main
package com.example.admin.s20172296_0910_01;

import android.content.Context;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import java.io.FileNotFoundException;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        Button btn01 = (Button) findViewById(R.id.btn01);
        Button btn02 = (Button) findViewById(R.id.btn02);

        btn01.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    FileOutputStream outFs = openFileOutput("file.txt",
                            Context.MODE_WORLD_WRITEABLE);
                    String str = "¾Èµå·ÎÀ̵å ÆÄÀÏ" + '\r' + '\n' + "ÀÔÃâ·Â Å×½ºÆ®";
                    outFs.write(str.getBytes());
                    outFs.close();
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
        btn02.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    FileInputStream inFs = openFileInput("file.txt");
                    byte[] txt = new byte[100];
                    inFs.read(txt);
                    String str = new String(txt);
                    Toast.makeText(getApplicationContext(), str, Toast.LENGTH_SHORT).show();
                    inFs.close();
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
    }
}














ac
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/btn01"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/btn02"
        android:text="ÆÄÀÏ Àбâ"/>

</LinearLayout>