Question

我想使用回收站视图显示来自ftp的内容。但是，除非我在应用程序运行时锁定和解锁手机，否则数据不会反映在视图中。我想在使用recycler视图启动应用程序时立即显示数据。请帮忙！

这就是我的代码的样子

MainActivity.java

package com.example.nishant.ftp1;

import android.annotation.SuppressLint;
import android.content.res.Configuration;
import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import org.apache.commons.net.ftp.*;

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

public class MainActivity extends Activity {

    public FTPClient mFTPClient = null;
    Button but;
    private RecyclerView.LayoutManager layoutManager;
    private ArrayList<FileListObject> fileList = new ArrayList<>();
    private RecyclerAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        recyclerView.setHasFixedSize(true);

        layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);

        adapter = new RecyclerAdapter(fileList, this);

        recyclerView.setAdapter(adapter);
        new setUpList().execute();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);

        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        recyclerView.setHasFixedSize(true);

        layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);

        Log.v("rec","in recycler");
        adapter = new RecyclerAdapter(fileList, this);
        recyclerView.setAdapter(adapter);
    }


   public class setUpList extends AsyncTask<Object, Void, Object> {

       String host = "test.rebex.net", username = "demo", password = "password";
       int port = 21;

       @Override
       protected Object doInBackground(Object[] objects) {
           try {
               mFTPClient = new FTPClient();
               // connecting to the host
               mFTPClient.connect(host,port);

               // Now check the reply code, if positive mean connection success
                if (FTPReply.isPositiveCompletion(mFTPClient.getReplyCode())) {

                   Log.v("wwww","Connected");
                   // Login using username & password
                   boolean status = mFTPClient.login(username, password);
                   mFTPClient.setFileType(FTP.BINARY_FILE_TYPE);
                   mFTPClient.enterLocalPassiveMode();

                   String toppath=null;

                   try {
                       FTPFile[] ftpDirs = mFTPClient.listFiles("/pub/example/");
                       for (int i = 0; i < ftpDirs.length; i++) 
                        {
                            toppath = ftpDirs[0].getName();
                            Log.d("CONNECT", "Directories in the ftp server are "+ ftpDirs[i].getName());
                            /*FileListObject fileListObject = new FileListObject(ftpDirs[i].getName());
                            fileList.add(fileListObject);*/
                            fileList.add(new FileListObject(ftpDirs[i].getName()));
                            // adapter.notifyDataSetChanged();
                        }
                        adapter.notifyDataSetChanged();
                    } catch (Exception e) {
                       e.printStackTrace();
                    }
                   return status;
                }
            } catch (Exception e) {
               return e;
            }
           return null;
        }

        public void onPostExecute(Object res) {
            if (res instanceof Exception) {
               int d = Toast.LENGTH_SHORT;
               Toast toast = Toast.makeText(getApplicationContext(), "" + res, d);
               toast.show();
           }
       }
   }
}

RecyclerAdapter.java

package com.example.nishant.ftp1;

/**
 * Created by Nishant on 1/24/2018.
 */


import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.support.v7.widget.RecyclerView;
import android.text.Html;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;

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

/**
 * Created by Hitayu on 18-01-2018.
 */

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder> {

    private ArrayList<FileListObject> fileList = new ArrayList<>();
    private Context context;

    public RecyclerAdapter(ArrayList<FileListObject> fileList, Context context) {
        this.fileList = fileList;
        this.context = context;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_recycler_view,parent,false);

        return new ViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {

        final FileListObject objec = fileList.get(position);
        Log.v("mmm",objec.getName());
        holder.fileText.setText(Html.fromHtml("<u>"+objec.getName()+"</u>"));

        /*holder.linearLayout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(objec.getLocation()));
                context.startActivity(intent);
            }
        });*/
    }

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

    public class ViewHolder extends RecyclerView.ViewHolder{

        public TextView fileText;
        public LinearLayout linearLayout;

        public ViewHolder(View itemView) {
            super(itemView);

            fileText = (TextView) itemView.findViewById(R.id.file);
            linearLayout = (LinearLayout) itemView.findViewById(R.id.layout);
        }
    }
}

FileListObject.java

package com.example.nishant.ftp1;

/**
 * Created by Nishant on 1/24/2018.
 */

public class FileListObject {
    String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public FileListObject(String name) {
        this.name = name;
    }
}

舱单

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.nishant.ftp1">

    <uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity"
            android:screenOrientation="portrait">

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

布局/ activity_main.xml中

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#F6F6F6"
    android:orientation="vertical"
    tools:context="com.example.nishant.ftp1.MainActivity">

    <android.support.v7.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/recycler_view"/>
</LinearLayout>

布局/ layout_recycler_view.xml

<?xml version="1.0" encoding="utf-8"?>


<LinearLayout android:id="@+id/layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <TextView
        android:id="@+id/file"
        android:layout_width="match_parent"
        android:textColor="@color/colorPrimaryDark"
        android:layout_height="wrap_content"
        android:textSize="18sp"/>

</LinearLayout>

Answer 1

下载后，您不必在适配器中设置数据。因此adapter.notifyDataSetChanged()在这一点上毫无用处。在适配器中创建一个方法来设置数据：

public void setData(ArrayList<FileListObject> fileList) {
    this.fileList = fileList;
}

然后在调用adapter.notifyDataSetChanged()之前调用它。

Answer 2

在asyncTask的onPostExectue中尝试adapter.notifyDataSetChanged();。在asyncTask中执行与onPostExecute或onPreExecute方法相关的操作。

使用recyclerview，屏幕上不会显示ftp的内容，直到手机被锁定并再次解锁

2 个答案: