- Android 的資料儲存方法有以下5 種：
- Shared Preferences
- Store private primitive data in key-value pairs.
- Internal Storage
- Store private data on the device memory.
- External Storage
- Store public data on the shared external storage.
- SQLite Databases
- Store structured data in a private database.
- Network Connection
- Store data on the web with your own network server.
-
（1) Shared Preferences
Shared Preferences 也有分2種：
getSharedPreferences()- Use this if you need multiple preferences files identified by name, which you specify with the first parameter. （這一個是可以用在不同的Activity 層面上，就是說如果需要在應用程序中多個Activity之間分享同一個SharedPreferences對象時，就用這一個）如果是只需要在同一個Actiticy內使用，就可以用下面這一個不用加名稱的getPreferences.
getPreferences()- Use this if you need only one preferences file for your Activity. Because this will be the only preferences file for your Activity, you don't supply a name.寫入時：
（1) 如果是使用SharedPreferences 提供名稱
SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
（2) 做用 edit() 開啟 SharedPreferences.Editor
SharedPreferences.Editor editor = settings.edit();
（3) 使用 putBoolean() or putString() methods 將需要儲存的資料存入editor
editor.putBoolean("silentMode", mSilentMode);
（4) 最後記得要commit
editor.commit();
讀取時：
只需要用 getBoolean() or getString() methods 就可以了。
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(); } }
留言列表
