[Experimental TitleBar] Collapse TitleText when empty (#6326)

* Add title property changed handler and visual states to collapsed empty title * Remove param from method and get the Title directly.
microsoft · Nov 17, 2021 · fc02d50 · fc02d50
1 parent 2562ac6
commit fc02d50
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Showing 4 changed files with 32 additions and 0 deletions.
diff --git a/dev/TitleBar/TitleBar.cpp b/dev/TitleBar/TitleBar.cpp
@@ -97,6 +97,7 @@ void TitleBar::OnApplyTemplate()
     UpdateIcon();
     UpdateBackButton();
     UpdateTheme();
+    UpdateTitle();
 }
 
 void TitleBar::OnBackButtonClick(winrt::IInspectable const& sender, winrt::RoutedEventArgs const& args)
@@ -119,6 +120,11 @@ void TitleBar::OnCustomContentPropertyChanged(const winrt::DependencyPropertyCha
     UpdateHeight();
 }
 
+void TitleBar::OnTitlePropertyChanged(const winrt::DependencyPropertyChangedEventArgs& args)
+{
+    UpdateTitle();
+}
+
 void TitleBar::OnSizeChanged(const winrt::IInspectable& sender, const winrt::SizeChangedEventArgs& args)
 {
     const auto titleTextBlock = m_titleTextBlock.get();
@@ -264,3 +270,17 @@ void TitleBar::UpdateTheme()
         }
     }
 }
+
+void TitleBar::UpdateTitle()
+{
+    const winrt::hstring titleText = Title();
+    if (titleText.empty())
+    {
+        winrt::VisualStateManager::GoToState(*this, L"TitleTextCollapsed", false);
+    }
+    else
+    {
+        winrt::VisualStateManager::GoToState(*this, L"TitleTextVisible", false);
+    }
+}
+
diff --git a/dev/TitleBar/TitleBar.h b/dev/TitleBar/TitleBar.h
@@ -27,6 +27,7 @@ class TitleBar :
     void OnIconSourcePropertyChanged(const winrt::DependencyPropertyChangedEventArgs& args);
     void OnIsBackButtonVisiblePropertyChanged(const winrt::DependencyPropertyChangedEventArgs& args);
     void OnCustomContentPropertyChanged(const winrt::DependencyPropertyChangedEventArgs& args);
+    void OnTitlePropertyChanged(const winrt::DependencyPropertyChangedEventArgs& args);
 
 private:
     void UpdateVisibility();
@@ -35,6 +36,7 @@ class TitleBar :
     void UpdateBackButton();
     void UpdateHeight();
     void UpdateTheme();
+    void UpdateTitle();
 
     void OnWindowActivated(const winrt::IInspectable& sender, const winrt::WindowActivatedEventArgs& args);
     void OnTitleBarMetricsChanged(const winrt::IInspectable& sender, const winrt::IInspectable& args);

diff --git a/dev/TitleBar/TitleBar.idl b/dev/TitleBar/TitleBar.idl
@@ -7,6 +7,7 @@ unsealed runtimeclass TitleBar : Windows.UI.Xaml.Controls.Control
 {
     TitleBar();
 
+    [MUX_PROPERTY_CHANGED_CALLBACK(TRUE)]
     String Title{ get; set; };
 
     [MUX_PROPERTY_CHANGED_CALLBACK(TRUE)]

diff --git a/dev/TitleBar/TitleBar.xaml b/dev/TitleBar/TitleBar.xaml
@@ -44,6 +44,15 @@
                                 </VisualState>
                             </VisualStateGroup>
 
+                            <VisualStateGroup x:Name="TitleTextVisibilityGroup">
+                                <VisualState x:Name="TitleTextVisible" />
+                                <VisualState x:Name="TitleTextCollapsed">
+                                    <VisualState.Setters>
+                                        <Setter Target="TitleText.Visibility" Value="Collapsed" />
+                                    </VisualState.Setters>
+                                </VisualState>
+                            </VisualStateGroup>
+
                             <VisualStateGroup x:Name="FullScreenGroup">
                                 <VisualState x:Name="TitleBarVisible"/>
                                 <VisualState x:Name="TitleBarCollapsed">