refact: [QR] Remove connectWithQrCode, the QR code only holds the IP address

FloconAndroid/qrscanner/qrscanner/src/androidMain/kotlin/io/github/openflocon/flocon/qrscanner/ScanQrCodeAndConnect.kt

@@ -1,20 +1,25 @@
 package io.github.openflocon.flocon.qrscanner
 
 import android.content.Context
+import com.google.android.gms.common.ConnectionResult
+import com.google.android.gms.common.GoogleApiAvailability
 import com.google.mlkit.vision.barcode.common.Barcode
 import com.google.mlkit.vision.codescanner.GmsBarcodeScannerOptions
 import com.google.mlkit.vision.codescanner.GmsBarcodeScanning
 import io.github.openflocon.flocon.Flocon
 import io.github.openflocon.flocon.FloconConnectResult
+import io.github.openflocon.flocon.connect
 import kotlinx.coroutines.suspendCancellableCoroutine
 import kotlin.coroutines.resume
 
 /**
  * Opens the Google code scanner, then connects to the desktop app at the address held by the QR code
- * it reads, see [connectWithQrCode].
+ * it reads. The QR code of Flocon Desktop holds only the IP address of the computer, the same value as
+ * `Flocon.connect(address)`.
  *
  * The scanner is a screen of Google Play Services: the app needs no camera permission. It requires
- * Google Play Services on the device, otherwise the result is [FloconConnectResult.Failed].
+ * Google Play Services on the device, otherwise the result is [FloconConnectResult.Failed]: connect with
+ * `Flocon.connect(address)` instead.
  *
  * ```
  * val result = Flocon.scanQrCodeAndConnect(context)
@@ -23,12 +28,16 @@ import kotlin.coroutines.resume
  * @param context preferably an `Activity`.
  * @return the result of the connection, or `null` if the user closed the scanner without scanning.
  */
-suspend fun Flocon.Companion.scanQrCodeAndConnect(context: Context): FloconConnectResult? =
-    when (val scan = scanQrCode(context)) {
+suspend fun Flocon.Companion.scanQrCodeAndConnect(context: Context): FloconConnectResult? {
+    if (GoogleApiAvailability.getInstance().isGooglePlayServicesAvailable(context) != ConnectionResult.SUCCESS) {
+        return FloconConnectResult.Failed("Google Play Services is required to scan a QR code: connect with the IP address instead")
+    }
+    return when (val scan = scanQrCode(context)) {
         ScanQrCodeResult.Cancelled -> null
         is ScanQrCodeResult.Failed -> FloconConnectResult.Failed(scan.reason)
-        is ScanQrCodeResult.Code -> connectWithQrCode(scan.content)
+        is ScanQrCodeResult.Code -> connect(scan.content)
     }
+}
 
 private sealed interface ScanQrCodeResult {
     data class Code(val content: String) : ScanQrCodeResult

docs/setup.md

@@ -127,7 +127,9 @@ Until a desktop is reachable, everything the plugins log is kept in memory. `Flo
 
 ### Connecting with a QR code
 
-The desktop app has a **Connect** button in the top bar (QR code icon). It opens a dialog listing the IP addresses of the computer on the local network (one per network interface) and, for each one, a button that shows the address as a QR code. The QR code contains only the IP address, the same value as `Flocon.connect("192.168.1.20")`. Scanning it from the SDK is not available yet.
+The desktop app has a **Connect** button in the top bar (QR code icon). It opens a dialog listing the IP addresses of the computer on the local network (one per network interface) and, for each one, a button that shows the address as a QR code. The QR code contains only the IP address, the same value as `Flocon.connect("192.168.1.20")`.
+
+To scan it from the app, add the optional `flocon-qr-scanner` module (and `flocon-qr-scanner-no-op` for release builds). `Flocon.scanQrCodeAndConnect(context)` opens the Google code scanner (a Google Play Services screen, no camera permission needed), then connects. It returns the `FloconConnectResult`, or `null` if the user closes the scanner. Without Google Play Services (an AOSP emulator, a Huawei device) it returns `Failed`: use `Flocon.connect("192.168.1.20")` instead. To use your own camera screen, pass the text it reads to `Flocon.connect(address)`.
 
 Up to 5000 messages are kept: above that, the oldest are dropped. `connect { bufferCapacity = ... }` changes this size.