先看下要实现的效果
可以看到中间那条灰线的高度是动态变化的，一开始觉得很好实现，直接获取Item的高度的然后设置给View不就好了吗？ 问题来了，获取Item的高度始终为0。原因是ItemView还没有测量完成，高度自然为0。我们都知道View绘制的顺序是onMeasure()—— onLayout()—— onDraw()，所以第一种解法来了，手动让ItemView测量一下不就好了吗？
//动态设置View高度 第一种方式
TextView view = bvh.getView(R.id.text_live_view);
RelativeLayout relativeLayout = bvh.getView(R.id.root);
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) view.getLayoutParams();
relativeLayout.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
int height = relativeLayout.getMeasuredHeight();
params.height = height;
view.setLayoutParams(params);
//动态设置View高度 第二种方式
final TextView view = bvh.getView(R.id.text_live_view);
final RelativeLayout relativeLayout = bvh.getView(R.id.root);
final RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) view.getLayoutParams();
relativeLayout.post(new Runnable()
{
public void run()
{
int height = relativeLayout.getMeasuredHeight();
params.height = height;
view.setLayoutParams(params);
}
});
//动态设置View高度 第三种方式
final TextView view = bvh.getView(R.id.text_live_view);
final RelativeLayout relativeLayout = bvh.getView(R.id.root);
final RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) view.getLayoutParams();
relativeLayout.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
int height = relativeLayout.getMeasuredHeight();
params.height = height;
view.setLayoutParams(params);
}
});
总体的思路都是在View显示之前改变高度，如果还有其他方法，欢迎补充！
- https://stackoverflow.com/questions/38764254/how-to-get-the-height-of-recyclerview-s-item-in-onbindviewholder
- https://stackoverflow.com/questions/8200896/how-to-find-the-width-of-the-a-view-before-the-view-is-displayed
- https://stackoverflow.com/questions/26566954/square-layout-on-gridlayoutmanager-for-recyclerview/26575808#26575808