在线性布局内看不到按钮

Question

我有这个 vehicle_list_fragment_layout.xml：

<?xml version="1.0" encoding="utf-8"?>
<!-- Layout per il fragment VehicleListFragment. -->
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <include layout="@layout/recycler_view_fragment_layout"/>
    <Button
        android:id="@+id/btnAddVehicle"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:text="+"/>
</LinearLayout>

我的VehicleListFragment以这种方式使用：

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
    View rootView = inflater.inflate(R.layout.vehicle_list_fragment_layout, container, false);
    btnStartActivity = (Button) rootView.findViewById(R.id.btnAddVehicle);
    mRecyclerView = (RecyclerView) rootView.findViewById(R.id.recyclerView);
    mLayoutManager = new LinearLayoutManager(getActivity());
    setRecyclerViewLayoutManager(LayoutManagerType.LINEAR_LAYOUT_MANAGER);
    initAdapter();
    mRecyclerView.setAdapter(mAdapter);
    setButtonClickListener();
    return rootView;
}

问题是RecyclerView显示正确，但我的btnAddVehicle未显示。

这是activity_vehicle_layout.xml，托有我的VehicleListFragment的Activity的布局：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="clyky.cartracker.activities.VehicleActivity">
    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/vehicleContainer">
    </FrameLayout>
</android.support.constraint.ConstraintLayout>

我使用vehicleContainer作为片段的容器。预先感谢！

编辑

这是我的recycler_view_fragment_layout：

<?xml version="1.0" encoding="utf-8"?>
<!-- Layout per un fragment che contiene una RecyclerView -->
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <android.support.v7.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:scrollbars="vertical"
        android:id="@+id/recyclerView">
    </android.support.v7.widget.RecyclerView>
</LinearLayout>

Answer 1

尝试一下。像我在下面添加的那样，基本all向父视图添加权级，并将其layout_weight添加到他们的孩子中，

  <?xml version="1.0" encoding="utf-8"?><!-- Layout per il fragment VehicleListFragment. -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:orientation="vertical"
    android:layout_height="match_parent"
    android:weightSum="1">
    <android.support.v7.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:scrollbars="vertical"
        android:layout_weight=".8"
        android:id="@+id/recyclerView">
    </android.support.v7.widget.RecyclerView>
    <Button
        android:id="@+id/btnAddVehicle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight=".2"
        android:text="+" />
</LinearLayout>

也需要向父添加方向，以显示回收器视图和按钮

Answer 2

在vehicle_list_fragment_layout.xml中尝试一下：

<?xml version="1.0" encoding="utf-8"?>
<!-- Layout per il fragment VehicleListFragment. -->
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <include
        layout="@layout/recycler_view_fragment_layout"/>
    <Button
        android:id="@+id/btnAddVehicle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="+"/>
</LinearLayout>

和recycler_view_fragment_layout.xml：

<?xml version="1.0" encoding="utf-8"?>
<!-- Layout per un fragment che contiene una RecyclerView -->
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1"
    android:orientation="vertical"
    tools:layout_height="match_parent"
>
    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:scrollbars="vertical"/>
</LinearLayout>