Android Open Source - screenstandby Preference List Fragment

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License

The source code is released under:
GNU General Public License
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Java Source Code

/*******************************************************************************
 * Copyright (c) 2014 Hoang Nguyen.//  w ww. j av a2  s . c o m
 * 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);
    }   
}
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