Update flutter_barcode_scanner to v2.0.2: Restore Android v1 Embedding, Improve Lifecycle Stability, Add Platform Checks, Tests, and Documentation

CHANGELOG.md

@@ -1,3 +1,16 @@
+## 2.0.2
+
+* Android: Restore support for the legacy v1 embedding via `registerWith` and
+	guard lifecycle cleanup to avoid crashes when activities change.
+* Android: Remove the strict `FlutterActivity` cast so the plugin works with
+	`FlutterFragmentActivity` and other activity types.
+
+## 2.0.1
+
+* Guard against unsupported platforms and provide clearer errors instead of
+	`MissingPluginException` when the plugin is invoked outside Android/iOS.
+* Document platform support expectations in the README.
+
 ## 2.0.0
 
 * Android: Fixes #137 and #132

README.md

@@ -6,6 +6,20 @@ A plugin for Flutter apps that adds barcode scanning support on both Android and
 
 ![Demo gif](https://github.com/AmolGangadhare/MyProfileRepo/blob/master/flutter_barcode_scanning_demo.gif "Demo")
 
+## Platform support
+
+> **Note**
+> `flutter_barcode_scanner` only provides native implementations for **Android** and
+> **iOS**. Invoking the plugin on the web, macOS, Windows, Linux, or Fuchsia now
+> throws a descriptive `PlatformException` instead of the previous
+> `MissingPluginException`. If you see this message, run the sample on a real or
+> emulated mobile device.
+
+> **Android embedding**
+> Apps that still rely on the legacy (pre-1.12) Android embedding are fully
+> supported again starting with **v2.0.2**. After upgrading, run `flutter clean`
+> and rebuild so Gradle picks up the refreshed plugin registration code.
+
 
 ## Try example
 Just clone or download the repository, open the project in `Android Studio/ VS Code`, open `pubspec.yaml` and click on `Packages get`.

android/build.gradle

@@ -4,11 +4,11 @@ version '1.0-SNAPSHOT'
 buildscript {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:8.3.2'
+        classpath 'com.android.tools.build:gradle:7.4.2'
     }
 }
 

android/src/main/java/com/amolg/flutterbarcodescanner/FlutterBarcodeScannerPlugin.java

@@ -2,6 +2,7 @@
 
     import android.app.Activity;
     import android.app.Application;
+    import android.content.Context;
     import android.content.Intent;
     import android.os.Bundle;
     import android.util.Log;
@@ -14,29 +15,31 @@
     import com.google.android.gms.common.api.CommonStatusCodes;
     import com.google.android.gms.vision.barcode.Barcode;
 
+    import java.lang.reflect.Method;
     import java.util.Map;
 
-    import io.flutter.embedding.android.FlutterActivity;
     import io.flutter.embedding.engine.plugins.FlutterPlugin;
     import io.flutter.embedding.engine.plugins.activity.ActivityAware;
     import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding;
+    import io.flutter.embedding.engine.plugins.lifecycle.FlutterLifecycleAdapter;
     import io.flutter.plugin.common.BinaryMessenger;
     import io.flutter.plugin.common.EventChannel;
+    import io.flutter.plugin.common.EventChannel.StreamHandler;
     import io.flutter.plugin.common.MethodCall;
     import io.flutter.plugin.common.MethodChannel;
     import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
     import io.flutter.plugin.common.MethodChannel.Result;
+    import io.flutter.plugin.common.PluginRegistry;
     import io.flutter.plugin.common.PluginRegistry.ActivityResultListener;
-    import io.flutter.plugin.common.EventChannel.StreamHandler;
-    import io.flutter.embedding.engine.plugins.lifecycle.FlutterLifecycleAdapter;
 
     /**
      * FlutterBarcodeScannerPlugin
      */
     public class FlutterBarcodeScannerPlugin implements MethodCallHandler, ActivityResultListener, StreamHandler, FlutterPlugin, ActivityAware {
-        private static final String CHANNEL = "flutter_barcode_scanner";
+    private static final String CHANNEL = "flutter_barcode_scanner";
+    private static final String LEGACY_REGISTRAR_KEY = "com.amolg.flutterbarcodescanner.FlutterBarcodeScannerPlugin";
 
-        private static FlutterActivity activity;
+        private static Activity activity;
         private static Result pendingResult;
         private Map<String, Object> arguments;
 
@@ -46,20 +49,57 @@ public class FlutterBarcodeScannerPlugin implements MethodCallHandler, ActivityR
         public static boolean isShowFlashIcon = false;
         public static boolean isContinuousScan = false;
         static EventChannel.EventSink barcodeStream;
-        private EventChannel eventChannel;
+    private EventChannel eventChannel;
 
         private MethodChannel channel;
         private FlutterPluginBinding pluginBinding;
         private ActivityPluginBinding activityBinding;
         private Application applicationContext;
         private Lifecycle lifecycle;
         private LifeCycleObserver observer;
+    private boolean isLifecycleObserverAdded = false;
+    private boolean isApplicationObserverAdded = false;
 
         public FlutterBarcodeScannerPlugin() {
         }
 
-        private FlutterBarcodeScannerPlugin(Activity activity) {
-            FlutterBarcodeScannerPlugin.activity = (FlutterActivity) activity;
+        @SuppressWarnings("deprecation")
+        public static void registerWith(PluginRegistry registry) {
+            if (registry == null) {
+                Log.w(TAG, "FlutterBarcodeScannerPlugin registration skipped: registry is null.");
+                return;
+            }
+
+            final Object registrar = getLegacyRegistrar(registry);
+            if (registrar == null) {
+                Log.w(TAG, "FlutterBarcodeScannerPlugin registration skipped: registrar unavailable.");
+                return;
+            }
+
+            final BinaryMessenger messenger = invokeRegistrarMethod(registrar, "messenger", BinaryMessenger.class);
+            final Activity legacyActivity = invokeRegistrarMethod(registrar, "activity", Activity.class);
+            final Context legacyContext = invokeRegistrarMethod(registrar, "context", Context.class);
+            Application application = null;
+            if (legacyActivity != null) {
+                application = legacyActivity.getApplication();
+            }
+            if (application == null && legacyContext instanceof Application) {
+                application = (Application) legacyContext;
+            } else if (application == null && legacyContext != null) {
+                final Context appContext = legacyContext.getApplicationContext();
+                if (appContext instanceof Application) {
+                    application = (Application) appContext;
+                }
+            }
+
+            if (messenger == null || legacyActivity == null || application == null) {
+                Log.w(TAG, "FlutterBarcodeScannerPlugin registration skipped: missing legacy dependencies.");
+                return;
+            }
+
+            FlutterBarcodeScannerPlugin plugin = new FlutterBarcodeScannerPlugin();
+            plugin.createPluginSetup(messenger, application, legacyActivity, null);
+            plugin.registerLegacyActivityResultListener(registrar);
         }
 
         @Override
@@ -98,6 +138,12 @@ public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
 
         private void startBarcodeScannerActivityView(String buttonText, boolean isContinuousScan) {
             try {
+                if (activity == null) {
+                    Log.e(TAG, "Activity reference is null. Cannot start scanner view.");
+                    pendingResult.success("-1");
+                    return;
+                }
+
                 Intent intent = new Intent(activity, BarcodeCaptureActivity.class).putExtra("cancelButtonText", buttonText);
                 if (isContinuousScan) {
                     activity.startActivity(intent);
@@ -152,7 +198,7 @@ public void onCancel(Object o) {
 
         public static void onBarcodeScanReceiver(final Barcode barcode) {
             try {
-                if (barcode != null && !barcode.displayValue.isEmpty()) {
+                if (barcode != null && !barcode.displayValue.isEmpty() && activity != null) {
                     activity.runOnUiThread(new Runnable() {
                         @Override
                         public void run() {
@@ -185,36 +231,45 @@ public void onReattachedToActivityForConfigChanges(ActivityPluginBinding binding
             onAttachedToActivity(binding);
         }
 
-        private void createPluginSetup(
+    private void createPluginSetup(
                 final BinaryMessenger messenger,
                 final Application applicationContext,
                 final Activity activity,
                 final ActivityPluginBinding activityBinding) {
 
-            this.activity = (FlutterActivity) activity;
+            if (activity == null) {
+                Log.e(TAG, "Unable to start flutter_barcode_scanner: activity is null");
+                return;
+            }
+
+            FlutterBarcodeScannerPlugin.activity = activity;
             eventChannel = new EventChannel(messenger, "flutter_barcode_scanner_receiver");
             eventChannel.setStreamHandler(this);
 
             this.applicationContext = applicationContext;
             channel = new MethodChannel(messenger, CHANNEL);
             channel.setMethodCallHandler(this);
 
+            observer = new LifeCycleObserver(activity);
             if (activityBinding != null) {
                 activityBinding.addActivityResultListener(this);
                 lifecycle = FlutterLifecycleAdapter.getActivityLifecycle(activityBinding);
-                observer = new LifeCycleObserver(activity);
                 lifecycle.addObserver(observer);
+                isLifecycleObserverAdded = true;
+            } else if (applicationContext != null) {
+                applicationContext.registerActivityLifecycleCallbacks(observer);
+                isApplicationObserverAdded = true;
             }
         }
 
         @Override
         public void onAttachedToActivity(ActivityPluginBinding binding) {
-            activityBinding = binding;
-            createPluginSetup(
-                    pluginBinding.getBinaryMessenger(),
-                    (Application) pluginBinding.getApplicationContext(),
-                    activityBinding.getActivity(),
-                    activityBinding);
+        activityBinding = binding;
+        createPluginSetup(
+            pluginBinding.getBinaryMessenger(),
+            (Application) pluginBinding.getApplicationContext(),
+            activityBinding.getActivity(),
+            activityBinding);
         }
 
         @Override
@@ -224,14 +279,35 @@ public void onDetachedFromActivity() {
 
         private void clearPluginSetup() {
             activity = null;
-            activityBinding.removeActivityResultListener(this);
-            activityBinding = null;
-            lifecycle.removeObserver(observer);
+
+            if (activityBinding != null) {
+                activityBinding.removeActivityResultListener(this);
+                activityBinding = null;
+            }
+
+            if (isLifecycleObserverAdded && lifecycle != null && observer != null) {
+                lifecycle.removeObserver(observer);
+                isLifecycleObserverAdded = false;
+            }
+
+            if (isApplicationObserverAdded && applicationContext != null && observer != null) {
+                applicationContext.unregisterActivityLifecycleCallbacks(observer);
+                isApplicationObserverAdded = false;
+            }
+
             lifecycle = null;
-            channel.setMethodCallHandler(null);
-            eventChannel.setStreamHandler(null);
-            channel = null;
-            applicationContext.unregisterActivityLifecycleCallbacks(observer);
+            observer = null;
+
+            if (channel != null) {
+                channel.setMethodCallHandler(null);
+                channel = null;
+            }
+
+            if (eventChannel != null) {
+                eventChannel.setStreamHandler(null);
+                eventChannel = null;
+            }
+
             applicationContext = null;
         }
 
@@ -299,4 +375,46 @@ public void onActivityDestroyed(Activity activity) {
             public void onActivityStopped(Activity activity) {
             }
         }
+
+        @SuppressWarnings("deprecation")
+        private static Object getLegacyRegistrar(PluginRegistry registry) {
+            if (registry == null) {
+                return null;
+            }
+            try {
+                Method method = registry.getClass().getMethod("registrarFor", String.class);
+                return method.invoke(registry, LEGACY_REGISTRAR_KEY);
+            } catch (Exception e) {
+                Log.e(TAG, "Unable to obtain legacy registrar", e);
+                return null;
+            }
+        }
+
+        private static <T> T invokeRegistrarMethod(Object registrar, String methodName, Class<T> clazz) {
+            if (registrar == null) {
+                return null;
+            }
+            try {
+                Method method = registrar.getClass().getMethod(methodName);
+                Object result = method.invoke(registrar);
+                if (clazz.isInstance(result)) {
+                    return clazz.cast(result);
+                }
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to invoke legacy registrar method " + methodName, e);
+            }
+            return null;
+        }
+
+        private void registerLegacyActivityResultListener(Object registrar) {
+            if (registrar == null) {
+                return;
+            }
+            try {
+                Method method = registrar.getClass().getMethod("addActivityResultListener", ActivityResultListener.class);
+                method.invoke(registrar, this);
+            } catch (Exception e) {
+                Log.e(TAG, "Failed to attach legacy activity result listener", e);
+            }
+        }
     }

example/ios/Flutter/ephemeral/flutter_lldb_helper.py

@@ -0,0 +1,32 @@
+#
+# Generated file, do not edit.
+#
+
+import lldb
+
+def handle_new_rx_page(frame: lldb.SBFrame, bp_loc, extra_args, intern_dict):
+    """Intercept NOTIFY_DEBUGGER_ABOUT_RX_PAGES and touch the pages."""
+    base = frame.register["x0"].GetValueAsAddress()
+    page_len = frame.register["x1"].GetValueAsUnsigned()
+
+    # Note: NOTIFY_DEBUGGER_ABOUT_RX_PAGES will check contents of the
+    # first page to see if handled it correctly. This makes diagnosing
+    # misconfiguration (e.g. missing breakpoint) easier.
+    data = bytearray(page_len)
+    data[0:8] = b'IHELPED!'
+
+    error = lldb.SBError()
+    frame.GetThread().GetProcess().WriteMemory(base, data, error)
+    if not error.Success():
+        print(f'Failed to write into {base}[+{page_len}]', error)
+        return
+
+def __lldb_init_module(debugger: lldb.SBDebugger, _):
+    target = debugger.GetDummyTarget()
+    # Caveat: must use BreakpointCreateByRegEx here and not
+    # BreakpointCreateByName. For some reasons callback function does not
+    # get carried over from dummy target for the later.
+    bp = target.BreakpointCreateByRegex("^NOTIFY_DEBUGGER_ABOUT_RX_PAGES$")
+    bp.SetScriptCallbackFunction('{}.handle_new_rx_page'.format(__name__))
+    bp.SetAutoContinue(True)
+    print("-- LLDB integration loaded --")

example/ios/Flutter/ephemeral/flutter_lldbinit

@@ -0,0 +1,5 @@
+#
+# Generated file, do not edit.
+#
+
+command script import --relative-to-command-file flutter_lldb_helper.py