WiFi getSSID () siempre devuelve "<ssid desconocido>"

Esta pregunta ya ha sido formulada por muchas personas, pero la solución que funcionó para ellos no funciona para mí. He probado en Android 8.1 y Android 9.0 y no puedo obtener el nombre del SSID.

Receptor de difusión para obtener cambios de estado de WiFi:

private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if(intent.getAction().equals(WifiManager.WIFI_STATE_CHANGED_ACTION) ||
                intent.getAction().equals(ConnectivityManager.CONNECTIVITY_ACTION) ||
                intent.getAction().equals(WifiManager.SUPPLICANT_STATE_CHANGED_ACTION) ||
                intent.getAction().equals(WifiManager.SUPPLICANT_CONNECTION_CHANGE_ACTION) ||
                intent.getAction().equals(WifiManager.NETWORK_STATE_CHANGED_ACTION)) {
            setWifiIndicator();
        }
    }
};

El receptor está registrado onCreatey no registrado onDestroy, lo que creo que es correcto, y estoy viendo las líneas de registro cuando se llama al receptor.

en onCreate:

IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(ScannerService.ACTION_READ_SCANNER);
intentFilter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);
intentFilter.addAction(WifiManager.SUPPLICANT_CONNECTION_CHANGE_ACTION);
intentFilter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION);
intentFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
intentFilter.addAction(WifiManager.SUPPLICANT_STATE_CHANGED_ACTION);
registerReceiver(mReceiver, intentFilter);
setWifiIndicator();

setWifiIndicator se implementa así:

private void setWifiIndicator() {
    ConnectivityManager connMgr = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
    //getApplicationContext solves memory leak issues prior to Android N (must use Application Context to get wifi system service.
    WifiManager wifiMgr = (WifiManager)getApplicationContext().getSystemService(Context.WIFI_SERVICE);
    ImageView wifiIndicator = (ImageView)findViewById(R.id.wifi_indicator);
    TextView wifiSSID = (TextView)findViewById(R.id.wifi_ssid);

    try {
        if (wifiMgr != null) {
            if (wifiMgr.isWifiEnabled()) {
                //wifi is enabled.  toggle on wifi indicator.
                wifiIndicator.setImageResource(R.drawable.wifi_indicator);
                String ssid = wifiMgr.getConnectionInfo().getSSID();
                if (ssid != null) {
                    Log.v(this.getClass().getSimpleName(), "SSID: " + ssid + "  Supplicant State: " + info.getSupplicantState());
                    wifiSSID.setText(ssid);
                }
            } else {
                //wifi is disabled.  toggle off wifi indicator.
                wifiSSID.setText("");

                //check for 3G
                NetworkInfo mobileInfo = connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
                if (mobileInfo != null && mobileInfo.getState().equals(NetworkInfo.State.CONNECTED)) {
                    wifiIndicator.setImageResource(R.drawable.cellular_indicator);
                } else {
                    wifiIndicator.setImageResource(R.drawable.down_indicator);
                }
            }
        } else {
            //check for 3G
            NetworkInfo mobileInfo = connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
            if (mobileInfo != null && mobileInfo.getState().equals(NetworkInfo.State.CONNECTED)) {
                wifiIndicator.setImageResource(R.drawable.cellular_indicator);
            } else {
                wifiIndicator.setImageResource(R.drawable.down_indicator);
            }
        }
    } catch(Exception e) {
        //catching anything thrown in this block just so it doesn't crash the program unnecessarily
        e.printStackTrace();
    }
}

Mi aplicación ya tenía permiso ACCESS_COARSE_LOCATIONpero también agregué por ACCESS_FINE_LOCATIONsi acaso. getSSID()es hasta que regrese <unknown ssid>.

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.GET_TASKS" />

Quizás tiene que ver con compilar SDK de destino? Estoy realmente despistado aquí.

archivo gradle:

aplique el complemento: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.noneofyour.business"
        minSdkVersion 15
        targetSdkVersion 28
        versionCode 59
        versionName "1.44"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support:appcompat-v7:28.0.0'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation files('libs/android.jar')
}

¿Has intentado comprobar si getSupplicantState()es así COMPLETED?

if(wifiInfo.getSupplicantState() == SupplicantState.COMPLETED){
        String ssid = wifiInfo.getSSID();
        wifiSSID.setText(ssid);
}

Además, ¿ha pedido esto antes de ejecutarlo BroadcastReceivero incluso dentro puede hacerlo:

 if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, LOCATION);
}else{setWifiIndicator();