Move button state logic into createExtensionButton helper. (#73)

* Move button state logic into createExtensionButton helper.

Author: kenzieschmoll

lib/timeline/timeline.dart

@@ -10,7 +10,6 @@ import 'package:vm_service_lib/vm_service_lib.dart' hide TimelineEvent;
 
 import '../framework/framework.dart';
 import '../globals.dart';
-import '../service_manager.dart' show ServiceExtensionState;
 import '../ui/elements.dart';
 import '../ui/primer.dart';
 import '../ui/ui_utils.dart';
@@ -48,10 +47,6 @@ class TimelineScreen extends Screen {
 
   PButton pauseButton;
   PButton resumeButton;
-  PButton trackWidgetBuildsButton;
-  PButton perfOverlayButton;
-  PButton repaintRainbowButton;
-  PButton debugPaintButton;
 
   @override
   void createContent(Framework framework, CoreElement mainDiv) {
@@ -68,13 +63,13 @@ class TimelineScreen extends Screen {
       ..disabled = true
       ..click(_resumeRecording);
 
-    trackWidgetBuildsButton = createExtensionButton(
+    final trackWidgetBuildsButton = createExtensionButton(
         'Track widget builds', extensions.profileWidgetBuilds);
-    perfOverlayButton = createExtensionButton(
+    final perfOverlayButton = createExtensionButton(
         'Performance overlay', extensions.performanceOverlay);
-    repaintRainbowButton =
+    final repaintRainbowButton =
         createExtensionButton('Repaint rainbow', extensions.repaintRainbow);
-    debugPaintButton =
+    final debugPaintButton =
         createExtensionButton('Debug paint', extensions.debugPaint);
 
     mainDiv.add(<CoreElement>[
@@ -140,10 +135,6 @@ class TimelineScreen extends Screen {
   }
 
   void _handleConnectionStart(VmServiceWrapper service) {
-    // Disables or selects buttons as needed based on the state of their service
-    // extensions.
-    _updateButtonStates();
-
     framesChart.disabled = false;
 
     framesTracker = new FramesTracker(service);
@@ -167,44 +158,6 @@ class TimelineScreen extends Screen {
     });
   }
 
-  void _updateButtonStates() {
-    // Disable buttons for unavailable service extensions.
-    serviceManager.serviceExtensionManager
-        .hasServiceExtension(extensions.profileWidgetBuilds, (bool available) {
-      trackWidgetBuildsButton.disabled = !available;
-    });
-    serviceManager.serviceExtensionManager
-        .hasServiceExtension(extensions.performanceOverlay, (bool available) {
-      perfOverlayButton.disabled = !available;
-    });
-    serviceManager.serviceExtensionManager
-        .hasServiceExtension(extensions.repaintRainbow, (bool available) {
-      repaintRainbowButton.disabled = !available;
-    });
-    serviceManager.serviceExtensionManager
-        .hasServiceExtension(extensions.debugPaint, (bool available) {
-      debugPaintButton.disabled = !available;
-    });
-
-    // Select buttons whose state is already enabled.
-    serviceManager.serviceExtensionManager.getServiceExtensionState(
-        extensions.profileWidgetBuilds, (ServiceExtensionState state) {
-      trackWidgetBuildsButton.toggleClass('selected', state.enabled);
-    });
-    serviceManager.serviceExtensionManager.getServiceExtensionState(
-        extensions.performanceOverlay, (ServiceExtensionState state) {
-      perfOverlayButton.toggleClass('selected', state.enabled);
-    });
-    serviceManager.serviceExtensionManager.getServiceExtensionState(
-        extensions.repaintRainbow, (ServiceExtensionState state) {
-      repaintRainbowButton.toggleClass('selected', state.enabled);
-    });
-    serviceManager.serviceExtensionManager.getServiceExtensionState(
-        extensions.debugPaint, (ServiceExtensionState state) {
-      debugPaintButton.toggleClass('selected', state.enabled);
-    });
-  }
-
   void _handleConnectionStop(dynamic event) {
     framesChart.disabled = true;
 

lib/ui/ui_utils.dart

@@ -12,11 +12,21 @@ import 'primer.dart';
 // This would help to build icon familiarity.
 PButton createExtensionButton(String text, String extensionName) {
   final PButton button = new PButton(text)..small();
+
   button.click(() {
     final bool wasSelected = button.element.classes.contains('selected');
     serviceManager.serviceExtensionManager
         .setServiceExtensionState(extensionName, !wasSelected, !wasSelected);
   });
+
+  // Disable button for unavailable service extensions.
+  serviceManager.serviceExtensionManager.hasServiceExtension(
+      extensionName, (available) => button.disabled = !available);
+
+  // Select button whose state is already enabled.
+  serviceManager.serviceExtensionManager.getServiceExtensionState(
+      extensionName, (state) => button.toggleClass('selected', state.enabled));
+
   return button;
 }