因为图片显示的宽高是固定的 所以测量那没有做判断 用 MeasureSpec.EXACTLY

自己写的自定义view 比较一般 如果各位有其他好的想法 可以一起讨论下 不足的地方欢迎大家指正。

public class MergePictureView extends LinearLayout {
public static int MAX_WIDTH = 0; 

private List<String> imagesList = new ArrayList<>();
private int pxImagePadding = DiPUtils.dip2px(getContext(), 1);// 图片间的间距

private LayoutParams onePicPara; //一张图的宽高
private LayoutParams twoPicPara; //四张图的宽高
private LayoutParams threePicPare;// 四张图的宽 一张图的高
private LayoutParams fourPicPare;//一张图的宽 四张图的高

public MergePictureView(Context context) {
    super(context);
}

public MergePictureView(Context context, @Nullable AttributeSet attrs) {
    super(context, attrs);
}

public MergePictureView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
}


public void setImagesList(List<String> imagesList) {
    this.imagesList = imagesList;
    initImageLayoutParams();
    initView();
}

private void initImageLayoutParams() {
    onePicPara = new LayoutParams(MAX_WIDTH, MAX_WIDTH);

    twoPicPara = new LayoutParams(MAX_WIDTH / 2, MAX_WIDTH / 2);

    threePicPare = new LayoutParams(MAX_WIDTH / 2, MAX_WIDTH);

    fourPicPare = new LayoutParams(MAX_WIDTH, MAX_WIDTH / 2);


}

private void initView() {
    this.setOrientation(HORIZONTAL);
    this.removeAllViews();
    ImageView imageViewOne;
    ImageView imageViewTwo;
    ImageView imageViewThree;
    ImageView imageViewFour;
    if (imagesList.size() == 1) {
        imageViewOne = new ImageView(getContext());
        imageViewOne.setLayoutParams(onePicPara);
        imageViewOne.setScaleType(ImageView.ScaleType.CENTER_CROP);
        Glide.with(getContext()).load(imagesList.get(0)).into(imageViewOne);
        addView(imageViewOne);
    } else if (imagesList.size() == 2) {
        imageViewOne = new ImageView(getContext());
        imageViewOne.setLayoutParams(threePicPare);
        imageViewOne.setPadding(0, 0, pxImagePadding, 0);
        imageViewOne.setScaleType(ImageView.ScaleType.CENTER_CROP);
        Glide.with(getContext()).load(imagesList.get(0)).into(imageViewOne);
        addView(imageViewOne);
        imageViewTwo = new ImageView(getContext());
        imageViewTwo.setLayoutParams(threePicPare);
        imageViewTwo.setPadding(pxImagePadding, 0, 0, 0);
        imageViewTwo.setScaleType(ImageView.ScaleType.CENTER_CROP);
        Glide.with(getContext()).load(imagesList.get(1)).into(imageViewTwo);
        addView(imageViewTwo);
    } else if (imagesList.size() == 3) {
        imageViewOne = new ImageView(getContext());
        imageViewOne.setLayoutParams(threePicPare);
        imageViewOne.setPadding(0, 0, pxImagePadding, 0);
        imageViewOne.setScaleType(ImageView.ScaleType.CENTER_CROP);
        Glide.with(getContext()).load(imagesList.get(0)).into(imageViewOne);
        addView(imageViewOne);

        LinearLayout linearLayout = new LinearLayout(getContext());
        linearLayout.setOrientation(VERTICAL);
        linearLayout.setLayoutParams(threePicPare);
        linearLayout.setPadding(pxImagePadding, 0, 0, 0);

        imageViewTwo = new ImageView(getContext());
        imageViewTwo.setLayoutParams(twoPicPara);
        imageViewTwo.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageViewTwo.setPadding(0, 0, 0, pxImagePadding);
        Glide.with(getContext()).load(imagesList.get(1)).into(imageViewTwo);
        linearLayout.addView(imageViewTwo);

        imageViewThree = new ImageView(getContext());
        imageViewThree.setLayoutParams(twoPicPara);
        imageViewThree.setPadding(0, pxImagePadding, 0, 0);
        imageViewThree.setScaleType(ImageView.ScaleType.CENTER_CROP);
        Glide.with(getContext()).load(imagesList.get(2)).into(imageViewThree);
        linearLayout.addView(imageViewThree);

        addView(linearLayout);

    } else if (imagesList.size() > 3) {
        this.setOrientation(VERTICAL);
        LinearLayout top = new LinearLayout(getContext());
        top.setOrientation(HORIZONTAL);
        top.setPadding(0, 0, 0, pxImagePadding);
        top.setLayoutParams(fourPicPare);

        imageViewOne = new ImageView(getContext());
        imageViewOne.setLayoutParams(twoPicPara);
        imageViewOne.setPadding(0, 0, pxImagePadding, 0);
        imageViewOne.setScaleType(ImageView.ScaleType.CENTER_CROP);
        Glide.with(getContext()).load(imagesList.get(0)).into(imageViewOne);
        top.addView(imageViewOne);

        imageViewTwo = new ImageView(getContext());
        imageViewTwo.setLayoutParams(twoPicPara);
        imageViewTwo.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageViewTwo.setPadding(pxImagePadding, 0, 0, 0);
        Glide.with(getContext()).load(imagesList.get(1)).into(imageViewTwo);
        top.addView(imageViewTwo);

        addView(top);

        LinearLayout bottom = new LinearLayout(getContext());
        bottom.setOrientation(HORIZONTAL);
        bottom.setLayoutParams(fourPicPare);
        bottom.setPadding(0, pxImagePadding, 0, 0);

        imageViewThree = new ImageView(getContext());
        imageViewThree.setLayoutParams(twoPicPara);
        imageViewThree.setPadding(0, 0, pxImagePadding, 0);
        imageViewThree.setScaleType(ImageView.ScaleType.CENTER_CROP);
        Glide.with(getContext()).load(imagesList.get(2)).into(imageViewThree);
        bottom.addView(imageViewThree);

        imageViewFour = new ImageView(getContext());
        imageViewFour.setLayoutParams(twoPicPara);
        imageViewFour.setPadding(pxImagePadding, 0, 0, 0);
        imageViewFour.setScaleType(ImageView.ScaleType.CENTER_CROP);
        Glide.with(getContext()).load(imagesList.get(3)).into(imageViewFour);
        bottom.addView(imageViewFour);

        addView(bottom);
    }

}


@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  if(MAX_WIDTH==0){
        MAX_WIDTH = measureWidth(widthMeasureSpec);
        if (imagesList != null && imagesList.size() > 0) {
              setImagesList(imagesList);
          }
    }
  
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);

}

private int measureWidth(int measureSpec) {
    int result = 0;
    int specMode = MeasureSpec.getMode(measureSpec);
    int specSize = MeasureSpec.getSize(measureSpec);

    if (specMode == MeasureSpec.EXACTLY) {
        // We were told how big to be
        result = specSize;
    } else {
        // Measure the text
        // result = (int) mTextPaint.measureText(mText) + getPaddingLeft()
        // + getPaddingRight();
        if (specMode == MeasureSpec.AT_MOST) {
            // Respect AT_MOST value if that was what is called for by
            // measureSpec
            result = Math.min(result, specSize);
        }
    }
    return result;
}