Read Write File (자동 저장할때 사용)

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button android:id="@+id/close"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="닫기" />
  
    <EditText
        android:id="@+id/editor"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:singleLine="false"
        android:gravity="top" />

</LinearLayout>

package com.commonsware.android.files;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class ReadWriteFileDemo extends Activity {
	private final static String NOTES="notes.txt";
	private final static String TAG = "ReadWriteFiledemo";
	private EditText editor;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		editor = (EditText)findViewById(R.id.editor);

		Button btn = (Button)findViewById(R.id.close);

		btn.setOnClickListener(new Button.OnClickListener(){

			public void onClick(View v) {
				//액티비티 종료
				//액티비티 종료시에 Activity 생명주기에 의해서 
				//onPause -> onStop -> onDestroy
				finish();
			}
		});
	}
	public void onResume(){
		super.onResume();


		try{
			InputStream in = openFileInput(NOTES);

			if(in!=null){
				InputStreamReader tmp = new InputStreamReader(in);
				BufferedReader reader = new BufferedReader(tmp);
				String str;
				StringBuffer buf = new StringBuffer();

				while((str = reader.readLine()) != null){
					buf.append(str+"\n");
				}
				in.close();
				editor.setText(buf.toString());
			}
		}catch(java.io.FileNotFoundException e){
			Log.e(TAG, "파일을 호출할 수 없습니다.",e);
		}catch(Throwable t){
			Log.e(TAG, "오류 발생",t);
			Toast.makeText(this,"예외 : "+t.toString(),2000)
			.show();
		}
	}
	public void onPause(){
		super.onPause();
		try{
			OutputStreamWriter out = new OutputStreamWriter(openFileOutput(NOTES,0));
			//MODE_PRIVATE :덮어쓰기
			//MODE_APPEND : 이어쓰기
			out.write(editor.getText().toString());
			out.close();
			Toast.makeText(this,"데이터를 저장합니다잉~~",4000).show();
		}catch(Throwable t){
			Toast.makeText(this,"예외 : "+t.toString(),2000).show();
		}
	}
}

이 기능은 데이터를 저장하는 어플리케이션에 모두(거의?) 적용되어 있지만 사용자의 불안함(?) 때문에 자동저장이 있어도 저장버튼을 따로 둔다고함