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
...
}

下面是我的代码片段:

v.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View v) {
        int newPosition = MainActivity.mRecyclerView.getChildAdapterPosition(v);
        Intent cardViewIntent = new Intent(c, MainActivityCards.class);
        cardViewIntent.putExtra("Position", newPosition);
        c.startActivity(cardViewIntent);
    }
});

v是onCreateViewHolder的视图 c为背景信息

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;
            }
        }
    });

根据Yigit Boyar的说法，在RecyclerView上注册点击的最好方法是在ViewHolder的创建中定义点击，而不是仅仅为onBindViewHolder绑定的每个项目创建一个新的onClickListener

例子:

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): BaseViewHolder<*> {
   val itemBinding = LayoutInflater.from(context).inflate(R.layout.my_layout, parent, false)

   val vh = MainViewHolder (itemBinding)
   vh.itemView.setOnClickListener {
       val pos = vh.adapterPosition
       if(pos != NO_POSITION){
           itemClickLister.onCocktailClick(myList[pos],pos)
       }
   }

   return vh
}

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();
    }
}

别白费力气了!这个特定用例的代码包含在Android Studio附带的Master/Detail Flow启动器项目中。

从Android Studio选择:

文件>新建>新建项目.... 在Phone and Tablet选项卡中选择如下所示的Master/Detail Flow。

用Kotlin或Java创建项目。 利润。

我不会在这里包括谷歌的ootb演示项目的代码，但我会概述谷歌提供的示例中的主要设计方法:

the item OnClickListener is created ONLY ONCE, and is assigned to a field in your RecyclerView.Adapter implementation. in the onBindViewHolder() you should set the same, pre-created onClickListener object on your ViewHolder instance with holder.itemView.setOnClickListener(mOnClickListener) (AVOID creating a new instance on every method call!); if you need to capture clicks on some specific elements inside the ViewHolder then extend ViewHolder and expose the elements you need as fields so that you can attach whatever listeners you need in onBindViewHolder() — and once again, do NOT re-create the listeners on every method call — initialise them as instance fields and attach them as needed. you can use .setTag() in order to pass state to your viewHolder, e.g. holder.itemView.setTag(mValues.get(position)); as used in the demo.