极客观点
项目管理
HarmonyOS
嗨，我有一个选项卡式活动，在第一个选项卡中，我从服务器获取数据并将其显示在卡片视图中的 recyclerview 中。为了从服务器获取数据，我使用了 volley 库。我想实现拉来刷新以加载数据（所以每当我拉它时都必须向网络发出请求）。而且我还想在选项卡之间切换时禁用网络请求（因为当我在应用程序中更改选项卡焦点时，它开始获取数据）我只想执行一次网络请求（当用户第一次登录时）然后其他请求只能通过拉刷新来处理。
这是我的片段，我在其中进行了 recyclerview 并显示数据：
public class Tab1History extends Fragment
{
private RecyclerView recyclerView;
private CespiteAdapter adapter;
UserSessionManager session;
private static final String URL_DATA = "http://mydata.php";
private List<CespiteOgg> cespiteOggList;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
View rootView = inflater.inflate(R.layout.tab1history, container, false);
recyclerView = (RecyclerView) rootView.findViewById(R.id.my_recycler_view);
recyclerView.setHasFixedSize(true);//every item of the RecyclerView has a fix size
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
cespiteOggList = new ArrayList<>();
loadRecyclerViewData();
return rootView;
}
private void loadRecyclerViewData()
{
// Session class instance
session = new UserSessionManager(getActivity());
//get user data from session
HashMap<String, String> user = session.getUserDetails();
//get name
String name = user.get(UserSessionManager.KEY_NAME);
// get username
final String usernameUtente = user.get(UserSessionManager.KEY_USERNAME);
final ProgressDialog progressDialog = new ProgressDialog(getActivity());
progressDialog.setMessage("Carimento dati...");
progressDialog.show();
StringRequest stringRequest = new StringRequest(Request.Method.POST,
URL_DATA,
new Response.Listener<String>() {
@Override
public void onResponse(String s) {
progressDialog.dismiss();
try {
JSONObject jsonObject = new JSONObject(s);
JSONArray array = jsonObject.getJSONArray("dates");
for(int i=0; i<array.length(); i++)
{
JSONObject o = array.getJSONObject(i);
CespiteOgg item = new CespiteOgg(
o.getString("CodNumInventario"),
o.getString("Nome"),
o.getString("DtCatalogazione"),
o.getString("CodIdA"),
o.getString("username")
);
cespiteOggList.add(item);
}
adapter = new CespiteAdapter(cespiteOggList, getActivity());
recyclerView.setAdapter(adapter);
} catch (JSONException e) {
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
progressDialog.dismiss();
}
})
{
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> params = new HashMap<String, String>();
params.put("Username", usernameUtente);
return params;
}
};
RegisterRequest.getmInstance(getActivity()).addToRequestque(stringRequest);
}
}
它是适配器：
public class CespiteAdapter extends RecyclerView.Adapter<CespiteAdapter.ViewHolder>
{
private List<CespiteOgg> cespiteOggList;
private Context context;
public CespiteAdapter(List<CespiteOgg> cespiteOggList, Context context) {
this.cespiteOggList = cespiteOggList;
this.context = context;
}
public class ViewHolder extends RecyclerView.ViewHolder
{
public CardView cv;
public TextView txtNumInventario;
public TextView txtNomeCespite;
public TextView txtDtCatalogazione;
public TextView txtAula;
public TextView txtNomeUser;
ViewHolder(View itemView)
{
super (itemView);
//cv = (CardView) itemView.findViewById(R.id.cardView);
txtNumInventario = (TextView) itemView.findViewById(R.id.txtNumeroInventario);
txtNomeCespite = (TextView) itemView.findViewById(R.id.txtNomeCespite);
txtDtCatalogazione = (TextView) itemView.findViewById(R.id.txtDataCatalogazione);
txtAula = (TextView) itemView.findViewById(R.id.txtAula);
txtNomeUser= (TextView) itemView.findViewById(R.id.txtNomeUser);
}
}
@Override
public CespiteAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
{
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
View cespiteView = inflater.inflate(R.layout.cespite_card_view, parent, false);
return new ViewHolder(cespiteView);
}
@Override
public void onBindViewHolder(ViewHolder holder, int position)
{
CespiteOgg cespiteOgg = cespiteOggList.get(position);
holder.txtNumInventario.setText(cespiteOgg.getNumInventario());
holder.txtNomeCespite.setText(cespiteOgg.getNomeCespite());
holder.txtDtCatalogazione.setText(cespiteOgg.getDtCatalogazione());
holder.txtAula.setText(cespiteOgg.getAula());
holder.txtNomeUser.setText(cespiteOgg.getNomeUser());
}
@Override
public int getItemCount()
{
return cespiteOggList.size();
}
}
原文由 arst3k 发布，翻译遵循 CC BY-SA 4.0 许可协议
android
您可以使用 android SwipeRefreshLayout 小部件代替
ProgressDialog。按照以下步骤将
SwipeRefreshLayout集成到您的Tab1history片段中：1. 在您的布局
tab1history，添加SwipeRefreshLayout作为根布局，并在其中放置RecyclewrView。2. 在您的
Tab1History片段中，使用SwipeRefreshLayout如下从服务器加载数据：希望这将正常工作。