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android-studio - 使用 Android 8 的手机上的 Wifi P2P 发送数据失败

问题描述

我想在两部手机之间通过 Wifi P2p 连接发送数据。这适用于低于 8 (Oreo) 的 Android 版本，但当我尝试发送内容时，程序会在 android 8 上停止。我多次检查代码，但我找不到错误。

package com.example.wificonnectiontry2;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.location.LocationManager;
import android.net.wifi.WifiManager;
import android.net.wifi.p2p.WifiP2pConfig;
import android.net.wifi.p2p.WifiP2pDevice;
import android.net.wifi.p2p.WifiP2pDeviceList;
import android.net.wifi.p2p.WifiP2pInfo;
import android.net.wifi.p2p.WifiP2pManager;
import android.os.Build;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private Button btnOnOff, btnDiscover, btnSend;
    private ListView listView;
    private TextView read_msg_box, connectionStatus;
    private EditText writeMsg;

    private WifiManager wifiManager;
    private WifiP2pManager mManager;
    private WifiP2pManager.Channel mChannel;

    private BroadcastReceiver mReceiver;
    private IntentFilter mIntentFilter;

    private List<WifiP2pDevice> peers = new ArrayList<WifiP2pDevice>();
    private String[] deviceNameArray;
    private WifiP2pDevice[] deviceArray;

    private static final int MESSAGE_READ = 1;

    ServerClass serverClass;
    ClientClass clientClass;
    SendReceive sendReceive;

    private boolean gpsGoOn = false;
    private boolean connected = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initialWork();
        exqListener();
    }

    Handler handler = new Handler(new Handler.Callback() {
        @Override
        public boolean handleMessage(Message msg) {
            switch(msg.what){
                case MESSAGE_READ:
                    byte[] readBuff = (byte[]) msg.obj;
                    String tempMsg = new String(readBuff, 0, msg.arg1);
                    read_msg_box.setText(tempMsg);
                    break;
            }
            return true;
        }
    });

    private void exqListener() {
    btnOnOff.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if(wifiManager.isWifiEnabled()) {
                wifiManager.setWifiEnabled(false);
                btnOnOff.setText("Wifi On");
            }else{
                wifiManager.setWifiEnabled(true);
                btnOnOff.setText("Wifi Off");
            }
        }
    });

    btnDiscover.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            discoverPeers();
        }
    });

    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            final WifiP2pDevice device = deviceArray[position];
            WifiP2pConfig config = new WifiP2pConfig();
            config.deviceAddress = device.deviceAddress;

            mManager.connect(mChannel, config, new WifiP2pManager.ActionListener() {
                @Override
                public void onSuccess() {
                    Toast.makeText(getApplicationContext(), "Connected to "+device.deviceName, Toast.LENGTH_SHORT).show();
                }

                @Override
                public void onFailure(int reason) {
                    Toast.makeText(getApplicationContext(), "Not connected", Toast.LENGTH_SHORT).show();
                }
            });
        }
    });

    btnSend.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if(connected) {
                String msg = writeMsg.getText().toString();
                sendReceive.write(msg.getBytes());
            }
        }
    });
    }

    private void discoverPeers(){
        mManager.discoverPeers(mChannel, new WifiP2pManager.ActionListener() {
            @Override
            public void onSuccess() {
                connectionStatus.setText("Discovery Started");
                if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
                    LocationManager L = (LocationManager) getSystemService(LOCATION_SERVICE);
                    if (!L.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
                        Toast.makeText(getApplicationContext(), "Please activate GPS", Toast.LENGTH_LONG).show();
                        gpsGoOn = true;
                        startActivity(new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS));
                    }
                }
            }

            @Override
            public void onFailure(int reason) {
                connectionStatus.setText("Discovery Starting Failed");
            }
        });
    }

    private void initialWork() {
    btnOnOff = (Button) findViewById(R.id.onOff);
    btnDiscover = (Button) findViewById(R.id.discover);
    btnSend = (Button) findViewById(R.id.sendButton);
    listView = (ListView) findViewById(R.id.peerListView);
    read_msg_box = (TextView) findViewById(R.id.readMsg);
    connectionStatus = (TextView) findViewById(R.id.connectionStatus);
    writeMsg = (EditText) findViewById(R.id.writeMsg);

    wifiManager =(WifiManager)getApplicationContext().getSystemService(Context.WIFI_SERVICE);

    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_DISCOVERY_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);
    }

    WifiP2pManager.PeerListListener peerListListener = new WifiP2pManager.PeerListListener() {
        @Override
        public void onPeersAvailable(WifiP2pDeviceList peerList) {
            if(!peerList.getDeviceList().equals(peers)){
                peers.clear();
                peers.addAll(peerList.getDeviceList());

                deviceNameArray = new String[peerList.getDeviceList().size()];
                deviceArray = new WifiP2pDevice[peerList.getDeviceList().size()];
                int index = 0;

                for(WifiP2pDevice device : peerList.getDeviceList()){
                    deviceNameArray[index] = device.deviceName;
                    deviceArray[index] = device;
                    index++;
                }

                ArrayAdapter<String> adapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, deviceNameArray);
                listView.setAdapter(adapter);
            }

            if(peers.size()==0){
                Toast.makeText(getApplicationContext(), "No Device Found", Toast.LENGTH_SHORT).show();
                return;
            }
        }
    };

    WifiP2pManager.ConnectionInfoListener connectionInfoListener = new WifiP2pManager.ConnectionInfoListener() {
        @Override
        public void onConnectionInfoAvailable(WifiP2pInfo info) {
            final InetAddress groupOwner = info.groupOwnerAddress;

            if(info.groupFormed && info.isGroupOwner){
                connectionStatus.setText("Host");
                serverClass = new ServerClass();
                serverClass.start();
            }else{
                connectionStatus.setText("Client");
                clientClass = new ClientClass(groupOwner);
                clientClass.start();
            }
            connected = true;
        }
    };

    public void setConnectionText(String text){
        connectionStatus.setText(text);
    }

    @Override
    protected void onResume() {
        super.onResume();
        registerReceiver(mReceiver, mIntentFilter);
        if(gpsGoOn){
            discoverPeers();
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        unregisterReceiver(mReceiver);

    }

    private class SendReceive extends Thread{
        private Socket socket;
        private InputStream inputStream;
        private OutputStream outputStream;

        public SendReceive(Socket skt){
            socket = skt;
            try {
                inputStream = socket.getInputStream();
                outputStream = socket.getOutputStream();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        @Override
        public void run() {
            byte[] buffer = new byte[1024];
            int bytes;

            while(socket!=null){
                try {
                    bytes = inputStream.read(buffer);
                    if(bytes>0){
                        handler.obtainMessage(MESSAGE_READ, bytes, -1, buffer).sendToTarget();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        public void write(byte[] bytes){
            try {
                outputStream.write(bytes);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public class ServerClass extends Thread{
        private Socket socket;
        private ServerSocket serverSocket;

        @Override
        public void run() {
            try {
                serverSocket = new ServerSocket(8888);
                socket = serverSocket.accept();
                sendReceive = new SendReceive(socket);
                sendReceive.start();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public class ClientClass extends Thread{
        Socket socket;
        String hostAdd;

        public ClientClass(InetAddress hostAddress){
            hostAdd = hostAddress.getHostAddress();
            socket = new Socket();
        }

        @Override
        public void run() {
            try {
                socket.connect(new InetSocketAddress(hostAdd, 8888), 500);
                sendReceive = new SendReceive(socket);
                sendReceive.start();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

那是我发送后收到的错误消息。

--------- 崩溃开始

2019-07-29 20:15:22.468 8068-8068/com.example.wificonnectiontry2 E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.wificonnectiontry2, PID: 8068
    android.os.NetworkOnMainThreadException
        at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1448)
        at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:108)
        at java.net.SocketOutputStream.write(SocketOutputStream.java:141)
        at com.example.wificonnectiontry2.MainActivity$SendReceive.write(MainActivity.java:320)
        at com.example.wificonnectiontry2.MainActivity$5.onClick(MainActivity.java:137)
        at android.view.View.performClick(View.java:6897)
        at android.widget.TextView.performClick(TextView.java:12693)
        at android.view.View$PerformClick.run(View.java:26101)
        at android.os.Handler.handleCallback(Handler.java:789)
        at android.os.Handler.dispatchMessage(Handler.java:98)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6944)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:327)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1374)

标签： android-studiosockets

解决方案

NetworkOnMainThreadException当您以 Honeycomb 或更高版本为目标时引发，并且您尝试从主 UI 线程执行网络操作。在旧版本的 Android 中，这是允许的（但不推荐）。现代 Android 版本不再是这种情况。您必须将网络代码移动到单独的线程或后台任务中。

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