如何将 ArrayList 从 AsyncTask 返回到另一个类? [英] How to return ArrayList from AsyncTask to another class?

问题描述

我想使用 AsyncTask 从服务器获取 Ftp 文件夹列表，并将文件夹名称 ArrayList 返回到主类并更新微调适配器.

i want to get Ftp folders list from server using AsyncTask and return folders names ArrayList to main class and update spinner adapter.

在主课上，我得到了带适配器的微调器

In main class i got spinner with adapter

//the array i want to update in AsyncTask
static ArrayList<String> directoriesTeacher = new ArrayList<String>();

//The adapter
createfile_spinTeacher = (Spinner) findViewById(R.id.createfile_spinTeacher);   
final ArrayAdapter<String> dataAdapterTeacher = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item,directoriesTeacher);
dataAdapterTeacher.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
createfile_spinTeacher.setAdapter(dataAdapterTeacher);

AsyncTask 中的一个:

An in AsyncTask:

    package com.nedoGarazas.learnanylanguage;

    import java.util.ArrayList;

    import org.apache.commons.net.ftp.FTP;
    import org.apache.commons.net.ftp.FTPClient;
    import org.apache.commons.net.ftp.FTPFile;
    import org.apache.commons.net.ftp.FTPReply;

    import android.os.AsyncTask;
    import android.util.Log;

    public class FtpTeacher extends AsyncTask<ArrayList<String>, Void, ArrayList<String>> {
    private static final String TAG = "MyFTPClient";
    public FTPClient mFTPClient = null; 
     ArrayList<String> ftpTeacher = new ArrayList<String>();
    @Override
    protected ArrayList<String> doInBackground(ArrayList<String>... params) {
        {                       
            try {
                mFTPClient = new FTPClient();
         // connecting to the host
                mFTPClient.connect("host.ftp.com", 21);

          // now check the reply code, if positive mean connection success
                if     (FTPReply.isPositiveCompletion(mFTPClient.getReplyCode())) {
      // login using username & password
                    boolean status = mFTPClient.login("admin", "admin");
                    if(status == true){

                            try {
                                FTPFile[] ftpFiles = mFTPClient.listFiles("/Wordsftp/");
                                int length = ftpFiles.length;

                                for (int i = 0; i < length; i++) {
                                    String name = ftpFiles[i].getName();
                                    boolean isDirectory = ftpFiles[i].isDirectory();

                                    if (isDirectory) {
//adding to arraylist
                                        ftpTeacher.add(name);
                                        Log.i(TAG, "Yra : " + name);
                                    }
                                    else {
                                        Log.i(TAG, "Directory : " + name);

                                }
                             }
                            } catch(Exception e) {
                            e.printStackTrace();
                        }


                    mFTPClient.setFileType(FTP.ASCII_FILE_TYPE);
                    mFTPClient.enterLocalPassiveMode();


}
                }
} catch(Exception e) {
Log.d(TAG, "Error: could not connect to host ");
}
return ftpTeacher;
} 
            }

    protected ArrayList<String>[] onPostExecute(ArrayList<String>... result) {
        ////How to return?

    }

    }

那么我应该如何用主类中的 ArrayList 替换 AsyncTask 中的 arraylist 并动态更新微调器更新程序?

So how should i replace arraylist in AsyncTask with ArrayList in main class and update spinner updater dinamicly?

推荐答案

您已经将 ArrayList 设为 static，也将其设为公开.并通过您的班级名称使用它.并在 onPostExecute() 中填充您的 ArrayList；喜欢

You already made your ArrayList static, make it public as well. and use that by your class name. and populate your ArrayList in onPostExecute(); like

     protected void onPostExecute(ArrayList<String>... result) {

    if(YourClassName.directoriesTeacher.size()>0)
     {
       YourClassName.directoriesTeacher.clear();
      }

      YourClassName.directoriesTeacher.addAll(result);

     }

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