Question

我是Android的新手，所以这可能是我犯下的一个非常明显的错误。

我正在尝试让我的片段显示谷歌地图，但它一直在崩溃应用程序。错误消息是

＆＃34; java.lang.RuntimeException：无法启动活动ComponentInfo {com.example.daniel.mts / com.example.daniel.mts.MainActivity}：android.view.InflateException：二进制XML文件行＃12 ：错误膨胀类片段＆＃34;

这是我的MainActivity，它显示了一个工具栏，并且还将activity_main.xml中的FrameLayout替换为我的HomeFragment。

public class MainActivity extends AppCompatActivity
implements OnFragmentInteractionListener {

private DrawerLayout mDrawer;
private Toolbar toolbar;
private NavigationView nvDrawer;
private ActionBarDrawerToggle drawerToggle;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    //Set toolbar to replace the action bar
    toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    //find drawer view
    mDrawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawerToggle = setupDrawerToggle();

    //Tie drawerlayout events to the action bar toggle for open and        close
    mDrawer.addDrawerListener(drawerToggle);

    //Find our drawer view
    nvDrawer = (NavigationView) findViewById(R.id.nvView);

    //Setup drawer view
    setUpDrawerContent(nvDrawer);

    Fragment fragment = null;
    Class fragmentClass = HomeFragment.class;
    try {
        fragment = (Fragment) fragmentClass.newInstance();
    } catch (Exception e) {
        e.printStackTrace();
    }
    FragmentTransaction def =   getSupportFragmentManager().beginTransaction();
    def.replace(R.id.flContent, fragment);
    def.commit();
}

这是我的活动主xml文件

<!-- This LinearLayout represents the contents of the screen  -->
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <!-- The toolbar displayed at the top -->
    <include
        layout="@layout/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <!-- The main content view where fragments are loaded -->
    <FrameLayout
        android:id="@+id/flContent"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

<!-- The navigation drawer that comes from the left -->
<!-- android:layout_gravity needs to be set to 'start' -->
<android.support.design.widget.NavigationView
    android:id="@+id/nvView"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    android:background="@android:color/white"
    app:menu="@menu/drawer_view"
    app:headerLayout="@layout/nav_header" />

</android.support.v4.widget.DrawerLayout>

My HomeFragment只包含创建新片段的样板代码，它显示我的home_fragment.xml

public class HomeFragment extends Fragment {

// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";

// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;

private OnFragmentInteractionListener mListener;

public HomeFragment() {
    // Required empty public constructor
}

/**
 * Use this factory method to create a new instance of
 * this fragment using the provided parameters.
 *
 * @param param1 Parameter 1.
 * @param param2 Parameter 2.
 * @return A new instance of fragment HomeFragment.
 */
// TODO: Rename and change types and number of parameters
public static HomeFragment newInstance(String param1, String param2)   {
    HomeFragment fragment = new HomeFragment();
    Bundle args = new Bundle();
    args.putString(ARG_PARAM1, param1);
    args.putString(ARG_PARAM2, param2);
    fragment.setArguments(args);
    return fragment;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (getArguments() != null) {
        mParam1 = getArguments().getString(ARG_PARAM1);
        mParam2 = getArguments().getString(ARG_PARAM2);
    }
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup   container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    return inflater.inflate(R.layout.home_fragment, container,   false); }


// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
    if (mListener != null) {
        mListener.onFragmentMessage("hello", uri);
    }
}

@Override
public void onAttach(Context context) {
    super.onAttach(context);
    if (context instanceof OnFragmentInteractionListener) {
        mListener = (OnFragmentInteractionListener) context;
    } else {
        throw new RuntimeException(context.toString()
                + " must implement OnFragmentInteractionListener");
    }
}

@Override
public void onDetach() {
    super.onDetach();
    mListener = null;
}

/**
 * This interface must be implemented by activities that contain this
 * fragment to allow an interaction in this fragment to be  communicated
 * to the activity and potentially other fragments contained in that
 * activity.
 * <p>
 * See the Android Training lesson <a href=
 *  "http://developer.android.com/training/basics/fragments/communicating.htm l"
 * >Communicating with Other Fragments</a> for more information.
 */
public void onFragmentMessage(String MSG, Object data) {

}

这是我的home_fragment.xml，它显示应该显示地图的片段。

<FrameLayout
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"
tools:context="com.example.daniel.mts.HomeFragment">

<TextView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:text="@string/home_frag" />

<fragment
    android:id="@+id/map"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    class="com.google.android.gms.maps.SupportMapFragment" />
</FrameLayout>

这是我的清单文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.daniel.mts">

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission   android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_bus"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity
        android:name=".MainActivity"
        android:screenOrientation="portrait"
        >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER"   />
        </intent-filter>
    </activity>

    <meta-data
        android:name="com.google.android.gms.version"
        android:value="@integer/google_play_services_version" />

    <meta-data
        android:name="com.google.android.geo.API_KEY"
        android:value="@string/google_api_key"/>
</application>



</manifest>

我在哪里弄乱？

Answer 1

基于Fragments，您可以使用以下两种方法之一将片段添加到活动布局中：

在活动的布局文件中声明片段。

在这种情况下，您可以为片段指定布局属性，就像它是视图一样。

当系统创建此活动布局时，它会实例化布局中指定的每个片段，并为每个片段调用onCreateView()方法，以检索每个片段的布局。系统直接插入片段返回的视图代替<fragment>元素。

或者，以编程方式将片段添加到现有ViewGroup。

要在活动中进行片段事务（例如添加，删除或替换片段），必须使用FragmentTransaction中的API。您可以从此活动中获取FragmentTransaction的实例，如下所示：

FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

然后，您可以使用add()方法添加片段，指定要添加的片段以及要插入的视图。例如：

ExampleFragment fragment = new ExampleFragment();
fragmentTransaction.add(R.id.fragment_container, fragment);
fragmentTransaction.commit();

您可以查看给定的文件以获取完整的详细信息。

除此之外，您还可以尝试@Edoardo Moreni在此SO post中使用的解决方案，其中他能够通过从xml中删除片段来解决类似问题，将其插入到活动xml中并将onCreateView (from the fragment class)传递给超类。

希望有所帮助！

试图动态显示片段内的谷歌地图，错误膨胀类片段

1 个答案: