如何在回收视图中为自定义ViewHolder实现OnClickListener？

Question

我正在创建一个应用程序，该应用程序应该在recyclerview中显示蓝牙设备，并且我希望用户能够单击这些项目以执行操作。现在我只是试图让吐司出现在点击后，但后来我想可能会显示一个对话框给对选择等，但我明显缺少一些在我onclicklistener的用法。我试图让我的ViewHolder类：DeviceHolder实施View.OnClickListener并将拨打号码Toast.makeText()置于我的onClick覆盖范围内。然而，没有任何事情发生。我相信我只是想念一些小事，并希望能帮助你找到问题。我也是在kotlin中做这个，我是新手，如果可能有更高效的kotlin类型的方式来做到这一点，也会有所帮助。我在下面发布我的代码。提前致谢。

class DeviceAdapter(val mContext : Context) : RecyclerView.Adapter<DeviceAdapter.DeviceHolder>(){ 

val mDevices = ArrayList<BluetoothDevice>() 

interface OnClickListener{ 
    fun onClick(v: View) 
} 

fun updateItems(list: ArrayList<BluetoothDevice>){ 
    mDevices.clear() 
    mDevices.addAll(list) 
    Log.d(TAG, "updating items : $mDevices") 
    notifyDataSetChanged() 
} 

fun ViewGroup.inflate(@LayoutRes res: Int, attachToRoot: Boolean = false): View{ 
    return LayoutInflater.from(mContext).inflate(res, this, attachToRoot) 
} 

override fun onBindViewHolder(holder: DeviceHolder, position: Int) { 
    Log.d(TAG, "onBindViewHolder called!") 
    holder.bindItems(mDevices.get(position)) 
} 

override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): DeviceAdapter.DeviceHolder{ 
    Log.d(TAG, "onCreateViewHolder called!") 
    val v = parent!!.inflate(R.layout.device_item, false) 
    return DeviceHolder(v) 
} 

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

inner class DeviceHolder(itemView: View) : RecyclerView.ViewHolder(itemView), View.OnClickListener { 

    override fun onClick(v: View?) { 
     Toast.makeText(mContext, "test", Toast.LENGTH_LONG).show() 
    } 

    val nameView = itemView.findViewById(R.id.nameView) as TextView 
    val addrView = itemView.findViewById(R.id.addressView) as TextView 

    fun bindItems(btDevice: BluetoothDevice) { 
     Log.d(TAG, "holder created!") 
     nameView.text = btDevice.name 
     addrView.text = btDevice.address 
     itemView.setOnClickListener { this } 
    } 

} 

companion object { 
    val TAG = "Device Adapter" 
} 
} 

这里的日志消息：

10-09 00:35:50.233 7581-7581/com.example.zemcd.toofxchange D/DiscoveryTask: device found! 
10-09 00:35:51.795 7581-7581/com.example.zemcd.toofxchange D/DiscoveryTask: device found! 
10-09 00:35:56.752 7581-7581/com.example.zemcd.toofxchange D/DiscoveryTask: device list : [**:B8:9A:39:1D:**, **:DF:BF:2A:F3:**] 
10-09 00:35:56.752 7581-7581/com.example.zemcd.toofxchange D/Device Adapter: updating items : [**:B8:9A:39:1D:**, **:DF:BF:2A:F3:**] 
10-09 00:35:56.752 7581-7581/com.example.zemcd.toofxchange D/DiscoveryTask: discovery finished 
10-09 00:35:56.762 7581-7581/com.example.zemcd.toofxchange D/Device Adapter: onCreateViewHolder called! 
10-09 00:35:56.774 7581-7581/com.example.zemcd.toofxchange D/Device Adapter: onBindViewHolder called! 
10-09 00:35:56.774 7581-7581/com.example.zemcd.toofxchange D/Device Adapter: holder created! 
10-09 00:35:56.783 7581-7581/com.example.zemcd.toofxchange D/Device Adapter: onCreateViewHolder called! 
10-09 00:35:56.786 7581-7581/com.example.zemcd.toofxchange D/Device Adapter: onBindViewHolder called! 
10-09 00:35:56.786 7581-7581/com.example.zemcd.toofxchange D/Device Adapter: holder created! 

Answer 1

我设法得到这通过消除OnClickListener的实现来解决，只需使用此语句代替itemView.setOnClickListener { /* lamda here */ }。我不相信这个确切的语法是在Java中可用，但在作品中的kotlin。这是我的修改后的代码：

inner class DeviceHolder(itemView: View) : RecyclerView.ViewHolder(itemView) { 

    val nameView = itemView.findViewById(R.id.nameView) as TextView 
    val addrView = itemView.findViewById(R.id.addressView) as TextView 

    fun bindItems(btDevice: BluetoothDevice) { 
     Log.d(TAG, "holder created!") 
     nameView.text = btDevice.name 
     addrView.text = btDevice.address 
     itemView.setOnClickListener { Toast.makeText(it.context, "testing", Toast.LENGTH_SHORT).show() } 
    } 

} 

通过使用it关键字我访问的ItemView控件对象的上下文拉姆达的内部，而不是使用上述我的原始mContext。我仍然不确定为什么我的旧方法不起作用，但是这样做对我很有用。

Answer 2

根据您的代码正在实施clicklistner但还没有添加任何寄存器点击listener.add的clickListener为nameView和AddrView。

nameView.setOnClickListener(this); 
addrView.setOnClickListener(this); 

Answer 3

这工作：

1套自己的点击收听到适配器，并保持对它的引用：

private OnItemClickListener onItemClickListener; 
// ... 
public interface OnItemClickListener { 
    // note: here you would need some params, for instance the view 
    void onItemClick(View v); 
} 

public void setOnItemClickListener(OnItemClickListener l) { 
    this.onItemClickListener = l; 
} 

2所创建的每个viewholder的时候，设置一个监听器，它，而一旦回调，回调传递给听者以1集：

@Override 
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 
    ViewHolder vh = getViewHolder(/*...*/); 
    vh.setOnItemClickListener(new OnItemClickListener() {     
     if (onItemClickListener != null) { 
      // each view holder calls the one listener set to the Adapter 
      onItemClickListener.onItemClick(v); 
     } 
    } 
} 

3让你viewholder李斯登到（holded者）查看的onClick，并让它转发呼叫：

public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener { 
// each view holder has a listener set to it 
private OnItemClickListener mListener; 

public ViewHolder(View v) {   
    super(v); 
    // ... 
    // set the viewholder as a listener to the view's clicks 
    v.setOnClickListener(this); 
} 

@Override 
public void onClick(View v) { 
    // when view is clicked, simply forward the call 
    if (mListener != null) { 
     mListener.onItemClick(v); 
    } 
} 

public void setOnItemClickListener(OnItemClickListener listener) { 
    mListener = listener; 
} 

}

4在这一点上，适配器的用户将拥有：

mAdapter = new MyAdapter(ctx); 
mAdapter.setOnItemClickListener(new MyAdapter.OnItemClickListener() { 
    @Override 
    public void onItemClick(View v) { 
     // the given view was clicked, do something with it 
    } 
});