在我的应用程序中，我需要将值保存到Sharedpreferences文件RKs_Data中，而不会覆盖现有数据。每次，我在我的应用程序中单击“是”，我需要存储在“RKs_Data”中的所有值，而不是仅将最新的“name”和“phoneNo”输入到文件中。
例如，
当我点击其他联系人说'Monet'时，我的RKs_Data应如下所示：
我搜索了但是到处都只提到了保存它，但没有关于附加或对数据做一些操作......
请指导......
代码段如下：
-------
public class RKsContacts_Main extends ListActivity {
// private ListView listView;
private List<ContactBean> list = new ArrayList<ContactBean>();
SharedPreferences sp;
File Fav_Contacts_file;
String contact = null;
List<String> listOfFavoritePhrases = new ArrayList<String>();
@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.rks_contactslist_main);
ListView listview = getListView();
sp = getSharedPreferences("PACKAGE", Context.MODE_PRIVATE);
-------
--------
@Override
public void onClick(DialogInterface dialog, int which) {
String serialized = sp.getString("phrases", null);
listOfFavoritePhrases = new ArrayList<String>(Arrays.asList(TextUtils.split(serialized, ","))); // Line 141
listOfFavoritePhrases.add(name);
listOfFavoritePhrases.add(phoneNo);
SharedPreferences.Editor editor = sp.edit();
editor.putString("phrases",TextUtils.join(",", listOfFavoritePhrases));
editor.commit();
}
});
alert.show();
}
--------
下面的LogCat：
07-03 09:00:51.014: E/AndroidRuntime(9574): FATAL EXCEPTION: main
07-03 09:00:51.014: E/AndroidRuntime(9574): Process: com.example.rkscontacts_list, PID: 9574
07-03 09:00:51.014: E/AndroidRuntime(9574): java.lang.NullPointerException
07-03 09:00:51.014: E/AndroidRuntime(9574): at android.text.TextUtils.split(TextUtils.java:332)
07-03 09:00:51.014: E/AndroidRuntime(9574): at com.example.rkscontacts_list.RKsContacts_Main$4.onClick(RKsContacts_Main.java:141)
07-03 09:00:51.014: E/AndroidRuntime(9574): at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:166)
07-03 09:00:51.014: E/AndroidRuntime(9574): at android.os.Handler.dispatchMessage(Handler.java:102)
07-03 09:00:51.014: E/AndroidRuntime(9574): at android.os.Looper.loop(Looper.java:136)
07-03 09:00:51.014: E/AndroidRuntime(9574): at android.app.ActivityThread.main(ActivityThread.java:5017)
07-03 09:00:51.014: E/AndroidRuntime(9574): at java.lang.reflect.Method.invokeNative(Native Method)
07-03 09:00:51.014: E/AndroidRuntime(9574): at java.lang.reflect.Method.invoke(Method.java:515)
07-03 09:00:51.014: E/AndroidRuntime(9574): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
07-03 09:00:51.014: E/AndroidRuntime(9574): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
07-03 09:00:51.014: E/AndroidRuntime(9574): at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：8)
请按照以下步骤操作：
提取SharedPreferences
String value = prefs.getString(<Key>, <DefaultValue>);
附加到提取的值
String appendedValue = append(value, newValue);
将结果写回SharedPreferences
editor.putString(<Key>, appendedValue).commit();
答案 1 :(得分：2)
您可以CSV格式化您的共享偏好数据。 例如，从共享首选项中获取CSV字符串并将其添加到列表中。附加到您的列表然后将其放回您的共享首选项中。代码示例
// init之前某处的字符串列表
List<String> listOfFavoritePhrases = new ArrayList<String>();
//将数据附加到列表中
listOfFavoritePhrases.add("Brian|99999299999");
listOfFavoritePhrases.add("Monet|00010000000");
//以CSV格式
返回更改后的字符串列表SharedPreferences prefs = getSharedPreferences("PACKAGE", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = prefs.edit();
editor.putString("phrases",TextUtils.join(",", listOfFavoritePhrases));
editor.commit();
//获取数据
SharedPreferences prefs = getSharedPreferences("PACKAGE", Context.MODE_PRIVATE);
String serialized = prefs.getString("phrases", "Brian");
listOfFavoritePhrases = new ArrayList<String>(Arrays.asList(TextUtils.split(serialized, ",")));
然后
String CurrentString = listOfFavoritePhrases.get(0); // first element
String[] separated = CurrentString.split("|");
Toast.makeText(this, separated[0], Toast.LENGTH_LONG).show(); // brian
Toast.makeText(this, separated[1], Toast.LENGTH_LONG).show(); // 99999299999
希望这有助于。
答案 2 :(得分：1)
最后我的代码如下所示：分享最终代码，因为它对像我这样的新手有用：）
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.rks_contactslist_main);
ListView listview = getListView();
sp = getSharedPreferences("PACKAGE", Context.MODE_PRIVATE);
String str = sp.getString("FAV_CONTACS",
"NO fav contacts are saved as of now");
---------
protected void onListItemClick(ListView listview, View view, int position,
long id) {
// TODO Auto-generated method stub
super.onListItemClick(listview, view, position, id);
ContactBean bean = (ContactBean) listview.getItemAtPosition(position);
showCallDialog(bean.getName(), bean.getPhoneNo());
}
---------
public void onClick(DialogInterface dialog, int which) {
Fav_Contacts_file = getFilesDir();
if (count <5) {
SharedPreferences.Editor editor = sp.edit();
String new_contact = name + " " + phoneNo;
String existing_contact = sp.getString("CONTACTS", "");
/*String existing_phone = sp.getString("phoneNo", "");
String existing_contact = existing_name + " " +existing_phone ;*/
String latestfavContacts = append(existing_contact, new_contact);
editor.putString("CONTACTS", latestfavContacts);
editor.commit();
count++;
Toast.makeText(
getApplicationContext(),
"The data saved successfully to ........ : "
+ Fav_Contacts_file + "/PACKAGE",
Toast.LENGTH_SHORT).show();
Toast.makeText(
getApplicationContext(),
"Name : " + name + " and Phone : "
+ phoneNo, Toast.LENGTH_SHORT)
.show();
}
else {
Toast.makeText(
getApplicationContext(),
"More than 5 Fav Contacts are NOT allowed",
Toast.LENGTH_SHORT).show();
}
}
});
alert.show();
}
protected String append(String existing_contact, String new_contact) {
String latestfavContacts = existing_contact + " | "+ new_contact ;
return latestfavContacts;
}
以及存储在SharedPreference文件中的数据＆＃39; PACAKAGE＆＃39;看起来像这样：
<?xml version="1.0" encoding="UTF-8" standalone="true"?>
-<map>
<string name="CONTACTS"> | Alen 1 231-231-231 | Alex Zun 1 234-321-231 | Dr. S.K. Taher Ali 040-7265587 | Gazer 1 312-345-452 | Helen (432) 341-1343</string>
</map>
我还没有处理格式化，并根据我的应用需求将其呈现为UI友好模式。