java - Android/Java WiFi 直接对端列表

Question

哟，

我正在尝试让 Android 设备(它是 Nexus 7，尽管我无法想象这有多大关系)通过 WiFi Direct 的奇迹与 Raspberry Pi 进行通信。据说这是可能的，六个小时前它似乎是比沿着服务器-客户端路线走更好的解决方案，但我遇到了问题

Android 开发者网站很不错，因为它有两个指南:

http://developer.android.com/training/connect-devices-wirelessly/wifi-direct.html http://developer.android.com/guide/topics/connectivity/wifip2p.html

这很好，因为我没有大量的 Java 经验。但问题是……实际上在该网站上有很多问题是，他们认为直接的代码元素(即放东西的地方)经常缺失。

我已经非常仔细地遵循了这两个指南，但我遇到了一个问题 - WIFI_P2P_PEERS_CHANGED_ACTION Intent 永远不会广播，所以当我寻找同伴时，它开始搜索，说一切都很好，但没有给出给我一份结果 list ……我猜应该是这样

我一天中的大部分时间都在与这个问题搏斗，我得了花粉症，让生活变得更加甜蜜

代码:

Activity :

package com.example.bingotest;

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

import android.net.wifi.p2p.WifiP2pDevice;
import android.net.wifi.p2p.WifiP2pDeviceList;
import android.net.wifi.p2p.WifiP2pManager;
import android.net.wifi.p2p.WifiP2pManager.Channel;
import android.net.wifi.p2p.WifiP2pManager.PeerListListener;
import android.os.Build;
import android.os.Bundle;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.ActivityInfo;
import android.util.Log;
import android.view.Menu;

public class BingoActivity extends Activity {

    private BingoView _view;

    private IntentFilter _intentFilter = new IntentFilter();

    private BroadcastReceiver _broadcastReceiver = null;
    private WifiP2pManager _manager;
    private Channel _channel;

    private List _peers = new ArrayList();
    private PeerListListener _peerListListener;

    //-------------------------------------------------------------------------------

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        _view = new BingoView(this);
        setContentView(_view);

        _intentFilter.addAction(WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION);
        _intentFilter.addAction(WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION);
        _intentFilter.addAction(WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION);
        _intentFilter.addAction(WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION);

        _manager = (WifiP2pManager) getSystemService(Context.WIFI_P2P_SERVICE);
        _channel = _manager.initialize(this, getMainLooper(), null);
        //_broadcastReceiver = new WiFiDirectBroadcastReceiver(_manager, _channel, this);
        //registerReceiver(_broadcastReceiver, _intentFilter);

        _peerListListener = new PeerListListener() {
            @Override
            public void onPeersAvailable(WifiP2pDeviceList peerList) {
                Log.d("wifi", "here");
                 // Out with the old, in with the new.
                _peers.clear();
                _peers.addAll(peerList.getDeviceList());

                if (_peers.size() == 0) {
                    Log.d("wifi", "No devices found");
                    return;
                }
            }
        };
    }

    //-------------------------------------------------------------------------------

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

    //-------------------------------------------------------------------------------

    @Override
    public void onResume() {
        super.onResume();
        _broadcastReceiver = new WiFiDirectBroadcastReceiver(_manager, _channel, this, _peerListListener);
        registerReceiver(_broadcastReceiver, _intentFilter);
    }

    //-------------------------------------------------------------------------------

    @Override
    public void onPause() {
        super.onPause();
        unregisterReceiver(_broadcastReceiver);
    }

}

WiFiDirectBroadcastReceiver 类:

package com.example.bingotest;

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

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

public class WiFiDirectBroadcastReceiver extends BroadcastReceiver {
    private WifiP2pManager _manager;
    private Channel _channel;
    private BingoActivity _activityRef;
    private List _peers = new ArrayList();

    PeerListListener _peerListListener;


    //-------------------------------------------------------------------------------

    public WiFiDirectBroadcastReceiver(WifiP2pManager manager, Channel channel, BingoActivity activity, PeerListListener peerListListener) {
        super();
        _manager = manager;
        _channel = channel;
        _activityRef = activity;        
        _peerListListener = peerListListener;


        _manager.discoverPeers(_channel, new WifiP2pManager.ActionListener() {
            @Override
            public void onSuccess() {
                Log.d("wifi", "onsuccess");
            }

            @Override
            public void onFailure(int reasonCode) {
                Log.d("wifi", "onfailure");
            }
        });



    }

    //-------------------------------------------------------------------------------

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();

        Log.d("wifi", "receive: " + 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) {
                Log.d("wifi", "WIFI DIRECT ON");

            } else {
                Log.d("wifi", "WIFI DIRECT OFF");
            }

        }
        else if (WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION.equals(action)) {
            Log.d("wifi", "Peers changed");        
            if (_manager != null) {
                _manager.requestPeers(_channel, _peerListListener);
            }

        }
        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
        }

    }

    //-------------------------------------------------------------------------------

}

(为可能困惑和浪费的代码道歉 - 我一直在尝试获得结果)

我们非常乐意提供帮助。我的猜测是 peerListListener 在错误的地方。我的 Android 知识非常少。

提前致谢。

Answer 1

我可以看到你在构造你的WiFiDirectBroadcastReceiver时做了一个初步的发现

然后在您的 Activity.onResume() 中，您首先构建 WiFiDirectBroadcastReceiver，然后构建 registerReceiver()。

@Override
public void onResume() {
    super.onResume();
    _broadcastReceiver = new WiFiDirectBroadcastReceiver(_manager, _channel, this, _peerListListener);
    registerReceiver(_broadcastReceiver, _intentFilter);
}

您没有看到响应返回的问题可能是因为序列。尝试将 discoverPeers() 移动到 Activity.onResume() 应该可以解决问题.