我有一个聊天屏幕,它包含两个视图:一个用于显示先前聊天的回收器视图和一个封装编辑文本的自定义视图、一个发送按钮和另一个允许用户选择其他要发送的内容(如照片)的回收器视图等。此自定义视图称为“面板”。
因此,我的聊天活动具有以下布局:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <chat.example.app.widget.Panel
        style="@style/PanelStyle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|center"
        android:id="@+id/panel" />

    <android.support.v7.widget.RecyclerView
        android:background="@android:color/holo_red_dark"
        android:layout_margin="@dimen/activity_horizontal_margin"
        android:scrollbars="vertical"
        android:id="@+id/previous_chat"
        android:layout_above="@id/panel"
        android:layout_alignParentTop="true"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</RelativeLayout>

我的“面板”视图有以下布局:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@android:color/white">
    <RelativeLayout
        android:id="@+id/staging_area_root"
        android:layout_gravity="center"
        android:gravity="center"
        android:paddingLeft="5dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <!-- Chat box and send -->
    </RelativeLayout>
    <!-- THIS GUY IS PROBLEMATIC -->
    <android.support.v7.widget.RecyclerView
        android:id="@+id/card_set"
        android:layout_margin="15dp"
        android:layout_below="@id/staging_area_root"
        android:background="@android:color/holo_blue_bright"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
</RelativeLayout>

问题是Panel中的回收器视图占用了整个屏幕空间。所以我只看到面板类中有问题的回收者视图。
这两个回收站视图都已分配给它们。还没有适配器。
我的LinearLayoutManager中有最新的支持库:
compile 'com.android.support:recyclerview-v7:23.2.0'

浏览最新的android开发者博客:
此版本为LayoutManager API带来了令人兴奋的新功能:
自动测量!这允许RecyclerView根据
其内容的大小。这意味着以前不可用
场景,例如对
回收服务,现在可以了。你会发现一切都是内在的
布局管理器现在支持自动测量。
我错过什么了吗?
更新1:
我在mr.problement recycler视图中添加了一个适配器,其中包含0个项。仍然没有解决办法。
更新2:
截图:
android - RecyclerView不尊重height = wrap_content?-LMLPHP

最佳答案

代码片段取自23.2RecyclerViewonMeasure()调用:

if (mLayout.mAutoMeasure) {
        final int widthMode = MeasureSpec.getMode(widthSpec);
        final int heightMode = MeasureSpec.getMode(heightSpec);
        final boolean skipMeasure = widthMode == MeasureSpec.EXACTLY
                && heightMode == MeasureSpec.EXACTLY;
        mLayout.onMeasure(mRecycler, mState, widthSpec, heightSpec);
        if (skipMeasure || mAdapter == null) {
            return;
        }
        if (mState.mLayoutStep == State.STEP_START) {
            dispatchLayoutStep1();
        }
        // set dimensions in 2nd step. Pre-layout should happen with old dimensions for
        // consistency
        mLayout.setMeasureSpecs(widthSpec, heightSpec);
        mState.mIsMeasuring = true;
        dispatchLayoutStep2();

        // now we can get the width and height from the children.
        mLayout.setMeasuredDimensionFromChildren(widthSpec, heightSpec);

        // if RecyclerView has non-exact width and height and if there is at least one child
        // which also has non-exact width & height, we have to re-measure.
        if (mLayout.shouldMeasureTwice()) {
            mLayout.setMeasureSpecs(
                    MeasureSpec.makeMeasureSpec(getMeasuredWidth(), MeasureSpec.EXACTLY),
                    MeasureSpec.makeMeasureSpec(getMeasuredHeight(), MeasureSpec.EXACTLY));
            mState.mIsMeasuring = true;
            dispatchLayoutStep2();
            // now we can get the width and height from the children.
            mLayout.setMeasuredDimensionFromChildren(widthSpec, heightSpec);
        }
    }

mLayout.setMeasuredDimensionFromChildren()调用将根据RecyclerView的子级的大小进行自动测量。也就是说,要触发自动测量,需要一个包含一个或多个子项的有效RecyclerView.Adapter

07-24 09:47
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