Android中數據的保存和提取

package com.sky;

import android.app.Activity;
import android.os.Bundle;
import android.content.SharedPreferences;
import android.widget.EditText;

public class saveData extends Activity {
/** Called when the activity is first created. */
public static final String SETTING_INFOS = "SETTING_Infos";
public static final String NAME = "NAME";
public static final String PASSWORD = "PASSWORD";
private EditText field_name; //接收用戶名的組件
private EditText filed_pass; //接收密碼的組件
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
field_name = (EditText) findViewById(R.id.EditText01); //首先獲取用來輸入用戶名的組件
filed_pass = (EditText) findViewById(R.id.EditText02); //同時也需要獲取輸入密碼

// Restore preferences
//獲取一個SharedPreferences對象，SETTING_INFOS與SETTING_INFOS.XML文件相對應
//效果相當於讀取SETTING_INFOS.XML文件，如果文件不存在，則進行創建
SharedPreferences settings = getSharedPreferences(SETTING_INFOS, 0);
//取出保存的NAME，取出改字段名的值，不存在則創建默認爲空
String name = settings.getString(NAME, "");
String password = settings.getString(PASSWORD, ""); //取出保存的PASSWORD，同上
field_name.setText(name); //將取出來的用戶名賦予field_name
filed_pass.setText(password); //將取出來的密碼賦予filed_pass

setTitle(name+password);//將NAME和PASSWORD顯示在標題欄
}

@Override
protected void onStop()
{
// TODO Auto-generated method stub
super.onStop();
//打開SETTING_INFOS.XML
//0表示打開模式，有則讀，沒有則創建
SharedPreferences settings = getSharedPreferences(SETTING_INFOS, 0);

//下面一句的語法比較神奇，每次執行都返回一個setting.edit(),commit()表示執行
settings.edit()
.putString(NAME, field_name.getText().toString())
.putString(PASSWORD, filed_pass.getText().toString())
.commit();//將field_name賦值給NAME字段，將filed_pass賦值給PASSWORD字段
}

}
//要查看錄入的數據，進到DDMS->File Explorer /<package name>/shared_prefs/SETTING_INFOS.XML