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Java 碎片不是'；t显示RecyclerView或任何元素

java xml android-studio android-fragments

Java 碎片不是'；t显示RecyclerView或任何元素,java,xml,android-studio,android-fragments,android-recyclerview,Java,Xml,Android Studio,Android Fragments,Android Recyclerview,我试着在我的屏幕上显示两个片段，目前只有一个片段出现，它是垂直的，而不是水平的，我认为这是因为我的第二个片段没有出现。 正在讨论的不起作用的片段是我的MapFragment public class MapFragment extends Fragment { //Private Classfields private MapData map; private MyAdapter adapter; @Override public View onCre

我试着在我的屏幕上显示两个片段，目前只有一个片段出现，它是垂直的，而不是水平的，我认为这是因为我的第二个片段没有出现。 正在讨论的不起作用的片段是我的MapFragment

public class MapFragment extends Fragment {

    //Private Classfields
    private MapData map;
    private MyAdapter adapter;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup ui, Bundle bundle)
    {
        //Takes a layout reference, instantiates all View objects.
        //Reads the XML and creates the UI Based on it.
        //Returns the root View object.
        View view = inflater.inflate(R.layout.fragment_map, ui, false);

        //Setup any event handlers below.

        //Setting up RecyclerView
        RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.mapRecyclerView);

        //Specify how it should be laid out.
        recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), MapData.HEIGHT, GridLayoutManager.HORIZONTAL, false));

        //Have your data ready.
        map = MapData.getInstance();

        //Create your adapter
        adapter = new MyAdapter(map);

        //Attach Adapter to Recycler View.
        recyclerView.setAdapter(adapter);

        return view;
    }


    //Nested ViewHolder inside Fragment
    private class MyDataVHolder extends RecyclerView.ViewHolder
    {
        private ImageView topLeftImageView, topRightImageView, bottomLeftImageView, bottomRightImageView, mainImageView;

        public MyDataVHolder(LayoutInflater li, ViewGroup parent)
        {
            super(li.inflate(R.layout.grid_cell, parent, false));
            //Divide the RecyclerViews runtime height by the number of cells
            //that must fit in that space(MapData.HEIGHT)
            //Add 1 to account for rounding errors that might leave a 1 pixel gap.
            //Size value becomes the width and the height of the grid cell.
            int size = parent.getMeasuredHeight()/MapData.HEIGHT + 1;
            ViewGroup.LayoutParams lp = itemView.getLayoutParams();
            lp.width = size;
            lp.height = size;
            //Grab UI Elements
            //textView = (TextView) itemView.findViewById(R.id.list_data);
            topLeftImageView = (ImageView) itemView.findViewById(R.id.topLeftImageView);
            topRightImageView = (ImageView) itemView.findViewById(R.id.topRightImageView);
            bottomLeftImageView = (ImageView) itemView.findViewById(R.id.bottomLeftImageView);
            bottomRightImageView = (ImageView) itemView.findViewById(R.id.bottomRightImageView);
            mainImageView = (ImageView) itemView.findViewById(R.id.mainImageView);

        }

        public void bind(MapElement mapElement)
        {
            //Set the image views.
            //ImageView iv = ...;
            //MapElement me = ...;
            //iv.setImageResource(me.getNorthWest());
            if (mapElement ==  null)
            {
                System.out.println("Map Element is null.");
            }
            else
            {
                System.out.println("Map Element is not null.");
            }
            topLeftImageView.setImageResource(mapElement.getNorthWest());
            topRightImageView.setImageResource(mapElement.getNorthEast());
            bottomLeftImageView.setImageResource(mapElement.getSouthWest());
            bottomRightImageView.setImageResource(mapElement.getSouthEast());
            if (mapElement.getStructure() != null)
            {
                mainImageView.setImageResource(mapElement.getStructure().getDrawableId());
            }
        }
    }

    private class MyAdapter extends RecyclerView.Adapter<MyDataVHolder>
    {
        private MapData map;

        public MyAdapter(MapData inMap)
        {
            map = inMap;
        }

        @NonNull
        @Override
        public MyDataVHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            LayoutInflater li = LayoutInflater.from(getActivity()); //Fragment Method

            return new MyDataVHolder(li, parent);
        }

        @Override
        public void onBindViewHolder(@NonNull MyDataVHolder holder, int position) {
            int row = position % MapData.HEIGHT;
            int column = position / MapData.HEIGHT;

            MapElement currentMapElement = map.get(row, column);
            holder.bind(currentMapElement);
        }

        @Override
        public int getItemCount() {
            return map.HEIGHT * map.WIDTH;
        }
    }

    private void updateUI(int pos)
    {
        adapter.notifyItemChanged(pos);
    }
}
首先，我将显示提交事务的代码

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        FragmentManager fragmentManager = getSupportFragmentManager();
        MapFragment mapFrag = (MapFragment) fragmentManager.findFragmentById(R.id.map);
        SelectorFragment selectorFrag = (SelectorFragment) fragmentManager.findFragmentById(R.id.selector);

        if (mapFrag == null)
        {
            //Create the Fragment Object
            mapFrag = new MapFragment();
            //Queues the operation to attach a Fragment
            //Tells it where to add and what to add.
            //Commit makes it happen
            fragmentManager.beginTransaction().add(R.id.map, mapFrag).commit();
        }

        if (selectorFrag == null)
        {
            //Create the Fragment Object
            selectorFrag = new SelectorFragment();
            //Queues the operation to attach a Fragment
            //Tells it where to add and what to add.
            //Commit makes it happen
            fragmentManager.beginTransaction().add(R.id.selector, selectorFrag).commit();
        }

    }
}
因此，选择器片段显示良好，除了垂直

现在我将发布与上述活动相关的主要xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    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="match_parent"
    tools:context=".MainActivity">
    <FrameLayout
        android:id="@+id/map"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toTopOf="@id/selector"
        />

    <FrameLayout
        android:id="@+id/selector"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="parent" 
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@id/map"
        app:layout_constraintBottom_toBottomOf="parent"
        />
</androidx.constraintlayout.widget.ConstraintLayout>
因此，地图应该限制在顶部，占据屏幕的3/4

现在，我将显示映射片段代码，后跟映射片段的xml

public class MapFragment extends Fragment {

    //Private Classfields
    private MapData map;
    private MyAdapter adapter;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup ui, Bundle bundle)
    {
        //Takes a layout reference, instantiates all View objects.
        //Reads the XML and creates the UI Based on it.
        //Returns the root View object.
        View view = inflater.inflate(R.layout.fragment_map, ui, false);

        //Setup any event handlers below.

        //Setting up RecyclerView
        RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.mapRecyclerView);

        //Specify how it should be laid out.
        recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), MapData.HEIGHT, GridLayoutManager.HORIZONTAL, false));

        //Have your data ready.
        map = MapData.getInstance();

        //Create your adapter
        adapter = new MyAdapter(map);

        //Attach Adapter to Recycler View.
        recyclerView.setAdapter(adapter);

        return view;
    }


    //Nested ViewHolder inside Fragment
    private class MyDataVHolder extends RecyclerView.ViewHolder
    {
        private ImageView topLeftImageView, topRightImageView, bottomLeftImageView, bottomRightImageView, mainImageView;

        public MyDataVHolder(LayoutInflater li, ViewGroup parent)
        {
            super(li.inflate(R.layout.grid_cell, parent, false));
            //Divide the RecyclerViews runtime height by the number of cells
            //that must fit in that space(MapData.HEIGHT)
            //Add 1 to account for rounding errors that might leave a 1 pixel gap.
            //Size value becomes the width and the height of the grid cell.
            int size = parent.getMeasuredHeight()/MapData.HEIGHT + 1;
            ViewGroup.LayoutParams lp = itemView.getLayoutParams();
            lp.width = size;
            lp.height = size;
            //Grab UI Elements
            //textView = (TextView) itemView.findViewById(R.id.list_data);
            topLeftImageView = (ImageView) itemView.findViewById(R.id.topLeftImageView);
            topRightImageView = (ImageView) itemView.findViewById(R.id.topRightImageView);
            bottomLeftImageView = (ImageView) itemView.findViewById(R.id.bottomLeftImageView);
            bottomRightImageView = (ImageView) itemView.findViewById(R.id.bottomRightImageView);
            mainImageView = (ImageView) itemView.findViewById(R.id.mainImageView);

        }

        public void bind(MapElement mapElement)
        {
            //Set the image views.
            //ImageView iv = ...;
            //MapElement me = ...;
            //iv.setImageResource(me.getNorthWest());
            if (mapElement ==  null)
            {
                System.out.println("Map Element is null.");
            }
            else
            {
                System.out.println("Map Element is not null.");
            }
            topLeftImageView.setImageResource(mapElement.getNorthWest());
            topRightImageView.setImageResource(mapElement.getNorthEast());
            bottomLeftImageView.setImageResource(mapElement.getSouthWest());
            bottomRightImageView.setImageResource(mapElement.getSouthEast());
            if (mapElement.getStructure() != null)
            {
                mainImageView.setImageResource(mapElement.getStructure().getDrawableId());
            }
        }
    }

    private class MyAdapter extends RecyclerView.Adapter<MyDataVHolder>
    {
        private MapData map;

        public MyAdapter(MapData inMap)
        {
            map = inMap;
        }

        @NonNull
        @Override
        public MyDataVHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            LayoutInflater li = LayoutInflater.from(getActivity()); //Fragment Method

            return new MyDataVHolder(li, parent);
        }

        @Override
        public void onBindViewHolder(@NonNull MyDataVHolder holder, int position) {
            int row = position % MapData.HEIGHT;
            int column = position / MapData.HEIGHT;

            MapElement currentMapElement = map.get(row, column);
            holder.bind(currentMapElement);
        }

        @Override
        public int getItemCount() {
            return map.HEIGHT * map.WIDTH;
        }
    }

    private void updateUI(int pos)
    {
        adapter.notifyItemChanged(pos);
    }
}


公共类MapFragment扩展了片段{
//私有类字段
私有地图数据地图；
专用MyAdapter适配器；
@凌驾
创建视图上的公共视图（布局、充气机、视图组用户界面、捆绑包）
{
//获取布局引用，实例化所有视图对象。
//读取XML并基于它创建UI。
//返回根视图对象。
视图=充气机。充气（R.layout.fragment\u map，ui，false）；
//在下面设置任何事件处理程序。
//设置RecyclerView
RecycleView RecycleView=（RecycleView）view.findViewById（R.id.MapRecycleView）；
//指定其布局方式。
setLayoutManager（新的GridLayoutManager（getActivity（），MapData.HEIGHT，GridLayoutManager.HORIZONTAL，false））；
//准备好你的数据。
map=MapData.getInstance（）；
//创建适配器
适配器=新的MyAdapter（映射）；
//将适配器连接到回收器视图。
recyclerView.setAdapter（适配器）；
返回视图；
}
//片段内部嵌套的ViewHolder
私有类MyDataVHolder扩展了RecyclerView.ViewHolder
{
private ImageView topLeftImageView、topRightImageView、bottomLeftImageView、bottomRightImageView、mainImageView；
公共MyDataVHolder（Layoutiner li，视图组父级）
{
super（li.inflate（R.layout.grid_单元格，父单元格，false））；
//将RecyclerViews运行时高度除以单元格数
//必须适合该空间（MapData.HEIGHT）
//添加1以说明舍入误差可能会留下1像素的间距。
//“大小”值将成为栅格单元的宽度和高度。
int size=parent.getMeasuredHeight（）/MapData.HEIGHT+1；
ViewGroup.LayoutParams lp=itemView.getLayoutParams（）；
lp.宽度=尺寸；
lp.高度=尺寸；
//抓取UI元素
//textView=（textView）itemView.findViewById（R.id.list\u数据）；
topLeftImageView=（ImageView）itemView.findViewById（R.id.topLeftImageView）；
topRightImageView=（ImageView）itemView.findViewById（R.id.topRightImageView）；
bottomLeftImageView=（ImageView）itemView.findViewById（R.id.bottomLeftImageView）；
bottomRightImageView=（ImageView）itemView.findViewById（R.id.bottomRightImageView）；
mainImageView=（ImageView）itemView.findViewById（R.id.mainImageView）；
}
公共void绑定（MapElement MapElement）
{
//设置图像视图。
//ImageView iv=。。。；
//MapElement me=。。。；
//iv.setImageResource（me.getNorthWest（））；
如果（mapElement==null）
{
System.out.println（“Map元素为null”）；
}
其他的
{
System.out.println（“映射元素不为null”）；
}
setImageResource（mapElement.getNorthWest（））；
setImageResource（mapElement.getNorthEast（））；
setImageResource（mapElement.getSouthWest（））；
bottomRightImageView.setImageResource（mapElement.getSouthwest（））；
if（mapElement.getStructure（）！=null）
{
mainImageView.setImageResource（mapElement.getStructure（）.getDrawableId（））；
}
}
}
私有类MyAdapter扩展了RecyclerView.Adapter
{
私有地图数据地图；
公共MyAdapter（MapData inMap）
{
map=inMap；
}
@非空
@凌驾
公共MyDataVHolder onCreateViewHolder（@NonNull ViewGroup父级，int-viewType）{
LayoutInflater li=LayoutInflater.from（getActivity（））；//片段方法
返回新的MyDataVHolder（li，父级）；
}
@凌驾
public void onBindViewHolder（@NonNull MyDataVHolder，int位置）{
int row=位置%MapData.HEIGHT；
int column=位置/MapData.HEIGHT；
MapElement currentMapElement=map.get（行、列）；
holder.bind（currentMapElement）；
}
@凌驾
public int getItemCount（）{
返回map.HEIGHT*map.WIDTH；
}
}
私有无效更新（int pos）
{
适配器已更改（pos）；
}
}
不，这是包含单个RecyclerView的映射XML

<?xml version="1.0" encoding="utf-8"?>
<androidx.recyclerview.widget.RecyclerView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/mapRecyclerView"
    />
下面是片段膨胀的网格单元xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <ImageView
        android:id="@+id/topLeftImageView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:src="@android:color/transparent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintRight_toLeftOf="@id/topRightImageView"
        app:layout_constraintBottom_toTopOf="@id/bottomLeftImageView"
        app:layout_constraintWidth_default="percent"
        app:layout_constraintHeight_default="percent"
        app:layout_constraintWidth_percent="0.5"
        app:layout_constraintHeight_percent="0.5"
        />

    <ImageView
        android:id="@+id/topRightImageView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:src="@android:color/transparent"
        app:layout_constraintLeft_toRightOf="@id/topLeftImageView"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toTopOf="@id/bottomRightImageView"
        app:layout_constraintWidth_default="percent"
        app:layout_constraintHeight_default="percent"
        app:layout_constraintWidth_percent="0.5"
        app:layout_constraintHeight_percent="0.5"
        />

    <ImageView
        android:id="@+id/bottomLeftImageView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:src="@android:color/transparent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toBottomOf="@id/topLeftImageView"
        app:layout_constraintRight_toLeftOf="@id/bottomRightImageView"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintWidth_default="percent"
        app:layout_constraintHeight_default="percent"
        app:layout_constraintWidth_percent="0.5"
        app:layout_constraintHeight_percent="0.5"
        />

    <ImageView
        android:id="@+id/bottomRightImageView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:src="@android:color/transparent"
        app:layout_constraintLeft_toRightOf="@id/bottomLeftImageView"
        app:layout_constraintTop_toBottomOf="@id/topRightImageView"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintWidth_default="percent"
        app:layout_constraintHeight_default="percent"
        app:layout_constraintWidth_percent="0.5"
        app:layout_constraintHeight_percent="0.5"
        />

    <ImageView
        android:id="@+id/mainImageView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:src="@android:color/transparent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        />

</androidx.constraintlayout.widget.ConstraintLayout>
我不知道为什么这不起作用，猜测这一定是我和我的同龄人所缺少的东西

干杯，如果有任何其他代码，你想为上下文我会挂在周围

提前谢谢你的帮助