实现接入多个U盘，读取各个U盘图片，并按U盘名在recyclerView分组展示图片，点击U盘名可以隐藏折叠U盘内的图片代码实现

以下是代码实现：

首先，需要在 AndroidManifest.xml 文件中添加以下权限：

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

然后，在布局文件中添加一个 RecyclerView 和一个 TextView，用于展示 U 盘名和图片：

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/recyclerView"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

<TextView
    android:id="@+id/tv_empty"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:text="No images found"
    android:textSize="20sp"
    android:visibility="gone" />

接下来，需要编写一个类来表示 U 盘和其内的图片：

public class UsbItem {
    private String name;
    private List<String> images;

    public UsbItem(String name, List<String> images) {
        this.name = name;
        this.images = images;
    }

    public String getName() {
        return name;
    }

    public List<String> getImages() {
        return images;
    }
}

然后，需要编写一个 Adapter 来展示 U 盘和其内的图片：

public class UsbAdapter extends RecyclerView.Adapter<UsbAdapter.ViewHolder> {
    private List<UsbItem> items;

    public UsbAdapter(List<UsbItem> items) {
        this.items = items;
    }

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

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        UsbItem item = items.get(position);
        holder.tvName.setText(item.getName());
        holder.rvImages.setAdapter(new ImageAdapter(item.getImages()));
    }

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

    static class ViewHolder extends RecyclerView.ViewHolder {
        TextView tvName;
        RecyclerView rvImages;

        ViewHolder(@NonNull View itemView) {
            super(itemView);
            tvName = itemView.findViewById(R.id.tv_name);
            rvImages = itemView.findViewById(R.id.rv_images);
            rvImages.setLayoutManager(new GridLayoutManager(itemView.getContext(), 3));
        }
    }
}

其中，item_usb.xml 布局文件如下：

<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:padding="16dp">

        <TextView
            android:id="@+id/tv_name"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textSize="20sp" />

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/rv_images"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:visibility="gone" />

    </LinearLayout>

</androidx.cardview.widget.CardView>

接下来，需要编写一个 Adapter 来展示 U 盘内的图片：

public class ImageAdapter extends RecyclerView.Adapter<ImageAdapter.ViewHolder> {
    private List<String> images;

    public ImageAdapter(List<String> images) {
        this.images = images;
    }

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

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        String image = images.get(position);
        Glide.with(holder.itemView.getContext()).load(image).into(holder.ivImage);
    }

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

    static class ViewHolder extends RecyclerView.ViewHolder {
        ImageView ivImage;

        ViewHolder(@NonNull View itemView) {
            super(itemView);
            ivImage = itemView.findViewById(R.id.iv_image);
        }
    }
}

其中，item_image.xml 布局文件如下：

<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/iv_image"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:adjustViewBounds="true"
    android:scaleType="centerCrop" />

最后，在 MainActivity 中，需要获取 U 盘列表，并将其展示在 RecyclerView 中：

public class MainActivity extends AppCompatActivity {
    private RecyclerView recyclerView;
    private TextView tvEmpty;

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

        recyclerView = findViewById(R.id.recyclerView);
        tvEmpty = findViewById(R.id.tv_empty);

        List<UsbItem> items = getUsbItems();
        if (items.isEmpty()) {
            recyclerView.setVisibility(View.GONE);
            tvEmpty.setVisibility(View.VISIBLE);
        } else {
            recyclerView.setVisibility(View.VISIBLE);
            tvEmpty.setVisibility(View.GONE);
            recyclerView.setLayoutManager(new LinearLayoutManager(this));
            recyclerView.setAdapter(new UsbAdapter(items));
        }
    }

    private List<UsbItem> getUsbItems() {
        List<UsbItem> items = new ArrayList<>();
        File[] files = new File("/storage").listFiles();
        if (files != null) {
            for (File file : files) {
                if (file.isDirectory() && file.canRead() && !file.getAbsolutePath().startsWith("/storage/emulated/")) {
                    String name = file.getName();
                    List<String> images = new ArrayList<>();
                    File[] imageFiles = file.listFiles(new FileFilter() {
                        @Override
                        public boolean accept(File file) {
                            return file.isFile() && file.canRead() && file.getName().toLowerCase().endsWith(".jpg");
                        }
                    });
                    if (imageFiles != null) {
                        for (File imageFile : imageFiles) {
                            images.add(imageFile.getAbsolutePath());
                        }
                    }
                    if (!images.isEmpty()) {
                        items.add(new UsbItem(name, images));
                    }
                }
            }
        }
        return items;
    }
}

以上就是实现接入多个 U 盘，读取各个 U 盘图片，并按 U 盘名在 RecyclerView 分组展示图片，点击 U 盘名可以隐藏折叠 U 盘内的图片的代码实现。