首选项片段未显示首选项

Question

I'm trying to get a preference screen to load, but it does not seem to be showing. I am able to load the Activity, but I can see no actual preferences. I have tried other solution on StackOverflow like adding setContentView(R.layout.activity_settings); to the SettingsActivity, but had no success.

SettingsActivity.java

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;

public class SettingsActivity extends ActionBarActivity {

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

        // Display the fragment as the main content.
        getFragmentManager().beginTransaction()
                .replace(android.R.id.content, new SettingsFragment())
                .commit();
    }

}

preferences.xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <PreferenceCategory
        android:title="@string/pref_start"
        android:key="pref_key_storage_settings">
        <CheckBoxPreference
            android:key="pref_key_auto_exit"
            android:summary="@string/pref_summary_exit"
            android:title="@string/pref_title_exit"
            android:defaultValue="false"/>
    </PreferenceCategory>
</PreferenceScreen>

SettingsFragment.java

import android.os.Bundle;
import android.preference.PreferenceFragment;
import android.view.LayoutInflater;
import android.view.ViewGroup;

public class SettingsFragment extends PreferenceFragment {

    public SettingsFragment() {
    }

    public void onCreate(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Load the preferences from an XML resource
        addPreferencesFromResource(R.xml.preferences);
    }
}

Answer 1

Since your activity extends ActionBarActivity which in turn extends FragmentActivity it can only use support Fragment s and their descendants. However the PreferenceFragment descends from native Fragment . Even if your minimum SDK is higher than 11 these two are not able to interoperate.

You have two options:

1) Go native preferences

Your activity would best extend PreferenceActivity . You can then continue using your current PreferenceFragment . The downside is you'll have to handle styling on API 11+ (or 14+) and API 21+ separately (but it can be done). Full documentation on native preferences

2) EASY: Go full support

There is a community made backport of PreferenceFragment (actually there are multiple, but I used this one) which can be found here: https://github.com/kolavar/android-support-v4-preferencefragment

You should be able to compile just after importing the library to your project and changing the import statement so instead of import android.preference.PreferenceFragment; you'd have import android.support.v4.preference.PreferenceFragment; .

How to decide

If you target API below 11 and you need the action bar you have no choice but option 2. This option is also best if you don't need the PreferenceActivity sugar like headers, master-detail view on large screens etc. (again see the docs)