Enable row height and content mode settings for Tree (#9540)

* Enable row height setting for Tree
* Add content mode for captions
* Align expander element by default to top

The content mode allows use of preformatted and
HTML captions that bring value to row height

Fixes #9411

1 files changed, 23 insertions, 1 deletions

diff --git a/server/src/main/java/com/vaadin/ui/Tree.java b/server/src/main/java/com/vaadin/ui/Tree.java
index aaff872c95..35bc680213 100644
--- a/server/src/main/java/com/vaadin/ui/Tree.java
+++ b/server/src/main/java/com/vaadin/ui/Tree.java
@@ -218,13 +218,14 @@ public class Tree<T> extends Composite
     private TreeGrid<T> treeGrid = new TreeGrid<>();
     private ItemCaptionGenerator<T> captionGenerator = String::valueOf;
     private IconGenerator<T> iconProvider = t -> null;
+    private final TreeRenderer renderer;
 
     /**
      * Constructs a new Tree Component.
      */
     public Tree() {
         setCompositionRoot(treeGrid);
-        TreeRenderer renderer = new TreeRenderer();
+        renderer = new TreeRenderer();
         treeGrid.getDataCommunicator().addDataGenerator(renderer);
         treeGrid.addColumn(i -> captionGenerator.apply(i), renderer)
                 .setId("column");
@@ -762,4 +763,25 @@ public class Tree<T> extends Composite
     public void setComponentError(ErrorMessage componentError) {
         treeGrid.setComponentError(componentError);
     }
+
+    /**
+     * Sets the height of a row. If -1 (default), the row height is calculated
+     * based on the theme for an empty row before the Tree is displayed.
+     * 
+     * @param rowHeight
+     *            The height of a row in pixels or -1 for automatic calculation
+     */
+    public void setRowHeight(double rowHeight) {
+        treeGrid.setRowHeight(rowHeight);
+    }
+
+    /**
+     * Sets the content mode of the item caption.
+     * 
+     * @param contentMode
+     *            the content mode
+     */
+    public void setContentMode(ContentMode contentMode) {
+        renderer.getState().mode = contentMode;
+    }
 }