Add support for different scan engines

pretixscan/app/build.gradle

@@ -174,6 +174,9 @@ dependencies {
     }
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
     implementation 'com.github.apg-mobile:android-round-textview:v1.0.0'
+
+    implementation "com.google.android.gms:play-services-base:18.7.2"
+    implementation "com.google.android.gms:play-services-mlkit-barcode-scanning:18.3.1"
 }
 
 sqldelight {

pretixscan/app/src/main/AndroidManifest.xml

@@ -112,6 +112,10 @@
                 android:resource="@xml/filepaths" />
         </provider>
 
+        <meta-data
+            android:name="com.google.mlkit.vision.DEPENDENCIES"
+            android:value="barcode" />
+
         <meta-data android:name="io.sentry.dsn" android:value="${SENTRY_DSN}" />
         <meta-data android:name="io.sentry.attach-screenshot" android:value="false" />
         <meta-data android:name="io.sentry.attach-view-hierarchy" android:value="false" />

pretixscan/app/src/main/java/eu/pretix/pretixscan/droid/AppConfig.kt

@@ -66,6 +66,12 @@ class AppConfig(ctx: Context) : ConfigStore {
                 .putString(PREFS_KEY_AUTOPRINTBADGES, "once")
                 .commit()
         }
+        if (prefs.contains(LEGACY_PREFS_KEY_USE_CAMERA)) {
+            prefs.edit()
+                .putString(PREFS_KEY_SCAN_ENGINE, if (prefs.getBoolean(LEGACY_PREFS_KEY_USE_CAMERA, true)) "zxing" else "hardware")
+                .remove(LEGACY_PREFS_KEY_USE_CAMERA)
+                .commit()
+        }
     }
 
     override fun isDebug(): Boolean {
@@ -339,9 +345,9 @@ class AppConfig(ctx: Context) : ConfigStore {
             }
         }
 
-    var useCamera: Boolean
-        get() = default_prefs.getBoolean(PREFS_KEY_USE_CAMERA, true)
-        set(value) = default_prefs.edit().putBoolean(PREFS_KEY_USE_CAMERA, value).apply()
+    @Deprecated("use scanEngine instead")
+    val useCamera: Boolean
+        get() = default_prefs.getString(PREFS_KEY_SCAN_ENGINE, "zxing") != "hardware"
 
     val hideNames: Boolean
         get() = default_prefs.getBoolean(PREFS_KEY_HIDE_NAMES, false)
@@ -397,6 +403,10 @@ class AppConfig(ctx: Context) : ConfigStore {
         get() = default_prefs.getBoolean(PREFS_KEY_SYNC_ORDERS, true)
         set(value) = default_prefs.edit().putBoolean(PREFS_KEY_SYNC_ORDERS, value).apply()
 
+    var scanEngine: String
+        get() = default_prefs.getString(PREFS_KEY_SCAN_ENGINE, "zxing") ?: "zxing"
+        set(value) = default_prefs.edit().putString(PREFS_KEY_SCAN_ENGINE, value).apply()
+
     override fun getKnownLiveEventSlugs(): Set<String> {
         return default_prefs.getStringSet(PREFS_KEY_KNOWN_LIVE_EVENT_SLUGS, emptySet()) as Set<String>
     }
@@ -435,7 +445,7 @@ class AppConfig(ctx: Context) : ConfigStore {
         val PREFS_KEY_SCAN_FLASH = "scan_flash"
         val PREFS_KEY_SYNC_ORDERS = "pref_sync_orders"
         val PREFS_KEY_AUTO_SWITCH = "pref_auto_switch"
-        val PREFS_KEY_USE_CAMERA = "pref_use_camera"
+        val LEGACY_PREFS_KEY_USE_CAMERA = "pref_use_camera"
         val PREFS_KEY_SCAN_OFFLINE = "pref_scan_offline"
         val PREFS_KEY_SCAN_OFFLINE_AUTO = "pref_auto_offline"
         val PREFS_KEY_SCAN_PROXY = "pref_scan_proxy"
@@ -451,6 +461,7 @@ class AppConfig(ctx: Context) : ConfigStore {
         val PREFS_KEY_SEARCH_DISABLE = "pref_search_disable"
         val PREFS_KEY_KIOSK_MODE = "pref_kiosk_mode"
         val PREFS_KEY_MULTI_EVENT_MODE = "multi_event_mode"
+        val PREFS_KEY_SCAN_ENGINE = "pref_scan_engine"
         private const val PREFS_KEY_KNOWN_LIVE_EVENT_SLUGS = "cache_known_live_event_slugs"
     }
 }

pretixscan/app/src/main/java/eu/pretix/pretixscan/droid/ui/MainActivity.kt

@@ -56,8 +56,16 @@ import androidx.vectordrawable.graphics.drawable.AnimatedVectorDrawableCompat
 import com.fasterxml.jackson.databind.DeserializationFeature
 import com.fasterxml.jackson.databind.ObjectMapper
 import com.fasterxml.jackson.databind.module.SimpleModule
+import com.google.android.gms.common.moduleinstall.InstallStatusListener
+import com.google.android.gms.common.moduleinstall.ModuleInstall
+import com.google.android.gms.common.moduleinstall.ModuleInstallRequest
+import com.google.android.gms.common.moduleinstall.ModuleInstallStatusUpdate
+import com.google.android.gms.common.moduleinstall.ModuleInstallStatusUpdate.InstallState.STATE_CANCELED
+import com.google.android.gms.common.moduleinstall.ModuleInstallStatusUpdate.InstallState.STATE_COMPLETED
+import com.google.android.gms.common.moduleinstall.ModuleInstallStatusUpdate.InstallState.STATE_FAILED
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.android.material.snackbar.Snackbar
+import com.google.mlkit.vision.barcode.BarcodeScanning
 import eu.pretix.libpretixsync.api.PretixApi
 import eu.pretix.libpretixsync.check.CheckException
 import eu.pretix.libpretixsync.check.OnlineCheckProvider
@@ -528,6 +536,66 @@ class MainActivity : AppCompatActivity(), ReloadableActivity, ScannerView.Result
                 pendingPinAction?.let { it(pin) }
             }
         }
+
+        if (conf.scanEngine == "mlkit") {
+            val moduleInstallClient = ModuleInstall.getClient(this)
+            val barcodeModule = BarcodeScanning.getClient()
+            moduleInstallClient.areModulesAvailable(
+                barcodeModule
+            )
+            class ModuleInstallProgressListener : InstallStatusListener {
+                override fun onInstallStatusUpdated(update: ModuleInstallStatusUpdate) {
+                    // Progress info is only set when modules are in the progress of downloading.
+                    update.progressInfo?.let {
+                        val progress = (it.bytesDownloaded * 100 / it.totalBytesToDownload).toInt()
+                        // Set the progress for the progress bar.
+                        //progressBar.setProgress(progress)
+                    }
+
+                    if (isTerminateState(update.installState)) {
+                        moduleInstallClient.unregisterListener(this)
+                    }
+                    if (update.installState == STATE_COMPLETED) {
+                        // -> switch engine
+                        switchScanEngine()
+                    }
+                }
+
+                fun isTerminateState(@ModuleInstallStatusUpdate.InstallState state: Int): Boolean {
+                    return state == STATE_CANCELED || state == STATE_COMPLETED || state == STATE_FAILED
+                }
+            }
+
+            val listener = ModuleInstallProgressListener()
+            val moduleInstallRequest = ModuleInstallRequest.newBuilder()
+                .addApi(barcodeModule)
+                .setListener(listener)
+                .build()
+
+            moduleInstallClient
+                .installModules(moduleInstallRequest)
+                .addOnSuccessListener {
+                    if (it.areModulesAlreadyInstalled()) {
+                        // Modules are already installed when the request is sent.
+                        // -> switch engine
+                        switchScanEngine()
+                    }
+                    // The install request has been sent successfully. This does not mean
+                    // the installation is completed. To monitor the install status, set an
+                    // InstallStatusListener to the ModuleInstallRequest.
+                }
+                .addOnFailureListener {
+                    // Handle failure…
+                }
+        }
+    }
+
+    private fun switchScanEngine() {
+        when(conf.scanEngine) {
+            "zxing" -> binding.scannerView.setAnalyzer(ScannerView.Companion.ANALYZER.ZXING)
+            "mlkit" -> binding.scannerView.setAnalyzer(ScannerView.Companion.ANALYZER.MLKIT)
+            else -> {}
+        }
     }
 
     private fun eventButtonText(): String {

pretixscan/app/src/main/java/eu/pretix/pretixscan/droid/ui/Settings.kt

@@ -175,6 +175,10 @@ class SettingsFragment : PreferenceFragmentCompat() {
                 true
             }
         }
+
+        // FIXME: pref_scan_engine. if BuildConfig.FLAVOR_edition == "foss", don't offer mlkit (disable?)
+        // FIXME: pref_scan_engine. check installation status of mlkit and warn for potential large download
+        // FIXME: pref_scan_engine. if changed to mlkit, check installation status
     }
 
     private fun asset_dialog(@RawRes htmlRes: Int, @StringRes title: Int) {

pretixscan/app/src/main/java/eu/pretix/pretixscan/droid/ui/SetupActivity.kt

@@ -83,7 +83,7 @@ class SetupActivity : AppCompatActivity(), SetupCallable {
 
     override fun config(useCamera: Boolean) {
         val conf = AppConfig(this)
-        conf.useCamera = useCamera
+        conf.scanEngine = if (useCamera) "zxing" else "hardware"
     }
 
     override fun setup(url: String, token: String) {

pretixscan/app/src/main/java/eu/pretix/pretixscan/droid/ui/WelcomeActivity.kt

@@ -59,7 +59,7 @@ class WelcomeActivity : AppCompatActivity() {
 
         if (defaultToScanner()) {
             val conf = AppConfig(this)
-            conf.useCamera = false
+            conf.scanEngine = "hardware"
         }
     }
 

pretixscan/app/src/main/res/values/arrays.xml

@@ -16,4 +16,9 @@
         <item>once</item>
         <item>true</item>
     </string-array>
+    <string-array name="settings_values_scan_engine">
+        <item>zxing</item>
+        <item>mlkit</item>
+        <item>hardware</item>
+    </string-array>
 </resources>

pretixscan/app/src/main/res/values/strings.xml

@@ -135,6 +135,7 @@
     <string name="preference_badgeprint_enable">Enable badge printing</string>
     <string name="preference_autobadgeprint_enable">Print badges automatically</string>
     <string name="preference_badgeprint_install_pretixprint">Printing badges requires the separate pretixPRINT app. Do you want to install it?</string>
+    <string name="preference_scan_engine">Barcode scanner to use</string>
     <string name="already_scanned">already scanned</string>
     <string name="total_tickets_sold">total tickets sold</string>
     <string name="ticket_attention">Attention, special ticket!</string>
@@ -169,6 +170,11 @@
         <item>Once, if not yet printed</item>
         <item>Always</item>
     </string-array>
+    <string-array name="settings_valuelabels_scan_engine">
+        <item>Zebra Crossing (ZXing)</item>
+        <item>Google ML Kit</item>
+        <item>Hardware scanner of this device</item>
+    </string-array>
     <string name="headline_please_reinstall">Please reinstall pretixSCAN</string>
     <string name="reinstall_text">Your previous pretixSCAN version was too old and your local data cannot be used for the current version.\n\nPlease clear the storage for the pretixSCAN app or delete and reinstall the app.</string>
     <string name="reinstall_open_app_settings">Open Android App Settings</string>

pretixscan/app/src/main/res/xml/app_restrictions.xml

@@ -5,6 +5,7 @@
         android:key="pref_sync_auto"
         android:restrictionType="bool"
         android:title="@string/settings_label_auto_sync" />
+    <!-- FIXME, remove/migrate? -->
     <restriction
         android:defaultValue="true"
         android:key="pref_use_camera"

pretixscan/app/src/main/res/xml/preferences.xml

@@ -32,10 +32,13 @@
             android:title="@string/settings_label_auto_switch" />
     </PreferenceCategory>
     <PreferenceCategory android:title="@string/settings_label_ui">
-        <CheckBoxPreference
-            android:defaultValue="true"
-            android:key="pref_use_camera"
-            android:title="@string/settings_label_device_camera" />
+        <ListPreference
+            android:key="pref_scan_engine"
+            android:defaultValue="zxing"
+            android:entries="@array/settings_valuelabels_scan_engine"
+            android:entryValues="@array/settings_values_scan_engine"
+            android:title="@string/preference_scan_engine"
+            android:summary="%s" />
         <CheckBoxPreference
             android:defaultValue="true"
             android:key="pref_sounds"