Android:how to store and retrieve Hashmap data in sharedpreferences?

Question

I want to store some data like key and value pair in internal storage. so i am using HashMap to store key,value pair .but i don'get sufficient solution to store and retrieve this HashMap into sharedpreferences. Please give me some solution.

i am put my code below:

HashMap<String, String> MapListMesasges = new HashMap<String, String>();
MapListMesasges.put(FromName, message.getBody());
preferences = mActivity.getSharedPreferences(
                                SharePreference_messages_history_name,
                                Context.MODE_PRIVATE);
                        SharedPreferences.Editor editor = preferences.edit();
                        for (Entry<String, String> entry : MapListMesasges
                                .entrySet()) {
                            editor.putString(entry.getKey(), entry.getValue());
                        }
                        editor.commit();

and retrieve data from Sharedprefernces:

preferences = mActivity.getSharedPreferences(
                SharePreference_messages_history_name, Context.MODE_PRIVATE);
        for (Entry<String, ?> entry : preferences.getAll().entrySet()) {
            MapListMesasges.put(entry.getKey(), entry.getValue().toString());
        }

i will also store hashmap in adapter and set into listview. My main purpose is to store and retrieve data into sharedprefernces and also show data into listview.

Thanks in advance.

What's the problem? Are you having null when you are retrieving the values? — Renan Bandeira, Aug 08 '13 at 10:41
`SharedPreferences` are not meant to be used like that. You can however use it like that and the code looks as if it would work. But you shoud consider using a database or something else if you have an undefined set of keys. — zapl, Aug 08 '13 at 10:56
i have to store that data into internal storage.so i am using sharedpreferences.yes i have to retrieve values.but i don't know how to store that hashmap in listview. — dipali, Aug 08 '13 at 11:05
Pass that hasmap list to your custom adpater as parameters..and set to it your listview. — Shani Goriwal, Aug 08 '13 at 11:09
if you are retrieving your data properly in hash map list then it is easier to store data with listview.. — Shani Goriwal, Aug 08 '13 at 11:18
@dipali....i think you are getting your data in listview properly..isn't it?? — Shani Goriwal, Aug 08 '13 at 13:16
if you have any query then you are get your solution in chat room where many android developers advised you. — Shani Goriwal, Aug 09 '13 at 08:43
At any where are you clear the data from shared preference before set to listview?? — Shani Goriwal, Aug 09 '13 at 09:45
yes.i have use simple arraylist using getter/setter method and store data into sharedprefernces. — dipali, Aug 09 '13 at 11:07
[saving hashmap to sharedpreferences][1] [1]: http://stackoverflow.com/questions/7944601/saving-a-hash-map-into-shared-preferences — Longwayto, Dec 17 '13 at 02:28
Serialize the Map in Json and save it like a simple string. Bad idea but I think it will work — Javaluca, Mar 04 '15 at 15:01

score 0 · Answer 1 · edited May 23 '17 at 12:08

0

The easiest way to store HashMap in Preferences is just convert it to the string and store it.

On the Otherside get that string convert it in HashMap and enjoy.

To Convert String to HashMap & vice-versa check this link.

edited May 23 '17 at 12:08

Community

1
1

answered Mar 10 '15 at 05:10

Dhrumil Shah - dhuma1981

15,166
6
31
39

score 0 · Answer 2 · answered Mar 10 '15 at 05:50

You can use json for solution.

For example:

**JSON**

    {
     [
      "name1","message1",
      "name2","message2"
     ]
    }

Store this entire json string with some key and use same key to retrieve. Just you need to parse/create JSON. You can use GSON lib for JSON creation/parsing

score 0 · Answer 3 · answered Mar 10 '15 at 06:08

There's special thing for doing operations like you described and this is SQLite. But if you really want to store them in SharedPreferences, you can do it. Your solution almost work. You just need to store keys as well.

StringBuilder b = new StringBuilder();
for (Entry<String, String> entry : MapListMesasges.entrySet()) {
      editor.putString(entry.getKey(), entry.getValue());
      if(b.length() != 0){
           b.append(",");
      }
      b.append(entry.getKey());
 }
editor.putString("KEY_FOR_PREF_KEYS",b.toString());

And to retrieve data use this

String[] keys = preferences.getString("KEY_FOR_PREF_KEYS","").split(",");
for (int i = 0; i < keys.length; i++) {
    MapListMesasges.put(keys[i], preferences.getString(keys[i]));
}

Android:how to store and retrieve Hashmap data in sharedpreferences?

3 Answers3