Improve state management

pom.xml

@@ -4,7 +4,7 @@
 
     <groupId>com.flowingcode.vaadin.addons</groupId>
     <artifactId>markdown-editor-addon</artifactId>
-    <version>1.0.1-SNAPSHOT</version>
+    <version>1.1.0-SNAPSHOT</version>
     <name>Markdown Editor Add-on</name>
     <description>Markdown Editor for Vaadin Flow</description>
     <url>https://www.flowingcode.com/en/open-source/</url>

src/main/java/com/flowingcode/vaadin/addons/markdown/BaseMarkdownComponent.java

@@ -23,6 +23,7 @@
 import com.vaadin.flow.component.dependency.CssImport;
 import com.vaadin.flow.component.dependency.NpmPackage;
 import com.vaadin.flow.component.react.ReactAdapterComponent;
+import com.vaadin.flow.function.SerializableConsumer;
 
 /**
  * Base class for Markdown based Components.
@@ -47,13 +48,16 @@ public class BaseMarkdownComponent extends ReactAdapterComponent implements HasS
    */
   public enum DataColorMode {DARK,LIGTH,AUTO};
 
+  private String content;
+
   /**
    * Base constructor that receives the content of the markdown component.
    * 
    * @param content content to be used in the Markdown component
    */
   public BaseMarkdownComponent(String content) {
     setContent(content);
+    this.addContentChangeListener(c->this.content = c);
   }
 
   /**
@@ -62,7 +66,7 @@ public BaseMarkdownComponent(String content) {
    * @return the content of the Markdown component
    */
   public String getContent() {
-    return getState("content", String.class);
+    return content;
   }
 
   /**
@@ -71,9 +75,19 @@ public String getContent() {
    * @param content retrieved from the state of the component
    */
   public void setContent(String content) {
+    this.content = content;
     setState("content", content);
   }
 
+  /**
+   * Adds the specified listener for the content change event.
+   * 
+   * @param listener the listener callback for receiving content changes
+   */
+  public void addContentChangeListener(SerializableConsumer<String> listener) {
+    addStateChangeListener("content", String.class, listener);
+  }
+
   /**
    * Sets the color mode of the Markdown component.
    * 

src/main/java/com/flowingcode/vaadin/addons/markdown/MarkdownEditor.java

@@ -37,7 +37,7 @@ public class MarkdownEditor extends BaseMarkdownComponent {
    * Constructor with empty content.
    */
   public MarkdownEditor() {
-    super(null);
+    super("");
   }
 
   /**

src/test/java/com/flowingcode/vaadin/addons/markdown/MarkdownEditorDemo.java

@@ -21,7 +21,10 @@
 
 import com.flowingcode.vaadin.addons.demo.DemoSource;
 import com.flowingcode.vaadin.addons.markdown.BaseMarkdownComponent.DataColorMode;
+import com.vaadin.flow.component.button.Button;
 import com.vaadin.flow.component.combobox.ComboBox;
+import com.vaadin.flow.component.notification.Notification;
+import com.vaadin.flow.component.orderedlayout.HorizontalLayout;
 import com.vaadin.flow.component.orderedlayout.VerticalLayout;
 import com.vaadin.flow.router.PageTitle;
 import com.vaadin.flow.router.Route;
@@ -58,6 +61,35 @@ public MarkdownEditorDemo() {
           break;
       }
     });
-    add(mde,cb);
+    Button getContentButton = new Button("Show content",ev->Notification.show(mde.getContent()));
+    Button setSampleContent = new Button("Set sample content",ev->{
+      mde.setContent("""
+# Markdown Editor Demo
+
+## This is a heading
+
+*This is a list item*
+
+[Link to Vaadin](https://vaadin.com)
+
+```java
+// Sample Java code
+public class Main {
+  public static void main(String[] args) {
+    System.out.println("Hello world!");
+  }
+}
+```
+
+> This is a blockquote
+
+**This is bold text**
+
+_This is italic text_
+
+~~This is strikethrough text~~
+      """);
+    });
+    add(mde,cb,new HorizontalLayout(getContentButton,setSampleContent));
   }
 }