Merge pull request #568 from OneSignal/feat/add_set_language_callback

[Feature] Add callbacks to `setLanguage`

Author: nan-li

android/src/main/java/com/onesignal/flutter/OneSignalPlugin.java

@@ -329,7 +329,7 @@ private void setLanguage(MethodCall call, final Result result) {
     if (language != null && language.length() == 0)
       language = null;
 
-      OneSignal.setLanguage(language);
+      OneSignal.setLanguage(language, new OSFlutterSetLanguageHandler(messenger, channel, result, "setLanguage"));
   }
 
   private void setExternalUserId(MethodCall call, final Result result) {
@@ -603,6 +603,47 @@ public void onFailure(JSONObject response) {
     }
   }
 
+  static class OSFlutterSetLanguageHandler extends OSFlutterHandler
+          implements OneSignal.OSSetLanguageCompletionHandler {
+
+    OSFlutterSetLanguageHandler(BinaryMessenger messenger, MethodChannel channel, Result res, String methodName) {
+      super(messenger, channel, res, methodName);
+    }
+
+    @Override
+    public void onSuccess(String results) {
+      if (this.replySubmitted.getAndSet(true)) {
+        OneSignal.onesignalLog(OneSignal.LOG_LEVEL.DEBUG, "OneSignal " + methodName + " handler called twice, ignoring! response: " + results);
+        return;
+      }
+
+      if (results == null) { // The results currently is always null.
+        results = "Successfully set language.";
+      }
+
+      HashMap<String, Object> responseMap = new HashMap<>();
+      responseMap.put("success", true);
+      responseMap.put("message", results);
+      replySuccess(result, responseMap);
+    }
+
+    @Override
+    public void onFailure(OneSignal.OSLanguageError error) {
+      if (this.replySubmitted.getAndSet(true)) {
+        return;
+      }
+
+      String errorMessage = error.getMessage();
+      if (errorMessage == null) {
+        errorMessage = "Failed to set language.";
+      }
+
+      replyError(result, "OneSignal",
+              "Encountered an error when " + methodName + ": " + errorMessage,
+              null);
+    }
+  }
+
   static class OSFlutterHandler extends FlutterRegistrarResponder {
     protected final Result result;
     protected final String methodName;

example/lib/main.dart

@@ -16,6 +16,7 @@ class _MyAppState extends State<MyApp> {
   String? _emailAddress;
   String? _smsNumber;
   String? _externalUserId;
+  String? _language;
   bool _enableConsentButton = false;
 
   // CHANGE THIS parameter to true if you want to test GDPR privacy consent
@@ -184,6 +185,18 @@ class _MyAppState extends State<MyApp> {
     });
   }
 
+  void _handleSetLanguage() {
+    if (_language == null) return;
+
+    print("Setting language");
+
+    OneSignal.shared.setLanguage(_language!).then((response) {
+      print("Successfully set language with response: $response");
+    }).catchError((error) {
+      print("Failed to set language with error: $error");
+    });
+  }
+
   void _handleLogoutEmail() {
     print("Logging out of email");
 
@@ -510,6 +523,30 @@ class _MyAppState extends State<MyApp> {
                     new OneSignalButton(
                         "Remove External User ID", _handleRemoveExternalUserId, !_enableConsentButton)
                   ]),
+                  new TableRow(children: [
+                    new TextField(
+                      textAlign: TextAlign.center,
+                      decoration: InputDecoration(
+                          hintText: "Language",
+                          labelStyle: TextStyle(
+                            color: Color.fromARGB(255, 212, 86, 83),
+                          )),
+                      onChanged: (text) {
+                        this.setState(() {
+                          _language = text == "" ? null : text;
+                        });
+                      },
+                    )
+                  ]),
+                  new TableRow(children: [
+                    Container(
+                      height: 8.0,
+                    )
+                  ]),
+                  new TableRow(children: [
+                    new OneSignalButton(
+                        "Set Language", _handleSetLanguage, !_enableConsentButton)
+                  ]),
                   new TableRow(children: [
                     new Container(
                       child: new Text(_debugLabelString),

ios/Classes/OneSignalPlugin.m

@@ -338,7 +338,12 @@ - (void)setLanguage:(FlutterMethodCall *)call withResult:(FlutterResult)result {
         language = nil;
     }
 
-    [OneSignal setLanguage:language];
+    [OneSignal setLanguage:language withSuccess:^(NSDictionary *results) {
+        result(results);
+    } withFailure:^(NSError *error) {
+        [OneSignal onesignalLog:ONE_S_LL_VERBOSE message:[NSString stringWithFormat:@"Set language Failure with error: %@", error]];
+        result(error.flutterError);
+    }];
 }
 
 - (void)initNotificationOpenedHandlerParams {

lib/onesignal_flutter.dart

@@ -379,6 +379,8 @@ class OneSignal {
     return results.cast<String, dynamic>();
   }
 
+  /// Sets the user's language.
+  /// Applies also to the email and/or SMS player if those are logged in on the device.
   Future<Map<String, dynamic>> setLanguage(String language) async {
     Map<dynamic, dynamic> results =
         await (_channel.invokeMethod("OneSignal#setLanguage", {'language' : language}));