Support lazy loading through DeviceApps.streamInstalledApplications()

android/src/main/java/fr/g123k/deviceapps/DeviceAppsPlugin.java

@@ -1,5 +1,8 @@
 package fr.g123k.deviceapps;
 
+import static fr.g123k.deviceapps.utils.Base64Utils.encodeToBase64;
+import static fr.g123k.deviceapps.utils.DrawableUtils.getBitmapFromDrawable;
+
 import android.content.Context;
 import android.content.Intent;
 import android.content.pm.ApplicationInfo;
@@ -35,9 +38,6 @@
 import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
 import io.flutter.plugin.common.MethodChannel.Result;
 
-import static fr.g123k.deviceapps.utils.Base64Utils.encodeToBase64;
-import static fr.g123k.deviceapps.utils.DrawableUtils.getBitmapFromDrawable;
-
 /**
  * DeviceAppsPlugin
  */
@@ -79,6 +79,11 @@ public void onAttachedToEngine(@NonNull FlutterPluginBinding binding) {
     @SuppressWarnings("ConstantConditions")
     public void onMethodCall(MethodCall call, @NonNull final Result result) {
         switch (call.method) {
+            case "getInstalledPackagesCount":
+                PackageManager packageManager = context.getPackageManager();
+                List<PackageInfo> apps = packageManager.getInstalledPackages(0);
+                result.success(apps.size());
+                break;
             case "getInstalledApps":
                 boolean systemApps = call.hasArgument("system_apps") && (Boolean) (call.argument("system_apps"));
                 boolean includeAppIcons = call.hasArgument("include_app_icons") && (Boolean) (call.argument("include_app_icons"));
@@ -143,28 +148,32 @@ public void run() {
 
     private void fetchInstalledApps(final boolean includeSystemApps, final boolean includeAppIcons, final boolean onlyAppsWithLaunchIntent, final InstalledAppsCallback callback) {
         asyncWork.run(new Runnable() {
-
             @Override
             public void run() {
-                List<Map<String, Object>> installedApps = getInstalledApps(includeSystemApps, includeAppIcons, onlyAppsWithLaunchIntent);
+                OnAppLoaded onAppLoadedCallback = new OnAppLoaded() {
+                    @Override
+                    public void onAppAvailable(Map<String, Object> app) {
+                        apps.add(app);
+                    }
+                };
+
+                getInstalledApps(includeSystemApps, includeAppIcons, onlyAppsWithLaunchIntent, onAppLoadedCallback);
 
                 if (callback != null) {
-                    callback.onInstalledAppsListAvailable(installedApps);
+                    callback.onInstalledAppsListAvailable(onAppLoadedCallback.apps);
                 }
             }
-
         });
     }
 
-    private List<Map<String, Object>> getInstalledApps(boolean includeSystemApps, boolean includeAppIcons, boolean onlyAppsWithLaunchIntent) {
+    private void getInstalledApps(boolean includeSystemApps, boolean includeAppIcons, boolean onlyAppsWithLaunchIntent, OnAppLoaded callback) {
         if (context == null) {
             Log.e(LOG_TAG, "Context is null");
-            return new ArrayList<>(0);
+            return;
         }
 
         PackageManager packageManager = context.getPackageManager();
         List<PackageInfo> apps = packageManager.getInstalledPackages(0);
-        List<Map<String, Object>> installedApps = new ArrayList<>(apps.size());
 
         for (PackageInfo packageInfo : apps) {
             if (!includeSystemApps && isSystemApp(packageInfo)) {
@@ -178,10 +187,9 @@ private List<Map<String, Object>> getInstalledApps(boolean includeSystemApps, bo
                     packageInfo,
                     packageInfo.applicationInfo,
                     includeAppIcons);
-            installedApps.add(map);
-        }
 
-        return installedApps;
+            callback.onAppAvailable(map);
+        }
     }
 
     private boolean openApp(@NonNull String packageName) {
@@ -295,14 +303,59 @@ private boolean uninstallApp(@NonNull String packageName) {
         return false;
     }
 
+    private void attachAppsChangedListener(Object arguments, final EventChannel.EventSink events) {
+        if (appsListener == null) {
+            appsListener = new DeviceAppsChangedListener(this);
+        }
+
+        appsListener.register(context, events);
+    }
+
+    private void attachGetInstalledAppsListener(Object arguments, final EventChannel.EventSink events) {
+        HashMap args = (HashMap) arguments;
+        final boolean systemApps = args.containsKey("system_apps") && (boolean) args.get("system_apps");
+        final boolean includeAppIcons = args.containsKey("include_app_icons") && (boolean) args.get("include_app_icons");
+        final boolean onlyAppsWithLaunchIntent = args.containsKey("only_apps_with_launch_intent") && (boolean) args.get("only_apps_with_launch_intent");
+
+        asyncWork.run(new Runnable() {
+            @Override
+            public void run() {
+                getInstalledApps(systemApps, includeAppIcons, onlyAppsWithLaunchIntent, new OnAppLoaded() {
+                    @Override
+                    public void onAppAvailable(final Map<String, Object> app) {
+                        new Handler(Looper.getMainLooper()).post(new Runnable() {
+                            @Override
+                            public void run() {
+                                events.success(app);
+                            }
+                        });
+                    }
+                });
+
+                new Handler(Looper.getMainLooper()).post(new Runnable() {
+                    @Override
+                    public void run() {
+                        events.endOfStream();
+                    }
+                });
+            }
+        });
+    }
+
     @Override
     public void onListen(Object arguments, final EventChannel.EventSink events) {
         if (context != null) {
-            if (appsListener == null) {
-                appsListener = new DeviceAppsChangedListener(this);
+            HashMap args = (HashMap) arguments;
+            String event = (String) args.get("event");
+
+            switch (event) {
+                case "listenToAppsChanges":
+                    attachAppsChangedListener(arguments, events);
+                    break;
+                case "getInstalledApps":
+                    attachGetInstalledAppsListener(arguments, events);
+                    break;
             }
-
-            appsListener.register(context, events);
         }
     }
 
@@ -379,3 +432,9 @@ public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
         context = null;
     }
 }
+
+interface OnAppLoaded {
+    List<Map<String, Object>> apps = new ArrayList<>(0);
+
+    void onAppAvailable(Map<String, Object> app);
+}

android/src/main/java/fr/g123k/deviceapps/listener/DeviceAppsChangedListener.java

@@ -15,16 +15,18 @@
 public class DeviceAppsChangedListener {
 
     private final DeviceAppsChangedListenerInterface callback;
-    private final Set<EventChannel.EventSink> sinks;
+    private EventChannel.EventSink eventSink;
 
     private BroadcastReceiver appsBroadcastReceiver;
 
     public DeviceAppsChangedListener(DeviceAppsChangedListenerInterface callback) {
         this.callback = callback;
-        this.sinks = new HashSet<>(1);
+        this.eventSink = null;
     }
 
     public void register(@NonNull Context context, EventChannel.EventSink events) {
+        unregister(context);
+
         if (appsBroadcastReceiver == null) {
             createBroadcastReceiver();
         }
@@ -36,7 +38,7 @@ public void register(@NonNull Context context, EventChannel.EventSink events) {
         intentFilter.addAction(Intent.ACTION_PACKAGE_REMOVED);
         intentFilter.addDataScheme("package");
 
-        sinks.add(events);
+        eventSink = events;
 
         context.registerReceiver(appsBroadcastReceiver, intentFilter);
     }
@@ -75,35 +77,31 @@ public void onReceive(Context context, Intent intent) {
     }
 
     void onPackageInstalled(String packageName) {
-        for (EventChannel.EventSink sink : sinks) {
-            callback.onPackageInstalled(packageName, sink);
-        }
+        callback.onPackageInstalled(packageName, eventSink);
     }
 
     void onPackageUpdated(String packageName) {
-        for (EventChannel.EventSink sink : sinks) {
-            callback.onPackageUpdated(packageName, sink);
-        }
+        callback.onPackageUpdated(packageName, eventSink);
     }
 
     void onPackageUninstalled(String packageName) {
-        for (EventChannel.EventSink sink : sinks) {
-            callback.onPackageUninstalled(packageName, sink);
-        }
+        callback.onPackageUninstalled(packageName, eventSink);
     }
 
     void onPackageChanged(String packageName) {
-        for (EventChannel.EventSink sink : sinks) {
-            callback.onPackageChanged(packageName, sink);
-        }
+        callback.onPackageChanged(packageName, eventSink);
     }
 
     public void unregister(@NonNull Context context) {
         if (appsBroadcastReceiver != null) {
             context.unregisterReceiver(appsBroadcastReceiver);
+            appsBroadcastReceiver = null;
+        }
+
+        if (eventSink != null) {
+            eventSink.endOfStream();
+            eventSink = null;
         }
-
-        sinks.clear();
     }
 
 }

lib/src/plugin.dart

@@ -16,6 +16,23 @@ class DeviceApps {
   static const EventChannel _eventChannel =
       EventChannel('g123k/device_apps_events');
 
+  static Stream<Application> streamInstalledApplications({
+    bool includeSystemApps: false,
+    bool includeAppIcons: false,
+    bool onlyAppsWithLaunchIntent: false,
+  }) {
+    final Stream<dynamic> apps = _eventChannel.receiveBroadcastStream(
+      <String, dynamic>{
+        'system_apps': includeSystemApps,
+        'include_app_icons': includeAppIcons,
+        'only_apps_with_launch_intent': onlyAppsWithLaunchIntent,
+        'event': 'getInstalledApps',
+      },
+    );
+
+    return apps.map<Application>((dynamic app) => Application._(app));
+  }
+
   /// List installed applications on the device
   /// [includeSystemApps] will also include system apps (or pre-installed) like
   /// Phone, Settings...
@@ -108,6 +125,13 @@ class DeviceApps {
         .catchError((dynamic err) => false);
   }
 
+  static Future<int> getInstalledPackagesCount() {
+    return _methodChannel
+        .invokeMethod<int>('getInstalledPackagesCount')
+        .then((int? value) => value ?? 0)
+        .catchError((dynamic err) => 0);
+  }
+
   /// Launch an app based on its [packageName]
   /// You will then receive in return if the app was opened
   /// (will be false if the app is not installed, or if no "launcher" intent is
@@ -164,7 +188,9 @@ class DeviceApps {
   /// is too verbose for you
   static Stream<ApplicationEvent> listenToAppsChanges() {
     return _eventChannel
-        .receiveBroadcastStream()
+        .receiveBroadcastStream(
+          <String, dynamic>{'event': 'listenToAppsChanges'},
+        )
         .map(((dynamic event) =>
             ApplicationEvent._(event as Map<dynamic, dynamic>)))
         .handleError((Object err) => null);