Get and set preference values

My objective is manage my custom preferences. For this, I have the following code:

MainActivity.java

public class MainActivity extends ActionBarActivity implements View.OnTouchListener, GoogleMap.OnInfoWindowClickListener, LocationListener, GoogleMap.OnMapClickListener{

             public boolean onOptionsItemSelected(MenuItem item) {
                int id = item.getItemId();

                if (id == R.id.action_settings) {
                    launchPreferences(null);
                    return true;
                }

                return super.onOptionsItemSelected(item);
            }
            public void launchPreferences(View view) {
                Intent i = new Intent(this, Preferences.class);
                startActivity(i);
            }
    }

Preferences.java

public class Preferences extends PreferenceActivity {

    @Override protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.settings);

        updatePreference();


    }

settings.xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:key="@+id/preferencias_principal" >
    <EditTextPreference
        android:key="@+id/perimer"
        android:title="Perimeter to list"
        android:summary="Maximum distance to list"
        android:defaultValue="2"/>
    <ListPreference
        android:key="@+id/leguage"
        android:title="Lenguage"
        android:summary="What language would you apply?"
        android:entries="@array/lenguage"
        android:entryValues="@array/lenguageva"
        android:defaultValue="1"/>

</PreferenceScreen>

arrays.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="lenguage">
        <item>English</item>
        <item>Basque</item>
        <item>Spanish</item>
    </string-array>
    <string-array name="lenguageva">
        <item>1</item>
        <item>2</item>
        <item>3</item>
    </string-array>

    <string-array name="number">
        <item>1</item>
        <item>2</item>
        <item>3</item>
        <item>4</item>
        <item>5</item>
        <item>6</item>
        <item>7</item>
        <item>8</item>
        <item>9</item>
        <item>10</item>
        <item>11</item>
        <item>12</item>
        <item>13</item>
        <item>14</item>
        <item>15</item>
    </string-array>

</resources>

I want to get the values of this preference, using this code:

SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
Integer peri = sharedPref.getInt("@+id/perimer", 1);
Integer leng = sharedPref.getInt("@+id/leguage", 2);

But this code return default values, peri=1 and leng=2.

Not only that, sometimes the information added by the preference activity is changed/deleted or in the ListPreference item is not appear the default item selected (as you can be seen in the image).

When I execute the code visible here, with debugger, this is the result:

What can I do?

Thank you!

Solution

The main problem is the KEY @+id/perimer and @+id/leguage that you used for your EditTextPreference and ListPreference.

SharedPreferences is unable to recognize it as preference KEY. As you added resource prefix @+id, its treated as int resource id that's why still it works with below lines but doing abnormal behavior and giving you incorrect output.

    Integer peri = sharedPref.getInt("@+id/perimer", 1); // WRONG
    Integer leng = sharedPref.getInt("@+id/leguage", 2); // WRONG

SOLUTION:

1. Do not use resource prefix @+id with preference KEY. Update your settings.xml as below:

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >

    <EditTextPreference
        android:key="perimer"
        android:title="Perimeter to list"
        android:summary="Maximum distance to list"
        android:defaultValue="2"/>
    <ListPreference
        android:key="leguage"
        android:title="Lenguage"
        android:summary="What language would you apply?"
        android:entries="@array/lenguage"
        android:entryValues="@array/lenguageva"
        android:defaultValue="1"/>

</PreferenceScreen>

2. Get preference values using SharedPreferences.getString(KEY_NAME, DEFAULT_VALUE).

    // Get current values
    String peri = mSharedPreferences.getString("perimer", "1");
    String leng = mSharedPreferences.getString("leguage", "2");

3. Add OnPreferenceChangeListener to your preferences to get the updated values and update the preference summary if needed.

    // Required to get the updated value and update summary when you input distance
    mPreferencePerimer.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
        @Override
        public boolean onPreferenceChange(Preference preference, Object value) {
            String peri = value.toString();

            //Update premier summary
            mPreferencePerimer.setSummary(peri);

            return true;
        }
    });

    // Required to get the updated value and update summary when you change language from list
    mPreferenceLeguage.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
        @Override
        public boolean onPreferenceChange(Preference preference, Object value) {

            String leng = value.toString();
            int lengIndex = Integer.parseInt(leng) - 1;

            // Update leguage summary
            mPreferenceLeguage.setSummary(mPreferenceLeguage.getEntries()[lengIndex]);
            return true;
        }
    });

Here is the full code:

public class Preferences extends PreferenceActivity {

    // Preference Keys
    public static final String KEY_PREF_PERIMER = "perimer";
    public static final String KEY_PREF_LEGUAGE = "leguage";

    // Shared preference
    SharedPreferences mSharedPreferences;

    EditTextPreference mPreferencePerimer;
    ListPreference mPreferenceLeguage;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.settings);

        // Shared preference
        mSharedPreferences = PreferenceManager.getDefaultSharedPreferences(getActivity());

        // Perimer
        mPreferencePerimer = (EditTextPreference) getPreferenceScreen().findPreference(KEY_PREF_PERIMER);
        // Leguage
        mPreferenceLeguage = (ListPreference) getPreferenceScreen().findPreference(KEY_PREF_LEGUAGE);

        // Get current values
        String peri = mSharedPreferences.getString(KEY_PREF_PERIMER, "1");
        String leng = mSharedPreferences.getString(KEY_PREF_LEGUAGE, "2");
        int lengIndex = Integer.parseInt(leng) - 1;

        // Set preference summary
        mPreferencePerimer.setSummary(peri);
        mPreferenceLeguage.setSummary(mPreferenceLeguage.getEntries()[lengIndex]);

        // Required to get the updated value and update summary when you input distance
        mPreferencePerimer.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
            @Override
            public boolean onPreferenceChange(Preference preference, Object value) {
                String peri = value.toString();

                //Update premier summary
                mPreferencePerimer.setSummary(peri);

                return true;
            }
        });

        // Required to get the updated value and update summary when you change language from list
        mPreferenceLeguage.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
            @Override
            public boolean onPreferenceChange(Preference preference, Object value) {

                String leng = value.toString();
                int lengIndex = Integer.parseInt(leng) - 1;

                // Update leguage summary
                mPreferenceLeguage.setSummary(mPreferenceLeguage.getEntries()[lengIndex]);
                return true;
            }
        });
    }
}

OUTPUT:

DEFAULT STATE

AFTER CHANGE

Hope this will help~