How to add a Header and Preference Object to PreferenceActivity not using an XML file but Java?

Question

I have PreferenceFragment and a PreferenceActivity from which I add headers from a XML file on this way:

PreferenceActivity

@Override
public void onBuildHeaders(List<Header> target) {  
    if(DEBUG) Log.i("PreferenceActivity", "onBuildHeaders() -> LogicAnalizerPrefs");
    if(android.os.Build.VERSION.SDK_INT >= 12) {
        loadHeadersFromResource(R.xml.preference_header_logicanalizer, target);
    }
}

PreferenceFragment:

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if(DEBUG) Log.i("PreferenceFragment", "onCreate() -> LogicAnalizerPrefsFragment");
        int res = getActivity().getResources().getIdentifier(getArguments().getString("logicprefsheaders"), "xml", getActivity().getPackageName());
        addPreferencesFromResource(res);
    }

And the XML file where I have the headers is:

R.xml.preference_header_logicanalizer:

<header
        android:fragment="com.protocolanalyzer.andres.LogicAnalizerPrefsFragment"
        android:icon="@drawable/settings"
        android:title="General" >
        <extra
            android:name="logicprefsheaders"
            android:value="logicgeneral" />
    </header>
    <header
        android:fragment="com.protocolanalyzer.andres.LogicAnalizerPrefsFragment"
        android:icon="@drawable/settings"
        android:title="Canal 1" >
        <extra
            android:name="logicprefsheaders"
            android:value="c1analizerprefs" />
    </header>
    <header
        android:fragment="com.protocolanalyzer.andres.LogicAnalizerPrefsFragment"
        android:icon="@drawable/settings"
        android:title="Canal 2" >
        <extra
            android:name="logicprefsheaders"
            android:value="c2analizerprefs" />
    </header>
    <header
        android:fragment="com.protocolanalyzer.andres.LogicAnalizerPrefsFragment"
        android:icon="@drawable/settings"
        android:title="Canal 3" >
        <extra
            android:name="logicprefsheaders"
            android:value="c3analizerprefs" />
    </header>
    <header
        android:fragment="com.protocolanalyzer.andres.LogicAnalizerPrefsFragment"
        android:icon="@drawable/settings"
        android:title="Canal 4" >
        <extra
            android:name="logicprefsheaders"
            android:value="c4analizerprefs" />
    </header>

And this is one of my xml files which is used to display one of the preferences when a Header is clicked:

c1analizerprefs.xml:

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

    <PreferenceCategory android:title="@string/AnalyzerProtocolTitle1" >
        <ListPreference
            android:defaultValue="0"
            android:entries="@array/protocolList"
            android:entryValues="@array/protocolValues"
            android:key="protocol1"
            android:summary="@string/AnalyzerProtocolSummary"
            android:title="@string/AnalyzerProtocolTitle1" />
        <ListPreference
            android:defaultValue="1"
            android:entries="@array/channelNames"
            android:entryValues="@array/protocolValues"
            android:key="SCL1"
            android:summary="@string/AnalyzerSCLSummary"
            android:title="@string/AnalyzerSCLTitle" />

        <EditTextPreference
            android:defaultValue="9600"
            android:title="@string/AnalyzerBaudTitle"
            android:key="BaudRate1"
            android:summary="@string/AnalyzerBaudSummary"
            android:inputType="number" />
    </PreferenceCategory>

</PreferenceScreen>

So in a large screen I have this result as expected and I use only one PreferenceFragment to add my 4 headers.

But my four Preferences defined in the XML like c1analizerprefs.xml are almost the same the only change is a number (For example: Pref. 1, Pref. 2, ...) so I want to add them in Java so I can use a for() to add 4 or more Preferences easily changing the number of repetitions because the text is always the same I only change a number so on this way I don't need to create one XML file for each preference, I create them dynamically in Java.

How can I add a Preference to a Header in Java instead of using a XML file? In PreferenceFragment I only have addPreferencesFromResource() or addPreferencesFromIntent(). Is any way to add a Preference Object?

Answer 1

Just in case someone is actually looking for some code...

The following example loads some headers from XML and then appends to them programatically.

1st override onBuildHeaders inside your PreferenceActivity:

@Override
public void onBuildHeaders(List<Header> target) {
    loadHeadersFromResource(R.xml.preference_headers, target);

    // Add layer as a new settings header
    Header header = new Header();
    header.title = "More Settings";
    header.summary = "Change even more settings";
    header.fragment = SettingsFragment.class.getName();

    Bundle b = new Bundle();
    b.putString("category", "MoreSettings");
    header.fragmentArguments = b;
    target.add(header);
}

Then override onHeaderClick inside your PreferenceActivity. Note that you pass the header's fragmentArguments to the fragment so you can detect which header was clicked (category):

@Override
public void onHeaderClick(Header header, int position) {    
    this.startPreferencePanel(SettingsFragment.class.getName(), header.fragmentArguments, header.titleRes, header.title, null, 0);
}

Then inside your PreferenceFragment override onCreate:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    if (savedInstanceState == null) {
        mCategory = getArguments().getString("category");
    }
    else {
        // Orientation Change
        mCategory = savedInstanceState.getString("category");
    }

    if (mCategory.equals("Map")) {
        // Load the preferences from an XML resource
        addPreferencesFromResource(R.xml.preferences_map);
    }
    if (mCategory.equals("MoreSettings")) {
        // Load the preferences from an XML resource
        PreferenceScreen preferenceScreen = getPreferenceManager().createPreferenceScreen(getActivity());
        // add prefrences using preferenceScreen.addPreference()
        this.setPreferenceScreen(preferenceScreen);
    }
}

In case you want to see the xml for predefined headers.

res/xml/preference_headers.xml

<?xml version="1.0" encoding="utf-8"?>
<preference-headers xmlns:android="http://schemas.android.com/apk/res/android">
    <header 
        android:fragment="com.appName.fragments.SettingsFragment"
        android:title="@string/pref_category_map_title"
        android:summary="@string/pref_category_map_sum" >
        <!-- key/value pairs can be included as arguments for the fragment. -->
        <extra android:name="category" android:value="Map" />
    </header>
</preference-headers>

res/xml/preferences_map.xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <CheckBoxPreference
        android:key="pref_zoomToCurrentLocationOnStart"
        android:title="@string/pref_zoomToCurrentLocationOnStart_title"
        android:summary="@string/pref_zoomToCurrentLocationOnStart_sum"
        android:defaultValue="true" />
    <CheckBoxPreference
        android:key="pref_myLocation"
        android:title="@string/pref_myLocation_title"
        android:summary="@string/pref_myLocation_sum"
        android:defaultValue="true" />
</PreferenceScreen>