SharedPreferences

SharedPreferences: 主要用於儲存單一資料類別的資料，以供下次進來程式時使用。


public class G_4_5_PreferenceActivity extends Activity {
    /** Called when the activity is first created. */

EditText ed;
SharedPreferences sp;
public final String EDIT_TEXT_KEY = "EDIT_TEXT"; //定義Preferences檔中的key

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        ed = (EditText) findViewById(R.id.ed);
        sp = getPreferences(MODE_PRIVATE);//獲得SharedPreferences物件
        String result = sp.getString(EDIT_TEXT_KEY, null);
        if (result != null) {     //判斷獲取的值是否為空
        ed.setText(result);   //EditText物件顯示的內容設定為讀取的資料
        }
     
    }// end of onCreate()

@Override
protected void onDestroy() {
// TODO Auto-generated method stub
SharedPreferences.Editor editor = sp.edit();  //獲得SharedPreferences的Editor物件
//editor.putString(EDIT_TEXT_KEY, String.valueOf(ed.getText())); 與下述的結果一樣
editor.putString(EDIT_TEXT_KEY, ed.getText().toString());
editor.commit();
super.onDestroy();
}//end of onDestroy()
 
 
 
}