Android仿微信群聊头像效果

public class NineGridImageView<T> extends ViewGroup{  private int mRowCount; //行数 private int mColumnCount; //列数  private int mMaxSize = 9; //最大图片数 private int mGap; //宫格间距  private int parentWidth;//父组件宽 private int parentHeight;//父组件高  private List<ImageView> mImageViewList = new ArrayList<>(); private List<T> mImgDataList;  private NineGridImageViewAdapter<T> mAdapter;  public NineGridImageView(Context context) {  this(context,null); }  public NineGridImageView(Context context, AttributeSet attrs) {  this(context, attrs, 0); }  public NineGridImageView(Context context, AttributeSet attrs, int defStyleAttr) {  super(context, attrs, defStyleAttr);  TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.NineGridImageView);  this.mGap = (int) typedArray.getDimension(R.styleable.NineGridImageView_imgGap, 8);  typedArray.recycle(); }  /**  * 设定宽高  */ @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {  super.onMeasure(widthMeasureSpec, heightMeasureSpec);  parentWidth = measureWidth(widthMeasureSpec);  parentHeight = measureHeight(heightMeasureSpec);   setMeasuredDimension(parentWidth,parentHeight); }  @Override protected void onLayout(boolean changed, int l, int t, int r, int b) {  layoutChildrenView(); }  /**  * 为子ImageView布局  */ private void layoutChildrenView(){  if(mImgDataList == null){   return;  }  int childrenCount = mImgDataList.size();  for(int i = 0; i < childrenCount; i++){   ImageView childrenView = (ImageView)getChildAt(i);   if(mAdapter != null){    mAdapter.onDisplayImage(getContext(), childrenView, mImgDataList.get(i));   }   int rowNum = i / mColumnCount;//当前行数   int columnNum = i % mColumnCount;//当前列数    int mImageSize = (parentWidth-(mColumnCount+1)*mGap)/mColumnCount;//图片尺寸    int t_center = (parentHeight + mGap)/2;//中间位置以下的顶点（有宫格间距）   int b_center = (parentHeight - mGap)/2;//中间位置以上的底部（有宫格间距）   int l_center = (parentWidth + mGap)/2;//中间位置以右的左部（有宫格间距）   int r_center = (parentWidth - mGap)/2;//中间位置以左的右部（有宫格间距）   int center = (parentHeight - mImageSize)/2;//中间位置以上顶部（无宫格间距）    int left = mImageSize * columnNum + mGap * (columnNum + 1);   int top = mImageSize * rowNum + mGap * (rowNum + 1);   int right = left + mImageSize;   int bottom = top + mImageSize;    /**    * 不同子view情况下的不同显示    */   if(childrenCount == 1){     childrenView.layout(left, top, right, bottom);   }else if(childrenCount == 2){     childrenView.layout(left, center, right, center + mImageSize);   }else if(childrenCount == 3){    if(i == 0){     childrenView.layout(center, top, center+mImageSize, bottom);    }else {     childrenView.layout(mGap * i +mImageSize * (i - 1), t_center, mGap * i +mImageSize * i, t_center+mImageSize);    }   }else if(childrenCount == 4){    childrenView.layout(left, top, right, bottom);   }else if(childrenCount == 5){    if(i == 0){     childrenView.layout(r_center - mImageSize, r_center - mImageSize, r_center, r_center);    }else if(i == 1){     childrenView.layout(l_center , r_center - mImageSize, l_center + mImageSize, r_center);    }else{     childrenView.layout(mGap * (i - 1) + mImageSize * (i - 2),t_center,mGap * (i - 1) + mImageSize * (i - 1),t_center+mImageSize);    }   }else if(childrenCount == 6){    if(i < 3) {     childrenView.layout(mGap * (i + 1) +mImageSize * i, b_center - mImageSize, mGap * (i + 1) + mImageSize * (i+1), b_center);    }else{     childrenView.layout(mGap * (i - 2) + mImageSize * (i - 3),t_center,mGap * (i - 2) + mImageSize * (i - 2),t_center+mImageSize);    }   }else if(childrenCount == 7){    if(i == 0){     childrenView.layout(center,mGap,center+mImageSize,mGap+mImageSize);    }else if(i > 0 && i < 4){     childrenView.layout(mGap * i +mImageSize * (i - 1),center,mGap * i +mImageSize * i,center+mImageSize);    }else{     childrenView.layout(mGap * (i - 3) + mImageSize * (i - 4),t_center+mImageSize/2,mGap * (i - 3) + mImageSize * (i - 3),t_center+mImageSize/2+mImageSize);    }   }else if(childrenCount == 8){    if(i == 0){     childrenView.layout(r_center - mImageSize,mGap,r_center,mGap+mImageSize);    }else if(i == 1){     childrenView.layout(l_center,mGap,l_center+mImageSize,mGap+mImageSize);    }else if(i > 1 && i < 5){     childrenView.layout(mGap * (i - 1) +mImageSize * (i - 2), center, mGap * (i - 1) +mImageSize * (i - 1), center+mImageSize);    }else{     childrenView.layout(mGap * (i - 4) + mImageSize * (i - 5), t_center+mImageSize/2, mGap * (i - 4) + mImageSize * (i - 4), t_center+mImageSize/2+mImageSize);    }   }else if(childrenCount == 9){    childrenView.layout(left, top, right, bottom);   }  } }  /**  * 设置图片数据  *  * @param lists 图片数据集合  */ public void setImagesData(List lists){  if(lists == null || lists.isEmpty()){   this.setVisibility(GONE);   return;  }else {   this.setVisibility(VISIBLE);  }   if(mMaxSize > 0 && lists.size() > mMaxSize){   lists = lists.subList(0, mMaxSize);  }   int[] gridParam = calculateGridParam(lists.size());  mRowCount = gridParam[0];  mColumnCount = gridParam[1];  if(mImgDataList == null){   int i = 0;   while (i < lists.size()){    ImageView iv = getImageView(i);    if(iv == null){     return;    }    addView(iv,generateDefaultLayoutParams());    i++;   }  }else {   int oldViewCount = mImgDataList.size();   int newViewCount = lists.size();   if(oldViewCount > newViewCount){    removeViews(newViewCount, oldViewCount - newViewCount);   }else if(oldViewCount < newViewCount){    for(int i = oldViewCount; i < newViewCount; i++){     ImageView iv = getImageView(i);     if(iv == null){      return;     }     addView(iv, generateDefaultLayoutParams());    }   }  }  mImgDataList = lists;  requestLayout(); }  /**  * 获得 ImageView  * 保证了 ImageView的重用  *  * @param position 位置  */ private ImageView getImageView(final int position){  if(position < mImageViewList.size()){   return mImageViewList.get(position);  }else{   if(mAdapter != null){    ImageView imageView = mAdapter.generateImageView(getContext());    mImageViewList.add(imageView);    return imageView;   }else{    Log.e("NineGirdImageView", "Your must set a NineGridImageViewAdapter for NineGirdImageView");    return null;   }  } }  /**  * 设置宫格参数  *  * @param imagesSize 图片数量  * @return 宫格参数 gridParam[0] 宫格行数 gridParam[1] 宫格列数  */ protected static int[] calculateGridParam(int imagesSize){  int[] gridParam = new int[2];  if(imagesSize < 3){   gridParam[0] = 1;   gridParam[1] = imagesSize;  }else if(imagesSize <= 4){   gridParam[0] = 2;   gridParam[1] = 2;  }else{   gridParam[0] = imagesSize/3 + (imagesSize % 3 == 0?0:1);   gridParam[1] = 3;  }  return gridParam; }  /**  * 设置适配器  *  * @param adapter 适配器  */ public void setAdapter(NineGridImageViewAdapter adapter){  mAdapter = adapter; }  /**  * 设置宫格间距  *  * @param gap 宫格间距 px  */ public void setGap(int gap){  mGap = gap; }  /**  * 对宫格的宽高进行重新定义  */ private int measureWidth(int measureSpec){  int result = 0;  int specMode = MeasureSpec.getMode(measureSpec);  int specSize = MeasureSpec.getSize(measureSpec);   if(specMode == MeasureSpec.EXACTLY){   result = specSize;  }else{   result = 200;   if(specMode == MeasureSpec.AT_MOST){    result = Math.min(result,specSize);   }  }  return result; }  private int measureHeight(int measureSpec){  int result = 0;   int specMode = MeasureSpec.getMode(measureSpec);  int specSize = MeasureSpec.getSize(measureSpec);   if(specMode == MeasureSpec.EXACTLY){   result = specSize;  }else{   result = 200;   if(specMode == MeasureSpec.AT_MOST){    result = Math.min(result,specSize);   }  }  return result; }}

public abstract class NineGridImageViewAdapter<T> { protected abstract void onDisplayImage(Context context, ImageView imageView, T t);  protected ImageView generateImageView(Context context){  ImageView imageView = new ImageView(context);  imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);  return imageView; }  //这里可以添加你所需要的事件之类的方法}

<declare-styleable name="NineGridImageView">  <attr format="dimension" name="imgGap"/> </declare-styleable>

NineGridImageViewAdapter<String> mAdapter = new NineGridImageViewAdapter<String>() {   @Override   protected void onDisplayImage(Context context, ImageView imageView, String s) {    Picasso.with(context).load(s).placeholder(R.mipmap.ic_holding).error(R.mipmap.ic_error).into(imageView);   }    @Override   protected ImageView generateImageView(Context context) {    return super.generateImageView(context);   }  };  groudIcon1.setAdapter(mAdapter);  groudIcon1.setImagesData(mPostList1);