getIndex(i);
 switch (attr){
  case R.styleable.CircleProgressView_initColor:
  initColor=typedArray.getColor(attr,Color.GRAY);
  break;
  case R.styleable.CircleProgressView_coverColor:
  coverColor=typedArray.getColor(attr,Color.BLACK);
  break;
  case R.styleable.CircleProgressView_strokeWidth:
  strokeWidth=typedArray.getDimensionPixelOffset(attr,5);
  break;
  case R.styleable.CircleProgressView_progressTextSize:
  textSize=typedArray.getDimensionPixelSize(attr,30);
  break;
  case R.styleable.CircleProgressView_progressTextColor:
  textColor=typedArray.getColor(attr,Color.BLACK);
  break;
  case R.styleable.CircleProgressView_isShowProgress:
  isShowProgress=typedArray.getBoolean(attr,false);
  break;
  default:
  break;
 }
 }
 typedArray.recycle();

 mPaint=new Paint();
 mPaint.setAntiAlias(true);
}