ファイル

// File.java

package org.example.test;

import java.util.*;
import java.io.*;
import android.app.*;
import android.os.*;
import android.view.*;
import android.view.View.*;
import android.widget.*;

public class File extends Activity
{
   Button bt;

   private String read(){
      String readString = new String();

      try{
        FileInputStream fileInputStream;
        fileInputStream = openFileInput("text.txt");
        byte[] readBytes = new byte[fileInputStream.available()];
        fileInputStream.read(readBytes);
        readString = new String(readBytes);
      }
      catch(FileNotFoundException e){
        return new String("none");
      }
      catch(IOException e){}

      return readString;
   }

   public void onCreate(Bundle savedInstanceState)
   {
      super.onCreate(savedInstanceState);

      LinearLayout ll = new LinearLayout(this); 
      ll.setOrientation(LinearLayout.VERTICAL);
      setContentView(ll);

      String readString = read();

      bt = new Button(this);
      bt.setText(readString);
      ll.addView(bt);

      bt.setOnClickListener(new SampleClickListener());
   }

   class SampleClickListener implements OnClickListener
   {
      public void onClick(View v)
      {
        Calendar calendar = Calendar.getInstance();
        try{
          FileOutputStream fileOutputStream = openFileOutput("text.txt", MODE_PRIVATE);
          String writeString = calendar.get(Calendar.HOUR_OF_DAY) + ":" + calendar.get(Calendar.MINUTE);
          fileOutputStream.write(writeString.getBytes());
          bt.setText(writeString);
        }
        catch(FileNotFoundException e){}
        catch(IOException e){}
      }
   }
}