android 写配置文件和读取配置文件

SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());

String ui_placement = sharedPreferences.getString("preference_IcCard_placement", "");

edt.setText(ui_placement);

SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());

SharedPreferences.Editor editor = sharedPreferences.edit();

editor.putString("preference_IcCard_placement", edt.getText().toString());

editor.apply();