xml片段中ListView上方的浮动操作按钮(FAB)

Question

我使用了这里的代码。就我而言，它看起来像

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".fragments.FragmentList"
    android:orientation="vertical"
    android:id="@+id/linear">
    <ListView
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:fab="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/listView" />
</LinearLayout>
<android.support.design.widget.CoordinatorLayout
    android:id="@+id/rootLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/ic_add_white_24dp"
    android:layout_gravity="bottom|end"
    fab:elevation="6dp"
    fab:pressedTranslationZ="12dp"
    fab:backgroundTint="@color/accent"
    app:layout_anchor="@id/listView"/>
</android.support.design.widget.CoordinatorLayout>

但我在安卓工作室中有"多个根标签"。我做错了什么？请帮帮我，我听不懂（

Answer 1

改为使用此布局：

<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".fragments.FragmentList"
android:orientation="vertical"
android:id="@+id/linear">
<ListView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:fab="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/listView" />

<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/ic_add_white_24dp"
    android:layout_gravity="bottom|end"
    fab:elevation="6dp"
    fab:pressedTranslationZ="12dp"
    fab:backgroundTint="@color/accent"
    app:layout_anchor="@id/listView"/>
</android.support.design.widget.CoordinatorLayout>

Answer 2

更改这行代码android:layout_gravity="bottom|end"到android:layout_gravity="top"

Answer 3

android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"

这会将FAB设置为右下角。