android - WifiP2pManager.requestPeers() 不断返回 onPeersAvailable() 中的旧节点

Question

于是我做了功课，找了类似的问题，居然在两年前找到了一个人有同样的问题... he didn't get any answer though.

问题如下:我正在做来自 android 的 WifiP2p 教程。我在 MainActivity 上使用此 FloatingActionButton 手动调用 discoverPeers()。然后在 WifiDirectBroadcastReceiver 类中广播和接收 WIFI_P2P_PEERS_CHANGED_ACTION。在那里，我调用了 requestPeers()，如果有至少一个可发现的点，它又会调用 onPeersAvailable() >(这很有道理。)

然而，问题是一旦它发现了一个点，它就永远不会离开列表。即使我关闭检测到的设备。让我用一个例子来说明:

• 3 台设备(A、B 和 C)，均支持 WiFi-Direct。
• 在设备 A 上启动应用，让设备 B 和 C 保持关闭状态。
• 尝试用 A 检测，没有检测到任何东西。没问题。
• 打开设备 B，转到 WiFi-Direct 设置，扫描。
• 尝试用A检测，检测B。没问题。
• 关闭设备 B。
• 尝试用 A 检测，没有检测到任何东西。没问题。
• 打开设备 C，转到 WiFi-Direct 设置，扫描。
• 尝试用 A 检测，检测 C 和 B。但是设备 B 仍然关闭。为什么它仍然被检测到？ (最糟糕的是，它被检测到状态为 3，对应于 AVAILABLE)

设备角色的任何排列都会发生这种情况。所以问题确实出在代码中，因为它们在官方 WiFi-Direct 设置窗口中的行为和检测都正常。

这是我的 MainActivity:

package com.gett.wifip2ptest;

import android.content.BroadcastReceiver;
import android.content.IntentFilter;
import android.net.wifi.p2p.WifiP2pDeviceList;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;

import android.content.Context;
import android.net.wifi.p2p.WifiP2pManager;
import android.net.wifi.p2p.WifiP2pManager.Channel;
import android.net.wifi.p2p.WifiP2pManager.PeerListListener;
import android.net.wifi.p2p.WifiP2pDevice;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity implements PeerListListener{

    private WifiP2pManager mManager;
    private Channel mChannel;
    private BroadcastReceiver mReceiver;

    private IntentFilter mIntentFilter;

    private List<WifiP2pDevice> peers = new ArrayList<WifiP2pDevice>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();

//                If the discovery process succeeds and detects peers, the system broadcasts the
//                WIFI_P2P_PEERS_CHANGED_ACTION intent.
                mManager.discoverPeers(mChannel, new WifiP2pManager.ActionListener() {
                    @Override
                    public void onSuccess() {
                        Toast.makeText(MainActivity.this, "Discovery Initiated",
                                Toast.LENGTH_SHORT).show();
                    }

                    @Override
                    public void onFailure(int reasonCode) {
                        Toast.makeText(MainActivity.this, "Discovery Failed : " + reasonCode,
                                Toast.LENGTH_SHORT).show();
                    }
                });
            }
        });

        mManager = (WifiP2pManager) getSystemService(Context.WIFI_P2P_SERVICE);
        mChannel = mManager.initialize(this, getMainLooper(), null);
        mReceiver = new WiFiDirectBroadcastReceiver(mManager, mChannel, this);

        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);
    }

    /* register the broadcast receiver with the intent values to be matched */
    @Override
    protected void onResume() {
        super.onResume();
        registerReceiver(mReceiver, mIntentFilter);
    }

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

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    /**
     * This function is called by requestPeers upon receiving the peers list.
     * @param peerList
     */
    @Override
    public void onPeersAvailable(WifiP2pDeviceList peerList) {
        peers.clear();
        System.out.println("Peers cleared : " + peers);

        peers.addAll(peerList.getDeviceList());

        System.out.println("Peers : " + peers);
        if (peers.size() == 0) {
            System.out.println("No devices found");
            return;
        }
    }
}

这是 WiFiDirectBroadCastReceiver:

package com.gett.wifip2ptest;

import android.content.BroadcastReceiver;
import android.net.wifi.p2p.WifiP2pManager;
import android.net.wifi.p2p.WifiP2pManager.Channel;
import android.net.wifi.p2p.WifiP2pManager.PeerListListener;
import android.content.Context;
import android.content.Intent;

public class WiFiDirectBroadcastReceiver extends BroadcastReceiver {

    private WifiP2pManager mManager;
    private Channel mChannel;
    private MainActivity mActivity;

    public WiFiDirectBroadcastReceiver(WifiP2pManager manager, Channel channel,
                                       MainActivity activity) {
        super();
        this.mManager = manager;
        this.mChannel = channel;
        this.mActivity = activity;
    }

    @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) {
                // Wifi P2P is enabled
                System.out.println("Wifi Direct has been enabled.");
            } else {
                // Wi-Fi P2P is not enabled
                System.out.println("Wifi Direct is NOT enabled.");
            }
        } else if (WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION.equals(action)) {
            // Call WifiP2pManager.requestPeers() to get a list of current peers
            System.out.println("Peers changed.");

            // 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 (mManager != null) {
                mManager.requestPeers(mChannel, (PeerListListener) mActivity);
            }
        } 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
        }
    }
}

这是一个在其中一个关闭时检测到两个对等点的示例:

02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out: Peers : [Device: Galaxy J1-2
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  deviceAddress: 2a:27:bf:3a:2e:55
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  primary type: 10-0050F204-5
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  secondary type: null
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  wps: 392
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  grpcapab: 0
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  devcapab: 37
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  status: 3
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  wfdInfo: null
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  groupownerAddress: null
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  GOdeviceName: null
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  interfaceAddress: 
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  SConnectInfo : null, Device: Test User (Galaxy J1)
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  deviceAddress: 2a:27:bf:3a:4a:8b
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  primary type: 10-0050F204-5
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  secondary type: null
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  wps: 392
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  grpcapab: 0
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  devcapab: 37
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  status: 3
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  wfdInfo: null
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  groupownerAddress: null
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  GOdeviceName: null
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  interfaceAddress: 
02-18 16:31:56.406 20833-20833/com.gett.wifip2ptest I/System.out:  SConnectInfo : null]

Answer 1

在 WIFI_P2P_PEERS_CHANGED_ACTION 中试试这个

else if(WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION.equals(action)){
            //Log.d("wifi", "WIFI PEERS CHANGED");
            mPeers = new ArrayList<WifiP2pDevice>();
            mConfigs = new ArrayList<WifiP2pConfig>();
            if(mManager != null){
                WifiP2pManager.PeerListListener peerListListener = new WifiP2pManager.PeerListListener(){
                    @Override
                    public void onPeersAvailable(WifiP2pDeviceList peerList) {
                        mPeers.clear();
                        mPeers.addAll(peerList.getDeviceList());
                        mActivity.displayPeers(peerList);
                        //mPeers.addAll(peerList.getDeviceList());
                        for(int i=0; i < peerList.getDeviceList().size(); i++){
                            WifiP2pConfig config = new WifiP2pConfig();
                            config.deviceAddress = mPeers.get(i).deviceAddress;
                            mConfigs.add(config);
                        }
                    }
                };
                mManager.requestPeers(mChannel, peerListListener);
            }
        }

displayPeers() 在 MainActivity.java 中

 public void displayPeers(WifiP2pDeviceList peerList){
        wifiP2pArrayAdapter.clear();
        for(WifiP2pDevice peer: peerList.getDeviceList()){
            wifiP2pArrayAdapter.add(peer.deviceName + "\n" + peer.deviceAddress);
        }
    }