Android 应用程序错误 android.view.InflateException。使用 Jetpack 导航组件

Question

尝试制作使用 Naviagtion Components 的应用程序和两个由 Navigation Graph 管理的简单屏幕，其中之一是:

主要 fragment :

public class MainFragment extends Fragment {

private MainViewModel mViewModel;

public static MainFragment newInstance() {
    return new MainFragment();
}

@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
                         @Nullable Bundle savedInstanceState) {
    return inflater.inflate(R.layout.main_fragment, container, false);
}

@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    mViewModel = new ViewModelProvider(this).get(MainViewModel.class);

    Button button = getView().findViewById(R.id.button);

    button.setOnClickListener(Navigation.createNavigateOnClickListener(R.id.mainToSecond,null));

    // TODO: Use the ViewModel
}

第二个屏幕:

public class SecondFragment extends Fragment {


public interface OnFragmentInteractionListener {
    // TODO: Update argument type and name
    void onFragmentInteraction(Uri uri);
}

// 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;


public SecondFragment() {
    // 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 SecondFragment.
 */
// TODO: Rename and change types and number of parameters
public static SecondFragment newInstance(String param1, String param2) {
    SecondFragment fragment = new SecondFragment();
    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.fragment_second, container, false);
}

我的“导航主机”是 MainActivity 类:

public class MainActivity extends AppCompatActivity implements
    SecondFragment.OnFragmentInteractionListener {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main_activity);
}
@Override
public void onFragmentInteraction(Uri uri){}}

在模拟器上运行时，Gradle 未显示任何错误，但应用程序未启动。这是我遇到的错误。

 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.navigationdemo/com.example.navigationdemo.ui.main.MainActivity}: android.view.InflateException: Binary XML file line #10

main_activity XML 代码:

<?xml version="1.0" encoding="utf-8"?>
 <FrameLayout 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:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".ui.main.MainActivity" >

<fragment
    android:id="@+id/demo_nav_host_fragment"
    android:name="androidx.navigation.fragment.NavHostFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:defaultNavHost="true"
    app:navGraph="@navigation/navigation_graph"/>

完全异常:

  Process: com.example.navigationdemo, PID: 13360
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.navigationdemo/com.example.navigationdemo.ui.main.MainActivity}: android.view.InflateException: Binary XML file line #11 in com.example.navigationdemo:layout/main_activity: Binary XML file line #11 in com.example.navigationdemo:layout/main_activity: Error inflating class fragment
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3270)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
    at android.os.Handler.dispatchMessage(Handler.java:107)
    at android.os.Looper.loop(Looper.java:214)
    at android.app.ActivityThread.main(ActivityThread.java:7356)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
 Caused by: android.view.InflateException: Binary XML file line #11 in com.example.navigationdemo:layout/main_activity: Binary XML file line #11 in com.example.navigationdemo:layout/main_activity: Error inflating class fragment
 Caused by: android.view.InflateException: Binary XML file line #11 in com.example.navigationdemo:layout/main_activity: Error inflating class fragment
 Caused by: java.lang.IllegalStateException: Fragment class was not set
    at androidx.navigation.fragment.FragmentNavigator$Destination.getClassName(FragmentNavigator.java:322)
    at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:158)
    at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:58)
    at androidx.navigation.NavGraphNavigator.navigate(NavGraphNavigator.java:71)
    at androidx.navigation.NavGraphNavigator.navigate(NavGraphNavigator.java:28)
    at androidx.navigation.NavController.navigate(NavController.java:1049)
    at androidx.navigation.NavController.onGraphCreated(NavController.java:633)
    at androidx.navigation.NavController.setGraph(NavController.java:586)
    at androidx.navigation.NavController.setGraph(NavController.java:551)
    at androidx.navigation.NavController.setGraph(NavController.java:533)
    at androidx.navigation.fragment.NavHostFragment.onCreate(NavHostFragment.java:238)
    at androidx.fragment.app.Fragment.performCreate(Fragment.java:2684)
    at androidx.fragment.app.FragmentStateManager.create(FragmentStateManager.java:280)
    at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1175)
    at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1356)
    at androidx.fragment.app.FragmentLayoutInflaterFactory.onCreateView(FragmentLayoutInflaterFactory.java:109)
    at androidx.fragment.app.FragmentController.onCreateView(FragmentController.java:135)
    at androidx.fragment.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:356)
    at androidx.fragment.app.FragmentActivity.onCreateView(FragmentActivity.java:335)
    at android.view.LayoutInflater.tryCreateView(LayoutInflater.java:1069)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:997)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:961)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:1123)
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1084)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:682)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:534)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:481)
    at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:696)
E/AndroidRuntime:     at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:170)
    at com.example.navigationdemo.ui.main.MainActivity.onCreate(MainActivity.java:15)
    at android.app.Activity.performCreate(Activity.java:7802)
    at android.app.Activity.performCreate(Activity.java:7791)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
    at android.os.Handler.dispatchMessage(Handler.java:107)
    at android.os.Looper.loop(Looper.java:214)
    at android.app.ActivityThread.main(ActivityThread.java:7356)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

使用时完全异常

<androidx.fragment.app.FragmentContainerView

 Process: com.example.navigationdemo, PID: 12977
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.navigationdemo/com.example.navigationdemo.ui.main.MainActivity}: android.view.InflateException: Binary XML file line #11 in com.example.navigationdemo:layout/main_activity: Binary XML file line #11 in com.example.navigationdemo:layout/main_activity: Error inflating class androidx.fragment.app.FragmentContainerView
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3270)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
    at android.os.Handler.dispatchMessage(Handler.java:107)
    at android.os.Looper.loop(Looper.java:214)
    at android.app.ActivityThread.main(ActivityThread.java:7356)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
 Caused by: android.view.InflateException: Binary XML file line #11 in com.example.navigationdemo:layout/main_activity: Binary XML file line #11 in com.example.navigationdemo:layout/main_activity: Error inflating class androidx.fragment.app.FragmentContainerView
 Caused by: android.view.InflateException: Binary XML file line #11 in com.example.navigationdemo:layout/main_activity: Error inflating class androidx.fragment.app.FragmentContainerView
 Caused by: java.lang.IllegalStateException: Fragment class was not set
    at androidx.navigation.fragment.FragmentNavigator$Destination.getClassName(FragmentNavigator.java:322)
    at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:158)
    at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:58)
    at androidx.navigation.NavGraphNavigator.navigate(NavGraphNavigator.java:71)
    at androidx.navigation.NavGraphNavigator.navigate(NavGraphNavigator.java:28)
    at androidx.navigation.NavController.navigate(NavController.java:1049)
    at androidx.navigation.NavController.onGraphCreated(NavController.java:633)
    at androidx.navigation.NavController.setGraph(NavController.java:586)
    at androidx.navigation.NavController.setGraph(NavController.java:551)
    at androidx.navigation.NavController.setGraph(NavController.java:533)
    at androidx.navigation.fragment.NavHostFragment.onCreate(NavHostFragment.java:238)
    at androidx.fragment.app.Fragment.performCreate(Fragment.java:2684)
    at androidx.fragment.app.FragmentStateManager.create(FragmentStateManager.java:280)
    at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1175)
    at androidx.fragment.app.FragmentManager.addAddedFragments(FragmentManager.java:2224)
    at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:1997)
    at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:1953)
    at androidx.fragment.app.FragmentManager.execSingleAction(FragmentManager.java:1818)
    at androidx.fragment.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:303)
    at androidx.fragment.app.FragmentContainerView.<init>(FragmentContainerView.java:166)
    at androidx.fragment.app.FragmentLayoutInflaterFactory.onCreateView(FragmentLayoutInflaterFactory.java:51)
    at androidx.fragment.app.FragmentController.onCreateView(FragmentController.java:135)
    at androidx.fragment.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:356)
    at androidx.fragment.app.FragmentActivity.onCreateView(FragmentActivity.java:335)
    at android.view.LayoutInflater.tryCreateView(LayoutInflater.java:1069)
2020-10-28 12:23:26.527 12977-12977/com.example.navigationdemo E/AndroidRuntime:     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:997)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:961)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:1123)
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1084)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:682)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:534)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:481)
    at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:696)
    at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:170)
    at com.example.navigationdemo.ui.main.MainActivity.onCreate(MainActivity.java:15)
    at android.app.Activity.performCreate(Activity.java:7802)
    at android.app.Activity.performCreate(Activity.java:7791)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
    at android.os.Handler.dispatchMessage(Handler.java:107)
    at android.os.Looper.loop(Looper.java:214)
    at android.app.ActivityThread.main(ActivityThread.java:7356)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

Answer 1

将 main_activity 中的完整代码替换为:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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=".ui.main.MainActivity">

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/demo_nav_host_fragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"

        app:defaultNavHost="true"
        app:navGraph="@navigation/navigation_graph" />

</androidx.constraintlayout.widget.ConstraintLayout>