How to Use WiFi Direct on Android?

This example demonstrate about How to Use WiFi Direct on Android

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<?xml version = "1.0" encoding = "utf-8"?>
<LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
   xmlns:tools = "http://schemas.android.com/tools"
   android:layout_width = "match_parent"
   android:layout_height = "match_parent"
   android:layout_margin = "16dp"
   android:orientation = "vertical"
   tools:context = ".MainActivity">
   <Button
      android:text = "Turn on wifi"
      android:id = "@+id/button"
      android:layout_width = "wrap_content"
      android:layout_height = "wrap_content"
      android:layout_gravity = "center" />
</LinearLayout>

Step 3 − Add the following code to src/WifiDirectBroadcastReceiver

package com.example.myapplication;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.wifi.p2p.WifiP2pManager;
import android.widget.Toast;

public class WifiDirectBroadcastReceiver extends BroadcastReceiver {
   WifiP2pManager wifiP2pManager;
   WifiP2pManager.Channel channel;
   MainActivity activity;
   public WifiDirectBroadcastReceiver(WifiP2pManager wifiP2pManager, WifiP2pManager.Channel channel, MainActivity activity) {
      this.wifiP2pManager = wifiP2pManager;
      this.channel = channel;
      this.activity = activity;
   }
   @Override
   public void onReceive(Context context, Intent intent) {
      String action = intent.getAction();
      if (WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION.equals(action)) {
         int state = intent.getIntExtra(WifiP2pManager.EXTRA_WIFI_STATE, -1);
         if (state = = WifiP2pManager.WIFI_P2P_STATE_ENABLED) {
            Toast.makeText(activity, "Wifi on", Toast.LENGTH_SHORT).show();
         } else {
            Toast.makeText(activity, "Wifi off", Toast.LENGTH_SHORT).show();
         }
      } else if (WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION.equals(action)) {
      } else if (WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION.equals(action)) {
      } else if (WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION.equals(action)) {
      }
   }
}

Step 4 − Add the following code to src/MainActivity.java

package com.example.myapplication;
import android.content.BroadcastReceiver;
import android.content.IntentFilter;
import android.net.wifi.WifiManager;
import android.net.wifi.p2p.WifiP2pManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
   TextView text;
   Button button;
   WifiManager mWifiMgr;
   WifiP2pManager mWifiP2pMgr;
   WifiP2pManager.Channel mChannel;
   BroadcastReceiver mReceiver;
   IntentFilter mIntentFilter;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      button = findViewById(R.id.button);
      mWifiMgr = (WifiManager) getApplicationContext().getSystemService(WIFI_SERVICE);
      mWifiMgr.setWifiEnabled(false);
      mWifiP2pMgr = (WifiP2pManager) getApplicationContext().getSystemService(WIFI_P2P_SERVICE);
      mChannel = mWifiP2pMgr.initialize(this, getMainLooper(), null);
      mReceiver = new WifiDirectBroadcastReceiver(mWifiP2pMgr, 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);
      button.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            if (mWifiMgr.isWifiEnabled()) {
               mWifiMgr.setWifiEnabled(false);
               button.setText("Turn on wifi");
            } else {
               mWifiMgr.setWifiEnabled(true);
               button.setText("Turn off wifi");
            }
         }
      });
   }
   @Override
   protected void onResume() {
      super.onResume();
      registerReceiver(mReceiver, mIntentFilter);
   }
   @Override
   protected void onPause() {
      super.onPause();
      unregisterReceiver(mReceiver);
   }
}

Step 5 − Add the following code to androidManifest.xml

<?xml version = "1.0" encoding = "utf-8"?>
<manifest xmlns:android = "http://schemas.android.com/apk/res/android"
   package = "com.example.myapplication">
   <uses-permission android:name = "android.permission.CHANGE_WIFI_STATE" />
   <application
      android:allowBackup = "true"
      android:icon = "@mipmap/ic_launcher"
      android:label = "@string/app_name"
      android:roundIcon = "@mipmap/ic_launcher_round"
      android:supportsRtl = "true"
      android:theme = "@style/AppTheme">
      <activity android:name = "com.example.myapplication.MainActivity">
         <intent-filter>
            <action android:name = "android.intent.action.MAIN" />
            <category android:name = "android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run    icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen –