NullPointerException 从 Kotlin 活动启动 Firebase 身份验证 UI 活动

Question

我有一个带有 androidx 导航（支持栏 + 导航抽屉）的 java android 应用程序，它正在启动 Firebase UI 以让用户登录。然后我决定使用 AS 转换器和一些将 Activity 代码迁移到 Kotlin手动设置导航。

尽管我努力了，但它仍然与这个堆栈中断

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.gabrielcalero.familytree, PID: 20260
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.gabrielcalero.familytree/com.firebase.ui.auth.KickoffActivity}: java.lang.NullPointerException: Attempt to invoke super method 'void androidx.fragment.app.FragmentActivity.onPanelClosed(int, android.view.Menu)' on a null object reference
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2793)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2864)
    at android.app.ActivityThread.-wrap12(ActivityThread.java)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1567)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:156)
    at android.app.ActivityThread.main(ActivityThread.java:6524)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:941)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:831)
 Caused by: java.lang.NullPointerException: Attempt to invoke super method 'void androidx.fragment.app.FragmentActivity.onPanelClosed(int, android.view.Menu)' on a null object reference
    at androidx.appcompat.app.AppCompatActivity.onPanelClosed(AppCompatActivity.java:505)
    at androidx.lifecycle.LiveData.observe(LiveData.java:172)
    at com.firebase.ui.auth.KickoffActivity.onCreate(KickoffActivity.java:35)
    at android.app.Activity.performCreate(Activity.java:6910)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2746)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2864) 
    at android.app.ActivityThread.-wrap12(ActivityThread.java) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1567) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:156) 
    at android.app.ActivityThread.main(ActivityThread.java:6524) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:941) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:831) 

奇怪的是，堆栈后面的异常是onPanelClosed，这意味着super为null。这怎么可能？

@Override
public void onPanelClosed(int featureId, Menu menu) {
    super.onPanelClosed(featureId, menu);
}

更新：这是活动代码

package com.gabrielcalero.familytree.ui
import android.content.Intent
import android.os.Bundle
import android.view.MenuItem
import android.widget.ImageView
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import androidx.navigation.NavController
import androidx.navigation.findNavController
import androidx.navigation.ui.AppBarConfiguration
import androidx.navigation.ui.setupWithNavController
import com.firebase.ui.auth.AuthUI
import com.gabrielcalero.familytree.R
import com.gabrielcalero.familytree.ServiceLocator
import com.gabrielcalero.familytree.entity.Constants
import com.gabrielcalero.familytree.ui.picasso.CropCircleTransformation
import com.google.android.material.navigation.NavigationView
import com.google.firebase.auth.FirebaseAuth
import com.squareup.picasso.Picasso
import kotlinx.android.synthetic.main.activity_main.*
import java.util.*

class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener, FirebaseAuth.AuthStateListener {

private var mUserPicture: ImageView? = null
private var mUserNameTextView: TextView? = null
private var mAuth: FirebaseAuth? = null

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    setupNavigation()

    mUserPicture = navView.getHeaderView(0).findViewById(R.id.picture)
    mUserNameTextView = navView.getHeaderView(0).findViewById(R.id.display_name)

    mAuth = FirebaseAuth.getInstance().apply { addAuthStateListener { this } }

    launchSignInUI()
}

override fun onStart() {
    super.onStart()
    updateLoggedInUser()
}

private fun updateLoggedInUser() {
    val currentUser = mAuth!!.currentUser
    if (currentUser == null) {
        mUserPicture!!.setImageResource(R.drawable.anonymous)
        mUserNameTextView!!.text = getString(R.string.not_logged_in)
        navView.menu.findItem(R.id.signout).isVisible = false
        navView.menu.findItem(R.id.signin).isVisible = true
        navView.menu.findItem(R.id.personFragment).isEnabled = false
        navView.menu.findItem(R.id.peopleListFragment).isEnabled = false
    } else {
        // show signout
        mUserNameTextView!!.text = currentUser.displayName
        Picasso.with(this)
                .load(currentUser.photoUrl)
                .placeholder(R.drawable.anonymous)
                .error(R.drawable.anonymous)
                .transform(CropCircleTransformation())
                .resize(resources.getDimension(R.dimen.profile_picture_width).toInt(),
                        resources.getDimension(R.dimen.profile_picture_height).toInt())
                .into(mUserPicture)
        navView.menu.findItem(R.id.signout).isVisible = true
        navView.menu.findItem(R.id.signin).isVisible = false
        navView.menu.findItem(R.id.personFragment).isEnabled = true
        navView.menu.findItem(R.id.peopleListFragment).isEnabled = true
    }
}

private fun setupNavigation() {
    setSupportActionBar(toolbar)

    supportActionBar!!.setDisplayShowHomeEnabled(true)
    supportActionBar!!.setDisplayHomeAsUpEnabled(true)

    val navController : NavController = findNavController(R.id.nav_host_fragment)
    val appBarConfiguration = AppBarConfiguration(navController.graph, drawerLayout)
    toolbar.setupWithNavController(navController, appBarConfiguration)
    navView.setupWithNavController(navController)
    navView.setNavigationItemSelectedListener(this)
}

private fun launchSignInUI() {
    // Choose authentication providers
    val providers = Arrays.asList(
            AuthUI.IdpConfig.EmailBuilder().build(),
            AuthUI.IdpConfig.GoogleBuilder().build())

    // Create and launch sign-in intent
    startActivityForResult(
            AuthUI.getInstance()
                    .createSignInIntentBuilder()
                    .setAvailableProviders(providers)
                    .setLogo(R.drawable.logo)
                    .build(),
            Constants.REQUEST_CODE_SIGN_IN)
}


override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    super.onActivityResult(requestCode, resultCode, data)
    //updateLoggedInUser()
}

override fun onNavigationItemSelected(menuItem: MenuItem): Boolean {
    val navController = findNavController(R.id.nav_host_fragment)
    when (menuItem.itemId) {
        R.id.signout -> signout()
        R.id.signin -> launchSignInUI()
        R.id.personFragment -> {
            navController.popBackStack(R.id.peopleListFragment, false)
            navController.navigate(R.id.personFragment)
            drawerLayout?.closeDrawers()
            return true
        }
        else -> {
            navController.popBackStack(R.id.peopleListFragment, false)
            drawerLayout?.closeDrawers()
            return true
        }
    }
    drawerLayout?.closeDrawers()
    return true
}

private fun signout() {
    val navController = findNavController(R.id.nav_host_fragment)

    AuthUI.getInstance()
            .signOut(this)
            .addOnCompleteListener {
                navView.menu.findItem(R.id.signout).isVisible = false
                navController.popBackStack(R.id.peopleListFragment, false)
            }

}

override fun onAuthStateChanged(firebaseAuth: FirebaseAuth) {
    ServiceLocator.getRepository(application).setCurrentUserId(firebaseAuth.uid)
    updateLoggedInUser()
}

}

Answer 1

问题在于 Java 到 Kotlin 的转换。在这种情况下，我通过删除未使用的依赖项来修复它

implementation "androidx.core:core-ktx:+"

我想当我完成所有 java 类的转换后，我将不得不用它们的 -ktx 对应项替换所有 androidx 依赖项