Question

How do I change label’s text on textarea’s onkeyup? I’ve tried this but does not work:

Form form;
TextArea ta;
MyLabel resultDiv;


  /**
   * Constructor that is invoked when page is invoked without a session.
   */
  public HomePage(final PageParameters parameters) {

      this.form = new Form("form");
      this.ta = new TextArea("text");
      this.resultDiv = new MyLabel("result");

      this.ta.add( new AjaxEventBehavior( "onKeyUp" ) {
        protected void onEvent( AjaxRequestTarget target ) {
          System.out.println( "Ajax!" );
          resultDiv.setText("Foobar");
          resultDiv.renderComponent();
        }
      } );


      form.add( ta );
      form.add( resultDiv );
      add( form );

  }// const

  public class MyLabel extends Label {
    private String text = "original";
    public String getText() {      return text;    }
    public void setText( String text ) {      this.text = text;    }
    public MyLabel( String id ) {
      super( id );
      this.setModel( new PropertyModel(this,"text") );
    }
  }

Solution

leonidv was almost there. The resulting code is:

Form form;
TextArea ta;
Label resultDiv = new Label( "result", new PropertyModel(this,"labelText") ){
  { setOutputMarkupId( true ); }
};

private String labelText = "original";


/**
 * Constructor that is invoked when page is invoked without a session.
 */
public HomePage(final PageParameters parameters) {

    this.form = new Form("form");

    this.ta = new TextArea("text");
    this.ta.add( new AjaxEventBehavior( "onKeyUp" ) {
      protected void onEvent( AjaxRequestTarget target ) {
        System.out.println( "Ajax!" );
        labelText = "Foobar";  // Doesn't even need get/set, which is great.
        target.addComponent( resultDiv );
        //resultDiv.renderComponent(); // WRONG!!
      }
    } );

    form.add( ta );
    form.add( resultDiv );
    add( form );

}// const

The last problem was my bad intuition about adding renderComponent() – that, for some reason, kept the label unchanged.

By the way, the result will serve soon as JTexy lightweight markup language sandbox.

Thanks for help!

Answer 1

If you want to update components after AJAX event, you must to do 2 things:

1. Updatable components must have setted flag setOutputMarkupId == true;

2. You must add this components to target onEvent method

   this.resultDiv.setMarkupOutputId(true);
   
   protected void onEvent( AjaxRequestTarget target ) {
         System.out.println( "Ajax!" );
         //resultDiv.setModel(  );
         resultDiv.setText("Foobar");
         resultDiv.renderComponent();
         target.add(resultDiv);
   }
   

PS I don’t understand many parts of your code.