从Android中单独的AsyncTask类连接WiFi Manager

Question

I have an application that uses an AsyncTask to connect to WiFi using WifiManager .
Now, I am using this in my MainActivity class as

public class connectWifi extends AsyncTask<Void, Void, Void> {
    private ProgressDialog dialog;

    public connectWifi(MyActivity activity) {
        dialog = new ProgressDialog(activity);
    }

    @Override
    protected void onPreExecute() {
        dialog.setIndeterminate(true);
        dialog.setCancelable(false);
        dialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        dialog.setMessage("Connecting to WiFi. Please Wait.");
        dialog.show();
    }

    @Override
    protected void onPostExecute(Void result) {
        connected = true;
        WifiManager wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        WifiInfo conn = wifi.getConnectionInfo();
        Context context = getApplicationContext();
        CharSequence wifi_on = "Connected to " + conn.getSSID();
        int duration = Toast.LENGTH_LONG;
        Toast responseToast = Toast.makeText(context, wifi_on, duration);
        responseToast.show();
        if (dialog.isShowing()) {
            dialog.dismiss();
        }
    }

    @Override
    protected Void doInBackground(Void... voids) {
        WifiManager wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        wifi.setWifiEnabled(true);
        try {
            Thread.sleep(3000);
        } catch (Exception e) {

        }
        return null;
    }
}

---

Now, I have another class AlarmReceiver which gets called via a Broadcast . I am performing some network based action in that class which needs me to connect to WiFi first.
How can I create a separate class for connectWifi which does not involve first running MainActivity ?
The issue I am facing is in creating the Context object which says Non-static 'getApplicationContext()' cannot be referenced from static context .
The same issue is with getSystemService() . How can I create this class as needed?

---

abc is the AsyncTask class.
AlarmReceiver is the BroadcastReceiver

My current flow of control is as follows:
START PROCEDURE
- AlarmManager receives Broadcast
- AlarmManager calls enableWifi() in abc
- enableWifi() connects to WiFi
- AlarmManager checks for connection state
- AlarmManager then calls new abc().execute("DATA1")
- abc then performs the doInBackground task (network request)
- AlarmManager calls disableWifi() in abc to end WiFi
END PROCEDURE

Answer 1

You can create a separated class that depends on Context . Both Activity and a BroadcastReceiver can provide a Context to this class.

Activity is a subclass of Context , so you can pass the Activity as parameter. And the first parameter of onReceive from BroadcastReceiver is the Context .

So you can create an class that receives an Context instance an use the WifiManager :

// This can run outside UI Thread
public static void enableWifi(Context context) {
   WifiManager wifi = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
   wifi.setWifiEnabled(true);
}

// This must run on UI Thread
public static void verifyWifi(Context context) {
    WifiManager wifi = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
    WifiInfo conn = wifi.getConnectionInfo();
    CharSequence wifi_on = "Connected to " + conn.getSSID();
    int duration = Toast.LENGTH_LONG;

    Toast.makeText(context, wifi_on, duration).show();
}

You can use this class to detect when Wifi is enabled or change it's state.

public class NetworkChangeReceiver extends BroadcastReceiver {

    // Static Listener, you can change this
    static OnNetworkConnectionChangedListener mListener;

    // Service to check if Wifi is connected or not
    ConnectivityManager mConnectivityManager;

    @Override
    public void onReceive(Context context, Intent intent) {
        if(mListener != null) {
            if(mConnectivityManager == null) {
                mConnectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
            }
            mListener.onConnectionChanged(NetworkStatusHelper.getConnectivityStatus(mConnectivityManager) != NetworkStatusHelper.TYPE_NOT_CONNECTED);
        }
    }

    public static boolean isConnected(Context context) {
        return NetworkStatusHelper.getConnectivityStatus((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE)) != NetworkStatusHelper.TYPE_NOT_CONNECTED;
    }

    public static void setOnNetworkConnectionChangedListener(OnNetworkConnectionChangedListener listener) {
        mListener = listener;
    }

    public interface OnNetworkConnectionChangedListener {
        public void onConnectionChanged(boolean connected);
    }
}

With this you i'll need to require the ACCESS_NETWORK_STATE permission.

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

And you i'll need to add a receiver for CONNECTIVITY_CHANGE and WIFI_STATE_CHANGED

<receiver
    android:name="yourpackage.NetworkChangeReceiver"
    android:label="NetworkChangeReceiver" >
    <intent-filter>
        <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
        <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
    </intent-filter>
</receiver>

With this you can track when Wifi change its connectivity and is connected.