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android - 可扩展回收站视图不显示我的项目

问题描述

我想使用一个可扩展的Recyler，但是当我使用适配器时它不起作用。它没有给我任何错误或任何东西。只是没有出现在屏幕上

我有这个片段，我称之为 recyclerView

public class RecFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";

// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;

Button btaddrec;
Dialog alerta;
View v;
RecyclerView rvRec;

public RecFragment() {
    // Required empty public constructor
}

/**
 * Use this factory method to create a new instance of
 * this fragment using the provided parameters.
 *
 * @param param1 Parameter 1.
 * @param param2 Parameter 2.
 * @return A new instance of fragment RecFragment.
 */
// TODO: Rename and change types and number of parameters
public static RecFragment newInstance(String param1, String param2) {
    RecFragment fragment = new RecFragment();
    Bundle args = new Bundle();
    args.putString(ARG_PARAM1, param1);
    args.putString(ARG_PARAM2, param2);
    fragment.setArguments(args);
    return fragment;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (getArguments() != null) {
        mParam1 = getArguments().getString(ARG_PARAM1);
        mParam2 = getArguments().getString(ARG_PARAM2);
    }
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    v = inflater.inflate(R.layout.fragment_rec, container, false);
    rvRec = v.findViewById(R.id.recyclerviewRec);
    btaddrec = (Button) v.findViewById(R.id.btaddRec);
    initData();
    setRecycler();

    btaddrec.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Toast.makeText(getContext(), MainActivity.listarec.size() + "", Toast.LENGTH_SHORT).show();
        }
    });

    return v;
}

private void setRecycler(){
    RecyclerRec recyclerRec = new RecyclerRec(MainActivity.listarec);
    rvRec.setLayoutManager(new LinearLayoutManager(getActivity()));
    rvRec.setAdapter(recyclerRec);
    rvRec.setHasFixedSize(true);
}

private void initData(){
    MainActivity.listarec.add(new Recordatorio("Homework","Math and Science Homewowk","14:00"));
    MainActivity.listarec.add(new Recordatorio("Homework","Math and Science Homewowk","14:00"));

}

}

函数 initData 将一些对象添加到我的列表中（我已经检查过它是否适用于 Button，我的列表有 2 个项目） 函数 setRecycler 为 recyclerview 设置适配器

这是我的课 RecyclerRec

public class RecyclerRec extends RecyclerView.Adapter<RecyclerRec.RecVh>{
ArrayList<Recordatorio> listarec;

public RecyclerRec (ArrayList<Recordatorio> lista){
    this.listarec = lista;
}

@NonNull
@Override
public RecVh onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_rec_layout,parent,false);
    return new RecVh(v);
}

@Override
public void onBindViewHolder(@NonNull RecVh holder, int position) {
    Recordatorio rec = listarec.get(position);
    holder.tvTitulo.setText(rec.getTitulo());
    holder.tvCuerpo.setText(rec.getCuerpo());
    holder.tvHora.setText(rec.getHora());

    boolean expanded = rec.isExpanded();
    holder.expandable.setVisibility(expanded ? View.VISIBLE : View.GONE);

}

@Override
public int getItemCount() {
    return listarec.size();
}

public class RecVh extends RecyclerView.ViewHolder {
    TextView tvTitulo,tvCuerpo,tvHora;
    LinearLayout linearLayout;
    ConstraintLayout expandable;
    public RecVh(@NonNull View itemView) {
        super(itemView);
        tvTitulo = itemView.findViewById(R.id.tvTituloRec);
        tvCuerpo = itemView.findViewById(R.id.tvCuerpo);
        tvHora = itemView.findViewById(R.id.tvHoraRec);
        linearLayout = itemView.findViewById(R.id.linearlayotuexpand);
        expandable = itemView.findViewById(R.id.expandableRec);

        linearLayout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Recordatorio rec = listarec.get(getAdapterPosition());
                rec.setExpanded(!rec.isExpanded());
                notifyItemChanged(getAdapterPosition());
            }
        });
    }
}

}

片段的 XML

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".Fragments.ClasesFragment">


<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/recyclerviewRec"
    android:layout_width="match_parent"
    android:layout_height="451dp"
    android:layout_marginTop="50dp" />

<Button
    android:id="@+id/btaddRec"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="160dp"
    android:layout_marginTop="520dp"
    android:text="Añadir" />

（Framelayout标签正确关闭，不知道为什么stackoverflow没有用ctrl+k写）

我的项目/行的 XML

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="8dp">

<androidx.cardview.widget.CardView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="8dp">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        >

        <TextView
            android:id="@+id/tvTituloRec"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="?attr/selectableItemBackground"
            android:padding="10dp"
            android:text="Titulo Recordatorio"
            android:textAppearance="@style/TextAppearance.AppCompat.Medium"
            android:textColor="@android:color/black"
            android:textStyle="bold"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.0"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/tvHoraRec"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hora"
            android:textSize="17dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="1.0"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <androidx.constraintlayout.widget.ConstraintLayout
            android:id="@+id/expandableRec"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:visibility="visible"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.0"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@id/tvTituloRec">

            <TextView
                android:id="@+id/tvCuerpo"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginStart="8dp"
                android:layout_marginLeft="8dp"
                android:text="Cuerpo del recordatorio"
                android:textAppearance="@style/TextAppearance.AppCompat.Small"
                app:layout_constraintStart_toEndOf="@+id/textView"
                app:layout_constraintTop_toTopOf="parent" />

        </androidx.constraintlayout.widget.ConstraintLayout>

    </androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>

一切似乎都井井有条，但是当我运行该应用程序时，它没有出现，也没有给我任何错误。

标签： androidandroid-recyclerview

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