在我的项目中，我有一个 map 。首先，我转到 Wifi 路由器位置，我扫描 wifi 列表并选择 Operator2 并标记它。接下来我去另一个位置收集相同的以前的 Operator2 详细信息(不要)，然后我换个位置再重复一遍。

我可以第一次选择 Wifi 运营商。下次我不知道如何锁定特定的先前选择的运营商详细信息并再次获取运营商详细信息。所以请帮我解决这个问题。

我的代码:

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;
    }
}
}

更新的答案:

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

将数据保存到 SharedPreferences :

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

从 SharedPreferences 获取数据:

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

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

最佳答案

如果我没理解错的话，您需要的是一种机制来保存用户之前选择的 WiFi 网络(如果有的话)。

您可以使用 SharedPreferences 实现此目的.

在 onReceive 方法的开头，您查询应用的共享首选项以查找任何已保存的 WiFi SSID:

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

如果 savedSsid 不为空，则用户之前选择了 WiFi，您可以跳过显示对话框:

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

您需要做的最后一件事是将选定的 WiFi SSID 存储为 onItemClick 的一部分:

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();

参见 the Android Developer Guide有关 SharedPreferences 的更多信息。

更新

对于您的特定用例，即 BroadcastReceiver 作为独立类驻留，您需要通过 Context 实例访问 SharedPreferences，您在 onReceive 中作为参数接收 像这样:

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

此行应替换该行的两次出现:

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

参见 documentation对于 getSharedPreferences(String, int)。

关于java - 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？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/31992164/