使用removeValue()删除firebase子级时，应用程序崩溃，IndexOutOfBoundsExceptio

Question

我正在制作一个基于firebase实时数据库的android应用程序。我正在读取RecyclerView中的数据。我的RecyclerView中有三项。

1. 文本视图=名称
2. 文本视图=数字
3. 按钮=删除

当我从RecyclerView中删除某个孩子时，可能会发生三件事：

1. 有时它会正常删除目标子

2. 有时它会删除其他子项(通常位于目标子项之下。(

3. 有时我的应用程序会崩溃。

这是我的适配器的代码：

public class holder extends RecyclerView.ViewHolder {
public Button btnDelete;
public TextView tvName;
public TextView tvRoll;
public holder(@NonNull View itemView) {
super(itemView);
btnDelete=(Button) itemView.findViewById(R.id.idDelete);
tvName=(TextView) itemView.findViewById(R.id.idName);
tvRoll=(TextView) itemView.findViewById(R.id.idRoll);
}
}

这是在回收器视图中显示项目的代码，也是删除按钮的代码：

options = new FirebaseRecyclerOptions.Builder<basic>()
.setQuery(myRef, basic.class)
.build();
adapter = new FirebaseRecyclerAdapter<basic, holder>(options) {
@SuppressLint("SetTextI18n")
@Override
protected void onBindViewHolder(@NonNull holder holder, final int i, @NonNull final basic basic) {
holder.tvName.setText(basic.getFb01name());
holder.tvRoll.setText(basic.getFb04roll());
holder.btnDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
myRef.child(getRef(i).getKey()).removeValue();
}
});
}
@NonNull
@Override
public holder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.items, parent, false);
return new holder(v);
}
};
//------------------------------
adapter.startListening();
Userlist.setAdapter(adapter);
//-----------------------------------

我猜不出问题出在哪里。

还请提供一个切实可行的解决方案。

这是坠机报告：

2020-11-30 23:27:45.968 10796-10796/com.my App Name E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.my App Name, PID: 10796
java.lang.IndexOutOfBoundsException: Index: 4, Size: 4
at java.util.ArrayList.get(ArrayList.java:437)
at com.firebase.ui.common.BaseObservableSnapshotArray.getSnapshot(BaseObservableSnapshotArray.java:70)
at com.firebase.ui.database.FirebaseRecyclerAdapter.getRef(FirebaseRecyclerAdapter.java:112)
at com.my App Name.ViewActivity$1$1.onClick(ViewActivity.java:72)
at android.view.View.performClick(View.java:7448)
at android.view.View.performClickInternal(View.java:7425)
at android.view.View.access$3600(View.java:810)
at android.view.View$PerformClick.run(View.java:28305)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
2020-11-30 23:27:46.701 1467-10685/com.google.android.googlequicksearchbox E/sb.v.u.LiteSuggestSourc: On-device lite suggest model loading error.
2020-11-30 23:27:46.818 1467-1774/com.google.android.googlequicksearchbox E/MDD: DownloadProgressMonitor: Can't find file group for uri: android://com.google.android.googlequicksearchbox/files/sharedminusonemodule/shared/SharedMinusOneData.pb.tmp

Answer 1

当您在按钮onClick回调中访问FirebasegetRef(i)时，它可能引用错误的位置i导致IndexOutOfBoundsException

因此，我们将获得回调之外的密钥，如下所示：

options = new FirebaseRecyclerOptions.Builder<basic>()
.setQuery(myRef, basic.class)
.build();
adapter = new FirebaseRecyclerAdapter<basic, holder>(options) {
@SuppressLint("SetTextI18n")
@Override
protected void onBindViewHolder(@NonNull holder holder, final int i, @NonNull final basic basic) {
holder.tvName.setText(basic.getFb01name());
holder.tvRoll.setText(basic.getFb04roll());
String refKey = getRef(i).getKey(); // <<<<<< Here is the change

holder.btnDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
myRef.child(refKey)).removeValue();
}
});
}
@NonNull
@Override
public holder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.items, parent, false);
return new holder(v);
}
};