让我们看看如何在Jetpack / AndroidX中实现这一点

你需要像这样在viewmodel类中创建一个观察对象

private MutableLiveData<Integer> adapterItem = new MutableLiveData<>();

public MutableLiveData<Integer> getAdapterItem() {
    return adapterItem;
}

public void setAdapterItem(int adapterItem) {
    this.getAdapterItem().setValue(adapterItem);
}

然后在适配器类中，确保将viewmodel引用作为构造函数的参数传递，然后在vieholder上实现clicklistener

    public MyViewHolder(@NonNull View itemView) {
        super(itemView);
        if(itemView != null){
            itemView.setOnClickListener(v -> {
                int adapterPosition = getAdapterPosition();
                viewModel.setAdapterItem(adapterPosition);
            });

        };
    }

然后从活动课上观察变化

    viewModel.getAdapterItem().observe(this, position -> {
        Log.w(TAG, "clicked: " + ridesArray.get(position));
    });

查看类似的问题@CommonsWare的评论链接到this，它在viewHolder中实现了OnClickListener接口。

下面是ViewHolder的一个简单例子:

/** Declare global with in adapter class. */
TextView textView;

public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

    private ViewHolder(View itemView) {
        super(itemView);
        itemView.setOnClickListener(this);
        textView = (TextView) view.findViewById(android.R.id.text1);   
    }

    @Override
    public void onClick(View view) {
        Toast.makeText(view.getContext(), "position = " + getLayoutPosition(), Toast.LENGTH_SHORT).show();
         
        /** Go through each item if you have few items within RecyclerView. */
        if (getLayoutPosition() == 0) {
           // Do whatever you want here
        } else if(getLayoutPosition() == 1) { 
           // Do whatever you want here
        } else if(getLayoutPosition() == 2) {
           // Do whatever you want here
        }

        /** Or you can use For loop if you have long list of items. */
        for (int i = 0; i < exampleList.size(); i++) {
            // Do whatever you want here
        }
    }
}

在你的RecyclerView中创建ViewHolder。适配器看起来像这样:

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    LayoutInflater inflater = LayoutInflater.from(parent.getContext())
    View view = inflater.inflate(android.R.layout.simple_list_item_1, parent, false);
    return new ViewHolder(view);
}

由于API已经发生了根本性的变化，如果你要为每个项目创建一个OnClickListener，这不会让我感到惊讶。不过也没那么麻烦。在你的RecyclerView的实现中。适配器<MyViewHolder>，你应该有:

private final OnClickListener mOnClickListener = new MyOnClickListener();

@Override
public MyViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType) {
    View view = LayoutInflater.from(mContext).inflate(R.layout.myview, parent, false);
    view.setOnClickListener(mOnClickListener);
    return new MyViewHolder(view);
}

onClick方法:

@Override
public void onClick(final View view) {
    int itemPosition = mRecyclerView.getChildLayoutPosition(view);
    String item = mList.get(itemPosition);
    Toast.makeText(mContext, item, Toast.LENGTH_LONG).show();
}

我知道有很多答案，但我想我也可以提供我的实现。(完整的细节可以在我回答的另一个问题中找到)。

所以，要添加一个点击监听器，你的内部ViewHolder类需要实现View.OnClickListener。这是因为你将设置一个OnClickListener到ViewHolder的构造函数的itemView参数。让我来告诉你我的意思:

public class ExampleClickViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

    TextView text1, text2;

    ExampleClickViewHolder(View itemView) {
        super(itemView);

        // we do this because we want to check when an item has been clicked:
        itemView.setOnClickListener(this);

        // now, like before, we assign our View variables
        title = (TextView) itemView.findViewById(R.id.text1);
        subtitle = (TextView) itemView.findViewById(R.id.text2);
    }

    @Override
    public void onClick(View v) {
        // The user may not set a click listener for list items, in which case our listener
        // will be null, so we need to check for this
        if (mOnEntryClickListener != null) {
            mOnEntryClickListener.onEntryClick(v, getLayoutPosition());
        }
    }
}

唯一需要添加的其他东西是适配器的自定义接口和setter方法:

private OnEntryClickListener mOnEntryClickListener;

public interface OnEntryClickListener {
    void onEntryClick(View view, int position);
}

public void setOnEntryClickListener(OnEntryClickListener onEntryClickListener) {
    mOnEntryClickListener = onEntryClickListener;
}

这样，新的支持单击的适配器就完成了。

现在，让我们用它…

    ExampleClickAdapter clickAdapter = new ExampleClickAdapter(yourObjects);
    clickAdapter.setOnEntryClickListener(new ExampleClickAdapter.OnEntryClickListener() {
        @Override
        public void onEntryClick(View view, int position) {
            // stuff that will happen when a list item is clicked
        }
    });

这基本上就是设置普通适配器的方法，除了使用您创建的setter方法来控制当用户单击特定列表项时要做什么。

你也可以看看我在GitHub上做的一组关于Gist的例子:

https://gist.github.com/FarbodSalamat-Zadeh/7646564f48ee708c1582c013e1de4f07

这个作品。

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

private final Context mContext;
private List<ServiceListModel> categoryList;
private View.OnClickListener onClickListener;

public ServiceListAdapter(Context mContext, List<ServiceListModel> categoryList, View.OnClickListener onClickListener) {
    this.categoryList = categoryList;
    this.mContext = mContext;
    this.onClickListener = onClickListener;
}

@Override
public ViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType) {
    final LayoutInflater inflater = LayoutInflater.from(parent.getContext());
    final RowServiceListBinding binding = DataBindingUtil.inflate(inflater, R.layout.row_service_list, parent, false);
    return new ViewHolder(binding.getRoot(), binding);
}

@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
    holder.binding.rlService.setOnClickListener(onClickListener);
    holder.binding.rlService.setTag(position);
}

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

public class ViewHolder extends RecyclerView.ViewHolder {
    private final RowServiceListBinding binding;

    public ViewHolder(final View view, final RowServiceListBinding binding) {
        super(view);
        this.binding = binding;
    }

    @UiThread
    public void bind(final ServiceListModel mAddressModel) {
        //this.binding.setAddress(mAddressModel);
    }
}
}

在活动/片段中使用

ServiceListAdapter adapter = new ServiceListAdapter(context, serviceList, new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            switch (v.getId()) {
                case R.id.rlService:
                    int pos = (int) v.getTag();
                    serviceList.remove(position);
                    break;
            }
        }
    });

很简单，添加这个类:

public class OnItemClickListener implements View.OnClickListener {
    private int position;
    private OnItemClickCallback onItemClickCallback;

    public OnItemClickListener(int position, OnItemClickCallback onItemClickCallback) {
        this.position = position;
        this.onItemClickCallback = onItemClickCallback;
    }

    @Override
    public void onClick(View view) {
        onItemClickCallback.onItemClicked(view, position);
    }

    public interface OnItemClickCallback {
        void onItemClicked(View view, int position);
    }
}

获取一个'OnItemClickCallback'接口实例，并把它放在你的activity或fragment中:

private OnItemClickListener.OnItemClickCallback onItemClickCallback = new OnItemClickListener.OnItemClickCallback() {
    @Override
    public void onItemClicked(View view, int position) {
    }
};

然后，将这个回调传递给你的recyclerView:

recyclerView.setAdapter(new SimpleStringRecyclerViewAdapter(Arrays.asList("1", "2", "3"), onItemClickCallback));

最后，这将是你的适配器:

public class SimpleStringRecyclerViewAdapter extends RecyclerView.Adapter<SimpleStringRecyclerViewAdapter.ViewHolder> {
    private List<String> mValues;
    private OnItemClickListener.OnItemClickCallback onItemClickCallback;

    public SimpleStringRecyclerViewAdapter(List<String> items, OnItemClickListener.OnItemClickCallback onItemClickCallback) {
        mValues = items;
        this.onItemClickCallback = onItemClickCallback;
    }

    public static class ViewHolder extends RecyclerView.ViewHolder {
        public final TextView mTextView;

        public ViewHolder(View view) {
            super(view);
            mTextView = (TextView) view.findViewById(R.id.txt_title);
        }
    }

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

    @Override
    public void onBindViewHolder(final ViewHolder holder, final int position) {
        holder.mTextView.setText(mValues.get(position));
        holder.mTextView.setOnClickListener(new OnItemClickListener(position, onItemClickCallback));
    }

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