Java tutorial
/******************************************************************************* * Copyright (c) 2014 Hoang Nguyen. * All rights reserved. This program and the accompanying materials * are made available under the terms of the GNU Public License v2.0 * which accompanies this distribution, and is available at * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html * * Contributors: * Hoang Nguyen - initial API and implementation ******************************************************************************/ package com.nkahoang.screenstandby; import java.lang.reflect.Constructor; import java.lang.reflect.Method; import android.app.Activity; import android.content.Context; import android.content.Intent; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.preference.Preference; import android.preference.PreferenceManager; import android.preference.PreferenceScreen; import android.support.v4.app.ListFragment; import android.view.LayoutInflater; import android.view.View; import android.view.ViewParent; import android.widget.ListView; import android.view.ViewGroup; public class PreferenceListFragment extends ListFragment { private PreferenceManager mPreferenceManager; /** * The starting request code given out to preference framework. */ private static final int FIRST_REQUEST_CODE = 100; private static final int MSG_BIND_PREFERENCES = 0; private Handler mHandler = new Handler() { @Override public void handleMessage(Message msg) { switch (msg.what) { case MSG_BIND_PREFERENCES: bindPreferences(); break; } } }; private ListView lv; private int xmlId; public PreferenceListFragment(int xmlId) { this.xmlId = xmlId; } //must be provided public PreferenceListFragment() { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle b) { postBindPreferences(); return lv; } @Override public void onDestroyView() { super.onDestroyView(); ViewParent p = lv.getParent(); if (p != null) ((ViewGroup) p).removeView(lv); } @Override public void onCreate(Bundle b) { super.onCreate(b); if (b != null) xmlId = b.getInt("xml"); mPreferenceManager = onCreatePreferenceManager(); lv = (ListView) LayoutInflater.from(getActivity()).inflate(R.layout.preference_list_content, null); lv.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY); addPreferencesFromResource(xmlId); postBindPreferences(); ((OnPreferenceAttachedListener) getActivity()).onPreferenceAttached(getPreferenceScreen(), xmlId); } @Override public void onStop() { super.onStop(); try { Method m = PreferenceManager.class.getDeclaredMethod("dispatchActivityStop"); m.setAccessible(true); m.invoke(mPreferenceManager); } catch (Exception e) { e.printStackTrace(); } } @Override public void onDestroy() { super.onDestroy(); lv = null; try { Method m = PreferenceManager.class.getDeclaredMethod("dispatchActivityDestroy"); m.setAccessible(true); m.invoke(mPreferenceManager); } catch (Exception e) { e.printStackTrace(); } } @Override public void onSaveInstanceState(Bundle outState) { outState.putInt("xml", xmlId); super.onSaveInstanceState(outState); } @Override public void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); try { Method m = PreferenceManager.class.getDeclaredMethod("dispatchActivityResult", int.class, int.class, Intent.class); m.setAccessible(true); m.invoke(mPreferenceManager, requestCode, resultCode, data); } catch (Exception e) { e.printStackTrace(); } } /** * Posts a message to bind the preferences to the list view. * <p> * Binding late is preferred as any custom preference types created in * {@link #onCreate(Bundle)} are able to have their views recycled. */ private void postBindPreferences() { if (mHandler.hasMessages(MSG_BIND_PREFERENCES)) return; mHandler.obtainMessage(MSG_BIND_PREFERENCES).sendToTarget(); } private void bindPreferences() { final PreferenceScreen preferenceScreen = getPreferenceScreen(); if (preferenceScreen != null && lv != null) { preferenceScreen.bind(lv); } } /** * Creates the {@link PreferenceManager}. * * @return The {@link PreferenceManager} used by this activity. */ private PreferenceManager onCreatePreferenceManager() { try { Constructor<PreferenceManager> c = PreferenceManager.class.getDeclaredConstructor(Activity.class, int.class); c.setAccessible(true); PreferenceManager preferenceManager = c.newInstance(this.getActivity(), FIRST_REQUEST_CODE); return preferenceManager; } catch (Exception e) { e.printStackTrace(); return null; } } /** * Returns the {@link PreferenceManager} used by this activity. * @return The {@link PreferenceManager}. */ public PreferenceManager getPreferenceManager() { return mPreferenceManager; } /** * Sets the root of the preference hierarchy that this activity is showing. * * @param preferenceScreen The root {@link PreferenceScreen} of the preference hierarchy. */ public void setPreferenceScreen(PreferenceScreen preferenceScreen) { try { Method m = PreferenceManager.class.getDeclaredMethod("setPreferences", PreferenceScreen.class); m.setAccessible(true); boolean result = (Boolean) m.invoke(mPreferenceManager, preferenceScreen); if (result && preferenceScreen != null) { postBindPreferences(); } } catch (Exception e) { e.printStackTrace(); } } /** * Gets the root of the preference hierarchy that this activity is showing. * * @return The {@link PreferenceScreen} that is the root of the preference * hierarchy. */ public PreferenceScreen getPreferenceScreen() { try { Method m = PreferenceManager.class.getDeclaredMethod("getPreferenceScreen"); m.setAccessible(true); return (PreferenceScreen) m.invoke(mPreferenceManager); } catch (Exception e) { e.printStackTrace(); return null; } } /** * Adds preferences from activities that match the given {@link Intent}. * * @param intent The {@link Intent} to query activities. */ public void addPreferencesFromIntent(Intent intent) { } /** * Inflates the given XML resource and adds the preference hierarchy to the current * preference hierarchy. * * @param preferencesResId The XML resource ID to inflate. */ public void addPreferencesFromResource(int preferencesResId) { try { Method m = PreferenceManager.class.getDeclaredMethod("inflateFromResource", Context.class, int.class, PreferenceScreen.class); m.setAccessible(true); PreferenceScreen prefScreen = (PreferenceScreen) m.invoke(mPreferenceManager, getActivity(), preferencesResId, getPreferenceScreen()); setPreferenceScreen(prefScreen); } catch (Exception e) { e.printStackTrace(); } } /** * Finds a {@link Preference} based on its key. * * @param key The key of the preference to retrieve. * @return The {@link Preference} with the key, or null. * @see PreferenceGroup#findPreference(CharSequence) */ public Preference findPreference(CharSequence key) { if (mPreferenceManager == null) { return null; } return mPreferenceManager.findPreference(key); } public interface OnPreferenceAttachedListener { public void onPreferenceAttached(PreferenceScreen root, int xmlId); } }