Android 使用recyclerview，在手机再次锁定和解锁之前，ftp的内容不会显示在屏幕上

我想使用回收器视图显示ftp中的内容。但是，除非在应用程序运行时锁定和解锁手机一次，否则数据不会反映在视图中。我想在应用程序启动后立即使用recycler视图显示数据。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();
           }
       }
   }
}

显示

<?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/活动\u main.xml

<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>

layout/layout\u recycler\u 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>

---

下载适配器后，您不会在适配器中设置数据。因此，

adapter.notifyDataSetChanged（）

在这一点上是无用的。 在适配器中创建一个方法以设置数据：

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

public void setData（ArrayList文件列表）{
this.fileList=文件列表；
}

---

然后在调用

adapter.notifyDataSetChanged（）

之前调用它。

尝试

adapter.notifyDataSetChanged（）。
在asyncTask中，在onPostExecute或onPreExecute方法中执行与ui相关的操作。
尝试
adapter.notifyDataSetChanged（）在asyncTask的OnPostExecutue中。它成功了，谢谢。我添加它作为答案。
<?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>

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