Android 2.3 wifi hotspot API

Question

What is the API call I need to make in Android 2.2 (Froyo) to create a Wifi hotspot (as seen in the Tethering and Portable Hotspot settings item).

Answer 1

There is no official API, but you can use reflection to handle it. I know some say, it's not recommended, however imho I say, screw it if Google doesn't want to provide an API for whatever reason.

Below is the code of an activity I used in my application, where the user can enable/disable the Wifi AP. When you enable Wifi AP, usually the regular Wifi will be turned off, so after the user disables the Wifi AP again, we'll be activating regular wifi again.

The code sample below is taken from one of my projects, hope you can get the logic there easily. Let me know if you have further questions.

Code is tested on Nexus One 2.2 (and I think also 2.3) as well as on Samsung Galaxy S (2.2).

package com.myapp.android.activity.wifi;

import android.app.ProgressDialog;
import android.content.Context;
import android.net.wifi.WifiConfiguration;
import android.net.wifi.WifiManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;

import java.lang.reflect.Method;

public class WifiAP extends BaseActivity {

    // boolean mIsWifiEnabled = false;
    private static final int WIFI_AP_STATE_UNKNOWN = -1;
    private static final int WIFI_AP_STATE_DISABLING = 0;
    private static final int WIFI_AP_STATE_DISABLED = 1;
    private static final int WIFI_AP_STATE_ENABLING = 2;
    private static final int WIFI_AP_STATE_ENABLED = 3;
    private static final int WIFI_AP_STATE_FAILED = 4;

    private final String[] WIFI_STATE_TEXTSTATE = new String[] {
        "DISABLING","DISABLED","ENABLING","ENABLED","FAILED"
    };

    private WifiManager wifi;

    @Override
    protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.wifi);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD
                |WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
                |WindowManager.LayoutParams.FLAG_DIM_BEHIND
        );

        wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
    }

    @Override
    public void onResume() {
        super.onResume();
        updateStatusDisplay();
    }

    public void toggleWifi(View v) {
        boolean wifiApIsOn = getWifiAPState()==WIFI_AP_STATE_ENABLED || getWifiAPState()==WIFI_AP_STATE_ENABLING;
        new SetWifiAPTask(!wifiApIsOn,false).execute();
    }

    public void close(View v) {
        boolean wifiApIsOn = getWifiAPState()==WIFI_AP_STATE_ENABLED || getWifiAPState()==WIFI_AP_STATE_ENABLING;
        if (wifiApIsOn) {
            new SetWifiAPTask(false,true).execute();
        } else {
            finish();
        }
    }


    /**
     * Endable/disable wifi
     * @param enabled
     * @return WifiAP state
     */
    private int setWifiApEnabled(boolean enabled) {
        Log.d("WifiAP", "*** setWifiApEnabled CALLED **** " + enabled);
        if (enabled && wifi.getConnectionInfo() !=null) {
            wifi.setWifiEnabled(false);
            try {Thread.sleep(1500);} catch (Exception e) {}
        }

        //int duration = Toast.LENGTH_LONG;
        //String toastText = "MobileAP status: ";
        int state = WIFI_AP_STATE_UNKNOWN;
        try {
            wifi.setWifiEnabled(false);
            Method method1 = wifi.getClass().getMethod("setWifiApEnabled",
                WifiConfiguration.class, boolean.class);
            method1.invoke(wifi, null, enabled); // true
            Method method2 = wifi.getClass().getMethod("getWifiApState");
            state = (Integer) method2.invoke(wifi);
        } catch (Exception e) {
           Log.e(WIFI_SERVICE, e.getMessage());
           // toastText += "ERROR " + e.getMessage();
        }

        if (!enabled) {
            int loopMax = 10;
            while (loopMax>0 && (getWifiAPState()==WIFI_AP_STATE_DISABLING
                    || getWifiAPState()==WIFI_AP_STATE_ENABLED
                    || getWifiAPState()==WIFI_AP_STATE_FAILED)) {
                try {Thread.sleep(500);loopMax--;} catch (Exception e) {}
            }
            wifi.setWifiEnabled(true);
        } else if (enabled) {
            int loopMax = 10;
            while (loopMax>0 && (getWifiAPState()==WIFI_AP_STATE_ENABLING
                    || getWifiAPState()==WIFI_AP_STATE_DISABLED
                    || getWifiAPState()==WIFI_AP_STATE_FAILED)) {
                try {Thread.sleep(500);loopMax--;} catch (Exception e) {}
            }
        }

        return state;
    }


    private int getWifiAPState() {
        int state = WIFI_AP_STATE_UNKNOWN;
        try {
            Method method2 = wifi.getClass().getMethod("getWifiApState");
            state = (Integer) method2.invoke(wifi);
        } catch (Exception e) {}
        Log.d("WifiAP", "getWifiAPState.state " + (state==-1?"UNKNOWN":WIFI_STATE_TEXTSTATE[state]));
        return state;
    }

    private void updateStatusDisplay() {

        if (getWifiAPState()==WIFI_AP_STATE_ENABLED || getWifiAPState()==WIFI_AP_STATE_ENABLING) {
            ((Button)findViewById(R.id.btnWifiToggle)).setText("Turn off");
            findViewById(R.id.bg).setBackgroundResource(R.drawable.bg_wifi_on);
        } else {
            ((Button)findViewById(R.id.btnWifiToggle)).setText("Turn on");
            findViewById(R.id.bg).setBackgroundResource(R.drawable.bg_wifi_off);
        }

    }


    class SetWifiAPTask extends AsyncTask<Void, Void, Void> {

        boolean mMode;
        boolean mFinish;

        public SetWifiAPTask(boolean mode, boolean finish) {
            mMode = mode;
            mFinish = finish;
        }

        ProgressDialog d = new ProgressDialog(WifiAP.this);

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            d.setTitle("Turning WiFi AP " + (mMode?"on":"off") + "...");
            d.setMessage("...please wait a moment.");
            d.show();
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            try {d.dismiss();} catch (IllegalArgumentException e) {};
            updateStatusDisplay();
            if (mFinish) finish();
        }

        @Override
        protected Void doInBackground(Void... params) {
            setWifiApEnabled(mMode);
            return null;
        }
    }


}

Answer 2

For anyone interested in getting this working on ICS, setting your AP name, and/or keeping all the WifiAP code in its own class I have updated and improved upon the code given in the other answer:

WifiAP.java:

package com.demo.wifiap;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.net.wifi.WifiConfiguration;
import android.net.wifi.WifiManager;
import android.os.AsyncTask;
import android.util.Log;

import java.lang.reflect.Method;

import com.demo.WifiAPActivity;

/**
 * Handle enabling and disabling of WiFi AP
 * @author http://stackoverflow.com/a/7049074/1233435
 */
public class WifiAP extends Activity {
    private static int constant = 0;

    private static final int WIFI_AP_STATE_UNKNOWN = -1;
    private static int WIFI_AP_STATE_DISABLING = 0;
    private static int WIFI_AP_STATE_DISABLED = 1;
    public int WIFI_AP_STATE_ENABLING = 2;
    public int WIFI_AP_STATE_ENABLED = 3;
    private static int WIFI_AP_STATE_FAILED = 4;

    private final String[] WIFI_STATE_TEXTSTATE = new String[] {
            "DISABLING","DISABLED","ENABLING","ENABLED","FAILED"
    };

    private WifiManager wifi;
    private String TAG = "WifiAP";

    private int stateWifiWasIn = -1;

    private boolean alwaysEnableWifi = true; //set to false if you want to try and set wifi state back to what it was before wifi ap enabling, true will result in the wifi always being enabled after wifi ap is disabled

    /**
     * Toggle the WiFi AP state
     * @param wifihandler
     * @author http://stackoverflow.com/a/7049074/1233435
     */
    public void toggleWiFiAP(WifiManager wifihandler, Context context) {
        if (wifi==null){
            wifi = wifihandler;
        }

        boolean wifiApIsOn = getWifiAPState()==WIFI_AP_STATE_ENABLED || getWifiAPState()==WIFI_AP_STATE_ENABLING;
        new SetWifiAPTask(!wifiApIsOn,false,context).execute();
    }

    /**
     * Enable/disable wifi
     * @param true or false
     * @return WifiAP state
     * @author http://stackoverflow.com/a/7049074/1233435
     */
    private int setWifiApEnabled(boolean enabled) {
        Log.d(TAG, "*** setWifiApEnabled CALLED **** " + enabled);

        WifiConfiguration config = new WifiConfiguration();
        config.SSID = "My AP";
        config.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.OPEN);

        //remember wirelesses current state
        if (enabled && stateWifiWasIn==-1){
            stateWifiWasIn=wifi.getWifiState();
        }

        //disable wireless
        if (enabled && wifi.getConnectionInfo() !=null) {
            Log.d(TAG, "disable wifi: calling");
            wifi.setWifiEnabled(false);
            int loopMax = 10;
            while(loopMax>0 && wifi.getWifiState()!=WifiManager.WIFI_STATE_DISABLED){
                Log.d(TAG, "disable wifi: waiting, pass: " + (10-loopMax));
                try {
                    Thread.sleep(500);
                    loopMax--;
                } catch (Exception e) {

                }
            }
            Log.d(TAG, "disable wifi: done, pass: " + (10-loopMax));
        }

        //enable/disable wifi ap
        int state = WIFI_AP_STATE_UNKNOWN;
        try {
            Log.d(TAG, (enabled?"enabling":"disabling") +" wifi ap: calling");
            wifi.setWifiEnabled(false);
            Method method1 = wifi.getClass().getMethod("setWifiApEnabled", WifiConfiguration.class, boolean.class);
            //method1.invoke(wifi, null, enabled); // true
            method1.invoke(wifi, config, enabled); // true
            Method method2 = wifi.getClass().getMethod("getWifiApState");
            state = (Integer) method2.invoke(wifi);
        } catch (Exception e) {
            Log.e(WIFI_SERVICE, e.getMessage());
            // toastText += "ERROR " + e.getMessage();
        }


        //hold thread up while processing occurs
        if (!enabled) {
            int loopMax = 10;
            while (loopMax>0 && (getWifiAPState()==WIFI_AP_STATE_DISABLING || getWifiAPState()==WIFI_AP_STATE_ENABLED || getWifiAPState()==WIFI_AP_STATE_FAILED)) {
                Log.d(TAG, (enabled?"enabling":"disabling") +" wifi ap: waiting, pass: " + (10-loopMax));
                try {
                    Thread.sleep(500);
                    loopMax--;
                } catch (Exception e) {

                }
            }
            Log.d(TAG, (enabled?"enabling":"disabling") +" wifi ap: done, pass: " + (10-loopMax));

            //enable wifi if it was enabled beforehand
            //this is somewhat unreliable and app gets confused and doesn't turn it back on sometimes so added toggle to always enable if you desire
            if(stateWifiWasIn==WifiManager.WIFI_STATE_ENABLED || stateWifiWasIn==WifiManager.WIFI_STATE_ENABLING || stateWifiWasIn==WifiManager.WIFI_STATE_UNKNOWN || alwaysEnableWifi){
                Log.d(TAG, "enable wifi: calling");
                wifi.setWifiEnabled(true);
                //don't hold things up and wait for it to get enabled
            }

            stateWifiWasIn = -1;
        } else if (enabled) {
            int loopMax = 10;
            while (loopMax>0 && (getWifiAPState()==WIFI_AP_STATE_ENABLING || getWifiAPState()==WIFI_AP_STATE_DISABLED || getWifiAPState()==WIFI_AP_STATE_FAILED)) {
                Log.d(TAG, (enabled?"enabling":"disabling") +" wifi ap: waiting, pass: " + (10-loopMax));
                try {
                    Thread.sleep(500);
                    loopMax--;
                } catch (Exception e) {

                }
            }
            Log.d(TAG, (enabled?"enabling":"disabling") +" wifi ap: done, pass: " + (10-loopMax));
        }
        return state;
    }

    /**
     * Get the wifi AP state
     * @return WifiAP state
     * @author http://stackoverflow.com/a/7049074/1233435
     */
    public int getWifiAPState() {
        int state = WIFI_AP_STATE_UNKNOWN;
        try {
            Method method2 = wifi.getClass().getMethod("getWifiApState");
            state = (Integer) method2.invoke(wifi);
        } catch (Exception e) {

        }

        if(state>=10){
            //using Android 4.0+ (or maybe 3+, haven't had a 3 device to test it on) so use states that are +10
            constant=10;
        }

        //reset these in case was newer device
        WIFI_AP_STATE_DISABLING = 0+constant;
        WIFI_AP_STATE_DISABLED = 1+constant;
        WIFI_AP_STATE_ENABLING = 2+constant;
        WIFI_AP_STATE_ENABLED = 3+constant;
        WIFI_AP_STATE_FAILED = 4+constant;

        Log.d(TAG, "getWifiAPState.state " + (state==-1?"UNKNOWN":WIFI_STATE_TEXTSTATE[state-constant]));
        return state;
    }

    /**
     * the AsyncTask to enable/disable the wifi ap
     * @author http://stackoverflow.com/a/7049074/1233435
     */
    class SetWifiAPTask extends AsyncTask<Void, Void, Void> {
        boolean mMode; //enable or disable wifi AP
        boolean mFinish; //finalize or not (e.g. on exit)
        ProgressDialog d;

        /**
         * enable/disable the wifi ap
         * @param mode enable or disable wifi AP
         * @param finish finalize or not (e.g. on exit)
         * @param context the context of the calling activity
         * @author http://stackoverflow.com/a/7049074/1233435
         */
        public SetWifiAPTask(boolean mode, boolean finish, Context context) {
            mMode = mode;
            mFinish = finish;
            d = new ProgressDialog(context);
        }

        /**
         * do before background task runs
         * @author http://stackoverflow.com/a/7049074/1233435
         */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            d.setTitle("Turning WiFi AP " + (mMode?"on":"off") + "...");
            d.setMessage("...please wait a moment.");
            d.show();
        }

        /**
         * do after background task runs
         * @param aVoid
         * @author http://stackoverflow.com/a/7049074/1233435
         */
        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            try {
                d.dismiss();
                WifiAPActivity.updateStatusDisplay();
            } catch (IllegalArgumentException e) {

            };
            if (mFinish){
                finish();
            }
        }

        /**
         * the background task to run
         * @param params
         * @author http://stackoverflow.com/a/7049074/1233435
         */
        @Override
        protected Void doInBackground(Void... params) {
            setWifiApEnabled(mMode);
            return null;
        }
    }
}

WifiAPActivity.java:

package com.demo;

import android.app.Activity;
import android.content.Context;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;

import com.demo.WifiAP;

public class WifiAPActivity extends Activity {
    //private String TAG = "WifiAPActivity";

    boolean wasAPEnabled = false;
    static WifiAP wifiAp;
    private WifiManager wifi;
    static Button btnWifiToggle;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.wifi);

        btnWifiToggle = (Button) findViewById(R.id.btnWifiToggle);

        wifiAp = new WifiAP();
        wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);

        btnWifiToggle.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                wifiAp.toggleWiFiAP(wifi, WifiAPActivity.this);
            }
        });

        getWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD|WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON|WindowManager.LayoutParams.FLAG_DIM_BEHIND);       
    }

    @Override
    public void onResume() {
        super.onResume();
        if (wasAPEnabled) {
            if (wifiAp.getWifiAPState()!=wifiAp.WIFI_AP_STATE_ENABLED && wifiAp.getWifiAPState()!=wifiAp.WIFI_AP_STATE_ENABLING){
                wifiAp.toggleWiFiAP(wifi, WifiAPActivity.this);
            }
        }
        updateStatusDisplay();
    }

    @Override
    public void onPause() {
        super.onPause();
        boolean wifiApIsOn = wifiAp.getWifiAPState()==wifiAp.WIFI_AP_STATE_ENABLED || wifiAp.getWifiAPState()==wifiAp.WIFI_AP_STATE_ENABLING;
        if (wifiApIsOn) {
            wasAPEnabled = true;
            wifiAp.toggleWiFiAP(wifi, WifiAPActivity.this);
        } else {
            wasAPEnabled = false;
        }
        updateStatusDisplay();
    }

    public static void updateStatusDisplay() {
        if (wifiAp.getWifiAPState()==wifiAp.WIFI_AP_STATE_ENABLED || wifiAp.getWifiAPState()==wifiAp.WIFI_AP_STATE_ENABLING) {
            btnWifiToggle.setText("Turn off");
            //findViewById(R.id.bg).setBackgroundResource(R.drawable.bg_wifi_on);
        } else {
            btnWifiToggle.setText("Turn on");
            //findViewById(R.id.bg).setBackgroundResource(R.drawable.bg_wifi_off);
        }
    }
}

wifi.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button
        android:id="@+id/btnWifiToggle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button" />

</LinearLayout>

permissions:

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"></uses-permission>

Answer 3

There is no public API for this.