如何在 Kotlin 中为 ItemClickListener 创建接口？

Question

我是 Android 和 Kotlin 的新手。我想单击我的行并将其用于其他活动。这就是为什么我试图在我的适配器中创建一个接口但它不起作用的原因。如何创建它？

我的适配器代码：

class NoteAdapter(private val titleTextArray: ArrayList<String>, private val imageArray: ArrayList<String>) : RecyclerView.Adapter<NoteAdapter.NoteHolder>() {

    class NoteHolder (view: View) : RecyclerView.ViewHolder(view) {
      
            var recyclerTitleText: TextView ?= null
            var recyclerImageView: ImageView ?= null

        init {
            recyclerTitleText = view.findViewById(R.id.recyclerTitleText)
            recyclerImageView = view.findViewById(R.id.recyclerImage)
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): NoteHolder {
        val inflater = LayoutInflater.from(parent.context)
        val view = inflater.inflate(R.layout.recycler_row, parent, false)
        return NoteHolder(view)
    }

    override fun onBindViewHolder(holder: NoteHolder, position: Int) {
        holder.recyclerTitleText?.text = titleTextArray[position]
        Picasso.get().load(imageArray[position]).into(holder.recyclerImageView)

    }

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

Answer 1

使用 Kotlin，您可以使用 lambda（高阶函数）来获取用户在持有人中的点击次数。例如，基本方法可能是下一个：

class YourAdapter(
    private val listener: (String) -> Unit
) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {

    private val yourDataList = emptyList<String>()

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.compound_checkbox_terms_layout, parent, false)
        return YourViewHolder(view)
    }

    override fun getItemCount(): Int {
        TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
    }

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
        TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
    }


    private inner class YourViewHolder(view: View) : RecyclerView.ViewHolder(view) {
        
        init {
            if (adapterPosition != RecyclerView.NO_POSITION) {
                val selectedData = yourDataList[adapterPosition]
                listener.invoke(selectedData)
            }
        }
    }
}

Answer 2

将 Activity 上下文从 Activity 传递给适配器，以便它可以启动 Intent

活动代码：

mAdapter = new CustomAdapter(this, imageArray, ArrayList);

适配器代码：

class NoteAdapter(private val titleTextArray: ArrayList, private val imageArray: ArrayList, private val context : Context) : RecyclerView.Adapter<NoteAdapter.NoteHolder>() {
    class NoteHolder (view: View) : RecyclerView.ViewHolder(view) {
        var recyclerTitleText: TextView?= null
        var recyclerImageView : ImageView?= null
        init {
            recyclerTitleText = view.findViewById(R.id.recyclerTitleText)
            recyclerImageView = view.findViewById(R.id.recyclerImage)
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): NoteHolder {

        val inflater = LayoutInflater.from(parent.context)
        val view = inflater.inflate(R.layout.recycler_row, parent, false)
        return NoteHolder(view)

    }

    override fun onBindViewHolder(holder: NoteHolder, position: Int) {

        holder.recyclerTitleText?.text = titleTextArray[position]
        Picasso.get().load(imageArray[position]).into(holder.recyclerImageView)
        holder.recyclerImageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(context, NesneTani.class);
                context.startActivity(intent);
            }
        });
    }

    override fun getItemCount(): Int {

        return titleTextArray.size

    }
}

Answer 3

创建一个接口来捕捉点击事件。 （位置是可选的）

interface OnItemClickListener {
fun onItemClick(position: Int)

}

在适配器类中添加 OnItemClickListener 作为参数

class NoteAdapter(
private val titleTextArray: ArrayList<String>,
private val imageArray: ArrayList<String>,
private val listener: OnItemClickListener
) : RecyclerView.Adapter<NoteAdapter.NoteHolder>() 

然后在onBindViewHolder里面做下面

 override fun onBindViewHolder(holder: NoteHolder, position: Int) {
 listener.onItemClick(position)
}

现在在您的活动中，实现 OnItemClickListener

class ActivityName implements OnItemClickListener{}

在启动适配器时，执行此操作

mAdapter = new CustomAdapter(this, imageArray, ArrayList);

然后在被覆盖的方法中做你想做的事

override fun onItemClick(position: Int) {
//start the activity you want.
}