Android实现读写本地文件

package com.pb.android_107_7_01;
 
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
 
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
 
public class MainActivity extends Activity implements OnClickListener {
    // 声明所有的控件
    public EditText edit_name, edit_password;
    public Button button_save, button_search;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // 实例化这几个控件
        edit_name = (EditText) findViewById(R.id.edit_text_id);
        edit_password = (EditText) findViewById(R.id.edit_text_id_1);
        button_save = (Button) findViewById(R.id.button_save_id);
        button_save.setOnClickListener(this);
        button_search = (Button) findViewById(R.id.button_save_id_1);
        button_search.setOnClickListener(this);
    }
    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        case R.id.button_save_id:
            // 首先获得用户输入的内容
            String name = edit_name.getText().toString().trim();
            // 获得输入密码
            String password = edit_password.getText().toString().trim();
            // 写内容 
            try {
                FileOutputStream fos = openFileOutput("data.txt",
                        Context.MODE_APPEND);
                // 写用户名
                fos.write(name.getBytes());
                // 写密码进文件
                fos.write(password.getBytes());
                fos.close();
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            // 吐丝
            Toast.makeText(MainActivity.this, "保存文件成功！！！", Toast.LENGTH_LONG)
                    .show();
            break;
        case R.id.button_save_id_1:
            String str = "";
            // 读写入文件的内容
            try {
                FileInputStream fis = openFileInput("data.txt");
                // 缓存
                byte[] buffer = new byte[fis.available()];
                fis.read(buffer);
                str = new String(buffer);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            Toast.makeText(MainActivity.this, "查看保存内容"   str, Toast.LENGTH_LONG)
                    .show();
            break;
        default:
            break;
        }
    }
}