完美 解决fragment中listview数据丢失问题和问题分析

解决fragment中listview数据丢失问题

private ListViewForScrollViewmListview;

private FindShareAdatptershareAdatpter = null;

private List<TaskFindInfo>tastlistdata=null;

首先分析下它的生命周期，与 activity 不同的是，这个 rootivew 被重复创建过

那listview 肯定也被重复初始化，自然它的 getAdapter 就为空了，那就相当于没有内容了；

但整个 fragment 只被创建过一次，并没有走onDestroy 死亡 的方法；

一个类中的私有成员只有在它 上层类被回收时才会被回收， 其实 tastlistdata和 shareAdatpter 都没有被回收，也就不需要反复加载数据了；

10-24 09:17:22.866 13330-13330/nabei.com.automat D/RonyDebug: onCreate

10-24 09:17:22.867 13330-13330/nabei.com.automat D/RonyDebug: onCreateView

10-24 09:17:22.956 13330-13330/nabei.com.automat D/RonyDebug: onActivityCreated

10-24 09:17:22.966 13330-13330/nabei.com.automat D/RonyDebug: onResume

10-24 09:18:00.205 13330-13330/nabei.com.automat D/RonyDebug: onCreateView

10-24 09:18:00.212 13330-13330/nabei.com.automat D/RonyDebug: onActivityCreated

10-24 09:18:00.212 13330-13330/nabei.com.automat D/RonyDebug: onResume

10-24 09:18:38.212 13330-13330/nabei.com.automat D/RonyDebug: onCreateView

10-24 09:18:38.224 13330-13330/nabei.com.automat D/RonyDebug: onActivityCreated

10-24 09:18:38.224 13330-13330/nabei.com.automat D/RonyDebug: onResume

关键代码：

@Override

public void onActivityCreated(@Nullable Bundle savedInstanceState) {

    super.onActivityCreated(savedInstanceState);

    if ( mListview.getAdapter()==null) {

        if (shareAdatpter==null) {

            shareAdatpter = new FindShareAdatpter(getActivity());

            new HttpRest(getActivity(), mhandler, 1).get_findActivityList();

        }else{

            showlist(tastlistdata);

        }

    }

}

完整代码，并不需要对 其它数据作任何处理：

public class MainpageFind extends Fragment  {

    private ListViewForScrollView mListview;

    private FindShareAdatpter shareAdatpter = null;

    private List<TaskFindInfo> tastlistdata=null;

    @Override

    public void onActivityCreated(@Nullable Bundle savedInstanceState) {

        super.onActivityCreated(savedInstanceState);

        if ( mListview.getAdapter()==null) {

            if (shareAdatpter==null) {

                shareAdatpter = new FindShareAdatpter(getActivity());

                new HttpRest(getActivity(), mhandler, 1).get_findActivityList();//网络请求加载数据

            }else{

                showlist(tastlistdata);

            }

        }

    }

    private Handler mhandler = new Handler(Looper.getMainLooper()) {

        @Override

        public void handleMessage(Message msg) {

            if (msg.what == 1) {

                List<TaskFindInfo> taskinfos = (List<TaskFindInfo>) msg.obj;

                tastlistdata=taskinfos;

                showlist(taskinfos);

            }

        }

    };

    private void showlist(List<TaskFindInfo> tastlist) {

        shareAdatpter.SetList(tastlist);

        mListview.setAdapter(shareAdatpter);

        shareAdatpter.notifyDataSetChanged();

    }

    @Override

    public View onCreateView(LayoutInflater inflater, ViewGroup container,

                             Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.mainpage3, null);

        bbstv = (TextView) view.findViewById(R.id.bbstv);

        helptv = (TextView) view.findViewById(R.id.helptv);

        helptv.setOnClickListener(this);

        bbstv.setOnClickListener(this);

        mListview = view.findViewById(R.id.actionlist);

        return view;

    }

}