第二十九课、主窗口中的状态栏------------------狄泰软件学院

一、主窗口中的状态栏

1、状态栏的概念和意义

（1）、状态栏是应用程序中输出简要信息的区域

（2）、状态栏一般位于主窗口的最底部

（3）、状态栏中的消息类型

A、实时消息：如当前程序状态

B、永久消息：如程序版本号，机构名称

C、进度消息：如进度条提示，百分百提示

2、Qt提供了与状态栏相关的类组件

3、在主窗口中创建状态栏

4、Qt状态栏的设计原则

（1）、左边区域用于输出实时消息

（2）、右边区域用于设置永久消息

（3）、addWidget在状态栏的左半部分添加组件

（4）、addPermanentWidget在状态栏右半部分添加组件

1、初探状态栏

#include "MainWindow.h"
#include <QStatusBar>
#include <QLabel>
#include <QPushButton>
#include <QLineEdit>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
/*******************************1、创建状态栏*****************************************/
    QStatusBar* sb = statusBar();
/*******************************2、创建组件*****************************************/
    QLabel* label = new QLabel("Label");
    QLineEdit* edit = new QLineEdit();
    QPushButton* Btn = new QPushButton();

/*******************************3、将组件添加到状态栏*****************************************/    
    sb->addPermanentWidget(label);
    sb->addPermanentWidget(edit);
    sb->addPermanentWidget(Btn);//显示在右边

    sb->showMessage("Hello Qt");//在左边
}

MainWindow::~MainWindow()
{
    
}

2、NotePad

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMenuBar>
#include <QMenu>
#include <QAction>
#include <QString>
#include <QtGui/QMainWindow>
#include <QToolBar>
#include <QIcon>
#include <QSize>
#include <QStatusBar>
#include <QLabel>

class MainWindow : public QMainWindow
{
    Q_OBJECT
private:
        MainWindow(QWidget *parent = 0);
        MainWindow(const MainWindow& obj);
        MainWindow* operator = (const MainWindow& obj);
        bool construct();

        bool initMenuBar();//菜单栏
        bool initToolBar();//工具栏
        bool initStatusBar();//状态栏

        bool initFileMenu(QMenuBar* mb);//文件菜单
        bool initEditMenu(QMenuBar* mb);//编辑菜单
        bool initFormatMenu(QMenuBar* mb);//格式菜单
        bool initViewMenu(QMenuBar* mb);//视图菜单
        bool initHelpMenu(QMenuBar* mb);//帮助菜单
        bool initFileToolItem(QToolBar* tb);

        bool makeAction(QAction*& action, QString text, int ket);//菜单项
        bool makeAction(QAction*& action, QString tip, QString icon);
public:
     static MainWindow* NewInstance();
    ~MainWindow();
};

#endif // MAINWINDOW_H

#include "MainWindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
}

bool MainWindow::construct()
{
    bool ret = true;
    ret = ret && initMenuBar();
    ret = ret && initToolBar();
    ret = ret && initStatusBar();
    return ret;
}
MainWindow* MainWindow::NewInstance()
{
    MainWindow* ret = new MainWindow();

    if((ret==NULL) || (!ret->construct()))
    {
        delete ret;
        ret = NULL;
    }

    return ret;
}
bool MainWindow::initMenuBar()//菜单栏
{
    bool ret = true;

    QMenuBar* mb = menuBar();//一定要注意是menuBar()，这是普通成员函数，不是构造函数

    ret = ret && initFileMenu(mb);//传一个参数是为了在initFileMenu()函数将menu加入菜单栏
    ret = ret && initEditMenu(mb);
    ret = ret && initFormatMenu(mb);
    ret = ret && initViewMenu(mb);
    ret = ret && initHelpMenu(mb);

    return ret;

}

bool MainWindow::initToolBar()//工具栏
{
    bool ret = true;

    QToolBar* tb = addToolBar("Tool Bar");
    tb->setMovable(false);
    tb->setFloatable(false);
    tb->setIconSize(QSize(16,16));

    ret = ret && initFileToolItem(tb);

    return ret;
}

bool MainWindow::initStatusBar()//状态栏
{
    bool ret = true;

    QStatusBar* sb = statusBar();

    QLabel* label = new QLabel("Made By LGC");

    if(label != NULL)
    {
        label->setMinimumWidth(200);
        label->setAlignment(Qt::AlignHCenter);
        sb->addPermanentWidget(label);
    }
    else
    {
        ret = false;
    }
    return ret;
}

/************************************************文件菜单********************************************************/
bool MainWindow::initFileMenu(QMenuBar* mb)
{
    bool ret = true;

    QMenu* menu = new QMenu("File(&F)");//创建文件菜单，（&F）是为了可以Alt+F打开
    ret = (menu != NULL);
    if(ret)
    {
        QAction* action = NULL;

        //New
        ret = ret &&  makeAction(action, "New(&N)",Qt::CTRL + Qt::Key_N);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Open
        ret = ret &&  makeAction(action, "Open(&O)...",Qt::CTRL + Qt::Key_O);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Save
        ret = ret &&  makeAction(action, "Save(&S)",Qt::CTRL + Qt::Key_S);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Save As
        ret = ret &&  makeAction(action, "Save As(&A)...",0);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //print
        ret = ret &&  makeAction(action, "Print(&P)...",Qt::CTRL + Qt::Key_P);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Exit
        ret = ret &&  makeAction(action, "Exit(&X)",0);
        if(ret)
        {
           menu->addAction(action);//将菜单项加入到菜单
        }

    }
    if(ret)
    {
        mb->addMenu(menu);//将菜单加入到菜单栏
    }
    else
    {
        delete mb;
    }
    return ret;
}

/************************************************编辑菜单********************************************************/
bool MainWindow::initEditMenu(QMenuBar* mb)
{
    bool ret = true;

    QMenu* menu = new QMenu("Edit(&E)");
    ret = (menu != NULL);
    if(ret)
    {
        QAction* action = NULL;

        //Undo
        ret = ret &&  makeAction(action, "Undo(&U)",Qt::CTRL + Qt::Key_Z);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Redo
        ret = ret &&  makeAction(action, "Redo(&R)...",Qt::CTRL + Qt::Key_Y);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Cut
        ret = ret &&  makeAction(action, "Cut(&T)",Qt::CTRL + Qt::Key_X);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Copy
        ret = ret &&  makeAction(action, "Copy(&C)...",Qt::CTRL + Qt::Key_C);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Pase
        ret = ret &&  makeAction(action, "Pase(&P)...",Qt::CTRL + Qt::Key_V);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Delete
        ret = ret &&  makeAction(action, "Delete(&L)",Qt::Key_Delete);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Find
        ret = ret &&  makeAction(action, "Find(&F)...",Qt::CTRL + Qt::Key_F);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Replace
        ret = ret &&  makeAction(action, "Replace(&R)...",Qt::CTRL + Qt::Key_H);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Goto
        ret = ret &&  makeAction(action, "Goto(&G)",Qt::CTRL + Qt::Key_G);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Select All
        ret = ret &&  makeAction(action, "Select All(&A)",Qt::CTRL + Qt::Key_A);
        if(ret)
        {
           menu->addAction(action);
        }

    }
    if(ret)
    {
        mb->addMenu(menu);
    }
    else
    {
        delete mb;
    }
    return ret;
}

/************************************************格式菜单********************************************************/
bool MainWindow::initFormatMenu(QMenuBar* mb)
{
    bool ret = true;

    QMenu* menu = new QMenu("Format(&O)");
    ret = (menu != NULL);
    if(ret)
    {
        QAction* action = NULL;

        //Auto Wrap
        ret = ret &&  makeAction(action, "Auto Wrap(&W)",0);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Font
        ret = ret &&  makeAction(action, "Font(&F)...",0);
        if(ret)
        {
           menu->addAction(action);
        }

    }
    if(ret)
    {
        mb->addMenu(menu);
    }
    else
    {
        delete mb;
    }
    return ret;
}

/************************************************视图菜单********************************************************/
bool MainWindow::initViewMenu(QMenuBar* mb)
{
    bool ret = true;

    QMenu* menu = new QMenu("View(&V)");
    ret = (menu != NULL);
    if(ret)
    {
        QAction* action = NULL;

        //Tool Bar
        ret = ret &&  makeAction(action, "Tool Bar(&T)",0);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //Status Bar
        ret = ret &&  makeAction(action, "Status Bar(&S)",0);
        if(ret)
        {
           menu->addAction(action);
        }

    }
    if(ret)
    {
        mb->addMenu(menu);
    }
    else
    {
        delete mb;
    }
    return ret;
}

/************************************************帮助菜单********************************************************/
bool MainWindow::initHelpMenu(QMenuBar* mb)
{
    bool ret = true;

    QMenu* menu = new QMenu("Help(&H)");
    ret = (menu != NULL);
    if(ret)
    {
        QAction* action = NULL;

        //User Manual
        ret = ret &&  makeAction(action, "User Manual",0);
        if(ret)
        {
           menu->addAction(action);
        }

        menu->addSeparator();

        //About NotePad
        ret = ret &&  makeAction(action, "About NotePad...",0);
        if(ret)
        {
           menu->addAction(action);
        }

    }
    if(ret)
    {
        mb->addMenu(menu);
    }
    else
    {
        delete mb;
    }
    return ret;
}

bool MainWindow::initFileToolItem(QToolBar* tb)
{
    bool ret = true;
    QAction* action = NULL;

    ret = ret && makeAction(action, "New", ":/Res/pic/new.png");
    if(ret)
    {
        tb->addAction(action);
    }

    ret = ret && makeAction(action, "Open", ":/Res/pic/open.png");
    if(ret)
    {
        tb->addAction(action);
    }

    ret = ret && makeAction(action, "Save", ":/Res/pic/save.png");
    if(ret)
    {
        tb->addAction(action);
    }

    ret = ret && makeAction(action, "Save As", ":/Res/pic/saveas.png");
    if(ret)
    {
        tb->addAction(action);
    }
    ret = ret && makeAction(action, "Print", ":/Res/pic/print.png");
    if(ret)
    {
        tb->addAction(action);
    }
    ret = ret && makeAction(action, "Undo", ":/Res/pic/undo.png");
    if(ret)
    {
        tb->addAction(action);
    }
    ret = ret && makeAction(action, "Redo", ":/Res/pic/redo.png");
    if(ret)
    {
        tb->addAction(action);
    }

    return ret;

}

bool MainWindow::makeAction(QAction*& action, QString text, int key)//菜单项
{
    bool ret = true;
    action = new QAction(text, NULL);
    if(action != NULL)
    {
        action->setShortcut(QKeySequence(key));//创建快捷键
    }
    else
    {
        ret = false;
    }

    return ret;
}
bool MainWindow::makeAction(QAction*& action, QString tip, QString icon)
{
    bool ret = true;
    action = new QAction("", NULL);
    if(action != NULL)
    {
        action->setToolTip(tip);
        action->setIcon(QIcon(icon));
    }
    else
    {
        ret = false;
    }
    return ret;
}
MainWindow::~MainWindow()
{
    
}

#include <QtGui/QApplication>
#include "MainWindow.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow* w = MainWindow::NewInstance();
    int ret = -1;
    if(w != NULL)
    {
        w->show();
        ret = a.exec();
    }

    delete w;
    return ret;
}

二、小结

（1）、状态栏是应用程序中输出简要信息的区域

（2）、QStatusBar是Qt中创建状态栏组件的类

（3）、QStatusBar中可以任意添加QWidget

（4）、QStatusBar有自己内置的设计原则

（5）、QStatusBar可以定制出各种形式的状态栏