Why can't I add the first header to getPreferenceScreen?

Question

In the standard settings mode from google android studio, the first "General" header is now displayed. So I changed the code, but I got java.lang.NullPointerException the first time getPreferenceScreen () was logged. 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> 

Answer 1

Well, I figured it out because it was annoying too. Therefore, to display the title bar for the first section of preferences (for example, general), I added another XML file (PreferenceScreen), which is used as a container. I called it pref_container.xml and it is in the xml directory along with other preference headers like pref_general.xml, pref_notification.xml, etc. 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 file 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 is a trick for me.