导航无法在导航抽屉 android 中使用

Question

I am new to android development and I have been stuck for days. I created a new android project with the android studio default Navigation Drawer Activity template as seen on the screenshot. My requirement is I wanted to get an instance of NavController so that I can navigate/push to another fragment from the home fragment on click of items in recycler view. I have used the same default code generated by an android studio with no changes from my side. Tried to get the instance of NavController but the app crashes on the line in HomeFragmnet:

navController = requireActivity().findNavController(R.id.nav_host_fragment_content_main)

in

 override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
            super.onViewCreated(view, savedInstanceState)
            navController = requireActivity().findNavController(R.id.nav_host_fragment_content_main)
        }

and yes nav_host_fragment_content_main is available in content_main.xml

I wanted to navigate to another fragment as in following code:

  private fun itemClicked(article: Article?) {
        val args = Bundle()
        args.putString("title", article?.title)
        navController.navigate(R.id.navigation_news_detail, args, NavAnimate.provideNavOptions().build())
    }

Project Create screenshot

The crash error Logs:

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.testnavigation, PID: 15256
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.testnavigation/com.example.testnavigation.MainActivity}: android.view.InflateException: Binary XML file line #15 in com.example.testnavigation:layout/activity_main: Binary XML file line #19 in com.example.testnavigation:layout/content_main: Error inflating class fragment
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3449)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
     Caused by: android.view.InflateException: Binary XML file line #15 in com.example.testnavigation:layout/activity_main: Binary XML file line #19 in com.example.testnavigation:layout/content_main: Error inflating class fragment
     Caused by: android.view.InflateException: Binary XML file line #19 in com.example.testnavigation:layout/content_main: Error inflating class fragment
     Caused by: java.lang.IllegalArgumentException: ID does not reference a View inside this Activity
        at android.app.Activity.requireViewById(Activity.java:3375)
        at androidx.core.app.ActivityCompat.requireViewById(ActivityCompat.java:366)
        at androidx.navigation.Navigation.findNavController(Navigation.java:58)
        at androidx.navigation.ActivityKt.findNavController(Activity.kt:30)
        at com.example.testnavigation.ui.home.HomeFragment.onViewCreated(HomeFragment.kt:45)
        at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:2987)
        at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:546)
        at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282)
        at androidx.fragment.app.FragmentStore.moveToExpectedState(FragmentStore.java:112)
        at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1647)
        at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3128)
        at androidx.fragment.app.FragmentManager.dispatchViewCreated(FragmentManager.java:3065)
        at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:2988)
        at androidx.fragment.app.FragmentStateManager.ensureInflatedView(FragmentStateManager.java:392)
        at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:281)
        at androidx.fragment.app.FragmentLayoutInflaterFactory.onCreateView(FragmentLayoutInflaterFactory.java:140)
        at androidx.fragment.app.FragmentController.onCreateView(FragmentController.java:135)
        at androidx.fragment.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:319)
        at androidx.fragment.app.FragmentActivity.onCreateView(FragmentActivity.java:298)
        at android.view.LayoutInflater.tryCreateView(LayoutInflater.java:1067)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:995)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:959)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:1121)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082)
        at android.view.LayoutInflater.parseInclude(LayoutInflater.java:1261)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:1117)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082)
        at android.view.LayoutInflater.parseInclude(LayoutInflater.java:1261)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:1117)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:680)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:532)
        at com.example.testnavigation.databinding.ActivityMainBinding.inflate(ActivityMainBinding.java:52)
        at com.example.testnavigation.databinding.ActivityMainBinding.inflate(ActivityMainBinding.java:46)
        at com.example.testnavigation.MainActivity.onCreate(MainActivity.kt:26)
        at android.app.Activity.performCreate(Activity.java:8000)
        at android.app.Activity.performCreate(Activity.java:7984)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3422)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

Somewhat the crash says "ID does not reference a View inside this Activity". I have been trying to find the solution and different things but no success at all.

My android studio version is 4.2.2 in Mac.

Any help is highly appreciable.

Answer 1

Edited 16 july 2021 14:39 :

use navController = findNavController(R.id.nav_host_fragment_content_main) in your activity rather than in fragment and make it public. In your fragment do this to get the navController: (activity as YourActivity)!!.navController

old answer :

the key is here: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.testnavigation/com.example.testnavigation.MainActivity}: android.view.InflateException: Binary XML file line #15 in com.example.testnavigation:layout/activity_main: Binary XML file line #19 in com.example.testnavigation:layout/content_main: Error inflating class fragment the error says you are trying to inflate a fragment into a container that does not exist. This is a common NavigationUI error, and it's easy to fix:

• check in your ../app/res/navigation/your_nav_graph that the navigation_id exist (like so:

  <fragment android:id="@+id/a" android:name="com.example.myapplication.FragmentA" android:label="a" tools:layout="@layout/a"> <action android:id="@+id/ action_a_to_b " app:destination="@id/b" app:enterAnim="@anim/nav_default_enter_anim" app:exitAnim="@anim/nav_default_exit_anim" app:popEnterAnim="@anim/nav_default_pop_enter_anim" app:popExitAnim="@anim/nav_default_pop_exit_anim"/> </fragment>

where action_a_to_b is the ID you should pass in navController.navigate( not the id of the fragment_container.

take a look at the official doc : Navigate to a destination in how to create an action / navigation to destination if it does not exist yet .