Android实现IM多人员组合的群组头像

@Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  mWidth = getWidth(widthMeasureSpec);
  mHeight = getHeight(heightMeasureSpec);
  setMeasuredDimension(mWidth, mHeight);
 }
 
 private int getWidth(int measureSpec) {
  int width = MIN_WIDTH_AND_HEIGHT;
  int specMode = MeasureSpec.getMode(measureSpec);
  int specSize = MeasureSpec.getSize(measureSpec);
  if (specMode == MeasureSpec.EXACTLY) {
   width = specSize;
  } else if (specMode == MeasureSpec.AT_MOST) {
   width = Math.min(MIN_WIDTH_AND_HEIGHT, specSize);
  }
  return width;
 }
 
 private int getHeight(int measureSpec) {
  int height = MIN_WIDTH_AND_HEIGHT;
  int specMode = MeasureSpec.getMode(measureSpec);
  int specSize = MeasureSpec.getSize(measureSpec);
  if (specMode == MeasureSpec.EXACTLY) {
   height = specSize;
  } else if (specMode == MeasureSpec.AT_MOST) {
   height = Math.min(MIN_WIDTH_AND_HEIGHT, specSize);
  }
  return height;
 }

@Override
 protected void onLayout(boolean changed, int l, int t, int r, int b) {
  layoutChild();
 }
 
 private void layoutChild() {
  if (mImgUrls == null || mImgUrls.isEmpty()) {
   return;
  }
  for (int i = 0; i < mImgSize; i++) {
   ImageView itemV = (ImageView) getChildAt(i);
   int left = 0, top = 0, right = 0, bottom = 0;
   /*
   对每个item的View计算left、top、right、bottom四个值
    */
   ...
   itemV.layout(left, top, right, bottom); //真正布局子头像位置
   showImage(itemV, mImgUrls.get(i)); //加载并显示子头像图片
  }
 }

private void showImage(Context context, ImageView iv, String url) {
  if (TextUtils.isEmpty(url)) {
   Bitmap bmp = BitmapFactory.decodeResource(context.getResources(), R.mipmap.user_default_icon);
   iv.setImageBitmap(bmp);
   return;
  }
  Glide.with(context).load(url)
    .diskCacheStrategy(DiskCacheStrategy.ALL)
    .dontAnimate()
    .placeholder(R.mipmap.user_default_icon)
    .error(R.mipmap.user_default_icon)
    .into(iv);
 }

@Override
 protected void dispatchDraw(Canvas canvas) {
  Path path = new Path();
  path.addCircle(mWidth / 2, mHeight / 2, mWidth / 2, Path.Direction.CW);
  canvas.clipPath(path);
  canvas.drawColor(Color.TRANSPARENT);
  super.dispatchDraw(canvas);
  drawGroupView(canvas);
 }
 
 /**
  * 绘制各头像间隔线
  * @param canvas
  */
 private void drawGroupView(Canvas canvas) {
  /*
  计算各条线的x和y坐标值
   */
  float[] point1 = new float[2], point2 = new float[2];
  ...
  drawLine(canvas, point1, point2);
 }
 
 /**
  * 绘制直线
  */
 private void drawLine(Canvas canvas, float[] point1, float[] point2) {
  mPaint.reset();
  mPaint.setAntiAlias(true);
  mPaint.setStrokeWidth(mInterval);
  mPaint.setColor(Color.WHITE);
  mPaint.setStyle(Paint.Style.STROKE);
  canvas.drawLine(point1[0], point1[1], point2[0], point2[1], mPaint);
 }

/**
  * 设置图片url集合
  *
  * @param imgs 图片url集合
  */
 public void setImages(List<String> imgs) {
  if (imgs == null || imgs.isEmpty()) {
   return;
  }
  if (imgs.size() > MAX_SIZE) {
   imgs = imgs.subList(0, MAX_SIZE);
  }
  removeAllViews();
  mImgUrls = imgs;
  mImgSize = imgs.size();
  for (int i = 0; i < mImgSize; i++) {
   View v = getItemView(i);
   if (v == null) {
    return;
   }
   addView(v, generateDefaultLayoutParams());
  }
  requestLayout();
 }
 
 /**
  * 设置单个图片url
  *
  * @param img 图片url
  */
 public void setImageUrl(String img) {
  ArrayList imgUrls = new ArrayList<>();
  imgUrls.add(img);
  setImages(imgUrls);
 }
 
 /**
  * 生成一个头像布局
  */
 private ImageView getItemView(int position) {
  ...
 }

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#f2f2f2"
    android:orientation="vertical">
 
 <com.yyh.im.ui.widget.HeadView
  android:id="@+id/cv_head"
  android:layout_width="150dp"
  android:layout_height="150dp"/>
 
</LinearLayout>

@BindView(R2.id.cv_head)
 public HeadView mHeadCv;
 
 private String[] IMG_URL_LIST = {
   "70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=416954025,2289731303&fm=27&gp=0.jpg",
   "70cFuXSh_Q1YnxGkpoWK1HF6hhy/it/u=704997830,3098922597&fm=27&gp=0.jpg",
   "70cFvXSh_Q1YnxGkpoWK1HF6hhy/it/u=1375449509,557259337&fm=27&gp=0.jpg",
   "70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=2825392570,1862752263&fm=27&gp=0.jpg",
   "70cFvXSh_Q1YnxGkpoWK1HF6hhy/it/u=3252489351,440833245&fm=27&gp=0.jpg",
   "70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=3586311245,3082636880&fm=27&gp=0.jpg"
 };
 
 private void showImage(){
  ArrayList<String> list = new ArrayList<>();
  for (int i = 0; i < 6; i++) {
   list.add(IMG_URL_LIST[i]);
  }
  mHeadCv.setImageUrls(list);
 }