我有要从Firebase检索的项目列表。为了删除这些项目，我实现了一个删除按钮。我试图在用户单击删除按钮后获取发布键。目前，我可以删除项目，但是当我从RecyclerView的中间删除内容，然后再删除第一个项目时，应用程序崩溃。
代码：
public class MyPosts extends AppCompatActivity {
private static final String TAG = "MyPosts";
Toolbar toolbar;
DatabaseReference WorkingData;
DatabaseReference WorkingDataForDeletion;
DatabaseReference tasks;
private BottomNavigationView navigationView;
RecyclerView recyclerView;
ArrayList<WorkInformation> workList;
private AppCompatButton deletePost;
private AppCompatButton editPost;
String currentUserID, postKey;
private FirebaseAuth firebaseAuth;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my_posts);
toolbar = (Toolbar) findViewById(R.id.my_post_toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("My Posts");
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
navigationView = findViewById(R.id.bottomNavigationView);
firebaseAuth = FirebaseAuth.getInstance();
currentUserID = firebaseAuth.getCurrentUser().getUid();
WorkingData = FirebaseDatabase.getInstance().getReference().child("UserIndividualTasks");
WorkingData.keepSynced(true);
recyclerView = findViewById(R.id.my_post_recycler_view);
recyclerView.setHasFixedSize(true);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
linearLayoutManager.setReverseLayout(true);
linearLayoutManager.setStackFromEnd(true);
recyclerView.setLayoutManager(linearLayoutManager);
deletePost = findViewById(R.id.myPostDelete);
editPost = findViewById(R.id.myPostEdit);
}
@Override
protected void onStart() {
super.onStart();
}
@Override
protected void onResume() {
super.onResume();
Query query = WorkingData.child(FirebaseAuth.getInstance().getCurrentUser().getUid());
FirebaseRecyclerOptions<WorkInformation> options = new FirebaseRecyclerOptions.Builder<WorkInformation>()
.setQuery(query, WorkInformation.class)
.build();
final FirebaseRecyclerAdapter<WorkInformation, MyViewHolder> adapter = new FirebaseRecyclerAdapter<WorkInformation, MyViewHolder>(options) {
@Override
protected void onBindViewHolder(@NonNull MyViewHolder holder, final int position, @NonNull WorkInformation model) {
holder.title.setText(model.getWorkTitle());
holder.date.setText(model.getWorkDueDate());
Picasso.get().load(model.getImg()).into(holder.imageView);
holder.deleteBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
notifyDataSetChanged();
postKey = getRef(position).getKey();
Log.d(TAG, "onClick: position is " + position);
Log.d(TAG, "onClick: post key is " + postKey);
notifyItemRemoved(position);
WorkingDataForDeletion = FirebaseDatabase.getInstance().getReference().child("UserIndividualTasks")
.child(currentUserID)
.child(postKey);
WorkingDataForDeletion.removeValue();
notifyItemRemoved(position);
notifyDataSetChanged();
}
});
}
@NonNull
@Override
public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.my_posts_individual_row_layout, parent, false);
MyViewHolder viewHolder = new MyViewHolder(view);
return viewHolder;
}
};
adapter.notifyDataSetChanged();
recyclerView.setAdapter(adapter);
adapter.startListening();
adapter.notifyDataSetChanged();
}
public static class MyViewHolder extends RecyclerView.ViewHolder {
public AppCompatTextView title;
public AppCompatTextView date;
public CircleImageView imageView;
public AppCompatButton deleteBtn;
public AppCompatButton editBtn;
public ConstraintLayout constraintLayout;
public MyViewHolder(View itemView) {
super(itemView);
title = itemView.findViewById(R.id.my_posts_title);
date = itemView.findViewById(R.id.myPostDate);
imageView = itemView.findViewById(R.id.UserImage);
deleteBtn = itemView.findViewById(R.id.myPostDelete);
editBtn = itemView.findViewById(R.id.myPostEdit);
}
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
switch (id) {
case android.R.id.home:
startActivity(new Intent(MyPosts.this, Services.class));
break;
}
return super.onOptionsItemSelected(item);
}
private void deleteUserPost() {
}
}
崩溃日志：
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.saqib.smarttaskk, PID: 19583
java.lang.IndexOutOfBoundsException: Index: 3, Size: 3
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.example.saqib.smarttaskk.MyPosts$1$1.onClick(MyPosts.java:131)
at android.view.View.performClick(View.java:6891)
at android.widget.TextView.performClick(TextView.java:12651)
at android.view.View$PerformClick.run(View.java:26083)
at android.os.Handler.handleCallback(Handler.java:789)
at android.os.Handler.dispatchMessage(Handler.java:98)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6938)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:327)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1374)
答案 0 :(得分：0)
永远不要在侦听器或异步任务中使用position。
在您的OnClickListener内，将position的任何使用替换为holder.getAdapterPosition()。
您还应该删除对适配器内部或外部的任何形式的数据通知（notifyDataSetChanged()，notifyItemRemoved()等）的所有调用。
您最终的onClick()方法应如下所示：
public void onClick(View v) {
//removed notifyDataSetChanged()
postKey = getRef(holder.getAdapterPosition()).getKey();
Log.d(TAG, "onClick: position is " + holder.getAdapterPosition());
Log.d(TAG, "onClick: post key is " + postKey);
//removed notifyItemRemoved()
//variable names should be camelCase not TitleCase
workingDataForDeletion = FirebaseDatabase.getInstance().getReference().child("UserIndividualTasks")
.child(currentUserID)
.child(postKey);
workingDataForDeletion.removeValue();
//removed notifyItemRemoved()
//removed notifyDataSetChanged()
}
答案 1 :(得分：0)
使用这个
product_list.remove(product_list.get(position))
notifyItemRemoved(position);
notifyItemRangeChanged(position, itemCount)