Recyclerview适配器与kotlin

在适配器中可以通过两种方式实现项目点击监听器。

第一种方法是使用界面

在你的活动课上:

class YourActivity : AppCompatActivity(), TestAdapter.ClickListener {
...
override fun itemClicked() {

}
...
}

在适配器类中:

class MyAdapter : RecyclerView.Adapter<MyAdapter.MyViewHolder> {
...
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
     holder.textView1.setOnClickListener { 
        clickListener.itemClicked(position) 
     }
}
...
interface ClickListener {
     fun itemClicked(position : Int)
}
...
}

第二种方法是使用callBack调用

在适配器类中:

class MyAdapter(val callBack: (pos:Int) -> Unit) : RecyclerView.Adapter<MyAdapter.MyViewHolder> {
...
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
     holder.textView1.setOnClickListener { 
        callBack(position)
     }
}
}

在你的活动课上:

class YourActivity : AppCompatActivity() {
...
val testAdapter = TestAdapter(
            callBack = { index ->
               
            })
binding.recyclerView.layoutManager = LinearLayoutManager(this)
binding.recyclerView.adapter = testAdapter
...
}

我是这样做的，没有不必要的类、检测器等。适配器中的简单代码。特别是针对longClick的更好解决方案。

public class PasswordAdapter extends RecyclerView.Adapter<PasswordAdapter.ViewHolder> {
    private final ClickListener clickListener;

    public PasswordAdapter(ClickListener clickListener) {
         this.clickListener = clickListener;
    }

    public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener {
        TextView name;

        public ViewHolder(View itemView) {
            super(itemView);
            itemView.setOnClickListener(this);
            itemView.setOnLongClickListener(this);
            name = (TextView) itemView.findViewById(R.id.card_name);
        }

        @Override
        public void onClick(View v) {
            int position = getBindingAdapterPosition();
            if (position >= 0) {
                clickListener.onItemClick(position, v);
            }
        }

        @Override
        public boolean onLongClick(View v) {
            int position = getBindingAdapterPosition();
            if (position >= 0) { 
                clickListener.onItemLongClick(position, v);
                return true;
            }
            return false;
        }
    }

    public interface ClickListener {
        void onItemClick(int position, View v);
        void onItemLongClick(int position, View v);
    }
}

然后在片段或活动中，点击:

PasswordAdapter mAdapter = new PasswordAdapter(
    new PasswordAdapter.ClickListener() {
        @Override
        public void onItemClick(int position, View v) {
            Log.d(TAG, "onItemClick position: " + position);
        }

        @Override
        public void onItemLongClick(int position, View v) {
            Log.d(TAG, "onItemLongClick pos = " + position);
        }
    }
);

这是我的自定义适配器的完整代码，这段代码将用XML文件“list_item”中定义的列表项膨胀行，它还将在具有各自位置的所有列表项行上执行单击事件。

public class MyCustomAdapter extends RecyclerView.Adapter`<`AdapterMyCustomAdapter.ViewHolder> {

    public static class ViewHolder extends RecyclerView.ViewHolder implements OnClickListener {
        public onItemClickListener mListener;
        public ViewHolder(View v, onItemClickListener listener) {
            super(v);
            mListener =listener;
            v.setOnClickListener(this);
        }

        @Override
        public void onClick(View v) {
            mListener.onRecyclerItemClick(v, getPosition());
        }

        public static interface onItemClickListener {
            public void onRecyclerItemClick(View view , int position);
        }
    }

    @Override
    public int getItemCount() {
        return 5;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int pos) {      

    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int position) {
        View v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.list_item, parent, false);

    /* here list_item is an xml file we want to inflate ...it is same as we do in case of listview for customization.*/

        MyCustomAdapter.ViewHolder vh = new ViewHolder(v, new MyCustomAdapter.ViewHolder.onItemClickListener() {

            @Override
            public void onRecyclerItemClick(View view, int position) {
                System.out.println("clicked on list item at position " +position);
            } 
        });
        return vh;
    }
}

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));
    });

我有一个很好的解决方案RecyclerView的onItemClickListener的项目和子项

步骤1—创建接口

public interface OnRecyclerViewItemClickListener
{
    /**
     * Called when any item with in recyclerview or any item with in item
     * clicked
     * 
     * @param position
     *            The position of the item
     * @param id
     *            The id of the view which is clicked with in the item or
     *            -1 if the item itself clicked
     */
    public void onRecyclerViewItemClicked(int position, int id);
}

步骤2-然后在适配器的onBindViewHolder方法中使用它，如下所示

/**
     * Custom created method for Setting the item click listener for the items and items with in items
     * @param listener OnRecyclerViewItemClickListener 
     */
    public void setOnItemClickListener(OnRecyclerViewItemClickListener listener)
    {
        this.listener = listener;
    }

    @Override
    public void onBindViewHolder(ViewHolder viewHolder, final int position)
    {
    
        // viewHolder.albumBg.setBackgroundResource(_itemData[position]
        // .getImageUrl());
    
        viewHolder.albumName.setText(arrayList.get(position).getName());
        viewHolder.artistName.setText(arrayList.get(position).getArtistName());
        String imgUrl = arrayList.get(position).getThumbImageUrl();
    
        makeImageRequest(imgUrl, viewHolder);
        viewHolder.parentView.setOnClickListener(new View.OnClickListener()
        {
    
            @Override
            public void onClick(View v)
            {
                listener.onRecyclerViewItemClicked(position, -1);
            }
        });
        viewHolder.settingButton.setOnClickListener(new View.OnClickListener()
        {
    
            @Override
            public void onClick(View v)
            {
                listener.onRecyclerViewItemClicked(position, v.getId());
            }
        });
    
    }
    
    // class to hold a reference to each item of RecyclerView
    public static class ViewHolder extends RecyclerView.ViewHolder
    {
    
        public TextView albumName, artistName;
        public ImageView albumIcon, settingButton;
        public LinearLayout parentView;
    
        public ViewHolder(View itemLayoutView)
        {
            super(itemLayoutView);
            // albumBg = (LinearLayout) itemLayoutView
            // .findViewById(R.id.albumDlbg);
            albumName = (TextView) itemLayoutView.findViewById(R.id.albumName);
            artistName = (TextView) itemLayoutView
                    .findViewById(R.id.artistName);
            albumIcon = (ImageView) itemLayoutView.findViewById(R.id.albumIcon);
            parentView = (LinearLayout) itemLayoutView
                    .findViewById(R.id.albumDlbg);
            settingButton = (ImageView) itemLayoutView
                    .findViewById(R.id.settingBtn);
        }
    
    }

步骤3-在活动或片段中找到并设置回收器视图，您正在使用此

recyclerView = (RecyclerView) rootview.findViewById(R.id.vmtopsongs);

        lm = new LinearLayoutManager(mActivity);
        lm.setOrientation(LinearLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(lm);
        recyclerView.addItemDecoration(
                new HorizontalDividerItemDecoration.Builder(getActivity())
                        .paint(Utils.getPaint()).build());
        PopularSongsadapter mAdapter = new PopularSongsadapter(gallery,
                mActivity, true);
        // set adapter
        recyclerView.setAdapter(mAdapter);
        mAdapter.setOnItemClickListener(this);
        // set item animator to DefaultAnimator
        recyclerView.setItemAnimator(new DefaultItemAnimator());

步骤4-最后在使用recyclerview的activity或fragment中实现接口

@Override
    public void onRecyclerViewItemClicked(int position, int id)
    {
        if(id==-1){
            Toast.makeText(mActivity, "complete item clicked", Toast.LENGTH_LONG).show();
        }else{
            Toast.makeText(mActivity, "setting button clicked", Toast.LENGTH_LONG).show();
        }
    }

更新Kotlin语言 我已经更新了kotlin的代码，其中只有整个视图有点击监听器。你可以根据上面的java代码编辑界面和代码来设置子项点击监听器。

适配器

class RecentPostsAdapter(private val list: MutableList<Post>) :
    RecyclerView.Adapter<RecentPostsAdapter.ViewHolder>() {
    private lateinit var onItemClickListener: OnItemClickListener

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        return ViewHolder(
            LayoutInflater.from(parent.context)
                .inflate(R.layout.listitem_recent_post, parent, false)
        )
    }

    override fun getItemCount(): Int {
        return list.size
    }

    fun setOnItemClickListener(onItemClickListener: OnItemClickListener) {
        this.onItemClickListener = onItemClickListener
    }

    private fun getItem(position: Int): Post {
        return list[position]
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        holder.bind(getItem(position))
        holder.itemView.setOnClickListener(View.OnClickListener {
            onItemClickListener.onItemClick(
                position
            )
        })
    }

    class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        private var imageView: NetworkImageView? = null
        private var tvTitle: TextView? = null
        private var tvExcerpt: TextView? = null
        private var htmlSpanner: HtmlSpanner = HtmlSpanner()

        init {
            imageView = itemView.findViewById(R.id.niv_post_image)
            tvTitle = itemView.findViewById(R.id.tv_post_title)
            tvExcerpt = itemView.findViewById(R.id.tv_post_excerpt)
        }

        fun bind(post: Post) {
            tvTitle?.text = post.title
            tvExcerpt?.text = htmlSpanner.fromHtml(post.excerpt)
        }
    }

    interface OnItemClickListener {
        fun onItemClick(position: Int)
    }
}

活动或片段

recyclerView = view.findViewById(R.id.rvHomeRecentPosts)
        recyclerView.layoutManager = LinearLayoutManager(view.context)
        list = mutableListOf()
        recentPostsAdapter = RecentPostsAdapter(list)
        recyclerView.adapter = recentPostsAdapter
        recentPostsAdapter.setOnItemClickListener(object:RecentPostsAdapter.OnItemClickListener{
            override fun onItemClick(position: Int) {
                (activity as MainActivity).findNavController(R.id.nav_host_fragment).navigate(R.id.action_nav_home_to_nav_post_detail)
            }

        })

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();
    }
}