Why can't i add first header to getPreferenceScreen?

android, java

Solution

OK, I figured it out because it was annoying to me as well. So in order to display the header title for the first preference section (e.g. general), I added another xml file (PreferenceScreen) which is used as a container. I called it pref_container.xml and it is located in xml directory along with other preference headers like pref_general.xml, pref_notification.xml, etc. The code in it:

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

Then, in the SettingsActivity.java I have:

// Add container
addPreferencesFromResource(R.xml.pref_container);

// Add 'general' preferences, and a corresponding header.
PreferenceCategory fakeHeader = new PreferenceCategory(this);
fakeHeader.setTitle(R.string.pref_header_general);
getPreferenceScreen().addPreference(fakeHeader);
addPreferencesFromResource(R.xml.pref_general);

// Add 'backup' preferences, and a corresponding header.
fakeHeader = new PreferenceCategory(this);
fakeHeader.setTitle(R.string.pref_header_backup);
getPreferenceScreen().addPreference(fakeHeader);
addPreferencesFromResource(R.xml.pref_backup);

This does the trick for me.

Problem

The standard settings activity from google android studio is now showing the first header "General". So i modified the code but i get java.lang.NullPointerException at first occurrence of getPreferenceScreen().addPreference(fakeHeader); ``` private void setupSimplePreferencesScreen() { if (!isSimplePreferences(this)) { return; } PreferenceCategory fakeHeader = new PreferenceCategory(this); fakeHeader.setTitle(R.string.pref_header_notifications); getPreferenceScreen().addPreference(fakeHeader); addPreferencesFromResource(R.xml.pref_general); fakeHeader = new PreferenceCategory(this); fakeHeader.setTitle(R.string.pref_header_notifications); getPreferenceScreen().addPreference(fakeHeader); addPreferencesFromResource(R.xml.pref_notification); bindPreferenceSummaryToValue(findPreference("username")); bindPreferenceSummaryToValue(findPreference("password")); bindPreferenceSummaryToValue(findPreference("server")); } @Override @TargetApi(Build.VERSION_CODES.HONEYCOMB) public void onBuildHeaders(List<Header> target) { if (!isSimplePreferences(this)) { loadHeadersFromResource(R.xml.pref_headers, target); } } ``` ``` <header android:fragment="com.example.eslam.rottapharm.SettingsActivity$GeneralPreferenceFragment" android:title="@string/pref_header_general" /> </preference-headers> ```

Original source