Qt学习: QListWidget程序示例

学习了上一条博客的关于QListWidget的成员函数的用法，下面就有一个相关的简单小程序来练下手:
程序完成如下图:

第一步，我们先通过ui设计师拖拽出我们想要的布局:

下面是”c.cpp”下的代码:我将逐句讲解:

#include "c.h"

c::c(QWidget *parent)
    : QMainWindow(parent)
{
    //应用ui设计师布局.
    ui.setupUi(this);
    //把两个按钮设置为选中.
    ui.listButton->setChecked(true);
    ui.upButton->setChecked(true);
    //列表部件采用排序.默认采用AAA-ZZZ排序.
    ui.listWidget->setSortingEnabled(true);
    //往列表部件中加入项组.一共3个.
    ui.listWidget->addItems(QStringList()<<QString::fromLocal8Bit("北京")<<QString::fromLocal8Bit("上海")<<QString::fromLocal8Bit("杭州"));
    //设置标题为"QListWidget".
    this->setWindowTitle(QString::fromLocal8Bit("QListWidget"));
    //对于前面的三个项设置图标.可根据实际情况使用.
    ui.listWidget->item(0)->setIcon(QIcon("Icons/1.jpg"));
    ui.listWidget->item(1)->setIcon(QIcon("Icons/2.jpg")); 
    ui.listWidget->item(2)->setIcon(QIcon("Icons/3.png"));
    //设置项的选择情况.
    ui.listWidget->setSelectionMode(QAbstractItemView::ExtendedSelection);

    //连接信号与槽.
    connect(ui.addButton, SIGNAL(clicked()), this, SLOT(addItemSlot()));
    connect(ui.delButton, SIGNAL(clicked()), this, SLOT(delItemSlot()));
    connect(ui.delAllButton, SIGNAL(clicked()), this, SLOT(delAllItemSlot()));
    //QLineEdit的信号:void returnPressed()的意思是:当焦点在lineEdit内时，敲击enter键，发出信号.
    connect(ui.lineEdit, SIGNAL(returnPressed()), this, SLOT(addItemSlot()));
    connect(ui.listButton, SIGNAL(clicked()), this, SLOT(changeListWidgetViewModeSlot()));
    connect(ui.iconButton, SIGNAL(clicked()), this, SLOT(changeListWidgetViewModeSlot()));
    connect(ui.upButton, SIGNAL(clicked()), this, SLOT(changeSortModeSlot()));
    connect(ui.downButton, SIGNAL(clicked()), this, SLOT(changeSortModeSlot()));
}

c::~c()
{

}
void c::addItemSlot()
{
    //创建一个QListWidget的项.
    QListWidgetItem *ite = new QListWidgetItem;
    //从lineEdit行编辑框中获取输入的文字.
    QString iteText = ui.lineEdit->text();
    //一定要检查是否空，否则也会输入进去!!!
    if (iteText.isEmpty())
        return;
    //然后设置项的文本.
    ite->setText(iteText);
    //最后把这个项加入到列表部件中去.
    ui.listWidget->addItem(ite);
    //清空行编辑器，坐下善后工作.
    ui.lineEdit->clear();
}
void c::delItemSlot()
{
    //直接使用QListWidget部件的删除函数，通过currentItem()成员函数来获取当前的选择项.
    ui.listWidget->removeItemWidget(ui.listWidget->currentItem());
}
void c::delAllItemSlot()
{
    /*//通过循环一个个删除QListWidget内的项.
    int count = ui.listWidget->count();
    for (int i = count - 1; i >= 0; --i)
    {
        QListWidgetItem* ite = ui.listWidget->takeItem(i);
        if (ite != 0)
            delete ite;
    }*/
    //也可以直接:
    ui.listWidget->clear();
}
void c::changeListWidgetViewModeSlot()
{
    //判断对于列表显示模式的选择情况.如果选择了列表模式，则设置列表模式.
    if (ui.listButton->isChecked())
    {
        ui.listWidget->setViewMode(QListView::ListMode);
    }
    //否则选择图标模式.
    else
    {
        ui.listWidget->setViewMode(QListView::IconMode);
    }
}
void c::changeSortModeSlot()
{
    //判断循环模式的选择情况.
    if (ui.upButton->isChecked())
    {
        ui.listWidget->sortItems(Qt::AscendingOrder);
    }
    else
    {
        ui.listWidget->sortItems(Qt::DescendingOrder);
    }
}

最后贴下”c.h”下的代码:

#ifndef C_H
#define C_H

#include <QtWidgets/QMainWindow>
#include "ui_c.h"
#include <QListWidget>
#include <QListWidgetItem>
#include <QMessageBox>

class c : public QMainWindow
{
    Q_OBJECT

public:
    c(QWidget *parent = 0);
    ~c();

private slots:
    void addItemSlot();
    void delItemSlot();
    void delAllItemSlot();
    void changeListWidgetViewModeSlot();
    void changeSortModeSlot();
private:
    Ui::cClass ui;
};

#endif // C_H

main.cpp下的代码:

#include "c.h"
#include <QtWidgets/QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    c w;
    w.show();
    return a.exec();
}