how to show data from a sharedPreferences in a Listactivity

Question

I’m starting to work with Sharedpreferences on android, a simple and fast way to store static and primitive data. However, my problem is showing these values stored in a Listactivity. I’ve looked here on the forum, tutorials on google, but no method worked. If anyone can help me thank you because I need to deliver this work this week.

Answer 1

To get all stored values use the method getAll() of Sharedpreferences:

Map<String,?> map = prefs.getAll();

For a list of values use:

List<Value> list = new ArrayList<Value>(map.values());

Use the list to build the Listview as usual.

If you want to get the list from Keys use:

List<Value> list = new ArrayList<Value>(map.keys());

---

Android provides the api Preferences to program an interface of the "system settings".
Instead of using objects View to create the user interface, the settings are created through several subclasses of the class Preference declared in an XML file.

To display the preferences list is used a Preferenceactivity(API < 10) or Preferencefragment(API >= 10).

To documentation has an article in which explains in detail how to do it.

Answer 2

Putting values:

public static final String PREFS = "MinhaPreferencia";
SharedPreferences.Editor editor = getSharedPreferences(PREFS, MODE_PRIVATE).edit();
editor.putString("nomeUsuario", "Marllon Nasser");
editor.putInt("idUsuario", 10);
editor.commit();

Getting values:

SharedPreferences prefs = getSharedPreferences(PREFS, MODE_PRIVATE); 
String textoArmazenado = prefs.getString("text", null);
if (textoArmazenado != null) {
   String nomeUsuario= prefs.getString("nomeUsuario", "Nenhum nome definido");//"Nenhum nome definido" é o valor "default"
   int idUsuario = prefs.getInt("idUsuario", 0); //0 é o valor "default"
}

More information here and here

Answer 3

Here’s an example of how to catch a Set<String> :

  // Pegamos a lista do SharedPreferences
        Set<String> itens = sharedPreferences.getStringSet(ITENS_LISTA, null);
        if(null == itens){
            // Se for nula, vamos popular..
            itens = new HashSet<>(0);
            int pt = 1;
            while(pt < 10){
                itens.add("Item "+pt);
                pt++;
            }
            // Editor , para atualizar a lista
            SharedPreferences.Editor editor = sharedPreferences.edit();
            editor.putStringSet(ITENS_LISTA, itens);
        }


        // criamos uma lista de String
        String[] valores = new String[itens.size()];
        int pt=0;
        for(String item : itens){
            valores[pt] = item;
            pt++;
        }

        // Instancia do ArrayAdapter
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,  android.R.layout.simple_list_item_1, valores);