GXT combo example.

ComboboxExample.java

package com.sencha.gxt.test.client.combo;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.shared.GWT;
import com.google.gwt.event.logical.shared.ValueChangeEvent;
import com.google.gwt.event.logical.shared.ValueChangeHandler;
import com.google.gwt.safehtml.shared.SafeHtmlUtils;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.Widget;
import com.sencha.gxt.cell.core.client.form.ComboBoxCell;
import com.sencha.gxt.cell.core.client.form.ComboBoxCell.TriggerAction;
import com.sencha.gxt.core.client.Style.Side;
import com.sencha.gxt.data.shared.LabelProvider;
import com.sencha.gxt.data.shared.ListStore;
import com.sencha.gxt.data.shared.ModelKeyProvider;
import com.sencha.gxt.widget.core.client.WidgetComponent;
import com.sencha.gxt.widget.core.client.container.MarginData;
import com.sencha.gxt.widget.core.client.container.VerticalLayoutContainer;
import com.sencha.gxt.widget.core.client.container.VerticalLayoutContainer.VerticalLayoutData;
import com.sencha.gxt.widget.core.client.container.Viewport;
import com.sencha.gxt.widget.core.client.event.InvalidEvent;
import com.sencha.gxt.widget.core.client.event.InvalidEvent.InvalidHandler;
import com.sencha.gxt.widget.core.client.form.ComboBox;
import com.sencha.gxt.widget.core.client.form.error.SideErrorHandler;
import com.sencha.gxt.widget.core.client.tips.ToolTip;
import com.sencha.gxt.widget.core.client.tips.ToolTipConfig;

public class ComboboxExample implements EntryPoint {

  public class SideErrorHandlerExt extends SideErrorHandler {

    public SideErrorHandlerExt(Widget target) {
      super(target);
    }
    
    public ToolTip getTip() {
      return tip;
    }
    
    public WidgetComponent getIcon() {
      return errorIcon;
    }
  }
  
  @Override
  public void onModuleLoad() {
    VerticalLayoutContainer vlc = new VerticalLayoutContainer();
    vlc.add(createCombo(), new VerticalLayoutData(-1, -1));

    Viewport vp = new Viewport();
    vp.add(vlc, new MarginData(50));

    RootPanel.get().add(vp);
  }

  private ComboBox<Company> createCombo() {
    ListStore<Company> store = new ListStore<Company>(new ModelKeyProvider<Company>() {
      @Override
      public String getKey(Company item) {
        return item.getId().toString();
      }
    });
    
    store.add(new Company("0", "Company 11"));
    store.add(new Company("1", "Company 22"));
    store.add(new Company("2", "Company 33"));
    store.add(new Company("3", "Company 44"));
    store.add(new Company("4", "Company 55"));

    LabelProvider<Company> labelProvider = new LabelProvider<Company>() {
      @Override
      public String getLabel(Company item) {
        if (item.getName() == null) {
          return "";
        }
        
        return item.getName();
      }
    };

    ComboBoxCell<Company> cell = new ComboBoxCell<Company>(store, labelProvider);

    final ComboBox<Company> combo = new ComboBox<Company>(cell);  
    //combo.setErrorSupport(null);
    combo.setTriggerAction(TriggerAction.ALL);
    combo.setValidateOnBlur(false); 
    combo.setClearValueOnParseError(false); 
    combo.addValueChangeHandler(new ValueChangeHandler<Company>(){
    @Override
    public void onValueChange(ValueChangeEvent<Company> event) {
      // TODO Auto-generated method stub
      if (event.getValue() != null){
        GWT.log("validate " + event.getValue().getName());
      } else {
        GWT.log("validate value null");
      }
      
          if (event.getValue() != null && event.getValue().getName().contains("11")) {
            combo.markInvalid("Invalid Option");
          } else {
            combo.setAllowBlank(true);
            combo.clearInvalid();
            combo.isValid();
            combo.removeToolTip();
          }
    }
    });

    combo.addInvalidHandler(new InvalidHandler() {
      @Override
      public void onInvalid(InvalidEvent event) {       
        ToolTipConfig config = new ToolTipConfig();
        config.setTitle("");
        config.setBody(SafeHtmlUtils.fromTrustedString("<span style=\"color:red;\">" + "Invalid Option 111111111 22222222 3333333333 44444444" +"</span>"));

        config.setMouseOffsetX(0);
        config.setMouseOffsetY(0);
        config.setAnchor(Side.BOTTOM);
        config.setMaxWidth(100);
        config.setMinWidth(20);
        config.setShowDelay(0);
        
        combo.setToolTipConfig(config);
      }
    });

    return combo;
  }

  public class Company {
    private String id;
    private String name;

    public Company(String id, String name) {
      this.id = id;
      this.name = name;
    }

    public String getId() {
      return id;
    }

    public String getName() {
      return name;
    }
    
    @Override
    public String toString() {
      return name;
    }
  }

}