GWT中的treeitem clickhandler

使用GWT的默认值 Tree ,没有特定的处理程序 TreeItem S,只有一个 SelectionHandler 对于整个树:

tree.addSelectionHandler(new SelectionHandler<TreeItem>() {
  @Override
  public void onSelection(SelectionEvent<TreeItem> event) {
    TreeItem item = event.getSelectedItem();
    // expand the selected item
  }
});

但是, GWT incubator 的 FastTree 按照字面上的意思,只是为了你想做的事情而构建的,懒惰地在扩展项时加载树,所以我将从那里开始。如果你有问题,可以问更多的问题。

// First create a new treeitem-class with a new method:
public class TreeItemAdv extends TreeItem {
    protected void doSelectionAction() {
        // TODO: The child should overwrite this method!
        System.out.println("The child should overwrite this method!");
    }
}

...
    // define your tree:
    Tree tree = new Tree();
    tree.addSelectionHandler(new SelectionHandler<TreeItem>() {
        @Override
        public void onSelection(SelectionEvent<TreeItem> event) {               
            TreeItemAdv item = (TreeItemAdv) event.getSelectedItem();
            item.doSelectionAction(); // do item-specific stuff
        }
    });

    // define and add your items:
    TreeItemAdv ti1 = new TreeItemAdv() {
        @Override
        protected void doSelectionAction() {
            // TODO: Do some stuff.
            System.out.println("1: Here I am.");
        }           
    };      
    ti1.setText("Item 1");      
    tree.addItem(ti1);
    // and an other item:
    TreeItemAdv ti2 = new TreeItemAdv() {
        @Override
        protected void doSelectionAction() {
            // TODO: Do some stuff.
            System.out.println("2: Here I am.");
        }           
    };      
    ti2.setText("Item 2");      
    tree.addItem(ti2);
...