android 本地存储

android的本地存储分为以下几种：--来自官方 http://developer.android.com/guide/topics/data/data-storage.html

Shared Preferences： 存储键值对
Internal Storage： 私有数据到内存

External Storage：公共数据 外部存储

SQLite Databases：数据库存储

Network Connection：网络存储

下面一一进行介绍：来源：http://www.ibm.com/developerworks/cn/xml/x-androidstorage/

Shared Preferences：

public class Calc extends Activity {
    public static final String PREFS_NAME = "MyPrefsFile";


    @Override
    protected void onCreate(Bundle state){
       super.onCreate(state);
       . . .


       // Restore preferences
       SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
       boolean silent = settings.getBoolean("silentMode", false);
       setSilent(silent);
    }


    @Override
    protected void onStop(){
       super.onStop();


      // We need an Editor object to make preference changes.
      // All objects are from android.context.Context
      SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
      SharedPreferences.Editor editor = settings.edit();
      editor.putBoolean("silentMode", mSilentMode);


      // Commit the edits!
      editor.commit();
    }
}

Internal Storage：

1从本地私有存储器写数据
public void writeInternalStoragePrivate(
        String filename, byte[] content) {
    try {
        //MODE_PRIVATE creates/replaces a file and makes 
        //  it private to your application. Other modes:
        //    MODE_WORLD_WRITEABLE
        //    MODE_WORLD_READABLE
        //    MODE_APPEND
        FileOutputStream fos = 
           openFileOutput(filename, Context.MODE_PRIVATE);
        fos.write(content);
        fos.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

2从内部私有存储器读取数据
public byte[] readInternalStoragePrivate(String filename) {
    int len = 1024;
    byte[] buffer = new byte[len];
    try {
        FileInputStream fis = openFileInput(filename);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        int nrb = fis.read(buffer, 0, len); // read up to len bytes
        while (nrb != -1) {
            baos.write(buffer, 0, nrb);
            nrb = fis.read(buffer, 0, len);
        }
        buffer = baos.toByteArray();
        fis.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return buffer;
}

 3从本地私有存储器删除数据
public void deleteInternalStoragePrivate(String filename) {
    File file = getFileStreamPath(filename);
    if (file != null) {
        file.delete();
    }
}

SQLite Databases：

未完待续