update document

Author: hnvn

README.md

@@ -64,7 +64,9 @@ void registerPlugins(NSObject<FlutterPluginRegistry>* registry) {
   // along with other plugins that need UI manipulation, you should register 
   // `FlutterDownloaderPlugin` and any 'background' plugins explicitly like this: 
   //   
-  // [FlutterDownloaderPlugin registerWithRegistrar:[registry registrarForPlugin:@"vn.hunghd.flutter_downloader"]];
+  // if (![registry hasPlugin:@"FlutterDownloaderPlugin"]) {
+  //    [FlutterDownloaderPlugin registerWithRegistrar:[registry registrarForPlugin:@"FlutterDownloaderPlugin"]];
+  // }
   //
   [GeneratedPluginRegistrant registerWithRegistry:registry];
 }
@@ -113,7 +115,9 @@ private func registerPlugins(registry: FlutterPluginRegistry) {
     // plugins that need UI manipulation, you should register `FlutterDownloaderPlugin` and any
     // 'background' plugins explicitly like this:
     //   
-    // FlutterDownloaderPlugin.register(with: registry.registrar(forPlugin: "vn.hunghd.flutter_downloader"))
+    // if (!registry.hasPlugin("FlutterDownloaderPlugin")) {
+    //    FlutterDownloaderPlugin.register(with: registry.registrar(forPlugin: "FlutterDownloaderPlugin"))
+    // }
     //
     GeneratedPluginRegistrant.register(with: registry)
 }

android_integration_note.md

@@ -29,7 +29,9 @@ public class MyApplication extends FlutterApplication implements PluginRegistry.
         // along with other plugins that need UI manipulation, you should register
         // `FlutterDownloaderPlugin` and any 'background' plugins explicitly like this:
         //   
-        // FlutterDownloaderPlugin.registerWith(registry.registrarFor("vn.hunghd.flutterdownloader.FlutterDownloaderPlugin"));
+        // if (!registry.hasPlugin("vn.hunghd.flutterdownloader.FlutterDownloaderPlugin")) {
+        //    FlutterDownloaderPlugin.registerWith(registry.registrarFor("vn.hunghd.flutterdownloader.FlutterDownloaderPlugin"));
+        // }
         //
         GeneratedPluginRegistrant.registerWith(registry);
     }
@@ -60,7 +62,9 @@ internal class MyApplication : FlutterApplication(), PluginRegistry.PluginRegist
         // along with other plugins that need UI manipulation, you should register
         // `FlutterDownloaderPlugin` and any 'background' plugins explicitly like this:
         // 
-        // FlutterDownloaderPlugin.registerWith(registry.registrarFor("vn.hunghd.flutterdownloader.FlutterDownloaderPlugin"))
+        // if (!registry.hasPlugin("vn.hunghd.flutterdownloader.FlutterDownloaderPlugin")) {
+        //    FlutterDownloaderPlugin.registerWith(registry.registrarFor("vn.hunghd.flutterdownloader.FlutterDownloaderPlugin"))
+        // }
         //
         GeneratedPluginRegistrant.registerWith(registry)
     }