Question

I am currently having trouble finding the index/location of a button in a table I am generating.

private class Node
   {
    String id;
    String[] data;
    List<Node> children = new ArrayList<Node>();
}

private Node root = buildTree();

private Node buildTree()
    {
        Node root = new Node();
        root.id = "Main Component";
        root.data = new String[]{ "example", "example", "example", "example", "example", "example",};

    Node child1 = new Node();
    child1.id = "Part 1";
    child1.data = new String[]{ "example", "example", "example", "example", "example", "example", "example"};
    root.children.add(child1);

    Node child11 = new Node();
    child11.id = "Part 1-1";
    child11.data = new String[]{ "example", "example", "example", "example", "example", "example", "example"};
    child1.children.add(child11);

    Node child2 = new Node();
    child2.id = "Part 2";
    child2.data = new String[]{ "example", "example", "example", "example", "example", "example", "example"};
    root.children.add(child2);

    Node child21 = new Node();
    child21.id = "Part 2-1";
    child21.data = new String[]{ "example", "example", "example", "example", "example", "example", "example"};
    child2.children.add(child21);

    Node child22 = new Node();
    child22.id = "Part 2-2";
    child22.data = new String[]{ "example", "example", "example", "example", "example", "example", "example"};
    child2.children.add(child22);

    Node child3 = new Node();
    child3.id = "Part 3";
    child3.data = new String[]{ "example", "example", "example", "example", "example", "example", "example"};
    root.children.add(child3);

    Node child31 = new Node();
    child31.id = "Part 3-1";
    child31.data = new String[]{ "example", "example", "example", "example", "example", "example", "example"};
    child3.children.add(child31);

    Node child32 = new Node();
    child32.id = "Part 3-2";
    child32.data = new String[]{ "example", "example", "example", "example", "example", "example", "example"};
    child3.children.add(child32);

    return root;
}

Here is my data model. The idea here is that I will add rows to the table with a couple functions however I am stuck at an early step.

private void addRow(Node nde)
{
    HorizontalPanel buttonPanel = new HorizontalPanel();

    ListBox comboBox = new ListBox();
    comboBox.addItem("option1");
    comboBox.addItem("option2");
    comboBox.addItem("option3");
    comboBox.addItem("option4");
    comboBox.addItem("option5");

    Button addRowButton = new Button("+/-");

    addRowButton.addClickHandler(new ClickHandler() {
        public void onClick(ClickEvent event) {
            //Get the button from the click event
            //Get the row from the button - could I possibly set a class to each button that equals the id of the element being added so that I could just pull the id from the button
            //Use the row to get the first column - returns a panel
            //Get the components on the panel, find the label, and get the text
            String id = "";
            clickFunction(id);
        }
    });

    buttonPanel.add(addRowButton);
    buttonPanel.add(new Label(nde.id));

    int row = flexTable.getRowCount();
    flexTable.setWidget(row,0,buttonPanel);
    flexTable.setWidget(row,1,comboBox);
    flexTable.setText(row,2,nde.data[0]);
    flexTable.setText(row,3,nde.data[1]);
    flexTable.setText(row,4,nde.data[2]);
    flexTable.setText(row,5,nde.data[3]);
    flexTable.setText(row,6,nde.data[4]);
    flexTable.setText(row,7,nde.data[5]);
}

This is how I am adding rows, there is a horizontal panel in the first column of every row, the first element is a button and the second is a title that matches the ID of whatever node is being displayed in that row. I need a way to get that id, set it equal to the string and pass it into my clickFunction.

private void clickFunction(String curRowId)
{
    Node rowNode = findNode(root, curRowId);

            //need to determine whether or not the tree needs to be expanded or minimized.

            for(Node n : rowNode.children) {
        addRow(n);
    }

}

clickFunction uses the id passed in my findNode function

private Node findNode(Node nde, String id)
{
    if(nde.id.equals(id))
    {
        return nde;
    }

    for(Node n : nde.children)
    {
        Node rtrn = findNode(n, id);
        if(rtrn != null)
        {
            return rtrn;
        }
    }

    return null;
}

Which is called recursively to tell the code which node needs its children extended. I hope this was not too long, I wanted to make sure I included all relevant info and proved I’m actually working hard to remedy problems I’m having. Its definitely frustrating when I’ve worked so much out but can’t figure out a seemingly simple problem.

Any information is greatly appreciated! Much thanks in advance!

Answer 1

To set the id for the button, you can do something like this…

Button b = new Button();
DOM.setElementAttribute(b.getElement(), "id", "my-button-id");

You should then be able to match it in your findNode method.

See http://google-web-toolkit.googlecode.com/svn/javadoc/1.5/com/google/gwt/user/client/DOM.html for more information on working with the DOM.