在 Fragment 中实现 RecyclerView

Question

我试图在 AppCompatActivity 的 ViewPager 中的 Fragment 中创建 ListView。在 AppCompatActivity 中，所有视图元素都包裹在 CoordinatorLayout 中。因为我使用了 CoordinatorLayout。我必须使用 RecylerView 我正在尝试从 developer.android.com，但我的应用程序在我的日志后停止了。这是我在 myFragment 中应用程序停止的代码。

import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

//...

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_city_list, container, false)

    mRecyclerView = (RecyclerView) view.findViewById(android.R.id.list);
    mLayoutManager = new LinearLayoutManager(this.getActivity());
    Log.d("debugMode", "The application stopped after this");
    mRecyclerView.setLayoutManager(mLayoutManager);

    mAdapter = new RecyclerAdapter(getNames());
    mRecyclerView.setAdapter(mAdapter);
    return view;
}

//...

Answer 1

使用这个

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_city_list, container, false)

    // Replace 'android.R.id.list' with the 'id' of your RecyclerView
    mRecyclerView = (RecyclerView) view.findViewById(android.R.id.list);
    mLayoutManager = new LinearLayoutManager(this.getActivity());
    Log.d("debugMode", "The application stopped after this");
    mRecyclerView.setLayoutManager(mLayoutManager);

    mAdapter = new RecyclerAdapter(getNames());
    mRecyclerView.setAdapter(mAdapter);
    return view;
}

您应该在Recyclerview 上调用setLayoutManager 和setAdapter 方法（分别）。

另外，

mRecyclerView = (RecyclerView) view.findViewById(android.R.id.list);

你不应该使用android.R.id.list，因为你没有使用ListFragment。将其替换为 id 中的 Recyclerview（在您的 XML 布局中）。

Answer 2

您是否将 android.R.id.list 设置为 recyclerview id？否则你应该在 xml 文件中为 recyclerview 设置一个 id，像这样：

android:id="@+id/recyclerview"

并改变这一行

mRecyclerView = (RecyclerView) view.findViewById(android.R.id.list);

到

mRecyclerView = (RecyclerView) view.findViewById(R.id.recyclerview);

Answer 3

public class HomeFragment extends Fragment {

private HomeViewModel homeViewModel;

public View onCreateView(@NonNull LayoutInflater inflater,
                         ViewGroup container, Bundle savedInstanceState) {
    homeViewModel =
            ViewModelProviders.of(this).get(HomeViewModel.class);
    View root = inflater.inflate(R.layout.fragment_home, container, false);
    final TextView textView = root.findViewById(R.id.text_home);
    homeViewModel.getText().observe(this, new Observer<String>() {
        @Override
        public void onChanged(@Nullable String s) {
            textView.setText(s);
        }
    });
     FragmentActivity c = getActivity();
     RecyclerView recyclerView = root.findViewById(R.id.my_recycler_view);
    recyclerView.setLayoutManager(new GridLayoutManager(c, 2));

    List<VillageModel> villageModels=new ArrayList<>();
    VillageModel villageModel =new VillageModel("",0,0,0,0,0,0);
    villageModels.add(villageModel);
    VillageModel villageModel1 =new VillageModel("",0,0,0,0,0,0);
    VillageModel villageModel2 =new VillageModel("",0,0,0,0,0,0);
    villageModels.add(villageModel1);
    villageModels.add(villageModel2);
    VillageAdapter adapter = new VillageAdapter(c,villageModels);
    recyclerView.setAdapter(adapter);
    return root;
 }
}

将回收适配器添加到 oncreateView 片段主页xml结构

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/my_recycler_view"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:scrollbars="vertical"
    />
</RelativeLayout>