[RN] Add the ability to set the default URL in the SDK

android/README.md

 This class encapsulates a high level API in the form of an Android `Activity`
 which displays a single `JitsiMeetView`.
 
+#### getDefaultURL()
+
+See JitsiMeetView.getDefaultURL.
+
 #### getWelcomePageEnabled()
 
 See JitsiMeetView.getWelcomePageEnabled.
 
 See JitsiMeetView.loadURL.
 
+#### setDefaultURL(URL)
+
+See JitsiMeetView.setDefaultURL.
+
 #### setWelcomePageEnabled(boolean)
 
 See JitsiMeetView.setWelcomePageEnabled.
 when the Activity holding this view is going to be destroyed, usually in the
 `onDestroy()` method.
 
+#### getDefaultURL()
+
+Returns the default URL for joining a conference when a non-full URL is given,
+or null if it's not set. If not set, the builtin default (in JavaScript) is
+used: https://meet.jit.si.
+
 #### getListener()
 
 Returns the `JitsiMeetViewListener` instance attached to the view.
 view.loadURLObject(urlBundle);
 ```
 
+#### setDefaultURL(URL)
+
+Sets the default URL. See `getDefaultURL` for more information.
+
+NOTE: Must be called before `loadURL`/`loadURLString` for it to take effect.
+
 #### setListener(listener)
 
 Sets the given listener (class implementing the `JitsiMeetViewListener`

android/sdk/src/main/java/org/jitsi/meet/sdk/JitsiMeetActivity.java

      */
     private JitsiMeetView view;
 
+    /**
+     * Default URL to be used when joining a conference. The value is used only
+     * while {@link #view} equals {@code null}.
+     */
+    private URL defaultURL;
+
     /**
      * Whether the Welcome page is enabled. The value is used only while
      * {@link #view} equals {@code null}.
                     >= Build.VERSION_CODES.M;
     }
 
+    /**
+     *
+     * @see JitsiMeetView#getDefaultURL
+     */
+    public URL getDefaultURL() {
+        return view == null ? defaultURL : view.getDefaultURL();
+    }
+
     /**
      *
      * @see JitsiMeetView#getWelcomePageEnabled
         JitsiMeetView view = new JitsiMeetView(this);
 
         // In order to have the desired effect
-        // JitsiMeetView#setWelcomePageEnabled(boolean) must be invoked before
+        // JitsiMeetView#setWelcomePageEnabled(boolean) or
+        // JitsiMeetView#setDefaultURL(URL) must be invoked before
         // JitsiMeetView#loadURL(URL).
+        view.setDefaultURL(defaultURL);
         view.setWelcomePageEnabled(welcomePageEnabled);
         view.loadURL(null);
 
         JitsiMeetView.onHostResume(this, defaultBackButtonImpl);
     }
 
+    /**
+     *
+     * @see JitsiMeetView#setDefaultURL
+     */
+    public void setDefaultURL(URL url) {
+        if (view == null) {
+            defaultURL = url;
+        } else {
+            view.setDefaultURL(url);
+        }
+    }
+
     /**
      *
      * @see JitsiMeetView#setWelcomePageEnabled

android/sdk/src/main/java/org/jitsi/meet/sdk/JitsiMeetView.java

         }
     }
 
+    /**
+     * Default base URL to use when joining a conference without a full URL.
+     */
+    private URL defaultURL;
+
     /**
      * The unique identifier of this {@code JitsiMeetView} within the process
      * for the purposes of {@link ExternalAPI}. The name scope was inspired by
         }
     }
 
+    /**
+     * Gets the default base URL. If set, it will be preferred over the builtin
+     * default (https://meet.jit.si) in JavaScript. When set, it will be used
+     * to compose the full URL for a conference, when no full URL is provided.
+     *
+     * @return {@URL} the default URL or {@null} if none was set.
+     */
+    public URL getDefaultURL() {
+        return defaultURL;
+    }
+
     /**
      * Gets the {@link JitsiMeetViewListener} set on this {@code JitsiMeetView}.
      *
     public void loadURLObject(@Nullable Bundle urlObject) {
         Bundle props = new Bundle();
 
+        // defaultURL
+        if (defaultURL != null) {
+            props.putString("defaultURL", defaultURL.toString());
+        }
         // externalAPIScope
         props.putString("externalAPIScope", externalAPIScope);
         // url
         loadURLObject(urlObject);
     }
 
+    /**
+     * Sets the default base URL. Must be called before {@link #loadURL(URL)}
+     * for it to take effect.
+     *
+     * @param url - The {@URL} to be set as the new default URL.
+     */
+    public void setDefaultURL(URL url) {
+        defaultURL = url;
+    }
+
     /**
      * Sets a specific {@link JitsiMeetViewListener} on this
      * {@code JitsiMeetView}.

ios/README.md

 
 Property for getting / setting the `JitsiMeetViewDelegate` on `JitsiMeetView`.
 
+#### defaultURL
+
+Property for getting / setting the base default URL. The default URL is used for
+joining a conference when a non-full URL is given. If not set (or nil), the
+builtin default (in JavaScript) is used: https://meet.jit.si.
+
+NOTE: Must be set before `loadURL:`/`loadURLString:` for it to take effect.
+
 #### welcomePageEnabled
 
 Property for getting / setting whether the Welcome page is enabled. If NO, a

ios/sdk/src/JitsiMeetView.h

 
 @property (nonatomic, nullable, weak) id<JitsiMeetViewDelegate> delegate;
 
+@property (copy, nonatomic) NSURL *defaultURL;
+
 @property (nonatomic) BOOL welcomePageEnabled;
 
 +             (BOOL)application:(UIApplication *_Nonnull)application

ios/sdk/src/JitsiMeetView.m

 - (void)loadURLObject:(NSDictionary *)urlObject {
     NSMutableDictionary *props = [[NSMutableDictionary alloc] init];
 
+    if (self.defaultURL) {
+        props[@"defaultURL"] = [self.defaultURL absoluteString];
+    }
+
     props[@"externalAPIScope"] = externalAPIScope;
     props[@"welcomePageEnabled"] = @(self.welcomePageEnabled);