今天用昨天學的sharepreferences
來完成之前記住密碼的操作

//宣告
private SharedPreferences preferences;
preferences = getSharedPreferences("config",MODE_PRIVATE);
//讀取上次有沒有勾選記住密碼
        boolean remember = preferences.getBoolean("remember", false);
        if(remember){
            reload();
        }
//reload
private void reload() {
            et_phone.setText(preferences.getString("phone",""));
            et_password.setText(preferences.getString("password",""));
            ck_remember.setChecked(true);
    }
    
//如果有勾選就把手機號碼跟密碼記住下次使用
//如果沒有清除資料
 SharedPreferences.Editor edit = preferences.edit();
        if(ck_remember.isChecked()){
            edit.putString("phone",et_phone.getText().toString());
            edit.putString("password",et_password.getText().toString());
            edit.putBoolean("remember",true);
            edit.commit();
        }else{
            edit.remove("phone");
            edit.remove("password");
            edit.remove("remember");
            edit.commit();
        }
    }