工厂模式加单例管理Fragment，同时解决fragment切换数据丢失问题

package com.itjfr.jfr.fragment;

import java.util.ArrayList;
import java.util.List;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;


/**
 * 本工厂管理fragment保证所有的fragment为单例
 * 
 * @author Nullifier
 * 
 */
public class FragmentFactory {
private static Fragment settingFragment;
private static HomeFragment homeFragment;
private static GuidanceFragment guidanceFragment;
private static MarketFragment marketFragment;
private static MeFragment meFragment;
private static PersonDetailFragment personDetailFragment;
private static ScoreFragment scoreFragment;
private static ImageFragment imageFragment;
//当前fragment缓存
private static Fragment cacheFragment;


public static Fragment getNowFragment() {
return cacheFragment;
}


/**
* 切换fragment工具方法 由于fragment经常切换如果使用replace方法则会造成fragment重新加载，所以只能hide/show
* 
* @param target
*            目标切换的fragment
* @param resourceId
*            要替换的资源ID
* @param fagmentManager
*            fragment管理者
*/
public static void switchPager(Fragment target, int resourceId,
FragmentManager fagmentManager) {
// 缓存cache第一次进来是空的要单独处理
if (cacheFragment == null) {
// 第一次进来要切换的fragment作为当前fragment加入到transaction中并显示
fagmentManager.beginTransaction().add(resourceId, target)
.show(target).commit();
// 将此fragment赋值给缓存fragment，停止代码执行
cacheFragment = target;
return;
}
// 如果目标fragment与当前fragment一样则直接返回不执行
if (cacheFragment == target) {
return;
}
// 如果目标frragment没有添加进来则添加进transaction中
if (!target.isAdded()) {
fagmentManager.beginTransaction().add(resourceId, target).commit();
}
// 隐藏当前的fragmeny显示目标的fragment
fagmentManager.beginTransaction().hide(cacheFragment).show(target)
.commit();
//将目标fragment复制给缓存标记
cacheFragment = target;
}


/**
* 获取fragment
* 
* @param fragment类型
*            FragmentType枚举
* @return fragment
*/
public static Fragment getFragment(FragmentType type) {
switch (type) {
case GUIDANCE:
if (guidanceFragment == null) {
guidanceFragment = new GuidanceFragment();
}
return guidanceFragment;


case HOME:
if (homeFragment == null) {
homeFragment = new HomeFragment();
}
return homeFragment;


case MARKET:
if (marketFragment == null) {
marketFragment = new MarketFragment();
}
return marketFragment;


case ME:
if (meFragment == null) {
meFragment = new MeFragment();
}
return meFragment;


case PERSONDETAIL:
if (personDetailFragment == null) {
personDetailFragment = new PersonDetailFragment();
}
return personDetailFragment;


case SCORE:
if (scoreFragment == null) {
scoreFragment = new ScoreFragment();
}
return scoreFragment;


case SETTING:
if (settingFragment == null) {
settingFragment = new SettingFragment();
}
return settingFragment;
case IMAGE:
if (imageFragment == null) {
imageFragment = new ImageFragment();
}
return imageFragment;


default:
break;
}


return null;
}


/**
* 通过网络地址集合获取fragment集合，集合不唯一
* 
* @param type
*            类型 一般为IMAGE
* @param urlList
*            图片集合
* @return
*/
public static List<Fragment> getFragment(FragmentType type,
List<String> urlList) {
switch (type) {
case IMAGE:
ArrayList<Fragment> listFragment = new ArrayList<Fragment>();
if (urlList != null && urlList.size() > 0) {
for (int i = 0; i < urlList.size(); i++) {
listFragment.add(new ImageFragment().setIamgeUrl(urlList
.get(i)));
}
}
return listFragment;


default:
break;
}


return null;
}


/**
* 枚举
* 
* @author Nullifier
* 
*/
public static enum FragmentType {
/**
* 导航
*/
GUIDANCE,
/**
* 主页
*/
HOME,
/**
* 市场
*/
MARKET,
/**
* 我
*/
ME,
/**
* 个人详情
*/
PERSONDETAIL,
/**
* 积分
*/
SCORE,
/**
* 设置
*/
SETTING,
/**
* 图像
*/
IMAGE;
}


}