android - 应用安装到手机后无法打开，应用崩溃
问题描述
**在这个应用程序中，我创建了一个回收器视图，我只是想更新回收器视图上的数据，但我的应用程序崩溃而没有给出任何错误。 当我没有在其主构造函数中将任何数组列表传递给适配器时，它运行良好 Main Activity Kotlin 代码
class MainActivity : AppCompatActivity(),NavigationView.OnNavigationItemSelectedListener {
//Variables
private lateinit var drawerLayout : DrawerLayout
lateinit var toggle : ActionBarDrawerToggle
lateinit var navView : NavigationView
lateinit var toolBar : androidx.appcompat.widget.Toolbar
lateinit var adapter: MyAdapter
lateinit var titles : ArrayList<String>
lateinit var contents : ArrayList<String>
//onCreate fun
override fun onCreate(savedInstanceState: Bundle?){
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// toolbar support
setSupportActionBar(toolbar)
supportActionBar?.setDisplayHomeAsUpEnabled(true)
// creating layout manager
val layoutManager = LinearLayoutManager(this)
recyclerView.layoutManager = layoutManager
//intiializing
drawerLayout = drawer
navView = navigation_view
toolBar = toolbar
titles = ArrayList<String>()
contents = ArrayList<String>()
update()
adapter = MyAdapter(titles,contents)
recyclerView.adapter = adapter
// navView button click managed
navView.setNavigationItemSelectedListener(this)
toggle = ActionBarDrawerToggle(this,drawerLayout,toolbar,R.string.open,R.string.close)
toggle.isDrawerIndicatorEnabled = true
toggle.syncState()
}
override fun onNavigationItemSelected(item: MenuItem): Boolean {
when(item.itemId){
else->{
Toast.makeText(this,"ButtonClicked",Toast.LENGTH_LONG).show()
}
}
return false
}
override fun onCreateOptionsMenu(menu: Menu?): Boolean {
menuInflater.inflate(R.menu.option_menu,menu)
return super.onCreateOptionsMenu(menu)
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
if(item.itemId == R.id.settings){
Toast.makeText(this,"Setting selected",Toast.LENGTH_LONG).show()
}
return super.onOptionsItemSelected(item)
}
private fun update(){
titles.add("Hey")
contents.add("hello")
titles.add("Hey")
contents.add("hello")
titles.add("Hey")
contents.add("hello")
titles.add("Hey")
contents.add("hello")
}
}
活动主
<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/drawer"
tools:context=".MainActivity">
<include
android:layout_height="match_parent"
android:layout_width="match_parent"
layout="@layout/content_main"
/>
<com.google.android.material.navigation.NavigationView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/navigation_view"
app:menu="@menu/nav_menu"
app:headerLayout="@layout/nav_header"
android:fitsSystemWindows="true"
android:layout_gravity = "start"
/>
</androidx.drawerlayout.widget.DrawerLayout>
适配器类
package com.example.mynotes.model
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
import com.example.mynotes.R
import kotlinx.android.synthetic.main.single_note_view.view.*
import java.util.*
class MyAdapter(private val titles : ArrayList<String>, private val content : ArrayList<String> ) : RecyclerView.Adapter<MyViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
val view = LayoutInflater.from(parent.context).inflate(R.layout.single_note_view,parent,false)
return MyViewHolder(view)
}
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
val currentTitle = titles[position]
val currentContent = content[position]
holder.content.text = currentContent
holder.titles.text = currentTitle
holder.view.setOnClickListener{
}
}
override fun getItemCount(): Int {
return titles.size
}
}
class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView){
val content : TextView = itemView.content
val titles : TextView = itemView.titles
lateinit var view : TextView
}
content_main
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
xmlns:app="http://schemas.android.com/apk/res-auto">
<androidx.appcompat.widget.Toolbar
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:id="@+id/toolbar"
android:background="@color/teal_700"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
/>
<androidx.recyclerview.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:layout_editor_absoluteX="79dp"
tools:layout_editor_absoluteY="174dp"
android:id="@+id/recyclerView"
/>
</LinearLayout>
单项寻找回收站视图
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@android:color/transparent"
android:orientation="vertical">
<androidx.cardview.widget.CardView
android:id="@+id/noteCard"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
app:cardBackgroundColor="#7B1FA2"
app:cardCornerRadius="0dp"
app:cardElevation="5dp"
app:contentPadding="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/content"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
android:padding="5dp"
android:text="TextView"
android:textColor="#000"
android:textSize="15sp"
android:textStyle="normal|italic"
app:layout_constraintBottom_toTopOf="@+id/cardView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />
<androidx.cardview.widget.CardView
android:id="@+id/cardView"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:cardCornerRadius="0dp"
app:cardElevation="5dp"
app:contentPadding="5dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="1.0"
android:orientation="horizontal">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="@+id/menuIcon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="@drawable/ic_baseline_vertical_bars_24"
tools:ignore="VectorDrawableCompat" />
<TextView
android:id="@+id/titles"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:padding="2dp"
android:text="TextView"
android:textColor="@color/design_default_color_primary_dark"
android:textSize="14sp"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="@+id/menuIcon"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
</androidx.constraintlayout.widget.ConstraintLayout>
日志猫
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.mynotes, PID: 29432
kotlin.UninitializedPropertyAccessException: lateinit property view has not been initialized
at com.example.mynotes.model.MyViewHolder.getView(MyAdapter.kt:35)
at com.example.mynotes.model.MyAdapter.onBindViewHolder(MyAdapter.kt:23)
at com.example.mynotes.model.MyAdapter.onBindViewHolder(MyAdapter.kt:12)
at androidx.recyclerview.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:7254)
at androidx.recyclerview.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:7337)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:6194)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6460)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6300)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6296)
at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2330)
at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1631)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1591)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:668)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4309)
at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:4012)
at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4578)
at android.view.View.layout(View.java:19693)
at android.view.ViewGroup.layout(ViewGroup.java:6079)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1791)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1635)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1544)
at android.view.View.layout(View.java:19693)
at android.view.ViewGroup.layout(ViewGroup.java:6079)
at androidx.drawerlayout.widget.DrawerLayout.onLayout(DrawerLayout.java:1231)
at android.view.View.layout(View.java:19693)
at android.view.ViewGroup.layout(ViewGroup.java:6079)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:19693)
at android.view.ViewGroup.layout(ViewGroup.java:6079)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1791)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1635)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1544)
at android.view.View.layout(View.java:19693)
at android.view.ViewGroup.layout(ViewGroup.java:6079)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:19693)
at android.view.ViewGroup.layout(ViewGroup.java:6079)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1791)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1635)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1544)
at android.view.View.layout(View.java:19693)
at android.view.ViewGroup.layout(ViewGroup.java:6079)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:764)
at android.view.View.layout(View.java:19693)
at android.view.ViewGroup.layout(ViewGroup.java:6079)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2541)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2257)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1437)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6886)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1029)
at android.view.Choreographer.doCallbacks(Choreographer.java:841)
2021-07-05 12:27:01.950 29432-29432/com.example.mynotes E/AndroidRuntime: at android.view.Choreographer.doFrame(Choreographer.java:772)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1015)
at android.os.Handler.handleCallback(Handler.java:794)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:176)
at android.app.ActivityThread.main(ActivityThread.java:6651)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:824)
2021-07-05 12:27:02.001 29432-29432/com.example.mynotes I/Process: Sending signal. PID: 29432 SIG: 9
解决方案
错误在您的适配器类中。在 MyViewHolder 类中注释这一行
lateinit var view : TextView
因为你没有初始化它，所以当你在 OnBindViewHolder 方法中添加 onClickListener 时它会产生异常
并在 OnBindViewHolder 方法中注释这一行
holder.view.setOnClickListener{
}
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