获取高度在运行时RecyclerView子视图 [英] Get height for RecyclerView child views at runtime

问题描述

我试图做一个可扩展的TextView的扩展，当用户presses按钮/崩溃。 TextView的和的ImageButton处于CardView，其被添加到RecyclerView

展开/折叠的工作很好，但现在我想只有当TextView的高度超过一定的最大高度添加的ImageButton。但是，当我评价LayoutManager的addView方法的高度，则返回0，可能是因为TextView中没有任何文字呢。

有没有办法，我可以覆盖CardView得到它的新内容之后被激发，这样我可以评估的TextView的高度，任何回调方法？

编辑：我已经试过onLayoutChildren作为yigit建议

  @覆盖
公共无效onLayoutChildren（RecyclerView.Recycler回收，RecyclerView.State州）{
    super.onLayoutChildren（回收，状态）;
    Log.d（LayoutManager的，状态计数：+ state.getItemCount（））;    的for（int i = 1; I＆LT; state.getItemCount（）;我++）{
        视图V = recycler.getViewForPosition（I）
        TextView的CT =（TextView中）v.findViewById（R.id.comment_text）;
        Log.d（LayoutManager的，评论高度：+ ct.getMeasuredHeight（））;
    }
}
 

输出结果：

  D / LayoutManager的：状态计数：4
D / LayoutManager的：评论高度：0
D / LayoutManager的：评论高度：0
D / LayoutManager的：评论高度：0
 

解决方案

LinearLayout.LayoutParams - 这可能会根据你的主要布局是RelativeLayout.LayoutParams
mParentContainer - 这是RecyclerView - 传递给你的适配器
Utils.dpToPx（8 + 15）; - 这里除了利润的表兄弟姐妹他们并不指望措施
totalHeight + = 1; - 是导致适配器下一个视图占位符绑定;）

在View持有人：

  INT totalHeight = 0;
        的for（int i = 0; I＆LT; getItemCount（）;我++）{            查看chView = viewHolder.itemView;
            chView.measure（
                   View.MeasureSpec.makeMeasureSpec（0，View.MeasureSpec.UNSPECIFIED），
                    View.MeasureSpec.makeMeasureSpec（0，View.MeasureSpec.UNSPECIFIED））;
            totalHeight + = chView.getMeasuredHeight（）;
            totalHeight + = Utils.dpToPx（8 + 15）;
        }        totalHeight + = 1;
        LinearLayout.LayoutParams listParams =（LinearLayout.LayoutParams）mParentContainer.getLayoutParams（）;
        listParams.height = totalHeight;
        mParentContainer.setLayoutParams（listParams）;
 

I'm trying to make an expandable TextView that expands/collapses when a user presses a button. The TextView and ImageButton are in a CardView, which is added to a RecyclerView.

The expand/collapse work nicely, but now I want to add the ImageButton only when the TextView height exceeds a certain maximum height. But when I evaluate the height in the LayoutManager's addView method, it returns 0, probably because the TextView does not have any text yet.

Is there any callback method that I can override that is fired after the CardView gets it's new content, so that I can evaluate the height of the TextView?

Edit: I've tried onLayoutChildren as yigit suggested

@Override
public void onLayoutChildren (RecyclerView.Recycler recycler, RecyclerView.State state) {
    super.onLayoutChildren(recycler, state);
    Log.d("LayoutManager","State Count: " + state.getItemCount());

    for (int i = 1; i < state.getItemCount(); i++) {
        View v = recycler.getViewForPosition(i);
        TextView ct = (TextView) v.findViewById(R.id.comment_text);
        Log.d("LayoutManager", "Comment height: " + ct.getMeasuredHeight());
    }
}

The resulting output:

D/LayoutManager﹕ State Count: 4
D/LayoutManager﹕ Comment height: 0
D/LayoutManager﹕ Comment height: 0
D/LayoutManager﹕ Comment height: 0

解决方案

LinearLayout.LayoutParams - this could be RelativeLayout.LayoutParams according to yours main layout mParentContainer - this is RecyclerView - passed to yours adapter Utils.dpToPx(8+15); - here addition of margins coz they are not counted on measure totalHeight += 1; - is to cause adapter to bind next view holder ;)

in View Holder:

int totalHeight = 0;
        for(int i=0; i<getItemCount(); i++){

            View chView = viewHolder.itemView;
            chView.measure(
                   View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
                    View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
            totalHeight += chView.getMeasuredHeight();
            totalHeight += Utils.dpToPx(8+15);
        }

        totalHeight += 1;
        LinearLayout.LayoutParams listParams = (LinearLayout.LayoutParams) mParentContainer.getLayoutParams();
        listParams.height = totalHeight;
        mParentContainer.setLayoutParams(listParams);

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