QT中菜单Menu与工具栏Toolbar中各个Action的动态添加删除

就像Swing里面的Action一样，Qt里面也有一个类似的类，叫做QAction。顾名思义，QAction类保存有关于这个动作，也就是action的信息，比如它的文本描述、图标、快捷键、回调函数(也就是信号槽)，等等。神奇的是，QAction能够根据添加的位置来改变自己的样子——如果添加到菜单中，就会显示成一个菜单项；如果添加到工具条，就会显示成一个按钮。

代码如下：

//MainWindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();

public slots:
void openFile();
void add();
void remove();
private:
Ui::MainWindow *ui;
//QAction *openAcition;
QMenu *file;
QAction *addscess;
QToolBar *toolbar;
QToolBar *toolbar1;
};

#endif // MAINWINDOW_H

//MainWindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDebug>

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);

QAction *openAcition = new QAction(tr("&Open"),this);
QAction *openAction = new QAction(tr("&apen"),this);
QAction *add = new QAction(tr("&add"),this);
QAction *remove = new QAction(tr("&remove"),this);

file = menuBar()->addMenu(tr("&File"));
file->addAction(openAcition);
file->addAction(add);
file->addAction(remove);

toolbar = addToolBar(tr("&File"));
toolbar->addAction(openAcition);
toolbar->addAction(openAction);

toolbar1 = addToolBar(tr("&File"));
//toolbar1->addAction(openAcition);
toolbar1->addAction(openAction);

connect(openAcition,SIGNAL(triggered()),this,SLOT(openFile()));
connect(add,SIGNAL(triggered()),this,SLOT(add()));
connect(remove,SIGNAL(triggered()),this,SLOT(remove()));
}

MainWindow::~MainWindow()
{
delete ui;
}

void MainWindow::openFile()
{
qDebug()<<"I did that!!";
}

void MainWindow::add()
{
addscess = new QAction(tr("&addscess"),this);
file->addAction(addscess);
toolbar->addAction(addscess);
}

void MainWindow::remove()
{
file->removeAction(addscess);
toolbar->removeAction(addscess);
}