我有一个简单的应用程序，其中包含片段和活动，托管一个回收器视图，vith数据来自数据库，我有删除功能，但我无法刷新回收器视图。我尝试了一些方法，但因为我的长按卡视图在适配器上，我无法使其在上工作
这是我的适配器：
public class LoyaltyCardRVAdapter extends RecyclerView.Adapter<LoyaltyCardRVAdapter.CardViewHolder> {
...
public LoyaltyCardRVAdapter(Context context, ArrayList<LoyaltyCardObject> cards) {
this.context = context;
this.cards = cards;
}
public void setData(ArrayList<LoyaltyCardObject> cards) {
this.cards = cards;
}
@Override
public int getItemCount() {
return cards.size();
}
@Override
public void onBindViewHolder(CardViewHolder holder, int position) {
LoyaltyCardObject card = cards.get(position);
holder.marque.setText(card.getMarque());
...
}
@Override
public CardViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.loyaltycard_row,
parent, false);
return new CardViewHolder(view, context, cards);
}
/**
* Cette classe initialise chaque cardview avec l'object correspondant
*/
public static class CardViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener {
CardView cardView;
TextView mail, marque, code;
ArrayList<LoyaltyCardObject> cards = new ArrayList<>();
Context context;
AlertDialog.Builder alertDialogBuilder;
RequestQueue requestQueue;
ImageView logo;
public CardViewHolder(View view, Context context, ArrayList<LoyaltyCardObject> cards) {
...
}
@Override
public void onClick(View v) { //Gère le clique sur une cardview
int position = getAdapterPosition();
LoyaltyCardObject card = this.cards.get(position);
Toast.makeText(context, "Codebarre pour la carte " + card.getMarque(), Toast.LENGTH_SHORT).show();
Intent intentcode = new Intent(this.context.getApplicationContext(), LoyaltyCardShowCodeActivity.class);
intentcode.putExtra("code", card.getCode());
this.context.startActivity(intentcode);
}
@Override
public boolean onLongClick(View v) {
int position = getAdapterPosition();
final LoyaltyCardObject card = this.cards.get(position);
requestQueue = Volley.newRequestQueue(context);
alertDialogBuilder
.setTitle("Effacer")
.setMessage("Voulez-vous vraiment effacer cette carte ?")
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
StringRequest request = new StringRequest(Request.Method.POST, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
Toast.makeText(context, "Carte n°" + card.getCode() + " chez " + card.getMarque() + " effacé", Toast.LENGTH_SHORT).show();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.i("MYAPP", "onErrorResponse()");
}
}) { // Paramètres de la requete
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> parameters = new HashMap<String, String>();
parameters.put("mail", card.getMail());
parameters.put("code", card.getCode());
return parameters;
}
};
requestQueue.add(request);
}
})
.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
})
.setIcon(R.drawable.ic_error_outline_black_24dp)
.show();
return false;
}
}
}
我在这个例子中的片段：
public class LoyaltyCardListFragment extends android.support.v4.app.Fragment {
LoyaltyCardRVAdapter adapter;
ProgressDialog dialog;
TextView addCards;
UserSharedPreferences userSharedPreferences;
ArrayList<LoyaltyCardObject> cards = new ArrayList<LoyaltyCardObject>();
String url = ServerURL.CARD_GET;
AlertDialog.Builder builder;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.loyaltycard_list_fragment, container, false);
RecyclerView recyclerView = (RecyclerView) rootView.findViewById(R.id.rv_cards);
recyclerView.setHasFixedSize(true);
adapter = new LoyaltyCardRVAdapter(getActivity(), cards);
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
llm.setOrientation(LinearLayoutManager.VERTICAL);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(llm);
recyclerView.setAdapter(adapter);
addCards = (TextView) rootView.findViewById(R.id.addCards);
adapter.setData(cards);
dialog = new ProgressDialog(getActivity());
dialog.setMessage("Chargement");
dialog.setCancelable(true);
showDialog();
addCards.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
builder = new AlertDialog.Builder(getActivity());
builder.setTitle("Ajout de carte");
builder.setMessage("Comment ajouter ?");
builder.setPositiveButton("Scanner", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
Log.i("Alert", "YES");
Intent intent = new Intent(getActivity(), LoyaltyCardAddWithScannerActivity.class);
startActivity(intent);
}
});
builder.setNegativeButton("Manuel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
Log.i("Alert", "NO");
startActivity(new Intent(getActivity(), LoyaltyCardAddActivity.class));
}
});
AlertDialog alertDialog = builder.create();
alertDialog.show();
}
});
getAndInitData();
return rootView;
}
public void getAndInitData() { //Recupère les cartes de l'utilisateur et les affiches dans un recycler view sous forme de cardview
userSharedPreferences = new UserSharedPreferences(getActivity());
final UserObject user = userSharedPreferences.getLoggedInUser();
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Request.Method.GET, url + user.mail,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
try {
for (int i = 0; i < response.length(); i++) {
JSONObject object = response.getJSONObject(i);
LoyaltyCardObject card = new LoyaltyCardObject();
card.setMail(object.getString("mail"));
card.setMarque(object.getString("marque"));
card.setCode(object.getString("code"));
cards.add(card);
}
hideDialog();
adapter.notifyDataSetChanged();
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
View view = getView();
LinearLayout ll = (LinearLayout) view.findViewById(R.id.cardlist);
Log.d("ERROR!!!", error.toString());
hideDialog();
Snackbar snackbar = Snackbar //Si l'utilisateur n'a pas de carte de fidelite, affiche un snackbar qui propose d'ajouter une carte
.make(ll, "Aucune carte", Snackbar.LENGTH_LONG)
.setAction("Ajouter", new View.OnClickListener() {
@Override
public void onClick(View view) {
builder = new AlertDialog.Builder(getActivity());
builder.setTitle("Ajout de carte");
builder.setMessage("Comment ajouter ?");
builder.setPositiveButton("Scanner", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
Log.i("Alert", "YES");
Intent intent = new Intent(getActivity(), LoyaltyCardAddWithScannerActivity.class);
startActivity(intent);
}
});
builder.setNegativeButton("Manuel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
Log.i("Alert", "NO");
startActivity(new Intent(getActivity(), LoyaltyCardAddActivity.class));
}
});
AlertDialog alertDialog = builder.create();
alertDialog.show();
}
});
snackbar.show();
}
});
AppController.getInstance().getRequestQueue().add(jsonArrayRequest);
}
public void showDialog() {
if (!dialog.isShowing())
dialog.show();
}
public void hideDialog() {
if (dialog.isShowing())
dialog.hide();
}
@Override
public void onDestroyView() {
super.onDestroyView();
dialog.hide();
dialog.dismiss();
}
}
当包含适配器的数据发生更改时，可以调用一个方法。例如：
- 创建您的ListView、RecyclerView
- 创建适配器
- 将适配器设置为ListView
- 做这项工作（更改数据、删除数据，等等…）
现在，如果您想刷新链接到适配器的视图中的实际信息，请调用方法：
adapter.notifyDataSetChanged();
这将使用正确和最新的信息更新您的视图信息。
希望它能有所帮助
从RecyclerView 中删除项目有4个步骤
list.remove(position);
recycler.removeViewAt(position);
mAdapter.notifyItemRemoved(position);
mAdapter.notifyItemRangeChanged(position, list.size());
您必须在活动/片段代码中执行此操作。