Activity-Fragment存储与返回

最新推荐文章于 2025-08-23 10:36:55 发布

原创最新推荐文章于 2025-08-23 10:36:55 发布 · 362 阅读

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文章标签：

#android #存储 #多个Fragment #返回 #跳转

本文介绍了一种基于Android平台的Fragment管理与缓存机制，通过定义一系列常量标识不同的Fragment，并利用HashMap缓存Fragment实例，实现快速切换及内存有效管理。

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package TokenLeiBao;

import java.lang.ref.SoftReference;
import java.util.HashMap;

import android.support.v4.app.Fragment;

import FragmentLeiBao.CaoMaFragment;
import FragmentLeiBao.ChakanFragment;
import FragmentLeiBao.DiaochaFragment;
import FragmentLeiBao.ViewDiaochaFragment;
import FragmentLeiBao.ViewGerensFragment;
import FragmentLeiBao.ViewGopgeFragment;
import FragmentLeiBao.ViewPhotoFragment;
import FragmentLeiBao.ViewXiugaiFragment;
import FragmentLeiBao.ViewYonghuFragment;
import FragmentLeiBao.ViewChouquFragment;
import FragmentLeiBao.ViewxianchaFragment;
import FragmentLeiBao.ViewxuanFragment;

public class ViewIndex {

   public static final int TEST1_VIEW= 0;
   public static final int VIEW_LOGIN = 1;
   public static final int VIEW_SURVEY_LIST = 2;
   public static final int VIEW_USER_CENTER = 3;
   public static final int VIEW_SURVEY_DETAIL = 4;
   public static final int VIEW_SURVEY_Nu = 5;
   public static final int View_SID_Niu=6;
   public static final int View_Chou_Qi=7;
   public static final int View_Cha_kan=8;
   public static final int View_Xuan_Ze=9;
   public static final int View_Xuan_cha=11;
   public static final int VIEW_USER_CENTE = 12;
   public static final int VIEW_Sao_Ma = 13;
// /**
   public static final int SWITCHINDEX_0 = 0;
   public static final int SWITCHINDEX_1 = 1;

   public static HashMap<String, SoftReference<Fragment>> viewMap = new HashMap<String, SoftReference<Fragment>>();
   public static Fragment getView(int index){
      Fragment contentViewTemp = null;
      SoftReference<Fragment> ref = viewMap.get(""+index);
      if(ref!=null){
         if(ref.get()!=null){
            contentViewTemp = ref.get();
            if(contentViewTemp!=null){
               if(contentViewTemp.getActivity()!=null&&
                     contentViewTemp.getActivity().isFinishing()){
                  viewMap.remove(ref);
                  contentViewTemp = null;
               }
            }
         }
      }

//每新建一个Fragment须在此注册


 Fragment contentView = null;      int switchIndex = index/10;/*0至第10个Fragment*/      try {         switch(switchIndex){            case SWITCHINDEX_0:               switch(index){                  case VIEW_LOGIN:                     contentView = contentViewTemp==null?new ViewGopgeFragment():contentViewTemp;
                     break;                  case VIEW_SURVEY_LIST:                     contentView = contentViewTemp==null?new DiaochaFragment():contentViewTemp;                     break;                   case VIEW_USER_CENTER:                     contentView = contentViewTemp==null?new ViewGerensFragment():contentViewTemp;                     break;                  case VIEW_SURVEY_DETAIL:                     contentView = contentViewTemp==null?new ViewXiugaiFragment():contentViewTemp;                     break;                  case VIEW_SURVEY_Nu:                     contentView = contentViewTemp==null?new ViewYonghuFragment():contentViewTemp;                     break;                  case View_SID_Niu:                     contentView = contentViewTemp==null?new ViewDiaochaFragment():contentViewTemp;                     break;                  case View_Chou_Qi:                     contentView = contentViewTemp==null?new ViewChouquFragment():contentViewTemp;                     break;                  case View_Cha_kan:                     contentView = contentViewTemp==null?new ChakanFragment():contentViewTemp;                     break;                  case View_Xuan_Ze:                     contentView = contentViewTemp==null?new ViewxuanFragment():contentViewTemp;                     break;               }               break;            case SWITCHINDEX_1:/*11至第20个Fragment*/                     switch (index){                   case View_Xuan_cha:                      contentView = contentViewTemp==null?new ViewxianchaFragment():contentViewTemp;                      break;                   case VIEW_USER_CENTE:                      contentView = contentViewTemp==null?new ViewPhotoFragment():contentViewTemp;                      break;                   case VIEW_Sao_Ma:                      contentView = contentViewTemp==null?new CaoMaFragment():contentViewTemp;                      break;                }               break;         }         if(contentViewTemp==null){            SoftReference<Fragment> ref0 =  new SoftReference<Fragment>(contentView);            viewMap.put(""+index, ref0);         }      } catch (Exception e) {         e.printStackTrace();      } catch(OutOfMemoryError e){           e.printStackTrace();           viewMap.clear();           System.gc();           System.gc();           System.gc();        }      return contentView;   }}

Activity类：

/*切换线性布局显示不同Fragment*/
        changeFragment(ViewIndex.VIEW_LOGIN, null);
fragment类：

View view = inflater.inflate(R.layout.shopping_main,container,false);
return view;

如果过要做保存：

搜索：Android-Fragment-界面保存


使用前先进入ViewIndex类，添加fragment类


后退：    Operation pre = ((MainActivity)getActivity()).accessedViews.pop();//从栈空间里面将上一条数据抛出来
                ((MainActivity)getActivity()).changeFragment(pre.getCode(), pre.getBundle(), false);
                
                
                
页面切换：  ((MainActivity) getActivity()).changeFragment(ViewIndex.View_Cha_kan, null);
               
               注：ViewIndex.VIEW_SURVEY_LIST为你想要跳转的页面，ViewIndex类可以添加Fragment