完整的示例

垂直RecyclerView和水平RecyclerView之间唯一真正的区别是如何设置LinearLayoutManager。下面是代码片段。完整的示例如下。

LinearLayoutManager horizontalLayoutManagaer = new LinearLayoutManager(MainActivity.this, LinearLayoutManager.HORIZONTAL, false);
recyclerView.setLayoutManager(horizontalLayoutManagaer);

这个更完整的例子是模仿我的垂直RecyclerView答案。

更新Gradle依赖项

确保以下依赖项在你的应用程序gradle中。构建文件:

implementation 'com.android.support:appcompat-v7:27.1.1'
implementation 'com.android.support:recyclerview-v7:27.1.1'

您可以将版本号更新为最新的版本号。

创建活动布局

将RecyclerView添加到xml布局中。

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rvAnimals"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</RelativeLayout>

创建项目布局

我们的RecyclerView中的每一项都将在TextView上有一个单独的彩色视图。创建一个新的布局资源文件。

recyclerview_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="10dp">

    <View
        android:id="@+id/colorView"
        android:layout_width="100dp"
        android:layout_height="100dp"/>

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

</LinearLayout>

创建适配器

RecyclerView需要一个适配器，用您的数据填充每行(水平项)中的视图。创建一个新的java文件。

MyRecyclerViewAdapter.java

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

    private List<Integer> mViewColors;
    private List<String> mAnimals;
    private LayoutInflater mInflater;
    private ItemClickListener mClickListener;

    // data is passed into the constructor
    MyRecyclerViewAdapter(Context context, List<Integer> colors, List<String> animals) {
        this.mInflater = LayoutInflater.from(context);
        this.mViewColors = colors;
        this.mAnimals = animals;
    }

    // inflates the row layout from xml when needed
    @Override
    @NonNull
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = mInflater.inflate(R.layout.recyclerview_item, parent, false);
        return new ViewHolder(view);
    }

    // binds the data to the view and textview in each row
    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        int color = mViewColors.get(position);
        String animal = mAnimals.get(position);
        holder.myView.setBackgroundColor(color);
        holder.myTextView.setText(animal);
    }

    // total number of rows
    @Override
    public int getItemCount() {
        return mAnimals.size();
    }

    // stores and recycles views as they are scrolled off screen
    public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
        View myView;
        TextView myTextView;

        ViewHolder(View itemView) {
            super(itemView);
            myView = itemView.findViewById(R.id.colorView);
            myTextView = itemView.findViewById(R.id.tvAnimalName);
            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View view) {
            if (mClickListener != null) mClickListener.onItemClick(view, getAdapterPosition());
        }
    }

    // convenience method for getting data at click position
    public String getItem(int id) {
        return mAnimals.get(id);
    }

    // allows clicks events to be caught
    public void setClickListener(ItemClickListener itemClickListener) {
        this.mClickListener = itemClickListener;
    }

    // parent activity will implement this method to respond to click events
    public interface ItemClickListener {
        void onItemClick(View view, int position);
    }
}

笔记

虽然不是严格必要的，但我包含了监听项目上的单击事件的功能。这在旧的listview中是可用的，是一种常见的需求。如果不需要，可以删除此代码。

在Activity中初始化RecyclerView

将以下代码添加到您的主活动中。

MainActivity.java

public class MainActivity extends AppCompatActivity implements MyRecyclerViewAdapter.ItemClickListener {

    private MyRecyclerViewAdapter adapter;

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

        // data to populate the RecyclerView with
        ArrayList<Integer> viewColors = new ArrayList<>();
        viewColors.add(Color.BLUE);
        viewColors.add(Color.YELLOW);
        viewColors.add(Color.MAGENTA);
        viewColors.add(Color.RED);
        viewColors.add(Color.BLACK);

        ArrayList<String> animalNames = new ArrayList<>();
        animalNames.add("Horse");
        animalNames.add("Cow");
        animalNames.add("Camel");
        animalNames.add("Sheep");
        animalNames.add("Goat");

        // set up the RecyclerView
        RecyclerView recyclerView = findViewById(R.id.rvAnimals);
        LinearLayoutManager horizontalLayoutManager
                = new LinearLayoutManager(MainActivity.this, LinearLayoutManager.HORIZONTAL, false);
        recyclerView.setLayoutManager(horizontalLayoutManager);
        adapter = new MyRecyclerViewAdapter(this, viewColors, animalNames);
        adapter.setClickListener(this);
        recyclerView.setAdapter(adapter);
    }

    @Override
    public void onItemClick(View view, int position) {
        Toast.makeText(this, "You clicked " + adapter.getItem(position) + " on item position " + position, Toast.LENGTH_SHORT).show();
    }
}

笔记

注意，该活动实现了我们在适配器中定义的ItemClickListener。这允许我们在onItemClick中处理项目单击事件。

完成了

就是这样。您现在应该能够运行您的项目，并获得与顶部图像类似的内容。

笔记

我示例中的彩色视图当然可以在实际项目中替换为图像。 Vertical RecyclerView示例

随着RecyclerView库的发布，现在您可以轻松地对齐与文本绑定的图像列表。您可以使用LinearLayoutManager来指定您想要定位列表的方向，可以是垂直的，也可以是水平的，如下所示。

你可以从这篇文章中下载一个完整的工作演示。

有没有更好的方法来实现这个现在与RecyclerView现在?

Yes.

当您使用RecyclerView时，您需要指定一个LayoutManager，该LayoutManager负责布局视图中的每个项。LinearLayoutManager允许你指定一个方向，就像一个正常的LinearLayout一样。

要用RecyclerView创建一个水平列表，你可以这样做:

LinearLayoutManager layoutManager
    = new LinearLayoutManager(requireContext(), LinearLayoutManager.HORIZONTAL, false);

RecyclerView myList = (RecyclerView) findViewById(R.id.my_recycler_view);
myList.setLayoutManager(layoutManager);

recyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false));

recyclerView.setAdapter(adapter);

XML文件

<HorizontalScrollView
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    
    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal"
        android:scrollbars="vertical|horizontal" />

</HorizontalScrollView>

Code

import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.content.ContextWrapper;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.ImageView;
import android.widget.Toast;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;

public class MainActivity extends AppCompatActivity{

    ImageView mImageView1;
    Bitmap bitmap;
    String mSavedInfo;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mImageView1 = (ImageView) findViewById(R.id.image);
    }
    public Bitmap getBitmapFromURL(String src) {
        try {
            java.net.URL url = new java.net.URL(src);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setDoInput(true);
            connection.connect();
            InputStream input = connection.getInputStream();
            Bitmap myBitmap = BitmapFactory.decodeStream(input);
            return myBitmap;
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }
    public void button2(View view) {
        new DownloadImageFromTherad().execute();
    }
    private class DownloadImageFromTherad extends AsyncTask<String, Integer, String> {
        @Override
        protected String doInBackground(String... params) {
            bitmap = getBitmapFromURL("https://cdn.pixabay.com/photo/2016/08/08/09/17/avatar-1577909_960_720.png");
            return null;
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            File sdCardDirectory = Environment.getExternalStorageDirectory();
            File image = new File(sdCardDirectory, "test.png");
            boolean success = false;
            FileOutputStream outStream;
            mSavedInfo = saveToInternalStorage(bitmap);
            if (success) {
                Toast.makeText(getApplicationContext(), "Image saved with success", Toast.LENGTH_LONG).show();
            } else {
                Toast.makeText(getApplicationContext(), "Error during image saving" + mSavedInfo, Toast.LENGTH_LONG).show();
            }
        }
    }
    private String saveToInternalStorage(Bitmap bitmapImage) {
        ContextWrapper cw = new ContextWrapper(getApplicationContext());
        // path to /data/data/yourapp/app_data/imageDir
        File directory = cw.getDir("imageDir", Context.MODE_PRIVATE);
        File mypath = new File(directory, "profile.jpg");
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(mypath);
            bitmapImage.compress(Bitmap.CompressFormat.PNG, 100, fos);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                fos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return directory.getAbsolutePath();
    }
    private void loadImageFromStorage(String path) {
        try {
            File f = new File(path, "profile.jpg");
            Bitmap b = BitmapFactory.decodeStream(new FileInputStream(f));
            mImageView1.setImageBitmap(b);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
    public void showImage(View view) {
        loadImageFromStorage(mSavedInfo);
    }
    
}

有一个名为HorizontalGridView的RecyclerView子类。你可以用它来表示水平方向。 垂直方向的VerticalGridView。