试图在回收视图中一次选择一个复选框，但应用程序崩溃

Question

我试图在回收视图中一次选择一个复选框，因为我需要项目中的数据，以便在不同的方法中使用它。目前，我可以选择一个项目，然后数据存储在一个变量中，然后在另一个类中使用，但如果我尝试选择一个不同的项目，使其成为回收视图中新的且唯一选择的项目，它就会崩溃。使用的变量：

private int lastCheckedPos = -1;

我正在使用一个火球回收适配器

adapter1 = new FirebaseRecyclerAdapter<contact, contactAdapter>(options1) {
@Override
protected void onBindViewHolder(@NonNull final contactAdapter holder, final int position, @NonNull contact model) {
holder.contactName.setText(model.getContactName());
holder.contactPhone.setText(model.getContactPhone());
holder.chk.setChecked(position == lastCheckedPos);
holder.chk.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (position == lastCheckedPos) {
holder.chk.setChecked(false);
lastCheckedPos = -1;
}else {
lastCheckedPos = position;
for (int i = 0; i < adapter1.getItemCount(); i++) {
if (adapter1.getItem(i).isSelected(true)) {
number = ((TextView) contactsView.findViewHolderForAdapterPosition(position).itemView.findViewById(R.id.contactPhone)).getText().toString();
Toast.makeText(getActivity(), "Data Inserted....." + number, Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(getActivity(), "Error", Toast.LENGTH_LONG).show();
}
}
notifyDataSetChanged();
}
}
});
}
@NonNull
@Override
public contactAdapter onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
return new contactAdapter(LayoutInflater.from(getActivity()).inflate(R.layout.item_contacts, parent, false));
}
};

这是我的完整堆叠

Process: com.example.carcrashdetection, PID: 16888
java.lang.IllegalStateException: Cannot call this method while RecyclerView is computing a layout or scrolling androidx.recyclerview.widget.RecyclerView{f5f26ef VFED..... ......ID 0,1821-1440,2521 #7f08005b app:id/contactsView}, adapter:com.example.carcrashdetection.Home$1@53a95fc, layout:androidx.recyclerview.widget.LinearLayoutManager@8cd485, context:com.example.carcrashdetection.MainActivity@2b025f1
at androidx.recyclerview.widget.RecyclerView.assertNotInLayoutOrScroll(RecyclerView.java:3051)
at androidx.recyclerview.widget.RecyclerView$RecyclerViewDataObserver.onChanged(RecyclerView.java:5536)
at androidx.recyclerview.widget.RecyclerView$AdapterDataObservable.notifyChanged(RecyclerView.java:12253)
at androidx.recyclerview.widget.RecyclerView$Adapter.notifyDataSetChanged(RecyclerView.java:7354)
at com.example.carcrashdetection.Home$1$1.onCheckedChanged(Home.java:118)
at android.widget.CompoundButton.setChecked(CompoundButton.java:180)
at com.example.carcrashdetection.Home$1.onBindViewHolder(Home.java:101)
at com.example.carcrashdetection.Home$1.onBindViewHolder(Home.java:96)
at com.firebase.ui.database.FirebaseRecyclerAdapter.onBindViewHolder(FirebaseRecyclerAdapter.java:149)
at androidx.recyclerview.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:7065)
at androidx.recyclerview.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:7107)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:6012)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6279)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6118)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6114)
at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2303)
at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1627)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:665)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4134)
at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3851)
at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4404)
at android.view.View.layout(View.java:22085)
at android.view.ViewGroup.layout(ViewGroup.java:6290)
at androidx.constraintlayout.widget.ConstraintLayout.onLayout(ConstraintLayout.java:1915)
at android.view.View.layout(View.java:22085)
at android.view.ViewGroup.layout(ViewGroup.java:6290)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at android.view.View.layout(View.java:22085)
at android.view.ViewGroup.layout(ViewGroup.java:6290)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
at android.view.View.layout(View.java:22085)
at android.view.ViewGroup.layout(ViewGroup.java:6290)
at androidx.drawerlayout.widget.DrawerLayout.onLayout(DrawerLayout.java:1231)
at android.view.View.layout(View.java:22085)
at android.view.ViewGroup.layout(ViewGroup.java:6290)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at android.view.View.layout(View.java:22085)
at android.view.ViewGroup.layout(ViewGroup.java:6290)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
2020-04-23 15:57:53.185 16888-16888/com.example.carcrashdetection E/AndroidRuntime:     at android.view.View.layout(View.java:22085)
at android.view.ViewGroup.layout(ViewGroup.java:6290)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at android.view.View.layout(View.java:22085)
at android.view.ViewGroup.layout(ViewGroup.java:6290)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
at android.view.View.layout(View.java:22085)
at android.view.ViewGroup.layout(ViewGroup.java:6290)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:780)
at android.view.View.layout(View.java:22085)
at android.view.ViewGroup.layout(ViewGroup.java:6290)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:3332)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2809)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1929)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7987)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1154)
at android.view.Choreographer.doCallbacks(Choreographer.java:977)
at android.view.Choreographer.doFrame(Choreographer.java:893)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1139)
at android.os.Handler.handleCallback(Handler.java:883)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7682)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:516)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)

联系人适配器

public class contactAdapter extends RecyclerView.ViewHolder{
public TextView contactName, contactPhone;
CheckBox chk;
AdapterView.OnItemClickListener itemClickListener;

public contactAdapter(@NonNull View itemView) {
super(itemView);
contactName = itemView.findViewById(R.id.contactName);
contactPhone = itemView.findViewById(R.id.contactPhone);
chk = itemView.findViewById(R.id.myCheckBox);
}
}

item_contacts.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="wrap_content" >
<LinearLayout
android:id="@+id/outer"
android:layout_width="match_parent"
android:layout_height="101dp"
android:layout_marginBottom="24dp"
android:paddingBottom="24dp"
android:paddingTop="5dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:background="#ffffff">
<ImageView
android:layout_width="80dp"
android:layout_height="65dp"
android:layout_marginTop="15dp"
android:src="@drawable/icon" />
<LinearLayout
android:layout_width="80dp"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:orientation="vertical"
android:id="@+id/inner">
<TextView
android:id="@+id/contactName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Name"
android:textSize="16sp" />
<TextView
android:id="@+id/contactPhone"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Phone"
android:textSize="16sp" />

</LinearLayout>
<LinearLayout
android:id="@+id/hello"
android:layout_width="150dp"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:orientation="horizontal"
android:padding="10dp">
<Button
android:id="@+id/edit"
android:layout_width="70dp"
android:layout_height="wrap_content"

android:text="Edit"
android:textSize="14sp" />
<Button
android:id="@+id/delete"
android:layout_width="70dp"
android:layout_height="wrap_content"
android:layout_marginLeft="5dp"
android:text="Delete"
android:textSize="14sp" />
</LinearLayout>

<CheckBox
android:layout_width="60dp"
android:layout_height="wrap_content"
android:layout_marginTop="25dp"
android:height="60dp"
android:id="@+id/myCheckBox"
/>
</LinearLayout>
</LinearLayout>

我可以从堆栈跟踪中看到它给了我一个NullPointerException，但我真的不知道为什么。任何建议都将不胜感激。

Answer 1

您不需要再次启动视图，您可以使用holder来获取它。

像这样：

number = ((TextView) holder.itemView.findViewById(R.id.contactPhone)).getText().toString();

出现该问题的原因是RecyclerAdapter中的项目具有生命周期。

我可以告诉你的另一件事是：注意有了NullPointerException，你可以使用验证!= null来处理不再发生的问题。

TextView tvNumber = holder.itemView.findViewById(R.id.contectPhone);
String number = tvNumber != null ? tvNumber.getText().toString() : ""

如果您的问题已经解决，请告诉我：(