拖一个TreeWidget 控件 改名 tv_Source
 
拖拉四个Button 按钮 分别取名btn_AddRoot，  btn_Add，  btn_Del，   btn_Modify
 
 
给四个按钮添加槽函数（clicked）
 
widget.h
 
#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QDialog>
#include <QString>
#include <QTreeWidgetItem>


namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT
    
public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();

public slots:
    void on_tv_Source_currentItemChanged(QTreeWidgetItem *current, QTreeWidgetItem *previous);
    void on_btn_Add_clicked();
    void on_btn_Modify_clicked();
    void on_btn_Del_clicked();
    void on_btn_AddRoot_clicked();


private:
    Ui::Widget *ui;
    QTreeWidgetItem * AddTreeRoot(QString name,QString desc);
    QTreeWidgetItem * AddTreeNode(QTreeWidgetItem *parent,QString name,QString desc);
};

#endif // WIDGET_H
 
widget.cpp
 
#include "widget.h"
#include "ui_widget.h"
#include <QStringList>


Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    ui->tv_Source->setColumnCount(2);
    ui->tv_Source->setHeaderLabels(QStringList()<<"Name"<<"Description");
    //ui->tv_Source->setHeaderHidden(true);
    QTreeWidgetItem * beiJingItem = AddTreeRoot("bejing","city");
    AddTreeNode(beiJingItem,"haidian","HaiDian");
    AddTreeNode(beiJingItem,"chaoYang","chaoYang");
    AddTreeNode(beiJingItem,"fengTai","fengTai");
    QTreeWidgetItem * HeiBeiItem =AddTreeRoot("hebei","city");
    AddTreeNode(HeiBeiItem,"baoDing","baoDing");
    AddTreeNode(HeiBeiItem,"shiJiaZhuang","shiJiaZhuang");
}

Widget::~Widget()
{
    delete ui;
}
QTreeWidgetItem * Widget::AddTreeRoot(QString name,QString desc)
{
    QTreeWidgetItem * item=new QTreeWidgetItem(QStringList()<<name<<desc);
    ui->tv_Source->addTopLevelItem(item);
    return item;
}

QTreeWidgetItem * Widget::AddTreeNode(QTreeWidgetItem *parent,QString name,QString desc)
{
    QTreeWidgetItem * item=new QTreeWidgetItem(QStringList()<<name<<desc);
    parent->addChild(item);
    return item;
}

void Widget::on_tv_Source_currentItemChanged(QTreeWidgetItem *current, QTreeWidgetItem *previous)
{
    if(current==NULL)
        return;
    if(previous!=NULL)
    {
        previous->setBackground(0,Qt::transparent);
        previous->setBackground(1,Qt::transparent);
        previous->setTextColor(0,Qt::black);
        previous->setTextColor(1,Qt::black);
    }
    current->setTextColor(0,Qt::blue);
    current->setTextColor(1,Qt::blue);
    current->setBackground(0,Qt::red);
    current->setBackground(1,Qt::red);
}

//添加
void Widget::on_btn_Add_clicked()
{
    QTreeWidgetItem * item= ui->tv_Source->currentItem();
    if(item!=NULL)
    {
        AddTreeNode(item,"new","new");
    }
    else
    {
        AddTreeRoot("new","new");
    }
}


//修改
void Widget::on_btn_Modify_clicked()
{
    QTreeWidgetItem * currentItem = ui->tv_Source->currentItem();

    if(currentItem==NULL)
    {
        return;
    }
    for(int i=0;i<currentItem->columnCount();i++)
    {
        currentItem->setText(i,tr("Modify")+QString::number(i));
    }
}

//删除
void Widget::on_btn_Del_clicked()
{
    QTreeWidgetItem * currentItem = ui->tv_Source->currentItem();

    if(currentItem==NULL)
    {
        return;
    }
    //如果没有父节点就直接删除
    if(currentItem->parent()==NULL)
    {
        delete ui->tv_Source->takeTopLevelItem(ui->tv_Source->currentIndex().row());
    }
    else
    {
        //如果有父节点就要用父节点的takeChild删除节点
        delete currentItem->parent()->takeChild(ui->tv_Source->currentIndex().row());
    }
}

void Widget::on_btn_AddRoot_clicked()
{
     AddTreeRoot("new","new");
}
 
实现效果： 
 
 
源码下载地址：https://download.csdn.net/download/weixin_40569991/10730744 
 
参考：https://www.cnblogs.com/li-peng/p/3652287.html

这两天写了个基于sqlite的学生管理系统，同时也复习了qt的一些知识，也加深了自己队sqlite用法的理解。
 
 
 
在此，总结下自己在写的时候复习到的知识。
 

 
 
 
一、  如何为treewidgetitem添加右键菜单
 
 
第一步：
 
// 设置右键编辑
 
   ui.TREEwidget->setContextMenuPolicy(Qt::CustomContextMenu);
 
 
 
第二步 ：
 
Connect 相关的信号和槽；
 
    connect(ui.TREEwidget, SIGNAL(customContextMenuRequested(const QPoint&)),this, 
 
       SLOT(OnlistContextMenu(const QPoint&)));
 
 
 
第三步  设置右键菜单项；
 
 
 
int demo003::OnlistContextMenu(const QPoint&pos)
 
{
 
 
 
    QMenu  menu;
 
    menu.addAction(ui.action_upload);
 
    menu.addAction(ui.action_delete);
 
    QPoint  pt_global =ui.TREEwidget->mapToGlobal(pos);
 
    menu.exec(pt_global);
 
 
 
    return0;
 
}
 
当然 这一切的前提是，你已经在qtdesigner里面添加好了相关的action，
 
并且每个action都有相关的槽函数；
 

记录一下QTreeWidget和QTreeWidgetItem在Qt中的应用，示例如下图所示
 
 
首先需要建立QTreeWidget对象
 
QHBoxLayout	*hLayout = new QHBoxLayout();
QTreeWidget *CameraTree = new QTreeWidget(this);
CameraTree->setColumnCount(2);//设置列
CameraTree->setHeaderLabels(QStringList()<<"feature"<<"value");//设置标题
hLayout->addWidget(CameraTree);
 
然后使用    QList<QTreeWidgetItem *> 类建立一个对象items，再使用QTreeWidgetItem建立first、second等等，想建立几个就建立几个，然后使用items.append(first)关联起来，最后使用 CameraTree->insertTopLevelItems(0, items)插入为顶端LevelItems
 
QList<QTreeWidgetItem *> items;
//items.append(new QTreeWidgetItem((QTreeWidget*)0, QStringList(QString("first"))));

first = new QTreeWidgetItem;
first->setText(0,"first");
items.append(first);

second = new QTreeWidgetItem;   //添加第二个父节点
second->setText(0, tr("second"));
items.append(second);
CameraTree->insertTopLevelItems(0, items);
first->setHidden(false);//设置隐藏
second->setHidden(false);//设置隐藏
 
再继续就可以给每一个添加进去的QTreeWidgetItem再添加控件或者child，使用first->addChild(item_ImageFormatControl)中addchild是父对象添加子对象函数，可以一直下去，不断添加...,CameraTree->setItemWidget(itemWidth, 1, spBoxckBoxWidget)中setItemWidget是在CameraTree添加的itemWidth对象中的第一列添加控控件（可以添加多个控件，效果图所示，代码如下）
 
QCheckBox *ckBox = new QCheckBox;
ckBox->setText("CheckBox");
ckBox->setChecked(true);
//ckBox->setFixedHeight(20);
QSpinBox *spBox = new QSpinBox;
//spBox->setFixedHeight(20);
QHBoxLayout *spBoxckBoxHBoxLayout = new QHBoxLayout();
spBoxckBoxHBoxLayout->addWidget(ckBox);
spBoxckBoxHBoxLayout->addWidget(spBox);

QWidget *spBoxckBoxWidget = new QWidget();
spBoxckBoxWidget->setLayout(spBoxckBoxHBoxLayout);

QTreeWidgetItem *item_ImageFormatControl = new QTreeWidgetItem;
item_ImageFormatControl->setText(0, "Image Format Control");
QTreeWidgetItem *item_AnalogControl = new QTreeWidgetItem;
item_AnalogControl->setText(0,"Analog Control");
QTreeWidgetItem *item_ImageQualityControl = new QTreeWidgetItem;
item_ImageQualityControl->setText(0, "Image Quality Control");
first->addChild(item_ImageFormatControl);
first->addChild(item_AnalogControl);
first->addChild(item_ImageQualityControl);

QTreeWidgetItem *itemWidth = new QTreeWidgetItem;
itemWidth->setText(0, "Width");
	
item_ImageFormatControl->addChild(itemWidth);
//CameraTree->setItemWidget(item, 1, spBox);
CameraTree->setItemWidget(itemWidth, 1, spBoxckBoxWidget);                //设置ckBox为item的第二列
	
QTreeWidgetItem *itemPixelFormat = new QTreeWidgetItem;
itemPixelFormat->setText(0, "Pixel Format");
item_ImageFormatControl->addChild(itemPixelFormat);

QComboBox *comboBoxPixelFormat = new QComboBox;
comboBoxPixelFormat->addItem("Mono 8");
comboBoxPixelFormat->addItem("RGB 8");
CameraTree->setItemWidget(itemPixelFormat, 1, comboBoxPixelFormat);

QSpinBox *spinHeight = new QSpinBox();
spinHeight->setFixedWidth(100);
QSlider *sliderHeight = new QSlider(Qt::Horizontal);
QHBoxLayout *hboxlayoutHeight = new QHBoxLayout();
hboxlayoutHeight->addWidget(spinHeight,8);
hboxlayoutHeight->addWidget(sliderHeight);

QWidget *widgetHeight = new QWidget();
widgetHeight->setLayout(hboxlayoutHeight);

QTreeWidgetItem *itemHeight = new QTreeWidgetItem;
itemHeight->setText(0, "Height");
item_ImageFormatControl->addChild(itemHeight);
//CameraTree->setItemWidget(item, 1, spBox);
CameraTree->setItemWidget(itemHeight, 1, widgetHeight);                //设置ckBox为item的第二列
QTreeWidgetItem *itemGainAuto = new QTreeWidgetItem;
itemGainAuto->setText(0,"Gain Auto");
item_AnalogControl->addChild(itemGainAuto);
//CameraTree->setItemWidget(item_AnalogControl,);

QTreeWidgetItem *itemBalanceWhiteAuto = new QTreeWidgetItem;
itemBalanceWhiteAuto->setText(0, "Balance White Auto");
itemBalanceWhiteAuto->setToolTip(0, "Balance White Auto");
item_ImageQualityControl->addChild(itemBalanceWhiteAuto);

QTreeWidgetItem *itemGamma= new QTreeWidgetItem;
itemGamma->setText(0, "Gamma");
item_ImageQualityControl->addChild(itemGamma);

QSpinBox *spinGamma = new QSpinBox();
spinGamma->setFixedWidth(100);
QSlider *sliderGamma = new QSlider(Qt::Horizontal);
QHBoxLayout *hboxlayoutGamma = new QHBoxLayout();
hboxlayoutGamma->addWidget(spinGamma, 8);
hboxlayoutGamma->addWidget(sliderGamma);

QWidget *widgetGamma = new QWidget();
widgetGamma->setLayout(hboxlayoutGamma);
CameraTree->setItemWidget(itemGamma, 1, widgetGamma);                //设置ckBox为item的第二列

QWidget *widget = new QWidget();
widget->setLayout(hLayout);
dock_CameraSet->setWidget(widget);

QTreeWidgetItem *itemOutputAlignment = new QTreeWidgetItem;
itemOutputAlignment->setText(0,"Output Alignment");
second->addChild(itemOutputAlignment);
 
 实现效果如下图：
 
 
 
 
QTreeWidget还有一些常见信号可用，可以用于一些软件中的点击QTreeWidget对象中添加的QTreeWidgeItem对象调用槽函数，常见信号如下
 
void itemPressed(QTreeWidgetItem *item, int column);
void itemClicked(QTreeWidgetItem *item, int column);
void itemDoubleClicked(QTreeWidgetItem *item, int column);
void itemActivated(QTreeWidgetItem *item, int column);

connect(CameraTree, SIGNAL(itemDoubleClicked(QTreeWidgetItem *, int)), this, SLOT(test(QTreeWidgetItem *, int)));//点击CameraTree中的QTreeWidgetItem对象即可调用槽函数
 
 
 
 

我想使用 insertChild 函数插入一个子项，但是一直不成功。该项一直被添加在所有项的末尾。
 
我的源代码
 
QTreeWidgetItem* newVtxItem = new QTreeWidgetItem(parentItem);
newVtxItem->setText(0, "vtx 1");
newVtxItem->setText(1, "-1");
childOfNameProfile->insertChild(0,newVtxItem);
 
将子元素插入到所有子元素之后的原因是：当创建QTreeWidgetItem并指定父元素时，Qt将它直接放在父元素的子元素列表的末尾。（Qt文档的说明）
 
QTreeWidgetItem* newVtxItem = new QTreeWidgetItem(parentItem); //在这里就已经被放到所有子元素的后面
 

 所以此时使用 insertChild 函数 也不会被再次插入了。
 
 
QTreeWidgetItem* newVtxItem = new QTreeWidgetItem();  //更改此处即可
newVtxItem->setText(0, "vtx 1");
newVtxItem->setText(1, "-1");
childOfNameProfile->insertChild(0,newVtxItem);

 
在项目中遇到的问题：
 百度之后得到答案，原文在这里：原文链接
 
https://stackoverflow.com/questions/27844221/qtreewidgetiteminsertchild-does-not-its-work