Qt模板库、工具即控件项目示例

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项目1 ：项目控件组（Item Widgets）

具体步骤如下。

（1）新建QtGui应用（详见本书第1章1.3.1节），项目名称为“TreeWidget”，基类选择“QWidget”，类名保持“Widget”不变，保持“创建界面”复选框的选中状态。

（2）双击“widget.ui”文件，打开Qt的设计器，拖曳出一个QTreeWidget。

（3）在头文件“widget.h”中添加代码：

#include <QTreeWidgetItem>

在类Widget声明中添加代码：

#ifndef WIDGET_H

#define WIDGET_H

#include <QWidget>

#include <QTreeWidgetItem>

namespace Ui {

class Widget;

class Widget : public QWidget

    Q_OBJECT

public:

    explicit Widget(QWidget *parent = 0);

    ~Widget();

    void init();

    void updateParentItem(QTreeWidgetItem* item);

private:

    Ui::Widget *ui;

public slots:

    void treeItemChanged(QTreeWidgetItem* item, int column);

};

#endif // WIDGET_H

widget.cpp

#include "widget.h"

#include "ui_widget.h"

Widget::Widget(QWidget *parent) :

    QWidget(parent),

    ui(new Ui::Widget)

    ui->setupUi(this);

    init(); /*初始化tree item*/

    connect (ui->treeWidget, SIGNAL(itemChanged(QTreeWidgetItem*,int)),

             this, SLOT(treeItemChanged(QTreeWidgetItem*,int)));

Widget::~Widget()

    delete ui;

void Widget::init ()

    ui->treeWidget->clear ();

    //第一分组(显示在ui->treeWidget框内)

    QTreeWidgetItem* group1 = new QTreeWidgetItem(ui->treeWidget);

    group1->setText (0, "group11");

    group1->setFlags (Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    group1->setCheckState (0, Qt::Unchecked);   //初始值是没有选中

    //添加第一个成员

    QTreeWidgetItem* subItem11 = new QTreeWidgetItem(group1);

    subItem11->setText (0, "subItem11");

    subItem11->setFlags (Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    subItem11->setCheckState (0, Qt::Unchecked);

    //添加第二个成员

    QTreeWidgetItem* subItem12 = new QTreeWidgetItem(group1);

    subItem12->setText (0, "subItem12");

    subItem12->setFlags (Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    subItem12->setCheckState (0, Qt::Unchecked);

    //添加第三个成员

    QTreeWidgetItem* subItem13 = new QTreeWidgetItem(group1);

    subItem13->setText (0, "subItem13");

    subItem13->setFlags (Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    subItem13->setCheckState (0, Qt::Unchecked);

    //添加第四个成员

    QTreeWidgetItem* subItem14 = new QTreeWidgetItem(group1);

    subItem14->setText (0, "subItem14");

    subItem14->setFlags (Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    subItem14->setCheckState (0, Qt::Unchecked);

    //第二分组(显示在ui->treeWidget框内)

    QTreeWidgetItem* group2 = new QTreeWidgetItem(ui->treeWidget);

    group2->setText (0, "group2");

    group2->setFlags (Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    group2->setCheckState (0, Qt::Unchecked);   //初始值是没有选中

    //添加第一个成员

    QTreeWidgetItem* subItem21 = new QTreeWidgetItem(group2);

    subItem21->setText (0, "subItem21");

    subItem21->setFlags (Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    subItem21->setCheckState (0, Qt::Unchecked);

    //添加第二个成员

    QTreeWidgetItem* subItem22 = new QTreeWidgetItem(group2);

    subItem22->setText (0, "subItem22");

    subItem22->setFlags (Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    subItem22->setCheckState (0, Qt::Unchecked);

    //添加第三个成员

    QTreeWidgetItem* subItem23 = new QTreeWidgetItem(group2);

    subItem23->setText (0, "subItem23");

    subItem23->setFlags (Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    subItem23->setCheckState (0, Qt::Unchecked);

    //添加第四个成员

    QTreeWidgetItem* subItem24 = new QTreeWidgetItem(group2);

    subItem24->setText (0, "subItem24");

    subItem24->setFlags (Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    subItem24->setCheckState (0, Qt::Unchecked);

void Widget::treeItemChanged (QTreeWidgetItem *item, int column)

    //返回第一列中指定的文本

    QString itemText = item->text (0);

    //选中时

    if(Qt::Checked == item->checkState (0))

        QTreeWidgetItem* parent = item->parent (); //父节点

        int count = item->childCount ();

        if(count > 0)

            for(int i = 0; i < count; i++)

                //子节点也选中

                item->child (i)->setCheckState (0, Qt::Checked);

        else

            //是子接点

            updateParentItem (item);

    else if(Qt::Unchecked == item->checkState (0))

        int count = item->childCount ();

        if(count > 0)

            for(int i = 0; i < count; i++)

                //子节点未选择

                item->child (i)->setCheckState (0, Qt::Unchecked);

        else

            updateParentItem (item);

void Widget::updateParentItem (QTreeWidgetItem *item)

    QTreeWidgetItem* parent = item->parent ();

    if(parent == NULL)

        return;

    //选中节点的个数

    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)

        //未中状态

        parent->setCheckState (0, Qt::Unchecked);

    else if(selectedCount > 0 && selectedCount < childCount)

        //部分选中状态                       部分 检查

        parent->setCheckState (0, Qt::PartiallyChecked);

    else if(selectedCount == childCount)

        //全选中状态

        parent->setCheckState (0, Qt::Checked);

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