Question

我刚开始使用Android，但遇到了问题。我有Recycler View的训练列表，在此视图中，我想制作无论滚动如何都位于静态位置的标题。但是，在recycler view上方的线性布局中，标题或文本视图不可见。我不知道如何解决我的问题，有人有任何解决方案或想法吗？下面，我介绍代码的各个元素。

我的回收者视图：

 <android.support.v7.widget.RecyclerView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/training_recycler"
    android:scrollbars="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />

我的示例线性布局

<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:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    tools:context=".TrainingFragment">


    <TextView
        android:id="@+id/anything"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="40sp"
        android:text="@string/monia"/>

</LinearLayout>

在RecyclerView内部，我具有卡片视图，看起来像：

<android.support.v7.widget.CardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:id="@+id/card_view"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:layout_margin="15dp"
    card_view:cardCornerRadius="10dp">


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical">

        <TextView
            android:id="@+id/info_text"
            android:layout_marginLeft="15dp"
            android:layout_marginBottom="15dp"
            android:layout_height="wrap_content"
            android:layout_width="match_parent"
            android:textSize="20sp"/>
    </LinearLayout>

</android.support.v7.widget.CardView>

当我看设计窗口时，我看到带有文本的textView，但是当我打开模拟器时，TextView没有显示。

谢谢您的建议。

编辑：

TrainingMaterialFragment.java

public class TrainingMaterialFragment extends Fragment {

    RecyclerView trainingRecycler;
    public TrainingMaterialFragment() {
        // Required empty public constructor
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        RecyclerView trainingRecycler = (RecyclerView)inflater.inflate(
                R.layout.fragment_training_material, container, false);
        int userNo = 1;

        String[] nameArray = new String[0];
        int[] idArray= new int[0];
        try {

            SQLiteOpenHelper myFitnessAppDatabaseHelper = new MyFitnessAppDatabaseHelper(inflater.getContext());
            View view = inflater.inflate(R.layout.fragment_training, container, false);

            SQLiteDatabase db = myFitnessAppDatabaseHelper.getReadableDatabase();

            Cursor cursor = db.query("TRAINING_DIARY",
                    new String[]{"TRAINING_NAME", "DATE",
                            "DISTANCE","_id"},
                    "USER = ?",
                    new String[]{Integer.toString(userNo)},
                    null, null, null);
            int count = cursor.getCount();
            nameArray = new String[count];
            idArray=new int[count];

            if (cursor.moveToFirst()) {

                String nameText = cursor.getString(0);
                TextView name = (TextView) view.findViewById(R.id.training_name);
                name.setText(nameText);
                nameArray[0] = nameText;
                idArray[0]=cursor.getInt(3);

                int i = 1;
                while(i < count) {
                    cursor.moveToNext();

                    nameText = cursor.getString(0);
                    nameArray[i] = nameText;
                    idArray[i]=cursor.getInt(3);
                    i++;

                }
            }
            cursor.close();
            db.close();
        } catch (SQLiteException e) {
            Toast toast = Toast.makeText(inflater.getContext(), "Baza danych jest niedostępna", Toast.LENGTH_SHORT);
            toast.show();
        }

        TrainingAdapter adapter =
                new TrainingAdapter(nameArray);
        trainingRecycler.setAdapter(adapter);
        LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
        trainingRecycler.setLayoutManager(layoutManager);


        adapter.setListener(new TrainingAdapter.Listener() {
            public void onClick(int position) {

                Intent intent = new Intent(getActivity(), TrainingDetailActivity.class);
                intent.putExtra(TrainingDetailActivity.EXTRA_TRAINING, position);

                getActivity().startActivity(intent);
            }
        });
        return trainingRecycler;           
    }
}

适配器

public class TrainingAdapter extends RecyclerView.Adapter<TrainingAdapter.ViewHolder> {

    private String[] captions;
    private Listener listener;

    public TrainingAdapter(String[] captions){
        this.captions = captions;
    }

    public static class ViewHolder extends RecyclerView.ViewHolder {
        private CardView cardView;
        public ViewHolder(CardView v) {
            super(v);
            cardView = v;
        }
    }
    @Override
    public TrainingAdapter.ViewHolder onCreateViewHolder(
            ViewGroup parent, int viewType){    
        CardView cv = (CardView) LayoutInflater.from(parent.getContext())
                .inflate(R.layout.training_card_view, parent, false);
        return new ViewHolder(cv);
    }
    @Override
    public void onBindViewHolder(ViewHolder holder, final int position){
        CardView cardView = holder.cardView;

        TextView textView = (TextView)cardView.findViewById(R.id.info_text);
        textView.setText(captions[position]);


        cardView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (listener != null) {
                    listener.onClick(position);
                }
            }
        });     
    }

    @Override
    public int getItemCount(){
        return captions.length;
    }

    public static interface Listener {
        public void onClick(int position);
    }

    public void setListener(Listener listener) {
        this.listener = listener;
    }
}

Answer 1

尝试这种方式。

正如您所说的LinearLayout in fragment_training.xml，所以将recylerview放在linearlayout内。

您的fragment_training.xml代码如下所示

<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:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
tools:context=".TrainingFragment">


<TextView
android:id="@+id/anything"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="40sp"
android:text="@string/monia"/>

<android.support.v7.widget.RecyclerView
android:id="@+id/training_recycler"
android:scrollbars="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content" />

<LinearLayout/>

然后最终在Java类中进行了更改。

更改此行

 RecyclerView trainingRecycler = (RecyclerView)inflater.inflate(
            R.layout.fragment_training_material, container, false);

收件人

View rootview = inflater.inflate(
            R.layout.fragment_training, container, false);
.....
..... 

return rootview;

然后您可以使用rootview找到recylerview。

trainingRecycler = rootview.findViewById(R.id.training_recycler);

并确保已添加返回rootview。.

您的OnCreateView方法如下所示

 @Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
View rootview = inflater.inflate(
            R.layout.fragment_training, container, false);
trainingRecycler = rootview.findViewById(R.id.findViewById);
.....
...
..
return rootview;

Answer 2

如果我错了，请纠正我，但是您没有将Recycler放在LinearLayout中。您的LinearLayout应该看起来像这样，然后您将能够得到想要的东西：

<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:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
tools:context=".TrainingFragment">


<TextView
    android:id="@+id/anything"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textSize="40sp"
    android:text="@string/monia"/>
<android.support.v7.widget.RecyclerView

    android:id="@+id/training_recycler"
    android:scrollbars="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />
<LinearLayout/>

Answer 3

我在这个项目中做了同样的事情。这是指向XML文件的链接 https://github.com/ShowYoungg/JournalApp/blob/master/app/src/main/res/layout/activity_main.xml。以及指向Java文件的链接； https://github.com/ShowYoungg/JournalApp/blob/master/app/src/main/java/com/example/android/journalapp/MainActivity.java。您可以下载整个应用程序并运行，看看我不仅在TcyclView上放了TexView，还放了按钮和其他按钮

TextView不会在带有RecycleView的LinearLayout中显示

3 个答案: