[Android] Support opening search page with shared text. Close #261

lib/utils/handle_text_share.dart

@@ -0,0 +1,22 @@
+import 'package:flutter/services.dart';
+import 'package:venera/foundation/app.dart';
+import 'package:venera/pages/aggregated_search_page.dart';
+
+bool _isHandling = false;
+
+/// Handle text share event.
+/// App will navigate to [AggregatedSearchPage] with the shared text as keyword.
+void handleTextShare() async {
+  if (_isHandling) return;
+  _isHandling = true;
+
+  var channel = EventChannel('venera/text_share');
+  await for (var event in channel.receiveBroadcastStream()) {
+    if (App.mainNavigatorKey == null) {
+      await Future.delayed(const Duration(milliseconds: 200));
+    }
+    if (event is String) {
+      App.rootContext.to(() => AggregatedSearchPage(keyword: event));
+    }
+  }
+}