Android DataBinding报错：java.lang.ArrayIndexOutOfBoundsException: length=2； index=2 fragment 更换成 Fragm

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前言

今天修复BUG的时候，顺带升级了一下，项目关联的库，升级后突然出现在DataBinding的报错，竟然还是java.lang.ArrayIndexOutOfBoundsException: length=2; index=2，竟然还是个列表位置错误，？？？满头问号

BUG

E/AndroidRuntime: FATAL EXCEPTION: mainProcess: com.xxx, PID: 27182java.lang.RuntimeException: Unable to start activity ComponentInfo{com.xxx/com.xxx.activity.main.MainActivity}: java.lang.ArrayIndexOutOfBoundsException: length=2; index=2at 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=2at 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) 

经过排查我怀疑时页面中使用了Fragment的问题，因为启动其他不带这个的页面Databinding就不会出现刚刚的问题；

点开页面布局 XML，就能看到提示：

Replace the < fragment > tag with FragmentContainerView.

更换FragmentContainerView

根据提示将 fragment 更换成 FragmentContainerView，重新运行，不再报“java.lang.ArrayIndexOutOfBoundsException: length=2; index=2”错误了，但是报了个新错误：

E/AndroidRuntime: FATAL EXCEPTION: mainProcess: com.xxx, PID: 27863java.lang.RuntimeException: Unable to start activity ComponentInfo{com.xxx/com.xxx.activity.main.MainActivity}: java.lang.IllegalStateException: Activity com.xxx.activity.main.MainActivity@1f5b1e does not have a NavController set on 2131296506at 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 com.xxx.activity.main.MainActivity@1f5b1e does not have a NavController set on 2131296506at 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) 

这个问题就报在了获取navController中，在stackoverflow上搜索了一下，就找到了FragmentContainerView获取navController的新方法

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

// 适配 FragmentContainerView
val navHostFragment = supportFragmentManager.findFragmentById(R.id.fragment) as NavHostFragment
navController = navHostFragment.navController
// 适配 Fragment
//navController = Navigation.findNavController(this, R.id.fragment)// 设置tab栏与fragment绑定
NavigationUI.setupWithNavController(binding.bottomNavigationView, navController)

混淆

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

完事

重新运行，问题解决。

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