qt TreeWidget复选框实现

首先借鉴了：(157条消息) QTreeWidget设置勾选按钮_qtreewidgetitem设置勾选框_QtHalcon的博客-优快云博客

但实际用的时候发现，当文件的层级增多，父节点的文件选中状态会出错，原因是选中文件的时候如果有字节点未反向考虑父节点的选中状态，另外在父节点的选中状态更新中，只考虑了子节点的选中状态，未考虑子节点的未完全选中状态导致了该错误。

实现效果：

直接上核心代码

//test.h
//在头文件里添加两个公用函数还有一个槽函数的声明
 
#include <QTreeWidgetItem>
public:
 void initTreeWidget();
 void updateParentItem(QTreeWidgetItem *item);
public:
 void treeItemChanged(QTreeWidgetItem *item,int column);
 
//test.cpp
//在构造函数里添加 connect()
 
 initTreeWidget();
 
 connect(ui->treeWidget,SIGNAL(itemChanged(QTreeWidgetItem *,int)),this,SLOT(treeItemChanged(QTreeWidgetItem*,int)));
 
//initTreeWidget() 的实现
 
void test::initTreeWidget()
{
    ui->treeWidget->clear();
    //第一组
    QTreeWidgetItem *group1=new QTreeWidgetItem(ui->treeWidget);
    group1->setText(0,"group1");
    group1->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    group1->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem *item11=new QTreeWidgetItem(group1);
    item11->setText(0,"item11");
    item11->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    item11->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem *item12=new QTreeWidgetItem(group1);
    item12->setText(0,"item12");
    item12->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    item12->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem *item13=new QTreeWidgetItem(group1);
    item13->setText(0,"item13");
    item13->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    item13->setCheckState(0,Qt::Unchecked);
 
    //第二组
    QTreeWidgetItem *group2=new QTreeWidgetItem(ui->treeWidget);
    group2->setText(0,"group2");
    group2->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    group2->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem *item21=new QTreeWidgetItem(group2);
    item21->setText(0,"item21");
    item21->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    item21->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem *item22=new QTreeWidgetItem(group2);
    item22->setText(0,"item22");
    item22->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    item22->setCheckState(0,Qt::Unchecked);
    QTreeWidgetItem *item23=new QTreeWidgetItem(group2);
    item23->setText(0,"item23");
    item23->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
    item23->setCheckState(0,Qt::Unchecked);
}
 
//treeItemChanged(QTreeWidgetItem *item, int column)的实现
void test::treeItemChanged(QTreeWidgetItem *item, int column)
{
    QString itemText = item->text(0);

	//选中时
	if (Qt::Checked == item->checkState(0))
	{

		int count = item->childCount();
		if (count > 0)
		{
			for (int i = 0; i < count; i++)
			{
				//子节点也被选中
				item->child(i)->setCheckState(0, Qt::Checked);
			}
			updateParentItem(item);
		}
		else
		{
			//是子节点
			updateParentItem(item);
		}
	}
	else if (Qt::Unchecked == item->checkState(0))
	{
		int count = item->childCount();
		if (count > 0)
		{
			for (int i = 0; i < count; i++)
			{
				item->child(i)->setCheckState(0, Qt::Unchecked);
			}
			updateParentItem(item);
		}
		else
		{
			//是子节点
			updateParentItem(item);
		}
	}
	else if (Qt::PartiallyChecked == item->checkState(0))
	{
		updateParentItem(item);
	}

}
//updateParentItem(QTreeWidgetItem *item) 的实现
void test::updateParentItem(QTreeWidgetItem *item)
{
    QTreeWidgetItem* parent = item->parent();
	if (parent == NULL)
	{
		return;
	}
	//选中的子节点个数
	int selectCount = 0;
	int partiallySelectCount = 0;

	int childCount = parent->childCount();
	for (int i = 0; i < childCount; i++)
	{
		QTreeWidgetItem* childItem = parent->child(i);
		if (childItem->checkState(0) == Qt::Checked )
		{
			selectCount++;
		}
		else if (childItem->checkState(0) == Qt::PartiallyChecked)
		{
			partiallySelectCount++;
		}
	}
	if (selectCount <= 0 && partiallySelectCount <= 0)
	{
		//未选中状态
		parent->setCheckState(0, Qt::Unchecked);
	}
	else if ((selectCount>0 && selectCount<childCount)||(partiallySelectCount > 0 ))
	{
		//部分选中状态
		parent->setCheckState(0, Qt::PartiallyChecked);
	}
	else if (selectCount == childCount)
	{
		//选中状态
		parent->setCheckState(0, Qt::Checked);
	}
}