Reading a simple text file

问题:

I am trying to read a simple text file in my sample Android Application. I am using the below written code for reading the simple text file.

InputStream inputStream = openFileInput(\"test.txt\");
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);

My questions is : Where should I place this \"test.txt\" file in my project?. I have tried putting the file under \"res/raw\" and \"asset\" folder but I get the exception \"FileNotFound\" when first live of the code written above gets executed.

Thanks for the help

回答1:

Place your text file in the /assets directory under the Android project. Use AssetManager class to access it.

AssetManager am = context.getAssets();
InputStream is = am.open(\"test.txt\");

Or you can also put the file in the /res/raw directory, where the file will be indexed and is accessible by an id in the R file:

InputStream is = context.getResources().openRawResource(R.raw.test);

回答2:

try this,

package example.txtRead;

import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;
import java.util.Vector;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class txtRead extends Activity {
    String labels=\"caption\";
    String text=\"\";
    String[] s;
    private Vector<String> wordss;
    int j=0;
    private StringTokenizer tokenizer;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        wordss = new Vector<String>();
        TextView helloTxt = (TextView)findViewById(R.id.hellotxt);
        helloTxt.setText(readTxt());
 }

    private String readTxt(){

     InputStream inputStream = getResources().openRawResource(R.raw.toc);
//     InputStream inputStream = getResources().openRawResource(R.raw.internals);
     System.out.println(inputStream);
     ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

     int i;
  try {
   i = inputStream.read();
   while (i != -1)
      {
       byteArrayOutputStream.write(i);
       i = inputStream.read();
      }
      inputStream.close();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }

     return byteArrayOutputStream.toString();
    }
}

回答3:

This is how I do it:

public static String readFromAssets(Context context, String filename) throws IOException {
    BufferedReader reader = new BufferedReader(new InputStreamReader(context.getAssets().open(filename)));

    // do reading, usually loop until end of file reading  
    StringBuilder sb = new StringBuilder();
    String mLine = reader.readLine();
    while (mLine != null) {
        sb.append(mLine); // process line
        mLine = reader.readLine();
    }
    reader.close();
    return sb.toString();
}

use it as follows:

readFromAssets(context,\"test.txt\")

回答4:

Having a file in your assets folder requires you to use this piece of code in order to get files from the assets folder:

yourContext.getAssets().open(\"test.txt\");

In this example, getAssets() returns an AssetManager instance and then you\'re free to use whatever method you want from the AssetManager API.

回答5:

In Mono For Android....

try
{
    System.IO.Stream StrIn = this.Assets.Open(\"MyMessage.txt\");
    string Content = string.Empty;
    using (System.IO.StreamReader StrRead = new System.IO.StreamReader(StrIn))
    {
      try
      {
            Content = StrRead.ReadToEnd();
            StrRead.Close();
      }  
      catch (Exception ex) { csFunciones.MostarMsg(this, ex.Message); }
      }
          StrIn.Close();
          StrIn = null;
}
catch (Exception ex) { csFunciones.MostarMsg(this, ex.Message); }

回答6:

To read the file saved in assets folder

public static String readFromFile(Context context, String file) {
        try {
            InputStream is = context.getAssets().open(file);
            int size = is.available();
            byte buffer[] = new byte[size];
            is.read(buffer);
            is.close();
            return new String(buffer);
        } catch (Exception e) {
            e.printStackTrace();
            return \"\" ;
        }
    }

回答7:

Here is a simple class that handles both raw and asset files :

public class ReadFromFile {

public static String raw(Context context, @RawRes int id) {
    InputStream is = context.getResources().openRawResource(id);
    int size = 0;
    try {
        size = is.available();
    } catch (IOException e) {
        e.printStackTrace();
        return \"\";
    }
    return readFile(size, is);
}

public static String asset(Context context, String fileName) {
    InputStream is = null;
    int size = 0;
    try {
        is = context.getAssets().open(fileName);
        AssetFileDescriptor fd = null;
        fd = context.getAssets().openFd(fileName);
        size = (int) fd.getLength();
        fd.close();
    } catch (IOException e) {
        e.printStackTrace();
        return \"\";
    }
    return readFile(size, is);
}


private static String readFile(int size, InputStream is) {
    try {
        byte buffer[] = new byte[size];
        is.read(buffer);
        is.close();
        return new String(buffer);
    } catch (Exception e) {
        e.printStackTrace();
        return \"\";
    }
}

}

For example :

ReadFromFile.raw(context, R.raw.textfile);

And for asset files :

ReadFromFile.asset(context, \"file.txt\");