如何在回收視圖中爲自定義ViewHolder實現OnClickListener？

Question

我正在創建一個應用程序，該應用程序應該在recyclerview中顯示藍牙設備，並且我希望用戶能夠單擊這些項目以執行操作。現在我只是試圖讓吐司出現在點擊後，但後來我想可能會顯示一個對話框給對選擇等，但我明顯缺少一些在我onclicklistener的用法。我試圖讓我的ViewHolder類：DeviceHolder實施View.OnClickListener並將撥打號碼Toast.makeText()置於我的onClick覆蓋範圍內。然而，沒有任何事情發生。我相信我只是想念一些小事，並希望能幫助你找到問題。我也是在kotlin中做這個，我是新手，如果可能有更高效的kotlin類型的方式來做到這一點，也會有所幫助。我在下面發佈我的代碼。提前致謝。

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" 
} 
} 

這裏的日誌消息：

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

我設法得到這通過消除OnClickListener的實現來解決，只需使用此語句代替itemView.setOnClickListener { /* lamda here */ }。我不相信這個確切的語法是在Java中可用，但在作品中的kotlin。這是我的修改後的代碼：

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() } 
    } 

} 

通過使用it關鍵字我訪問的ItemView控件對象的上下文拉姆達的內部，而不是使用上述我的原始mContext。我仍然不確定爲什麼我的舊方法不起作用，但是這樣做對我很有用。

Answer 2

根據您的代碼正在實施clicklistner但還沒有添加任何寄存器點擊listener.add的clickListener爲nameView和AddrView。

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

Answer 3

這工作：

1套自己的點擊收聽到適配器，並保持對它的引用：

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所創建的每個viewholder的時候，設置一個監聽器，它，而一旦回調，回調傳遞給聽者以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讓你viewholder李斯登到（holded者）查看的onClick，並讓它轉發呼叫：

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在這一點上，適配器的用戶將擁有：

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