[Solved] Android DataBinding Error: java.lang.ArrayIndexOutOfBoundsException: length=2; index=2 fragment Changes to Fragm

Android databinding error: Java. Lang. ArrayIndexOutOfBoundsException: length = 2; Index = 2 replace fragment with fragmentcontainerview

Preface bug replacing fragmentcontainerview

preface

When fixing the bug today, I upgraded the library associated with the project. After upgrading, an error appears in the databinding. Unexpectedly, it is still java.lang.arrayindexoutofboundsexception: length = 2; Index = 2, it’s still a list position error,???Full of question marks

BUG

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.xxx, PID: 27182
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.xxx/com.xxx.activity.main.MainActivity}: java.lang.ArrayIndexOutOfBoundsException: length=2; index=2
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3898)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4081)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:91)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:149)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:103)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2462)
        at android.os.Handler.dispatchMessage(Handler.java:110)
        at android.os.Looper.loop(Looper.java:219)
        at android.app.ActivityThread.main(ActivityThread.java:8393)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1055)
     Caused by: java.lang.ArrayIndexOutOfBoundsException: length=2; index=2
        at androidx.databinding.ViewDataBinding.mapBindings(ViewDataBinding.java:1211)
        at androidx.databinding.ViewDataBinding.mapBindings(ViewDataBinding.java:1268)
        at androidx.databinding.ViewDataBinding.mapBindings(ViewDataBinding.java:1268)
        at androidx.databinding.ViewDataBinding.mapBindings(ViewDataBinding.java:1268)
        at androidx.databinding.ViewDataBinding.mapBindings(ViewDataBinding.java:1268)
        at androidx.databinding.ViewDataBinding.mapBindings(ViewDataBinding.java:719)
        at com.xxx.databinding.ActivityMainBindingImpl.<init>(ActivityMainBindingImpl.java:28)
        at com.xxx.DataBinderMapperImpl.internalGetViewDataBinding0(DataBinderMapperImpl.java:378)
        at com.xxx.DataBinderMapperImpl.getDataBinder(DataBinderMapperImpl.java:663)
        at androidx.databinding.MergedDataBinderMapper.getDataBinder(MergedDataBinderMapper.java:74)
        at androidx.databinding.DataBindingUtil.bind(DataBindingUtil.java:199)
        at androidx.databinding.DataBindingUtil.bindToAddedViews(DataBindingUtil.java:327)
        at androidx.databinding.DataBindingUtil.setContentView(DataBindingUtil.java:306)
        at androidx.databinding.DataBindingUtil.setContentView(DataBindingUtil.java:284)
        at com.xxx.activity.main.MainActivity.onCreate(MainActivity.kt:72)
        at android.app.Activity.performCreate(Activity.java:8121)
        at android.app.Activity.performCreate(Activity.java:8109)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1320)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3871)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4081) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:91) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:149) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:103) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2462) 
        at android.os.Handler.dispatchMessage(Handler.java:110) 
        at android.os.Looper.loop(Looper.java:219) 
        at android.app.ActivityThread.main(ActivityThread.java:8393) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1055) 

After troubleshooting, I suspect that the fragment is used in the page, because the problem will not occur when starting other pages without this data binding;

Click the page layout XML to see the prompt:


replace the & lt; fragment > tag with FragmentContainerView.

Replace fragmentcontainerview

Replace the fragment with fragmentcontainerview according to the prompt, run it again, and no longer report “Java. Lang. ArrayIndexOutOfBoundsException: length = 2; “Index = 2” is wrong, but a new error is reported:

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.xxx, PID: 27863
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.xxx/com.xxx.activity.main.MainActivity}: java.lang.IllegalStateException: Activity [email protected] does not have a NavController set on 2131296506
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3898)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4081)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:91)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:149)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:103)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2462)
        at android.os.Handler.dispatchMessage(Handler.java:110)
        at android.os.Looper.loop(Looper.java:219)
        at android.app.ActivityThread.main(ActivityThread.java:8393)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1055)
     Caused by: java.lang.IllegalStateException: Activity [email protected] does not have a NavController set on 2131296506
        at androidx.navigation.Navigation.findNavController(Navigation.java:61)
        at com.xxx.activity.main.MainActivity.onCreate(MainActivity.kt:75)
        at android.app.Activity.performCreate(Activity.java:8121)
        at android.app.Activity.performCreate(Activity.java:8109)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1320)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3871)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4081) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:91) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:149) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:103) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2462) 
        at android.os.Handler.dispatchMessage(Handler.java:110) 
        at android.os.Looper.loop(Looper.java:219) 
        at android.app.ActivityThread.main(ActivityThread.java:8393) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1055) 

This problem is reported in obtaining the navcontroller. After searching the StackOverflow, we found the new method of fragmentcontainerview to obtain the navcontroller

reference resources: https://stackoverflow.com/questions/64170603/replace-the-fragment-tag-with-fragmentcontainerview


// FragmentContainerView
val navHostFragment = supportFragmentManager.findFragmentById(R.id.fragment) as NavHostFragment
navController = navHostFragment.navController
// Fragment
//navController = Navigation.findNavController(this, R.id.fragment)

// Set the tab bar to bind to the fragment
NavigationUI.setupWithNavController(binding.bottomNavigationView, navController)

confusion

-keepnames class androidx.navigation.fragment.NavHostFragment
-keepnames class com.google.android.gms.maps.SupportMapFragment

Finish

Re-run and solve the problem.


Read More: