add transitions

lib/src/router.dart

@@ -10,6 +10,11 @@ part of router;
 enum TransitionType {
   native,
   nativeModal,
+  inFromLeft,
+  inFromRight,
+  inFromBottom,
+  fadeIn,
+  custom, // if using custom then you must also provide a transition
 }
 
 class Router {
@@ -32,11 +37,12 @@ class Router {
   }
 
   ///
-  void navigateTo(BuildContext context, String path, {TransitionType transition = TransitionType.native}) {
-    Route<Null> route;
-    if (transition == TransitionType.native) {
-      route = matchRoute(path);
-    }
+  void navigateTo(BuildContext context, String path, {TransitionType transition = TransitionType.native,
+    Duration transitionDuration = const Duration(milliseconds: 250),
+    RouteTransitionsBuilder transitionBuilder})
+  {
+    Route<Null> route = matchRoute(path, transitionType: transition,
+        transitionsBuilder: transitionBuilder, transitionDuration: transitionDuration);
     if (route == null && notFoundHandler != null) {
       route = _notFoundRoute(context, path);
     }
@@ -58,7 +64,10 @@ class Router {
   }
 
   ///
-  Route<Null> matchRoute(String path, {RouteSettings routeSettings = null}) {
+  Route<Null> matchRoute(String path, {RouteSettings routeSettings = null,
+    TransitionType transitionType, Duration transitionDuration = const Duration(milliseconds: 250),
+    RouteTransitionsBuilder transitionsBuilder})
+  {
     RouteSettings settingsToUse = routeSettings;
     if (routeSettings == null) {
       settingsToUse = new RouteSettings(name: path);
@@ -71,13 +80,57 @@ class Router {
     RouteHandler handler = (route != null ? route.handler : notFoundHandler);
     Map<String, String> parameters = match?.parameters ?? <String, String>{};
     RouteCreator creator = (RouteSettings routeSettings, Map<String, String> params) {
-      return new MaterialPageRoute<Null>(settings: routeSettings, builder: (BuildContext context) {
-        return handler(params);
-      });
+      bool isNativeTransition = (transitionType == TransitionType.native || transitionType == TransitionType.nativeModal);
+      if (isNativeTransition) {
+        return new MaterialPageRoute<Null>(settings: routeSettings, fullscreenDialog: transitionType == TransitionType.nativeModal,
+            builder: (BuildContext context) {
+              return handler(params);
+            });
+      } else {
+        var routeTransitionsBuilder;
+        if (transitionType == TransitionType.custom) {
+          routeTransitionsBuilder = transitionsBuilder;
+        } else {
+          routeTransitionsBuilder = _standardTransitionsBuilder(transitionType);
+        }
+        return new PageRouteBuilder<Null>(settings: routeSettings,
+          pageBuilder: (BuildContext context, Animation<double> animation, Animation<double> secondaryAnimation) {
+            return handler(params);
+          },
+          transitionDuration: transitionDuration,
+          transitionsBuilder: routeTransitionsBuilder,
+        );
+      }
     };
     return creator(settingsToUse, parameters);
   }
 
+  RouteTransitionsBuilder _standardTransitionsBuilder(TransitionType transitionType) {
+    return (BuildContext context, Animation<double> animation, Animation<double> secondaryAnimation, Widget child) {
+      if (transitionType == TransitionType.fadeIn) {
+        return new FadeTransition(opacity: animation, child: child);
+      } else {
+        FractionalOffset startOffset = FractionalOffset.bottomLeft;
+        FractionalOffset endOffset = FractionalOffset.topLeft;
+        if (transitionType == TransitionType.inFromLeft) {
+          startOffset = new FractionalOffset(-1.0, 0.0);
+          endOffset = FractionalOffset.topLeft;
+        } else if (transitionType == TransitionType.inFromRight) {
+          startOffset = FractionalOffset.topRight;
+          endOffset = FractionalOffset.topLeft;
+        }
+
+        return new SlideTransition(
+          position: new FractionalOffsetTween(
+            begin: startOffset,
+            end: endOffset,
+          ).animate(animation),
+          child: child,
+        );
+      }
+    };
+  }
+
   /// Route generation method. This function can be used as a way to create routes on-the-fly
   /// if any defined handler is found. It can also be used with the [MaterialApp.onGenerateRoute]
   /// property as callback to create routes that can be used with the [Navigator] class.