Skip to main content

Documentation Index

Fetch the complete documentation index at: https://mintlify.com/anfegomezver/spectrum24ghz/llms.txt

Use this file to discover all available pages before exploring further.

Spectrum 2.4 GHz uses Android’s WifiManager API to discover nearby 2.4 GHz networks. Every scan follows a strict lifecycle — from permission checks through result filtering — to ensure the app never overwhelms the system while still delivering up-to-date signal data. Understanding this flow helps you get the most accurate readings and troubleshoot situations where results look stale.

​
Scan Lifecycle

1

Tap Escanear

Pressing the Escanear button calls requestPermissionsAndScan(). The app checks whether ACCESS_FINE_LOCATION, ACCESS_COARSE_LOCATION, and (on Android 13+) NEARBY_WIFI_DEVICES permissions are already granted.
  • If all permissions are present, startScanFlow() is called immediately.
  • If any permission is missing, the system permission dialog is shown. After the user responds, startScanFlow() is called on success or a rationale dialog is shown on denial.
2

Cooldown check (30 s)

startScanFlow() compares the current elapsed time against lastScanStartMs. If fewer than 30,000 ms (30 seconds) have passed since the last scan started, the app skips the new scan and calls loadCachedResults() instead, displaying the most recent WifiManager.getScanResults() data.The status bar immediately reflects this with a · caché suffix (see Status bar format below).
3

Wi-Fi availability check

If the cooldown has elapsed, startScanFlow() verifies that either wifiManager.isWifiEnabled() or wifiManager.isScanAlwaysAvailable() returns true. If neither is true, a dialog prompts the user to open Wi-Fi Settings or Location Settings before proceeding.
4

Initiate scan — initiateWifiScan()

initiateWifiScan() records the current timestamp in lastScanStartMs, sets the UI to scanning state, clears any previous results, registers a BroadcastReceiver for SCAN_RESULTS_AVAILABLE_ACTION, and calls wifiManager.startScan().A 12-second timeout (SCAN_TIMEOUT_MS = 12_000L) is simultaneously posted. If the BroadcastReceiver has not fired by then, handleScanResults(false) is called automatically as a fallback.
5

Receive results — BroadcastReceiver

When Android delivers the SCAN_RESULTS_AVAILABLE_ACTION broadcast, handleScanResults(fresh) is called with the EXTRA_RESULTS_UPDATED boolean. A value of false means the OS returned cached results.
6

Filter and populate

populateNetworks() iterates wifiManager.getScanResults() and discards any result whose frequency falls outside 2410–2486 MHz (FREQ_MIN / FREQ_MAX). This window covers channels 1–14 with a ±2 MHz margin for non-standard chipsets. Accepted results are wrapped into ScannedNetwork objects and sorted by RSSI descending.
7

Push to history and refresh UI

The new network list is appended to scanHistory (capped at 20 entries). All adapters are notified, the Time Graph view is updated, and if the Statistics tab is currently visible it is refreshed. The scanning state is cleared and the status bar is updated.

​
Scanning State UI

While a scan is in progress the interface changes to prevent duplicate scans:
  • The progress bar becomes visible.
  • The Escanear button is disabled and its label changes to “Escaneando…”.
  • Both states are restored by setScanningState(false) once handleScanResults completes.

​
Status Bar Text Format

After every scan (or cache load), the status bar displays a single line built from this template: 
Escaneo: HH:mm:ss · N redes
SegmentValue
HH:mm:ssWall-clock time of result delivery (24-hour format)
N redesTotal accepted network count; "sin redes detectadas" when zero
· cachéAppended when fresh == false (OS returned stale results or timeout fired)
Example: Escaneo: 14:32:07 · 8 redes · caché

​
Auto-Scan on the Time Graph Tab

When the Tiempo tab (index 2) is active, a Handler fires every 5,000 ms and calls initiateWifiScan() directly — bypassing the 30-second cooldown check. This keeps the time-series graph continuously updated without requiring manual interaction. 
private final Runnable autoUpdateTask = new Runnable() {
    @Override
    public void run() {
        if (currentTab == 2) {
            initiateWifiScan();
        }
        autoUpdateHandler.postDelayed(this, 5000L);
    }
};
The handler is started in onCreate() and cancelled in onDestroy(), so it only runs while the activity is alive.

​
Frequency Filter Constants

private static final int FREQ_MIN = 2410; // MHz
private static final int FREQ_MAX = 2486; // MHz
Results outside this range — including 5 GHz, 6 GHz, and any 2.4 GHz outliers — are silently discarded during populateNetworks().
The 30-second cooldown means tapping Escanear rapidly will serve cached results on every tap after the first. The · caché suffix in the status bar is your indicator that no new radio scan occurred. Wait 30 seconds from the last scan timestamp before expecting a fresh radio sweep.
If the app shows a “Wi-Fi desactivado” dialog, you have two options without turning on Wi-Fi fully: navigate to Settings → Location → Advanced → Wi-Fi scanning and enable “Scan Always Available”. This lets Spectrum (and Android location services) perform background scans even when the Wi-Fi toggle is off.

Build docs developers (and LLMs) love

Get started for freeTalk to us