✨ Issue phonegap#1949: add a listChannels method

Author: macdonst

docs/API.md

@@ -4,6 +4,7 @@
 - [.hasPermission()](#pushnotificationhaspermissionsuccesshandler)
 - [.createChannel() - Android only](#pushnotificationcreatechannel)
 - [.deleteChannel() - Android only](#pushnotificationdeletechannel)
+- [.listChannels() - Android only](#pushnotificationlistchannels)
 - [push.on()](#pushonevent-callback)
   - [push.on('registration')](#pushonregistration-callback)
   - [push.on('notification')](#pushonnotification-callback)
@@ -194,6 +195,34 @@ PushNotification.deleteChannel(() => {
 });
 ```
 
+## PushNotification.listChannels(successHandler)
+
+Returns a list of currently configured channels.
+
+### Parameters
+
+Parameter | Type | Default | Description
+--------- | ---- | ------- | -----------
+`successHandler` | `Function` | | Is called when the api successfully retrieves the list of channels.
+
+### Callback parameters
+
+#### `successHandler`
+
+Parameter | Type | Description
+--------- | ---- | -----------
+`channels` | `JSONArrary` | List of channel objects.
+
+### Example
+
+```javascript
+PushNotification.listChannels((channels) => {
+    for(let channel of channels) {
+      console.log(`ID: ${channel.id} Description: ${channel.description}`);
+    }
+});
+```
+
 ## push.on(event, callback)
 
 ### Parameters

spec/index.spec.js

@@ -47,6 +47,11 @@ describe('phonegap-plugin-push', function () {
       expect(typeof PushNotification.deleteChannel === 'function').toBe(true);
     });
 
+    it('should contain a listChannels function', function () {
+      expect(PushNotification.listChannels).toBeDefined();
+      expect(typeof PushNotification.listChannels === 'function').toBe(true);
+    });
+
     it('should contain a unregister function', function () {
       var push = PushNotification.init({});
       expect(push.unregister).toBeDefined();

src/android/com/adobe/phonegap/push/PushConstants.java

@@ -97,4 +97,5 @@ public interface PushConstants {
   public static final String CREATE_CHANNEL = "createChannel";
   public static final String DELETE_CHANNEL = "deleteChannel";
   public static final String ONGOING = "ongoing";
+  public static final String LIST_CHANNELS = "listChannels";
 }

src/android/com/adobe/phonegap/push/PushPlugin.java

@@ -56,6 +56,24 @@ private Context getApplicationContext() {
     return this.cordova.getActivity().getApplicationContext();
   }
 
+  @TargetApi(26)
+  private JSONArray listChannels() throws JSONException {
+    JSONArray channels = new JSONArray();
+    // only call on Android O and above
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+      final NotificationManager notificationManager = (NotificationManager) cordova.getActivity()
+          .getSystemService(Context.NOTIFICATION_SERVICE);
+      List<NotificationChannel> notificationChannels = notificationManager.getNotificationChannels();
+      for (NotificationChannel notificationChannel : notificationChannels) {
+        JSONObject channel = new JSONObject();
+        channel.put(CHANNEL_ID, notificationChannel.getId());
+        channel.put(CHANNEL_DESCRIPTION, notificationChannel.getDescription());
+        channels.put(channel);
+      }
+    }
+    return channels;
+  }
+
   @TargetApi(26)
   private void deleteChannel(String channelId) {
     // only call on Android O and above
@@ -358,6 +376,17 @@ public void run() {
           }
         }
       });
+    } else if (LIST_CHANNELS.equals(action)) {
+      // un-subscribing for a topic
+      cordova.getThreadPool().execute(new Runnable() {
+        public void run() {
+          try {
+            callbackContext.success(listChannels());
+          } catch (JSONException e) {
+            callbackContext.error(e.getMessage());
+          }
+        }
+      });
     } else {
       Log.e(LOG_TAG, "Invalid action : " + action);
       callbackContext.sendPluginResult(new PluginResult(PluginResult.Status.INVALID_ACTION));

src/js/push.js

@@ -313,6 +313,10 @@ module.exports = {
     exec(successCallback, errorCallback, 'PushNotification', 'deleteChannel', [channelId]);
   },
 
+  listChannels: (successCallback, errorCallback) => {
+    exec(successCallback, errorCallback, 'PushNotification', 'listChannels', []);
+  },
+
   /**
    * PushNotification Object.
    *

www/push.js

@@ -354,6 +354,10 @@ module.exports = {
     exec(successCallback, errorCallback, 'PushNotification', 'deleteChannel', [channelId]);
   },
 
+  listChannels: function listChannels(successCallback, errorCallback) {
+    exec(successCallback, errorCallback, 'PushNotification', 'listChannels', []);
+  },
+
   /**
    * PushNotification Object.
    *