QT学习之[QTreeWidgetItem]详解，示例-Toy模板网

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QTreeWidgetItem

树形控件，当选中顶层树形节点时，子节点全部被选中，当取消选择顶层数节点时，子节点全部被取消，当选中子节点时候，父节点显示被选中，示例如下：

用法以及API详解如图：

图片 qtreewidgetitem,QT,qt,学习,ui,c++

第一步：

双击UI文件选择，打开ui设计器，拖拽一个Tree Widget 控件，文章来源地址https://www.toymoban.com/news/detail-597482.html

第二步：

在.h头文件中添加代码：

#include <QTreeWidgetItem>

在widget声明处添加代码：

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
    void init();
    void updataParentItem(QTreeWidgetItem* item);
private slots:
    void treeItemChanged(QTreeWidgetItem* item,int column);
private:
    QTreeWidgetItem* group1;
    QTreeWidgetItem* group2;
    QTreeWidgetItem* group3;
    QTreeWidgetItem* subItem1;
    QTreeWidgetItem* subItem2;
    QTreeWidgetItem* subItem3;
    QTreeWidgetItem* subItem4;
    QTreeWidgetItem* subItem5;
    QTreeWidgetItem* subItem6;
    QTreeWidgetItem* subItem7;
    QTreeWidgetItem* subItem8;
    QTreeWidgetItem* subItem9;

在widget构造函数添加代码：


 //初始化页面
    init();
    //发射信号接受相应
    connect(ui>treeWidget,SIGNAL(itemChanged(QTreeWidgetItem*,int)),this,SLOT(treeItemChanged(QTreeWidgetItem*,int)));
}

init():

void Widget::init()
{
    ui->treeWidget->clear();
    //第一个分组
   group1 = new QTreeWidgetItem(ui->treeWidget);
   group1->setText(0,"group1");
   group1->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
   group1->setCheckState(0,Qt::Unchecked);

   subItem1 = new QTreeWidgetItem(group1);
   subItem1->setText(0,"subItem1");
   subItem1->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
   subItem1->setCheckState(0,Qt::Unchecked);

   subItem2 = new QTreeWidgetItem(group1);
   subItem2->setText(0,"subItem2");
   subItem2->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
   subItem2->setCheckState(0,Qt::Unchecked);

   subItem3 = new QTreeWidgetItem(group1);
   subItem3->setText(0,"subItem3");
   subItem3->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
   subItem3->setCheckState(0,Qt::Unchecked);

   subItem4 = new QTreeWidgetItem(group1);
   subItem4->setText(0,"subItem4");
   subItem4->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
   subItem4->setCheckState(0,Qt::Unchecked);
    //分组2

   group2 = new QTreeWidgetItem(ui->treeWidget);
   group2->setText(0,"group2");
   group2->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
   group2->setCheckState(0,Qt::Unchecked);

   subItem5 = new QTreeWidgetItem(group2);
   subItem5->setText(0,"subItem5");
   subItem5->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
   subItem5->setCheckState(0,Qt::Unchecked);

   subItem6 = new QTreeWidgetItem(group2);
   subItem6->setText(0,"subItem6");
   subItem6->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
   subItem6->setCheckState(0,Qt::Unchecked);

   subItem7 = new QTreeWidgetItem(group2);
   subItem7->setText(0,"subItem7");
   subItem7->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
   subItem7->setCheckState(0,Qt::Unchecked);

   subItem8 = new QTreeWidgetItem(group2);
   subItem8->setText(0,"subItem8");
   subItem8->setFlags(Qt::ItemIsUserCheckable|Qt::ItemIsEnabled|Qt::ItemIsSelectable);
   subItem8->setCheckState(0,Qt::Unchecked);
}

updataParentItem():

void Widget::updataParentItem(QTreeWidgetItem *item)
{
    QTreeWidgetItem* parent = item->parent();
    if(parent == NULL)
    {
        return;
    }

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

}

treeItemChanged（）：

//QTreeWidgetItem自带的信号changItem两个参数，所以这里槽函数也有两个参数
void Widget::treeItemChanged(QTreeWidgetItem *item,int column)
{
    QString itemText = item->text(0);

    //选中时候未点击
    if(Qt::Checked == item->checkState(0))
    {
        //QTreeWidgetItem* parent = item->parent();
        int count = item->childCount();
        if(count > 0)
        {
            for (int i = 0;i < count;i++) {
                //子节点选中
                item->child(i)->setCheckState(0,Qt::Checked);
            }
        }
        else
        {
            //是子节点
           updataParentItem(item);
        }

    }
    else if (Qt::Unchecked == item->checkState(0))
    {
        int count = item->childCount();
        if(count > 0)
        {
            for (int i = 0;i < count;i++) {
                //子节点选中
                item->child(i)->setCheckState(0,Qt::Unchecked);
            }
        }
        else
        {
           updataParentItem(item);
        }
    }

}