Android Wi-Fi Direct：onPeersAvailable

Posted 2023-02-23

【中文标题】Android Wi-Fi Direct：onPeersAvailable

【英文标题】：Android Wi-Fi Direct: onPeersAvailable

【发布时间】：2012-10-25 14:24:59

【问题描述】：

我正在为 android 开发一个基于 WiFi Direct 的简单应用程序，它必须连接两个设备。为此，我需要调用函数 onPeersAvailable(myPeerListListener)，但我不知道如何。

我的应用有这两个元素：

1-主要活动：

package android.nacho.WifiDirect;



import android.net.wifi.p2p.WifiP2pManager.Channel;

import android.net.wifi.p2p.WifiP2pManager;
import android.os.Bundle;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class WifiDirect extends Activity 


    WifiP2pManager mManager;
    Channel mChannel;
    BroadcastReceiver mReceiver;

    IntentFilter mIntentFilter;

    @Override
    public void onCreate(Bundle savedInstanceState) 

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_wifi_direct);


        //To register the BroadastReceiver
        mManager = (WifiP2pManager) getSystemService(Context.WIFI_P2P_SERVICE);
        mChannel =   mManager.initialize(this, getMainLooper(), null); //It was necessary to make a cast (Channel)
        mReceiver = new WiFiBroadcastReceiver(mManager, mChannel, this); //, this);

        //Layout
        final Button btnScan = (Button)findViewById(R.id.btnScan); 
        final TextView TextDebug=(TextView)findViewById(R.id.TextDebug);


        //To define the filter in the BroadcastReceiver
        mIntentFilter = new IntentFilter();
        mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION);
        mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION);
        mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION);
        mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION);




        final OnClickListener ScanListener=new OnClickListener() //Sacado de TEstPsycologico
        
            public void onClick(View v)



                TextDebug.setText("Se intentan buscar Peers");

                mManager.discoverPeers(mChannel, new WifiP2pManager.ActionListener() 


                    public void onSuccess() 

                        TextDebug.setText("Ha habido éxito buscando Peers");//DEBUG: Para ver si es posible encontrar Peers

                    


                    public void onFailure(int reasonCode) 

                        TextDebug.setText("Algo ha salido mal buscando Peers"); //DEBUG: Para ver si pasó algo raro busando Peers
                    
                );


                onPeersAvailable(myPeerListListener);

            


        ;

        btnScan.setOnClickListener(ScanListener);

    


    @Override
    public boolean onCreateOptionsMenu(Menu menu) 
        getMenuInflater().inflate(R.menu.activity_wifi_direct, menu);
        return true;
    

    //


    @Override
    protected void onResume() 
        super.onResume();
        registerReceiver(mReceiver, mIntentFilter);
    

   // unregister the broadcast receiver
    @Override
    protected void onPause() 
        super.onPause();
        unregisterReceiver(mReceiver);
    

2 类广播接收器：

package android.nacho.WifiDirect;

import android.net.wifi.p2p.WifiP2pManager.Channel;
import android.net.wifi.p2p.WifiP2pManager.PeerListListener;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.wifi.p2p.WifiP2pManager;
import android.widget.Toast;



/**
 * A BroadcastReceiver that notifies of important Wi-Fi p2p events.
 */

public class WiFiBroadcastReceiver extends BroadcastReceiver 

    private WifiP2pManager manager;
    private Channel channel;
    private WifiDirect activity;
    private PeerListListener myPeerListListener;

    //For toast, add also context
    //private Context context;

    public WiFiBroadcastReceiver(WifiP2pManager manager, Channel channel, WifiDirect activity)//, Context context) 

        super();
        this.manager = manager;
        this.channel = channel;
        this.activity = activity;
       // this.context= context;
    

    @Override
    public void onReceive(Context context, Intent intent) 

        String action = intent.getAction();     


        if (WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION.equals(action)) 

            // Check to see if Wi-Fi is enabled and notify appropriate activity
             int state = intent.getIntExtra(WifiP2pManager.EXTRA_WIFI_STATE, -1);
             if (state == WifiP2pManager.WIFI_P2P_STATE_ENABLED) 

                //Toast.makeText(context, "Wi-Fi Direct is enable", Toast.LENGTH_LONG).show();

              else 

                //Toast.makeText(context, "Wi-Fi Direct is not enable", Toast.LENGTH_LONG).show();
                   

         else if (WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION.equals(action)) 
            // Call WifiP2pManager.requestPeers() to get a list of current peers

             // request available peers from the wifi p2p manager. This is an
            // asynchronous call and the calling activity is notified with a
            // callback on PeerListListener.onPeersAvailable()
            if (manager != null) 
                 manager.requestPeers(channel, myPeerListListener);
                 manager.onPeersAvailable(myPeerListListener);

            



         else if (WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION.equals(action)) 
            // Respond to new connection or disconnections
         else if (WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION.equals(action)) 
            // Respond to this device's wifi state changing
        
    

到目前为止，我的代码应该能够检测到运行应用程序的设备周围的对等点，该 ID 应该存储在变量 myPeerListListener 中。所有这一切都发生在 BroadcastReceiver 方法的第二个意图 OnReceiv() 中，通过调用：

 manager.requestPeers(channel, myPeerListListener);

现在我想操作该列表。因此，按照它应该调用 requestPeers 的 API 信息，您可以在此处查看 API：

http://developer.android.com/guide/topics/connectivity/wifip2p.html

*部分发现同行

所以我尝试在下面写一个调用：

manager.onPeersAvailable(myPeerListListener); 

但我收到此错误：

未定义类型 WifiP2pManager 的 onPeersAvailable(WifiP2pManager.PeerListListener) 方法

谁能告诉我如何正确地将 PeerListListener 发送到主要活动？

非常感谢您的宝贵时间

【参考方案1】：

dtheo 已回答并指向关于此主题的不错的 Android 教程。我将仅对 OP 的代码进行更改，以展示如何实现所请求的功能。

根据Android官方指南here，wifip2p发现api应该这样使用：

在您的 MainActivity 类中：

mManager.discoverPeers(mChannel, new WifiP2pManager.ActionListener() 
    public void onSuccess() 
        TextDebug.setText("Ha habido éxito buscando Peers");
    

    public void onFailure(int reasonCode) 
        TextDebug.setText("Algo ha salido mal buscando Peers");
    
);

// ############# DELETE THE FOLLOWING LINE #############
onPeersAvailable(myPeerListListener); // <<<<<<< DELETE THIS LINE

在您的 BroadcastReceiver 类中，改为执行以下操作：

@Override
public void onReceive(Context context, Intent intent) 
    ...    
    if (WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION.equals(action)) 
        ...
     else if (WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION.equals(action)) 
        if (manager != null) 
            manager.requestPeers(channel, new WifiP2pManager.PeerListListener() 
            @Override
            public void onPeersAvailable(WifiP2pDeviceList peers) 
                Log.d(TAG,String.format("PeerListListener: %d peers available, updating device list", peers.getDeviceList().size()));

                // DO WHATEVER YOU WANT HERE
                // YOU CAN GET ACCESS TO ALL THE DEVICES YOU FOUND FROM peers OBJECT

            
        );
        
     else if (WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION.equals(action)) 
        // Respond to new connection or disconnections
     else if (WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION.equals(action)) 
        // Respond to this device's wifi state changing
    

【讨论】：

谢谢张。节省了我的时间。干杯。

【参考方案2】：

dtheo 已经回答了这个问题。

我想补充一点：对于 Wi-Fi Direct，两个设备需要同时扫描才能发现对方。还有一个扫描超时，这意味着一段时间后可能会失去可发现性。

【参考方案3】：

您应该在 PeerListListener 中实现 onPeersAvailable 方法。

请查看http://developer.android.com/training/connect-devices-wirelessly/wifi-direct.html了解更多信息。