如何在Android中一次又一次地从wifi列表中选择相同的wifi运营商？

Question

In my Project I have a Map.First I go to the Wifi router position,I scan the wifi List and select Operator2 and Mark it.Next I go to another position gather the Same Previous Operator2 details(don't ), then I go another position repeat it again.

I can able to First Time select the Wifi Operator.Next time I don't know How to lock the Particular previous selected Operator details and get the operator details again.So Please help me how to fix this.

My Code :

public class WifiReceiver extends BroadcastReceiver {

private WifiManager wifiManager;
private PlanMapperActivity viewerActivity;
private Context newContext;

private String operator;
private String macAddress;
private int signalStrength;
private String wifiMode;
private int frequency;
private String htMode;
private String security;
private int channelNumber;



private AlertDialog wifiAlertDialog;
private ListView  wifiListView;
private ProgressDialog progress;

private Boolean checkWifiSelected;
private Boolean checkServayStart;

private String operatorName;

List<ScanResult> wifiSRList;

private static final String WPA2 = "WPA2";
private static final String WEP = "WEP";
private static final String EAP = "EAP";
private static final String STORED_OPERATOR = "com.kenturf.wifiheatmap.SELECTED_OPERATOR";

private int requiredLevel;
private int ssidCount;

public WifiReceiver(Context ctx,PlanMapperActivity planMapper) {
    this.viewerActivity = planMapper;
    this.newContext = ctx;
}

public WifiReceiver(WifiManager myWifiManager,ProgressDialog wifiProgress,Boolean isWifiSelected,Boolean isSurveyStart) {
    this.wifiManager = myWifiManager;
    this.progress = wifiProgress;
    this.checkWifiSelected = isWifiSelected;
    this.checkServayStart = isSurveyStart;
}

@Override
public void onReceive(final Context context, Intent intent) {

    wifiSRList = wifiManager.getScanResults();

    if (wifiSRList.size() == 0) {
        Toast.makeText(context,"wifi List 0",Toast.LENGTH_SHORT).show();
    }

    if (checkWifiSelected) {
        LayoutInflater wifiLayout = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View wifiView = wifiLayout.inflate(R.layout.dialog_fragment_wifi,null);

        AlertDialog.Builder wifiDialog = new AlertDialog.Builder(context);
        wifiDialog.setCancelable(false);
        wifiDialog.setView(wifiView);

        wifiAlertDialog = wifiDialog.create();
        wifiListView = (ListView)wifiView.findViewById(R.id.user_wifi_detail);
    }


    Collections.sort(wifiSRList, new Comparator<ScanResult>() {
        @Override
        public int compare(ScanResult lhs, ScanResult rhs) {
            return (lhs.level > rhs.level ? -1 : (lhs.level == rhs.level ? 0 : 1));
        }
    });


    if (checkWifiSelected) {
        String[] wifiListString = new String[wifiSRList.size()];

        for (int i = 0; i < wifiSRList.size(); i++) {
            wifiListString[i] = (wifiSRList.get(i).SSID);
        }

        wifiListView.setAdapter(new ArrayAdapter<>(context, android.R.layout.simple_list_item_1, wifiListString));

        wifiAlertDialog.show();
        progress.dismiss();

        wifiListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                operator = wifiSRList.get(position).SSID;
                macAddress = wifiSRList.get(position).BSSID;
                signalStrength = wifiSRList.get(position).level;
                frequency = wifiSRList.get(position).frequency;

                final String cap = wifiSRList.get(position).capabilities;
                final String[] securityModes = {WEP, WPA2, EAP};
                for (int i = securityModes.length - 1; i >= 0; i--) {
                    if (cap.contains(securityModes[i])) {
                        security = securityModes[i];
                    }
                }

                setOperator(operator);
                GetSetClass.wifiOperator = operator;

                /* error start ..cannot resolved method getPreferences() */
                SharedPreferences sharedPref = context.getPreferences(Context.MODE_PRIVATE); // error line
                SharedPreferences.Editor editor = sharedPref.edit();
                editor.putString(STORED_OPERATOR, operator);
                editor.apply();
                /* error end */

                operatorName = operator;
                setMacAddress(macAddress);
                setSignalStrength(signalStrength);
                setFrequency(frequency);
                setSecurity(security);
                setChannelNumber(convertFrequencyToChannel(frequency));
                wifiAlertDialog.dismiss();

                checkWifiSelected = false;
            }
        });
    }

    if(checkServayStart) {
        /* error start ..cannot resolved method getPreferences()*/
        SharedPreferences shPref = context.getPreferences(Context.MODE_PRIVATE); // error line
        String savedOperator = shPref.getString(STORED_OPERATOR,null);

        Log.e("operator : ", "saved operator is : " + savedOperator);
        /* error end */

        if (wifiSRList != null) {
            ssidCount = wifiSRList.size();
            for(int i = wifiSRList.size() - 1; i >= 0; i--) {
                if (GetSetClass.wifiOperator.equals(wifiSRList.get(i).SSID)) {
                    String requiredOperator = wifiSRList.get(i).SSID;
                        requiredLevel = wifiSRList.get(i).level;
                        context.unregisterReceiver(this);
                    AlertDialog.Builder myBuilder = new AlertDialog.Builder(context);

                    setRequiredLevel(requiredLevel);

                    myBuilder.setTitle("Current Signal");
                    myBuilder.setMessage("Operator : " + requiredOperator + " \n\nSignal Strength : " + requiredLevel + " dBm");
                    myBuilder.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            dialog.dismiss();
                        }
                    });
                    myBuilder.show();
                } else {
                    Toast.makeText(context,"Operator Mismatch",Toast.LENGTH_SHORT).show();
                }
            }

            progress.dismiss();
        }
    }
}

public static int convertFrequencyToChannel(int freq) {
    if (freq >= 2412 && freq <= 2484) {
        return (freq - 2412) / 5 + 1;
    } else if (freq >= 5170 && freq <= 5825) {
        return (freq - 5170) / 5 + 34;
    } else {
        return -1;
    }
}
}

UPDATED ANSWER :

private static final String STORED_FILE = "com.package.name.SELECTED_FILE";
private static final String STORED_OPERATOR = "com.package.name.SELECTED_OPERATOR";

Save data to SharedPreferences :

SharedPreferences sharedPref = context.getSharedPreferences(STORED_FILE,Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putString(STORED_OPERATOR, operator);
editor.apply();

Get the data from SharedPreferences :

SharedPreferences shPref = context.getSharedPreferences(STORED_FILE,Context.MODE_PRIVATE);
String savedOperator = shPref.getString(STORED_OPERATOR,null);

Log.e("operator : ", "saved operator is : " + savedOperator);

Answer 1

If I understand you correctly, what you need is a mechanism for persisting what WiFi network the user has previously selected (if any).

You can achieve this using SharedPreferences .

In the beginning of your onReceive method, you query your app's shared preferences for any saved WiFi SSID:

SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
String savedSsid = sharedPref.getString("saved_wifi_ssid", null);

If savedSsid is non-null, the user has previously selected a WiFi, and you can skip showing your dialog:

if (savedSsid != null) {
    // Do whatever you need to do with the stored SSID.
    // Return from onReceive to avoid displaying your dialog.
    return;
}

The last thing you need to do is to store the selected WiFi SSID as part of your onItemClick :

wifi_SSID = wifiList.get(position).SSID;
// ... other code ...
SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putString("saved_wifi_ssid", wifi_SSID);
editor.commit();

See the Android Developer Guide for more information about SharedPreferences.

---

UPDATE

For your specific usecase, ie the BroadcastReceiver resides as a standalone class, you need to access SharedPreferences through the Context instance you receive as an argument in onReceive like so:

SharedPreferences sharedPref = context.getSharedPreferences("name_for_your_shared_preferences_file", Context.MODE_PRIVATE);

This line should replace both occurrences of the line:

SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);

See the documentation for getSharedPreferences(String, int).