我是這方面的絕對初學者，如果這是一個愚蠢的錯誤，我很抱歉。所以，我創建了我有recyclerView的片段，但是我的回收器視圖是空的，我看到我的背景關系是空的，我認為這可能是這個原因，我嘗試使用getActivity
這是我的片段的代碼
package com.example.pocketcinema;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.QueryDocumentSnapshot;
import com.google.firebase.firestore.QuerySnapshot;
import java.util.ArrayList;
import java.util.List;
public class SearchFragment extends Fragment implements RecyclerViewInterface {
private RecyclerView recyclerView;
RecyclerViewInterface rci;
MyAdapter myAdapter;
public List<String> nameOfFilm, youTubeUrl, photoUrl, descriptionToFilm, category;
FirebaseFirestore db = FirebaseFirestore.getInstance();
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
recyclerView = inflater.inflate(R.layout.fragment_search, container,
false).findViewById(R.id.filmsList);
rci = this;
nameOfFilm = new ArrayList<>();
youTubeUrl = new ArrayList<>();
photoUrl = new ArrayList<>();
descriptionToFilm = new ArrayList<>();
category = new ArrayList<>();
loadFilmsFromDB();
return inflater.inflate(R.layout.fragment_search, container, false);
}
private void loadFilmsFromDB() {
Context context = requireContext();
db.collection("films").get().addOnCompleteListener(new
OnCompleteListener<QuerySnapshot>()
{
@Override
public void onComplete(@NonNull Task<QuerySnapshot> task) {
for (QueryDocumentSnapshot document : task.getResult()) {
nameOfFilm.add(document.get("nameOfFilm").toString());
descriptionToFilm.add(document.get("descriptionToFilm").toString());
photoUrl.add(document.get("imageUrl").toString());
youTubeUrl.add(document.get("videoURL").toString());
category.add(document.get("category").toString());
myAdapter = new MyAdapter(context, nameOfFilm, descriptionToFilm,
photoUrl, youTubeUrl,
rci, category);
recyclerView.setAdapter(myAdapter);
recyclerView.setLayoutManager(new LinearLayoutManager(context));
}
}
});
}
這是帶有除錯器的螢屏截圖，您可以看到 context = null
背景關系 = 空
在這里你可以看到我 用 logcat為 recyclerView 設定了布局
這是配接器
package com.example.pocketcinema;
import android.content.Context;
import android.content.Intent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.cardview.widget.CardView;
import androidx.recyclerview.widget.RecyclerView;
import com.squareup.picasso.Picasso;
import java.util.List;
public class MyAdapter extends
RecyclerView.Adapter<MyAdapter.MyViewHolder> {
Context ct;
List<String> name, description, image, video, category;
private final RecyclerViewInterface recyclerViewInterface;
public MyAdapter(Context ct, List<String> nameOfFilm, List<String>
descriptionOfFilm, List<String> imageUrl, List<String> videoUrl,
RecyclerViewInterface rci,List<String> category) {
name = nameOfFilm;
description = descriptionOfFilm;
image = imageUrl;
video = videoUrl;
this.ct = ct;
recyclerViewInterface = rci;
this.category = category;
}
@NonNull
@Override
public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int
viewType) {
LayoutInflater inflater = LayoutInflater.from(ct);
View view = inflater.inflate(R.layout.my_row, parent, false);
return new MyViewHolder(view, recyclerViewInterface);
}
@Override
public void onBindViewHolder(@NonNull MyViewHolder holder, int
position) {
holder.nameFilm.setText(name.get(position));
holder.cardView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(ct, PlayerActivity.class);
}
});
Picasso.get().load(image.get(position)).into(holder.image2);
}
@Override
public int getItemCount() {
return image.size();
}
public static class MyViewHolder extends RecyclerView.ViewHolder {
TextView nameFilm;
ImageView image2;
CardView cardView;
public MyViewHolder(@NonNull View itemView, RecyclerViewInterface
recyclerViewInterface) {
super(itemView);
nameFilm = itemView.findViewById(R.id.nameTV);
image2 = itemView.findViewById(R.id.imageView2);
cardView = itemView.findViewById(R.id.cardView);
itemView.findViewById(R.id.sectionOFRecyclerView).setOnClickListener
(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (recyclerViewInterface != null) {
int pos = getAdapterPosition();
if (pos != RecyclerView.NO_POSITION) {
recyclerViewInterface.onItemClick(pos);
}
}
}
});
}
}
}
myAdapter 不為空
uj5u.com熱心網友回復：
您正在嘗試創建一個活動實體作為全域變數。這意味著尚未生成背景關系。
基本上你可以只使用requireContext()Fragment 類的方法。這將為您提供背景關系。
正如我在評論中提到的，您需要更新您的onCreateView方法，如下所示：
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_search, container, false);
}
然后，您需要在onViewCreated方法上初始化您的視圖和其他內容。您可以像這樣更新該方法：
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
recyclerView = view.findViewById(R.id.filmsList);
textView = view.findViewById(R.id.test);
rci = this;
nameOfFilm = new ArrayList<>();
youTubeUrl = new ArrayList<>();
photoUrl = new ArrayList<>();
descriptionToFilm = new ArrayList<>();
category = new ArrayList<>();
loadFilmsFromDB();
}
筆記
- 您不必向配接器發送許多字串引數。最好為該專案創建一個模型類，并發送該專案的串列。因此，模型類將擁有您需要的所有資料，您可以從該模型中使用它們。這將為您提供更好的編碼風格，并讓您更輕松地管理資料。
- 要與您的 XML 布局進行通信，您可以為此使用ViewBinding或DataBinding。這也將幫助您使用視圖元素，而無需為每個元素創建變數。
轉載請註明出處，本文鏈接：https://www.uj5u.com/qiye/493041.html