未加载片段中的RecyclerView

Question

Tl:dr：我创建了自己的底部导航栏，它重定向到3个不同的片段。1个片段(Trips(有一个回收视图，我在其中显示3个信息(ImageView，2个TextViews(。这个回收视图没有加载(没有错误消息(，该片段上有一个空白屏幕。我怀疑问题在于我从Fragment Java类加载回收器的方式，但没有成功(通过了多个YT教程和我能找到的stackoverflow文章(

我尝试过的一些步骤(我对Android相对陌生，所以尝试过不同的场景(-清洁项目-检查@override(其他stackoverflow文章(-在片段中：将我的代码拆分为2:OncreateView(我在其中展开布局(和OnViewCreated(我在那里加载适配器(。-另一个片段(带有硬编码文本(起作用，这表明片段管理器似乎起的作用

谢谢你的任何建议

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片段

package com.example.projectapp;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.ListAdapter;
import androidx.recyclerview.widget.RecyclerView;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class Trip extends Fragment {

private RecyclerView.Adapter adapter;
private RecyclerView recyclerView;
private RecyclerView.LayoutManager layoutManager;

@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_trips, container, false);
RecyclerView recyclerView= (RecyclerView) v.findViewById(R.id.recycler);
adapter listAdapter= new adapter();
recyclerView.setAdapter(listAdapter);
RecyclerView.LayoutManager layoutManager= new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(layoutManager);
return v;
}}


---------------------------------------------------------
Adapter class
---------------------------------------------------------

package com.example.projectapp;
import android.provider.ContactsContract;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class adapter extends RecyclerView.Adapter<adapter.adapterview> {
public class adapterview extends RecyclerView.ViewHolder{
public LinearLayout linearLayout;
public ImageView imageView;
public TextView title;
public TextView short_desc;

public adapterview(@NonNull View itemView) {
super(itemView);
linearLayout=itemView.findViewById(R.id.card);
imageView=itemView.findViewById(R.id.pix);
title=itemView.findViewById(R.id.titlecard);
short_desc=itemView.findViewById(R.id.short_desc);
}

}
public List<card> item_list= Arrays.asList(
new card(R.drawable.ic_home,"this is a test","testing 2"),
new card(R.drawable.ic_home,"this is a test1","testing 3"),
new card(R.drawable.ic_home,"this is a test2","testing 4")
);
@NonNull
@Override
public adapterview onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View v= LayoutInflater.from(parent.getContext()).inflate(R.layout.card,parent,false);
return new adapterview(v);
}
@Override
public void onBindViewHolder(@NonNull adapterview holder, int position) {
card current= item_list.get(position);
holder.title.setText(current.getTitle());
holder.short_desc.setText(current.getDesc());
holder.imageView.setImageResource(current.getimage());
}
@Override
public int getItemCount() {
return item_list.size();
}
}

Answer 1

不要在onCreateView上调用回收器，而是在onViewCreated中调用。

@Override
public View onViewCreated(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
RecyclerView recyclerView= (RecyclerView) v.findViewById(R.id.recycler);
adapter listAdapter= new adapter();
recyclerView.setAdapter(listAdapter);
RecyclerView.LayoutManager layoutManager= new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(layoutManager);
}
}

Answer 2

只需在设置LayoutManager之后设置RecyclerView适配器。因此，将行重新排序为：

RecyclerView recyclerView = (RecyclerView) v.findViewById(R.id.recycler);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(layoutManager);   
adapter listAdapter= new adapter();
recyclerView.setAdapter(listAdapter);

Answer 3

好消息是我解决了这个问题(但不确定根本原因(。我基本上做了两个改变，以防这对其他人有所帮助：1.我(在片段文件中(向适配器传递了一个对象和上下文的列表。2.我从布局中删除了1个文本视图(回收器视图中的项目(，这可能会阻止它加载(？(

现在，下一个挑战是尝试使用卡片视图，因为这种线性布局并不好感谢所有