java - 删除文件后更新视图适配器

Question

我有（删除文件操作）从适配器（Myadpter）内部工作，删除文件后我无法刷新此适配器，屏幕将保持与已删除文件相同但我需要通过按返回手动刷新状态并重新插入相同的布局，所以我会发现布局缺少我删除的文件，但需要备份并重新设置相同的布局以使其刷新。

有人知道为什么notifyDataSetChanged();不工作吗？

package com.example.boc.storage;

import android.app.DownloadManager;
import android.content.Context;
import android.net.Uri;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.example.boc.R;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.storage.FirebaseStorage;

import java.util.ArrayList;
import java.util.List;

import static android.os.Environment.DIRECTORY_DOWNLOADS;
import static com.example.boc.Pdf.pdfDownloader.TAG;

public class MyAdapter extends RecyclerView.Adapter<MyViewHolder> {

    public MainActivity mainActivity;
    public ArrayList<DownModel> downModels;
    RecyclerView mRecyclerView;
    ArrayList<DownModel> downModelArrayList = new ArrayList<>();



    public MyAdapter (MainActivity mainActivity, ArrayList<DownModel> downModels) {
        this.mainActivity = mainActivity;
        this.downModels = downModels;
    }


    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {

        LayoutInflater layoutInflater = LayoutInflater.from(mainActivity.getBaseContext());
        View view = layoutInflater.inflate( R.layout.storage_elements, null, false);


        return new MyViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull final MyViewHolder myViewHolder, final int i) {

        myViewHolder.mName.setText( downModels.get( i ).getName() );
        myViewHolder.deletePdfBtn.setOnClickListener( new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Context context = myViewHolder.mName.getContext();
                if (context != null) {
                    FirebaseFirestore db = FirebaseFirestore.getInstance();
                    FirebaseStorage firebaseStorage = FirebaseStorage.getInstance();
                    String filenamed = (String) myViewHolder.mName.getText();
                    String url = downModels.get( i ).getLink() ;
                    firebaseStorage.getReferenceFromUrl( url ).delete()
                            .addOnSuccessListener( new OnSuccessListener<Void>() {
                                @Override
                                public void onSuccess(Void aVoid) {
                                    Log.d( TAG, "DocumentSnapshot successfully written!" );
                                }
                            } );
                    db.collection( "Storage" ).document( filenamed ).delete()

                            .addOnSuccessListener( new OnSuccessListener<Void>() {
                                @Override
                                public void onSuccess(Void aVoid) {
                                    Log.d( TAG, "DocumentSnapshot successfully written!" );

                                    notifyDataSetChanged();// this method never helped //






                                }
                            } )
                            .addOnFailureListener( new OnFailureListener() {
                                @Override
                                public void onFailure(@NonNull Exception e) {
                                    Log.w( TAG, "Error writing document", e );

                                }
                            } )
                    ;

                } else {
                    return;


                }

            }
        } );




        myViewHolder.mDownload.setOnClickListener( new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                downloadFile( myViewHolder.mName.getContext(), downModels.get( i ).getName(), ".pdf", DIRECTORY_DOWNLOADS, downModels.get( i ).getLink() );
            }
        } );
    }

    public void downloadFile(Context context, String fileName, String fileExtension, String destinationDirectory, String url) {

        DownloadManager downloadmanager = (DownloadManager) context.
                getSystemService(Context.DOWNLOAD_SERVICE);
        Uri uri = Uri.parse(url);
        DownloadManager.Request request = new DownloadManager.Request(uri);

        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
        request.setDestinationInExternalFilesDir(context, destinationDirectory, fileName + fileExtension);

        downloadmanager.enqueue(request);
    }






    @Override
    public int getItemCount() {
        return downModels.size();
    }


}

标签： javaandroidandroid-recyclerviewadapter

Answer 1

尝试这个！

public void onSuccess(Void aVoid) {
      Log.d( TAG, "DocumentSnapshot successfully written!" );
      notifyItemRangeChanged(i, downModels.size());
      downModels.remove(i);
      notifyItemRemoved(i);
   }