Android的4種數據存儲方法

Android的4種數據存儲方法

一.保存到私有目錄文件

• 無權限模式

  File file = new File(context.getFilesDir(),"文件名.擴展名");
  FileOutputStream fileOutputStream = new FileOutputStream(file);
  fileOutputStream.write(文件名.getBytes());
  fileOutputStream.close();
  

• 有權限模式

  FileOutputStream fileOutputStream =context.openFileOutput("文件名.擴展名"，Context.權限模式);
  fileOutputStream.write(文件名.getBytes());
  fileOutputStream.close();
  FileInputStream fileInputStream = context.openFileOutput("文件名.擴展名");
  

• 讀取文件

  無權限模式

  File file = new File (context.getFilesDir(),”文件名.擴展名”);
  FileInputStream fis = new FileInputStream(file);
  BufferedReader br = new BufferedReader(new InputStreamReader(fis));

  有權限模式

  FileInputStream fis = context.openFileInput("文件名.擴展名");
      BufferedReader br = new BufferedReader(new InputStreamReader(fis));
  

注意：☆☆☆關閉輸入輸出流

實例源碼http://pan.baidu.com/s/1kVJKPFp
http://pan.baidu.com/s/1cyy42M

二.使用SharePerence存儲

• 存

  SharePreferences.Editor editor = getPreferences(MODE_PRIVATE).edit();
  editor.putString(String KEY,name);
  editor.commit();
  

• 取

  SharePreferences myPref = getPreferences(MODE_PRIVATE);
  String str = myPref.getString(String KEY,"不存在返回的數值");
  

三.使用SD卡存儲

• 存

  //  String path = "/mnt/sdcard/";
  //指定保存的路徑
  //通過Environment獲取sdcard的目錄
  String path = Environment.getExternalStorageDirectory().getPath();
  File file = new File(path,"文件名.擴展名");//創建file
  FileOutputStream fileOutputStream = new FileOutputStream(file);
  fileOutputStream.close();
  

  • 取

    FileInputStream fileInputStream = context.openFileOutput(“文件名.擴展名”);

    http://pan.baidu.com/s/1dE757uL

四.SQLite存儲

• 新建繼承SQLiteOpenHelper類

  public class MySQlite extends SQLiteOpenHelper {
  private Context mContext;
  //定義一個名爲Person的表
  public static final String CREATE_PERSON = "create table Person ("
      + "id integer primary key autoincrement, "      
      + "ages integer, "
      + "name text)";
  // 爲表裏添加phone數據
  public static final String UPDATE_BOOK = "alter table BookStore add phone integer(11)";
  
  public MySQlite(Context context) {
  super(context,"BookStore.db", null,1);
  mContext = context;
  }
  
  public void onCreate(SQLiteDatabase db) {
  // 創建表
  db.execSQL(CREATE_BOOK);
  //添加數據
  db.execSQL(UPDATE_BOOK);
  }
  
   public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
  // 添加沒有break的switch的語句可以使後版本才下載的客戶可使用以前的數據結構    
  db.execSQL(CREATE_PERSON);
   }
  }
  

• 提取數據庫中數據

  使用SQLite的query方法

  public ArrayList query(String name){
  ArrayList list = new ArrayList();
  private MySqliteOpenHelper mySqliteOpenHelper;
  SQLiteDatabase db = mySqliteOpenHelper.getReadableDatabase();
  Cursor cursor = db.query(“info”, new String[]{“_id”,”name”,”phone”}, “name = ?”, new String[]{name}, null, null, “_id desc”);
  //解析Cursor中的數據
  if(cursor != null && cursor.getCount() >0){//判斷cursor中是否存在數據

      //循環遍歷結果集，獲取每一行的內容
      while(cursor.moveToNext()){//條件，遊標能否定位到下一行
          InfoBean bean= new InfoBean();
          //往javabean中獲取數據
          bean. id = cursor.getInt(0)+"";
          bean. name = cursor.getString(1);
          bean. phone = cursor.getString(2);
          list.add(bean);     
      }
   //關閉遊標和數據庫
      cursor.close();
     ｝
      db.close();
    return list;
   ｝
  

實例源碼 http://pan.baidu.com/s/1c12NSyc