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首页 > 解决方案 > 多个异常：无法启动活动、无法实例化片段、错误膨胀类

android - 多个异常：无法启动活动、无法实例化片段、错误膨胀类

问题描述

我是 Kotlin 的新手，我正在学习教程。运行我的应用程序会导致它在运行时崩溃。我在底部导航栏应用程序中有三个片段和一个主要活动。我的目标实际上只是成功运行应用程序，以便我可以尝试 Room 数据库、数据绑定和此类概念。我搜索了它对我不起作用但没有运气的可能原因。这是当前的完整错误消息：

    2021-02-27 14:58:23.967 23883-23883/com.jwanhsulaiman.talktag E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.jwanhsulaiman.talktag, PID: 23883
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.jwanhsulaiman.talktag/com.jwanhsulaiman.talktag.MainActivity}: android.view.InflateException: Binary XML file line #21: Binary XML file line #21: Error inflating class androidx.fragment.app.FragmentContainerView
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2919)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3054)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1814)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:280)
        at android.app.ActivityThread.main(ActivityThread.java:6706)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: android.view.InflateException: Binary XML file line #21: Binary XML file line #21: Error inflating class androidx.fragment.app.FragmentContainerView
     Caused by: android.view.InflateException: Binary XML file line #21: Error inflating class androidx.fragment.app.FragmentContainerView
     Caused by: androidx.fragment.app.Fragment$InstantiationException: Unable to instantiate fragment com.jwanhsulaiman.talktag.ui.home.HomeFragment: could not find Fragment constructor
        at androidx.fragment.app.Fragment.instantiate(Fragment.java:625)
        at androidx.fragment.app.FragmentContainer.instantiate(FragmentContainer.java:57)
        at androidx.fragment.app.FragmentManager$3.instantiate(FragmentManager.java:483)
        at androidx.navigation.fragment.FragmentNavigator.instantiateFragment(FragmentNavigator.java:132)
        at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:162)
        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:1059)
        at androidx.navigation.NavController.onGraphCreated(NavController.java:639)
        at androidx.navigation.NavController.setGraph(NavController.java:592)
        at androidx.navigation.NavController.setGraph(NavController.java:557)
        at androidx.navigation.NavController.setGraph(NavController.java:539)
        at androidx.navigation.fragment.NavHostFragment.onCreate(NavHostFragment.java:248)
        at androidx.fragment.app.Fragment.performCreate(Fragment.java:2936)
        at androidx.fragment.app.FragmentStateManager.create(FragmentStateManager.java:472)
        at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:278)
        at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2177)
        at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2094)
        at androidx.fragment.app.FragmentManager.execSingleAction(FragmentManager.java:1959)
        at androidx.fragment.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:311)
        at androidx.fragment.app.FragmentContainerView.<init>(FragmentContainerView.java:176)
        at androidx.fragment.app.FragmentLayoutInflaterFactory.onCreateView(FragmentLayoutInflaterFactory.java:52)
        at androidx.fragment.app.FragmentController.onCreateView(FragmentController.java:135)
        at androidx.fragment.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:313)
        at androidx.fragment.app.FragmentActivity.onCreateView(FragmentActivity.java:292)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:780)
2021-02-27 14:58:23.971 23883-23883/com.jwanhsulaiman.talktag E/AndroidRuntime:     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:863)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:374)
        at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:696)
        at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:170)
        at com.jwanhsulaiman.talktag.MainActivity.onCreate(MainActivity.kt:15)
        at android.app.Activity.performCreate(Activity.java:7136)
        at android.app.Activity.performCreate(Activity.java:7127)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1272)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2899)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3054)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1814)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:280)
        at android.app.ActivityThread.main(ActivityThread.java:6706)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.lang.NoSuchMethodException: <init> []
        at java.lang.Class.getConstructor0(Class.java:2327)
        at java.lang.Class.getConstructor(Class.java:1725)
        at androidx.fragment.app.Fragment.instantiate(Fragment.java:610)
            ... 50 more

我尝试将第 21 行的 XML 文件（根据错误）从fragment更改为androidx.fragment.app.FragmentContainerView（根据 Android Studio 在鼠标悬停时的建议。我尝试添加依赖项，但似乎没有任何改变。我将提供如何我的代码看起来像。

MainActivity.kt（错误说它在 setContentView(R.layout.activity_main) 上崩溃）

package com.jwanhsulaiman.talktag

import android.os.Bundle
import com.google.android.material.bottomnavigation.BottomNavigationView
import androidx.appcompat.app.AppCompatActivity
import androidx.navigation.findNavController
import androidx.navigation.ui.AppBarConfiguration
import androidx.navigation.ui.setupActionBarWithNavController
import androidx.navigation.ui.setupWithNavController

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val navView: BottomNavigationView = findViewById(R.id.nav_view)

        val navController = findNavController(R.id.nav_host_fragment)
        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        val appBarConfiguration = AppBarConfiguration(setOf(
                R.id.navigation_home, R.id.navigation_dashboard, R.id.navigation_notifications))
        setupActionBarWithNavController(navController, appBarConfiguration)
        navView.setupWithNavController(navController)
    }
}

activity_main.xml

<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
<androidx.constraintlayout.widget.ConstraintLayout
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingTop="?attr/actionBarSize">

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/nav_view"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="0dp"
        android:layout_marginEnd="0dp"
        android:background="?android:attr/windowBackground"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:menu="@menu/bottom_nav_menu" />

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/nav_host_fragment"
        class = "androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toTopOf="@id/nav_view"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/mobile_navigation" />

</androidx.constraintlayout.widget.ConstraintLayout>
</layout>

以及 HomeFragment 的完整片段，以防它相关

    package com.jwanhsulaiman.talktag.ui.home

import android.content.Context
import android.os.Bundle
import android.util.Log
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.databinding.DataBindingUtil
import androidx.fragment.app.Fragment
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModelProvider
import com.jwanhsulaiman.talktag.R
import com.jwanhsulaiman.talktag.database.VocabData
import com.jwanhsulaiman.talktag.database.VocabRepository
import com.jwanhsulaiman.talktag.databinding.FragmentHomeBinding

class HomeFragment(val applicationContext: Context) : Fragment() {

    private lateinit var homeViewModel: HomeViewModel
    private lateinit var binding: FragmentHomeBinding

    override fun onCreateView(
            inflater: LayoutInflater,
            container: ViewGroup?,
            savedInstanceState: Bundle?
    ): View? {
        homeViewModel =
                ViewModelProvider(this).get(HomeViewModel::class.java)
        val root = inflater.inflate(R.layout.fragment_home, container, false)
        val textView: TextView = root.findViewById(R.id.text_home)
        homeViewModel.text.observe(viewLifecycleOwner, Observer {
            textView.text = it
        })

        binding = DataBindingUtil.inflate(inflater, R.layout.fragment_home, container, false)
        val dao = VocabData.getInstance(this).VocabDao
        val repository = VocabRepository(dao)
        val factory = HomeViewModelFactory(repository)
        homeViewModel = ViewModelProvider(this, factory).get(HomeViewModel::class.java)
        binding.myViewModel = homeViewModel
        binding.lifecycleOwner = this
        displayVocabList()

        return binding.root
    }

    private fun displayVocabList() {
    homeViewModel.vocabs.observe(viewLifecycleOwner, Observer {
        Log.i("MYTAG", it.toString())
    })

    }
}

感谢您的任何见解！

标签： androidandroid-studiokotlinandroid-fragmentscrash

解决方案

Caused by: java.lang.NoSuchMethodException: <init> []

从 中删除构造函数HomeFragment，原因有两个：

  1. 它不起作用，因为片段系统需要一个公共的零参数构造函数

  2. 你不需要传入 a Context，因为一旦你的片段被附加到一个活动，你可以调用requireContext()来检索 a来使用（如果你真的需要Context，可以参考它）applicationContextApplication

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