仿微信 发起群聊页面的搜索

第一次写文章，多多包涵。别的不多说，直接看效果

1550912724834.gif

仿照的

1550912289585.gif

顶部的搜索+选中时显示的头像，通过自定义ViewGroup，RecycleView+EditText。

通过onMeasure测量，当EditText的长度小于指定的最小长度时，对RecycleView 的长度固定

 @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        int count = getChildCount();
        for (int i = 0; i < count; i++) {
            View view = getChildAt(i);
            if (view instanceof ViewGroup) {
                childMeasure((ViewGroup) view);
            }
        }
    }

    private void childMeasure(ViewGroup viewGroup) {
        int childCount = viewGroup.getChildCount();
        for (int j = 0; j < childCount; j++) {
            View child = viewGroup.getChildAt(j);

            if (child == scRecycler) {
                //如果子view 是RecycleView
                int rootWidth = getMeasuredWidth(); //根View的长度
                int width = scRecycler.getMeasuredWidth(); //当前RecycleView的长度
                if (rootWidth - width < searchMinWidth) { //如果小于EditText指定的最小宽度
                    setMeasureChildSpec(rootWidth - searchMinWidth, scRecycler.getMeasuredHeight(), scRecycler);
                    setMeasureChildSpec(searchMinWidth, scEditQuery.getMeasuredHeight(), scEditQuery);
                }
                break;
            } else {
                if (child instanceof ViewGroup) {
                    childMeasure((ViewGroup) child);
                    break;
                }
            }
        }
    }

    private void setMeasureChildSpec(int width, int height, View view) {
        int measuredWidthSpec = MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY);
        int measuredHeightSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
        view.measure(measuredWidthSpec, measuredHeightSpec);
    }

搜索icon是通过监听 RecycleView.AdapterDataObserver的变化实现显示和隐藏

  private final RecyclerView.AdapterDataObserver adapterDataObserver = new RecyclerView.AdapterDataObserver() {

        private void update() {
            if (scRecycler != null && scRecycler.getAdapter() != null) {
                boolean isShow = true;
                if (scRecycler.getAdapter().getItemCount() == 0) {
                    isShow = true;
                    scRecycler.setVisibility(GONE);
                } else {
                    isShow = false;
                    scRecycler.setVisibility(VISIBLE);
                    scRecycler.scrollToPosition(scRecycler.getAdapter().getItemCount() - 1);
                }
                updateSearchIcon(isShow);
            }
        }

        @Override
        public void onChanged() {
            super.onChanged();
            update();
        }

        @Override
        public void onItemRangeChanged(int positionStart, int itemCount) {
            super.onItemRangeChanged(positionStart, itemCount);
            update();
        }

        @Override
        public void onItemRangeInserted(int positionStart, int itemCount) {
            super.onItemRangeInserted(positionStart, itemCount);
            update();
        }

        @Override
        public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) {
            super.onItemRangeMoved(fromPosition, toPosition, itemCount);
            update();
        }

        @Override
        public void onItemRangeRemoved(int positionStart, int itemCount) {
            super.onItemRangeRemoved(positionStart, itemCount);
            update();
        }
    };

第一次点击返回键头像颜色变浅，是通过Drawable tint着色实现的

 ImageView image = holder.findViewById(R.id.img_head);
                Drawable drawable = image.getDrawable();

                Drawable tintDrawable = DrawableCompat.wrap(drawable.getConstantState() == null ?
                        drawable : drawable.getConstantState().newDrawable()).mutate();

                DrawableCompat.setTintMode(tintDrawable, PorterDuff.Mode.SCREEN);
                DrawableCompat.setTint(tintDrawable, Color.parseColor("#D9D9D9"));
                image.setImageDrawable(tintDrawable);

需要注意 Drawable mutate，由于Android为了优化系统性能，同一个Drawable实例只会存一份在内存中，如果对Drawable进行修改，会导致全局的同一Drawable进行修改
不使用mutate 共享模式

image.png

使用mutate 不共享模式

image.png

项目地址