Question

我遇到了问题我无法解决。在我的应用程序中，我有一个导航抽屉定义如下：

activity_main.xml中

<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<!-- As the main content view, the view below consumes the entire
     space available using match_parent in both dimensions. -->
<FrameLayout
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

<!-- android:layout_gravity="start" tells DrawerLayout to treat
     this as a sliding drawer on the left side for left-to-right
     languages and on the right side for right-to-left languages.
     If you're not building against API 17 or higher, use
     android:layout_gravity="left" instead. -->
<!-- The drawer is given a fixed width in dp and extends the full height of
     the container. -->
<fragment android:id="@+id/navigation_drawer"
    android:layout_width="@dimen/navigation_drawer_width"
    android:layout_height="match_parent"
    android:layout_gravity="start"  />

在MainActivity类中，我通常使用setContentView传递这个xml：的 MainActivity.java

setContentView(R.layout.activity_main);

    mNavigationDrawerFragment = (NavigationDrawerFragment)
        getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);

在我的NavigationDrawerFragment onCreateView上，我通常用它来膨胀它的xml：

NavigationDrawerFragment.java

public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View root = (View)inflater.inflate(R.layout.fragment_navigation_drawer,null,false);
    mDrawerListView = (ListView)root.findViewById(R.id.drawer_list_view);

    mDrawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            selectItem(position);
        }
    });

这是fragment_navigation_drawer.xml：的 fragment_navigation_drawer.xml

<LinearLayout
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:android="http://schemas.android.com/apk/res/android">

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:padding="10dp">

    <ImageView
            android:id="@+id/profile_picture"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:layout_alignParentLeft="true"/>

    <TextView
            android:id="@+id/user_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            android:layout_toRightOf="@id/profile_picture"
            android:textStyle="bold"
            android:textSize="15sp" />

    <TextView
            android:id="@+id/user_mail"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/user_name"
            android:layout_alignLeft="@id/user_name"
            android:fontFamily="sans-serif-light" />


    <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:src="@android:drawable/ic_menu_close_clear_cancel"/>

</RelativeLayout>

<ListView xmlns:android="http://schemas.android.com/apk/res/android"
          xmlns:tools="http://schemas.android.com/tools"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:choiceMode="singleChoice"
          android:id="@+id/drawer_list_view"
          android:dividerHeight="0dp"
          android:background="@color/navigation_drawer_background" />

当我运行代码时，我在MainActivity的setContentView上得到一个例外：

Caused by: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.

我认为NavigationDrawer布局有问题。我做错了什么？

编辑：我将布局更改为：

<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
<!-- The main content view -->
<FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
<!-- The navigation drawer -->
<FrameLayout
        android:id="@+id/left_drawer_frame"
        android:layout_width="@dimen/navigation_drawer_dimension"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:background="@android:color/white"/>

所以使用FrameLayout，在我的活动中我使用：

mFragment = new Fragment();
        getSupportFragmentManager()
            .beginTransaction()
            .replace(R.id.content_frame, mFragment)
            .commit();

我用这个膨胀片段：

View root = inflater.inflate(R.layout.fragment_main, container, false);

一切似乎都有效

Answer 1

迟到总比没有好。

查看您的代码（变量名称，布局结构等）我假设您使用的是Android Studio，并使用＆＃34;导航抽屉＆＃34;创建了项目。 Android Studio提供的模板＆＃34;创建项目＆＃34;向导。

如果上述假设属实，那么您的问题就在onCreateView NavigationDrawerFragment。您必须从onCreateView返回夸大的视图，在这种特定情况下您应返回的内容为root而不是mDrawerListView

public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View root = (View)inflater.inflate(R.layout.fragment_navigation_drawer,null,false);
    mDrawerListView = (ListView)root.findViewById(R.id.drawer_list_view);

    mDrawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            selectItem(position);
        }
    });

    return root;

    // This is wrong
    // return mDrawerListView;
}

编辑IDE生成的代码时，这是一个常见的错误。

希望这有帮助。

Answer 2

片段ID中的

：导航抽屉添加

tools:layout="@layout/fragment_navigation_drawer"

带有ListView和自定义标题的导航抽屉片段

2 个答案: