【接口封装】——18、添加目录项列表响应

 解释：

1、封装内容：列表显示

2、Qt::UserRole：设置不同的值，以此区分多级目录项

函数定义：

	void onTreeItemClicked(QTreeWidgetItem* item);
	void onTreeItemDoubleClicked(QTreeWidgetItem* item);
	void onTreeItemExpanded(QTreeWidgetItem* item);
	void onTreeItemCollapsed(QTreeWidgetItem* item);	//缩放
    void initContact();

源代码：

void CCMainWindow::initContact()
{

	//根项
	QTreeWidgetItem* rootItem = new QTreeWidgetItem;
	rootItem->setData(0, Qt::UserRole, 0);  //根项设置为 0，子项为 1， 以示区分根项子项

	RootContactItem* rootWidget = new RootContactItem(true, ui.treeWidget);
	rootWidget->setText(RootContact_TEXT);

	ui.treeWidget->addTopLevelItem(rootItem);	//添加顶级项
	ui.treeWidget->setItemWidget(rootItem, 0, rootWidget);

	//连接根项目录的信号与槽函数
	connect(ui.treeWidget, &QTreeWidget::itemClicked, this, &CCMainWindow::onTreeItemClicked);
	connect(ui.treeWidget, &QTreeWidget::itemDoubleClicked, this, &CCMainWindow::onTreeItemDoubleClicked);
	connect(ui.treeWidget, &QTreeWidget::itemExpanded, this, &CCMainWindow::onTreeItemExpanded);
	connect(ui.treeWidget, &QTreeWidget::itemCollapsed, this, &CCMainWindow::onTreeItemCollapsed);		//折叠


}

void CCMainWindow::onTreeItemClicked(QTreeWidgetItem * item)
{
	bool isRoot = !(item->data(0, Qt::UserRole).toBool());	//根项被设置为0，isRoot:true
	if (isRoot) {
		item->setExpanded(!item->isExpanded());
	}

}

void CCMainWindow::onTreeItemDoubleClicked(QTreeWidgetItem * item)
{
	bool isChild = item->data(0, Qt::UserRole).toBool();//子项被设置为1
	if (isChild) {
		qDebug() << QString::fromLocal8Bit("打开聊天窗口：") << item->data(0, Qt::UserRole + 1);
		
	}

}

void CCMainWindow::onTreeItemExpanded(QTreeWidgetItem * item)
{
	bool isRoot = !(item->data(0, Qt::UserRole).toBool());	//根项被设置为0，isRoot:true
	if (isRoot) {
		RootContactItem* rootWidget = dynamic_cast<RootContactItem*>(ui.treeWidget->itemWidget(item, 0));
		if (rootWidget) {
			rootWidget->setExpanded(true);
		}
	}
}

//折叠：collapsed
void CCMainWindow::onTreeItemCollapsed(QTreeWidgetItem * item)
{
	bool isRoot = !(item->data(0, Qt::UserRole).toBool());	//根项被设置为0，isRoot:true
	if (isRoot) {
		//dynamic_cast：强制类型转换
		RootContactItem* rootWidget = dynamic_cast<RootContactItem*>(ui.treeWidget->itemWidget(item, 0));
		if (rootWidget) {
			rootWidget->setExpanded(false);
		}
	}

}

	RootContactItem(bool hasArrow = true, QWidget *parent = nullptr);