java - 构建 RecyclerView 时创建的自动生成文件出错

标签 java android android-recyclerview indexoutofboundsexception auto-generate

我是一名 Android Studio 新用户,也是 Java 新手。我正在构建一个新项目,并按照本教程将 RecyclerView 添加到我的项目中:https://www.youtube.com/watch?v=Vyqz_-sJGFk 。该应用程序似乎构建正确,但现在在我的设备上打开时立即崩溃。在此之前它运行良好。错误消息引导我找到在此过程中创建的自动生成的文件。

我已尝试按照文件的错误消息进行操作,但无法弄清楚如何修复它们(如果这确实是问题所在)。在使用搜索词“recyclerview”、“android studio”“无法解析符号”等搜索解决方案时,我发现了一些升级到 Android Studio 3.3 的建议。我已经在使用 3.4.0,但我尝试升级到 3.4.1。不用找了。我尝试更改 build.gradle 文件中的依赖项,但这似乎也没有改变任何内容。我发现的大多数其他答案都与无法解析符号'RecyclerView'有关,这不是我目前遇到的问题。我还多次尝试过文件 > 使缓存无效/重新启动...>使缓存无效并重新启动,因为我在几个地方看到了推荐的方法。

在跟踪这些文件时,我发现了几个地方 import androidx.recyclerview.R; 导致 无法解析符号“R” 错误,以及几个地方 >lst.elementData 在文件的一个部分工作正常,但在另一部分则不然,导致无法解析符号“elementData”。 我当前的 build.gradle 依赖项如下所示:

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.0.2'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation 'com.google.android.material:material:1.0.0'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
    implementation 'androidx.recyclerview:recyclerview-selection:1.0.0'
}

我可以确定被调用的最后一个函数是:

@Override
    public void onBindViewHolder(@NonNull ViewHolder holder, final int position) {
        Log.d(TAG, "onBindViewHolder: called");

        holder.itemName.setText(mItemName.get(position));
        holder.itemDue.setText(mItemDue.get(position));

        holder.listItem.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d(TAG, "onClick: clicked on: " + mItemName.get(position));

                // Insert navigation here
            }
        });
    }

正如您从下面的错误日志中看到的那样。
我上次项目工作时添加的唯一代码来 self 遵循的教程,对某些变量的名称进行了细微调整,并用第二个 TextView 替换每个列表项上的图像。

日志中的错误消息是:

2019-05-16 00:46:04.247 12824-12824/? D/RecyclerViewAdapter: onBindViewHolder: called
2019-05-16 00:46:04.248 12824-12824/? D/AndroidRuntime: Shutting down VM
2019-05-15 23:44:28.830 4480-4480/com.example.divideanddestress E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.divideanddestress, PID: 4480
    java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
        at java.util.ArrayList.get(ArrayList.java:411)
        at com.example.divideanddestress.RecyclerViewAdapter.onBindViewHolder(RecyclerViewAdapter.java:42)
        at com.example.divideanddestress.RecyclerViewAdapter.onBindViewHolder(RecyclerViewAdapter.java:16)
        at androidx.recyclerview.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6781)
        at androidx.recyclerview.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:6823)
        at androidx.recyclerview.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:5752)
        at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6019)
        at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5858)
        at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5854)
        at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2230)
        at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1557)
        at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1517)
        at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:612)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3924)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3641)
        at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4194)
        at android.view.View.layout(View.java:19039)
        at android.view.ViewGroup.layout(ViewGroup.java:5935)
        at androidx.constraintlayout.widget.ConstraintLayout.onLayout(ConstraintLayout.java:1915)
        at android.view.View.layout(View.java:19039)
        at android.view.ViewGroup.layout(ViewGroup.java:5935)
        at com.google.android.material.appbar.HeaderScrollingViewBehavior.layoutChild(HeaderScrollingViewBehavior.java:142)
        at com.google.android.material.appbar.ViewOffsetBehavior.onLayoutChild(ViewOffsetBehavior.java:41)
        at com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior.onLayoutChild(AppBarLayout.java:1556)
        at androidx.coordinatorlayout.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:888)
        at android.view.View.layout(View.java:19039)
        at android.view.ViewGroup.layout(ViewGroup.java:5935)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
        at android.view.View.layout(View.java:19039)
        at android.view.ViewGroup.layout(ViewGroup.java:5935)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
        at android.view.View.layout(View.java:19039)
        at android.view.ViewGroup.layout(ViewGroup.java:5935)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
        at android.view.View.layout(View.java:19039)
        at android.view.ViewGroup.layout(ViewGroup.java:5935)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
        at android.view.View.layout(View.java:19039)
        at android.view.ViewGroup.layout(ViewGroup.java:5935)
        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:954)
        at android.view.View.layout(View.java:19039)
        at android.view.ViewGroup.layout(ViewGroup.java:5935)
        at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2711)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2426)
2019-05-15 23:44:28.831 4480-4480/com.example.divideanddestress E/AndroidRuntime:     at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1569)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7296)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:930)
        at android.view.Choreographer.doCallbacks(Choreographer.java:705)
        at android.view.Choreographer.doFrame(Choreographer.java:640)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:916)
        at android.os.Handler.handleCallback(Handler.java:751)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6816)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1563)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1451)

最佳答案

在使用 arraylist 之前声明 mItemName=new ArrayList() 并检查 itemCount 值。

关于java - 构建 RecyclerView 时创建的自动生成文件出错,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/56163900/

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