Hi,
I encounter this problem and I think it might be related to the Wt framework. I
want to see if anyone can help me with it.
Synopsis: When a WTreeNode is added to the WTree and then is removed using
removeChildNode() but without completely destroying the node and re-adds it
back to the WTree using addChildNode(), the select() / emit() signal
underneaths the node apparently is now duplicated. And each time the node is
removed and re-added the signal grows in a polynomial rate.
Below is a prove of concept code snippet
-------------------------------ExamplePage.h-------------------------------------
#ifndef EXAMPLEPAGE_H_
#define EXAMPLEPAGE_H_
#include <Wt/WContainerWidget>
#include <Wt/WTree>
#include <Wt/WTreeNode>
#include <vector>
#include <string>
#include <iostream>
#include "WtApp.h"
class ValueTreeNode : public Wt::WTreeNode
{
std::wstring value_;
public:
ValueTreeNode(const std::wstring& value,
const std::wstring &labelText,
Wt::WIconPair *labelIcon=0,
Wt::WTreeNode *parentNode=0) :
Wt::WTreeNode(labelText, labelIcon, parentNode),
value_(value)
{
}
virtual ~ValueTreeNode()
{
}
const std::wstring value() const
{
return value_;
}
};
class ExamplePage : public Wt::WContainerWidget
{
public:
ExamplePage(Wt::WContainerWidget* parent=0);
virtual ~ExamplePage();
private:
Wt::WTree *tree;
std::vector<ValueTreeNode*> children_;
void addButtonAction();
void removeButtonAction();
void updates(bool b);
};
#endif
-------------------------------ExamplePage.cpp-------------------------------------
#include "ExamplePage.h"
#include <Wt/WIconPair>
#include <Wt/WSignalMapper>
#include <Wt/WSignal>
#include <Wt/WText>
#include <Wt/WPushButton>
ExamplePage::ExamplePage(Wt::WContainerWidget* parent) :
Wt::WContainerWidget(parent)
{
Wt::WIconPair * labelIcon = new
Wt::WIconPair("resources/icons/universes_closed.png","resources/icon
/universes_open.png",true);
ValueTreeNode * root = new ValueTreeNode(L"Root",L"Root",labelIcon,NULL);
root->selected().connect(SLOT(this,ExamplePage::updates));
root->setLoadPolicy(Wt::WTreeNode::PreLoading);
root->expand();
tree = new Wt::WTree(this);
tree->setSelectionMode(Wt::SingleSelection);
tree->setTreeRoot(root);
addWidget(tree);
std::vector<std::wstring> values;
values.push_back(L"Node 1");
for (std::vector<std::wstring>::iterator i = values.begin(); i !=
values.end(); i++)
{
Wt::WIconPair * labelIcon = new
Wt::WIconPair("resources/icons/studies_closed.png","resources/icons/studies_open.png",true);
ValueTreeNode* childNode = new
ValueTreeNode(*i,*i,labelIcon,tree->treeRoot());
childNode->selected().connect(SLOT(this,ExamplePage::updates));
children_.push_back(childNode);
}
new Wt::WBreak(this);
Wt::WPushButton * addButton = new Wt::WPushButton("Add", this);
addButton->clicked().connect(SLOT(this,ExamplePage::addButtonAction));
Wt::WPushButton * removeButton = new Wt::WPushButton("Remove", this);
removeButton->clicked().connect(SLOT(this,ExamplePage::removeButtonAction));
}
ExamplePage::~ExamplePage()
{
delete tree;
}
void ExamplePage::addButtonAction()
{
new Wt::WBreak(this);
new Wt::WBreak(this);
Wt::WText* buttonClicked = new Wt::WText("Add Button Clicked", this);
Wt::WTreeNode *treeRoot = tree->treeRoot();
for(int i=0; i<children_.size(); i++)
{
treeRoot->addChildNode(children_[i]);
}
}
void ExamplePage::removeButtonAction()
{
new Wt::WBreak(this);
new Wt::WBreak(this);
Wt::WText* buttonClicked = new Wt::WText("Remove Button Clicked", this);
Wt::WTreeNode *treeRoot = tree->treeRoot();
for(int i=0; i<children_.size(); i++)
{
treeRoot->removeChildNode(children_[i]);
}
}
void ExamplePage::updates(bool b)
{
new Wt::WBreak(this);
Wt::WText* valueSelected = new Wt::WText("Tree Node is Clicked!", this);
}
----------------------------------------------------------------------------------------------------
Here is a link to the code in action:
http://slice4.aheh.com:8050/
Sincerely,
Jimmy
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