//封裝一個判斷網路類
public class HttpNet {
   public static boolean isNetConnected(Context context) {
   	 boolean isNetConnected;
    // 獲得網路連線服務
   	 ConnectivityManager connManager = (ConnectivityManager) context
            .getSystemService(Context.CONNECTIVITY_SERVICE);
 	  NetworkInfo info = connManager.getActiveNetworkInfo();
    if (info != null && info.isAvailable()) {
        isNetConnected = true;
    } else {
        isNetConnected = false;
    }
    return isNetConnected;
    }
}
 

//有網路時,網上載入資料,沒網時,載入本地的資料 public class Frag21 extends Fragment {

private PullToRefreshListView pulllistview;
private int num = 1;
private String Url = "http://www.xieast.com/api/news/news.php?page=";
private HttpUtils httpUtils;
private ArrayList<User.DataBean> list = new ArrayList<>();
//private DbUtils dbUtils;
private MyAdapter myAdapter;
private DbUtils dbUtils;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_frag21, container, false);
    //初始化控制元件
    pulllistview = view.findViewById(R.id.pulllistview);

    dbUtils = new DbUtils(getActivity());
    //設定模型
    pulllistview.setMode(PullToRefreshBase.Mode.BOTH);


    //設定介面卡
    myAdapter = new MyAdapter(getActivity(), list);
    pulllistview.setAdapter(myAdapter);

    //設定監聽
    pulllistview.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener2<ListView>() {
        @Override
        public void onPullDownToRefresh(PullToRefreshBase<ListView> refreshView) {
            Toast.makeText(getActivity(), "fd", Toast.LENGTH_SHORT).show();
            list.clear();
            getmData(1);
        }

        @Override
        public void onPullUpToRefresh(PullToRefreshBase<ListView> refreshView) {
            Toast.makeText(getActivity(), "上拉", Toast.LENGTH_SHORT).show();
            num++;
            getmData(num);
        }
    });
    getmData(1);
    return view;
}


//獲取資料
public void getmData(int num) {

    boolean flag = new HttpNet().isNetConnected(getActivity());
    // Toast.makeText(getActivity(),""+b,Toast.LENGTH_SHORT).show();
    if (flag) {
        //例項化物件
        httpUtils = new HttpUtils();
        httpUtils.getpath(Url + num);
        httpUtils.gethttpUtils(new HttpUtils.SetDate() {

            @Override
            public void getData(String str) {
                Gson gson = new Gson();
                User user = gson.fromJson(str, User.class);
                //把資料快取到本地資料庫
                dbUtils.insert(str);
                list.addAll(0, user.getData());
                myAdapter.getList(list);
                pulllistview.onRefreshComplete();
            }
        });
    } else {
        Toast.makeText(getActivity(), "親,沒網啦", Toast.LENGTH_SHORT).show();
        String query = dbUtils.query();
        Toast.makeText(getActivity(), query.toString(), Toast.LENGTH_SHORT).show();
        User userdata = new Gson().fromJson(query, User.class);
        List<User.DataBean> dataBeanList = userdata.getData();
        list.addAll(dataBeanList);
        myAdapter.getList(list);
    }
}
 

}