无法读取存储卡中存储的多个文本文件

Question

package com.paad.trial;

import java.io.File;
import java.util.ArrayList;
import java.util.List;
import android.app.AlertDialog;
import android.app.ListActivity;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
public class AndroindApplication extends ListActivity {
 private List<String> item = null;
 static public List<String> path = null;
 private String root="/";
 private TextView myPath;
 static public int pathh;
private Object sdcardEnvironment;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sdcard);
        myPath = (TextView)findViewById(R.id.path);
        getDir("/sdcard/");

    }
    private void getDir(String dirPath)
    {
     myPath.setText("Location: " + dirPath);
     item = new ArrayList<String>();
     path = new ArrayList<String>();
     File f = new File(dirPath);
     File[] files = f.listFiles();

     if(!dirPath.equals(root))
     {
      item.add(root);
      path.add(root);
      item.add("../");
      path.add(f.getParent());
     }
     for(int i=0; i < files.length; i++)
     {
       File file = files[i];
       path.add(file.getPath());
       if(file.isDirectory())
        item.add(file.getName() + "/");
       else
        item.add(file.getName());
     }
     ArrayAdapter<String> fileList =
      new ArrayAdapter<String>(this, R.layout.row, item);
     setListAdapter(fileList);
    }
 @Override
 protected void onListItemClick(ListView l, View view, int position, long id) {
  File file = new File(path.get(position));
pathh=position;
//  Log.e("path="+path,"dxgx");
  if (file.isDirectory())
  {
   if(file.canRead())
    getDir(path.get(position));
   else
   {
    new AlertDialog.Builder(this)
    .setIcon(R.drawable.icon)
    .setTitle("[" + file.getName() + "] folder can't be read!")
    .setPositiveButton("OK", 
      new DialogInterface.OnClickListener() {
       public void onClick(DialogInterface dialog, int which) {
        // TODO Auto-generated method stub
       }
      }).show();
   }
  }
  else
  {
      Intent  myIntent = new Intent(view.getContext(), Readfile.class);
      startActivityForResult(myIntent, 0);
      Bundle b=new Bundle();
     // Bundle
      //myIntent.p
      /* new AlertDialog.Builder(this)
    .setIcon(R.drawable.icon)
    .setTitle("[" + file.getName() + "]")
    .setPositiveButton("OK", 
      new DialogInterface.OnClickListener() {
       @Override
       public void onClick(DialogInterface dialog, int which) {
        // TODO Auto-generated method stub
       }
      }).show();*/
  }
 }
}

---

package com.paad.trial;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class Readfile extends Activity {
    /** Called when the activity is first created. */
    AndroindApplication ob=new AndroindApplication();
    Intent i;
    String[] arr=null;
    private Button pButton;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.text);
    //File sdcard = Environment.getExternalStorageDirectory();
    String myPath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/myfolder/";
//Get the text file
File file = new File(myPath + AndroindApplication.path.get(AndroindApplication.pathh));
//ob.pathh
 //Read text from file
 StringBuilder text = new StringBuilder();
 try {
     BufferedReader br = new BufferedReader(new FileReader(file));
     String line=null;
     //int i=0;
     List<String> lines = new ArrayList<String>();
     while ((line = br.readLine()) != null) {
         lines.add(line);
//       arr[i]=line;
//       i++;
         text.append(line);
         text.append('n');
     }
     arr = lines.toArray(new String[lines.size()]);
 }
 catch (IOException e) {
     //You'll need to add proper error handling here
 }
//Find the view by its id
 TextView tv = (TextView)findViewById(R.id.text_view);
 //Set the text
 tv.setText(text);
 pButton = (Button) findViewById(R.id.Button01);
 pButton.setOnClickListener(new View.OnClickListener() {
     public void onClick(View v) {
    Bundle b=new Bundle();
        b.putStringArray("strings", arr);
        i=new Intent(v.getContext(),texttospeech.class);
        i.putExtras(b);
        startActivityForResult(i, 0);          
     }
});  



}
    }

---

my sdcard包含两个文本文件。我希望当用户在应用程序中选择其中一个时，它应该打开所选文件。在上面的代码中，我试图将变量路径，位置从AndroindApplication.java传递到Readfile.java，但是在Readfile中无法获得路径。

文本文件存储在sd卡下的myfolder中。这两个变量被readfile.java中的File object用来读取文件。

帮助

Answer 1

在Readfile中，您没有-也不应该-实例化AndroindApplication。要在两个活动之间传递字符串，你应该使用intent .

对于字符串来说非常简单。参见Android在activity之间传递数据