新建Qt專案，選擇Qt Widgets Application，填入專案名稱“ImageView”，點選完成。

在Qt Designer裡會生成如圖所示的幾個檔案：

此時我們右鍵刪除imageviewer.ui這個檔案，因為我們本次是用純程式碼的方式生成介面，所以不需要這個ui檔案了。

關鍵程式碼主要在imageviewer.h和imageviewer.cpp裡。下面是程式碼：

imageviewer.h

 1 #ifndef IMAGEVIEWER_H
 2 #define IMAGEVIEWER_H
 3  
 4 #include <QMainWindow>
 5 #include <QLabel>
 6
 
 #include <QScrollArea>
 7 #include <QMenu>
 8 #include <QMenuBar>
 9 #include <QToolBar>
10  
11 namespace Ui {
12 class ImageViewer;
13 }
14  
15 class ImageViewer : public QMainWindow
16 {
17     Q_OBJECT
18  
19 public:
20     explicit ImageViewer(QWidget *parent = nullptr);
 
21     ~ImageViewer();
22  
23     void initMenu();
24     void initToolBar();
25     void initConnect();
26  
27 private:
28     Ui::ImageViewer *ui;
29     QLabel *imageLabel;
30     QScrollArea *scrollAera;
31  
32     QMenu *fileMenu;
33     QMenu *viewMenu;
34     QMenu *helpMenu;
35  
36     QToolBar *fileToolBar;
 
37  
38     QAction *openAct;
39     QAction *printAct;
40     QAction *exitAct;
41     QAction *zoomInAct;
42     QAction *zoomOutAct;
43     QAction *normalSizeAct;
44     QAction *fitToWindowAct;
45     QAction *aboutAct;
46     QAction *aboutQtAct;
47  
48 private slots:
49     void open();
50     void print();
51     void exit();
52     void zoomIn();
53     void zoomOut();
54     void normalSize();
55     void fitToWindow();
56     void about();
57     void aboutQt();
58 };
59  
60 #endif // IMAGEVIEWER_H

imageviewer.cpp

  1 #include "imageviewer.h"
  2 #include "ui_imageviewer.h"
  3  
  4 ImageViewer::ImageViewer(QWidget *parent) :
  5     QMainWindow(parent),
  6     ui(new Ui::ImageViewer)
  7 {
  8     ui->setupUi(this);
  9  
 10     //initalize
 11     initMenu();
 12     initToolBar();
 13     initConnect();
 14 }
 15  
 16 ImageViewer::~ImageViewer()
 17 {
 18     delete ui;
 19 }
 20  
 21 void ImageViewer::initMenu()
 22 {
 23     //QMenuBar *menuBar = this->menuBar();
 24     //add three menus
 25     fileMenu = new QMenu(tr("&File"),this);
 26     viewMenu = new QMenu(tr("&View"),this);
 27     helpMenu = new QMenu(tr("&About"),this);
 28  
 29     //add actions and add it into corresponding menu
 30     openAct = new QAction(tr("&Open"),this);
 31     openAct -> setShortcut(tr("ctrl+O"));
 32     printAct = new QAction(tr("&Print"),this);
 33     printAct -> setShortcut(tr("ctrl+P"));
 34     exitAct = new QAction(tr("&Exit"),this);
 35     exitAct -> setShortcut(tr("ctrl+Q"));
 36     fileMenu -> addAction(openAct);
 37     fileMenu -> addAction(printAct);
 38     fileMenu -> addSeparator();
 39     fileMenu -> addAction(exitAct);
 40  
 41     zoomInAct = new QAction(tr("Zoom &In"),this);
 42     zoomInAct -> setShortcut(tr("ctrl+="));
 43     zoomOutAct = new QAction(tr("Zoom &Out"),this);
 44     zoomOutAct -> setShortcut(tr("ctrl+-"));
 45     normalSizeAct = new QAction(tr("&Normal Size"),this);
 46     normalSizeAct -> setShortcut(tr("ctrl+S"));
 47     fitToWindowAct = new QAction(tr("&Fit to Window"),this);
 48     fitToWindowAct -> setShortcut(tr("ctrl+F"));
 49     viewMenu -> addAction(zoomInAct);
 50     viewMenu -> addAction(zoomOutAct);
 51     viewMenu -> addAction(normalSizeAct);
 52     viewMenu -> addSeparator();
 53     viewMenu -> addAction(fitToWindowAct);
 54  
 55     aboutAct = new QAction(tr("&About"),this);
 56     aboutQtAct = new QAction(tr("&About Qt"),this);
 57     helpMenu -> addAction(aboutAct);
 58     helpMenu -> addAction(aboutQtAct);
 59  
 60     //add menus to menubar
 61     menuBar() -> addMenu(fileMenu);
 62     menuBar() -> addMenu(viewMenu);
 63     menuBar() -> addMenu(helpMenu);
 64 }
 65  
 66 void ImageViewer::initToolBar()
 67 {
 68     //add a toolbar and add its actions
 69      fileToolBar = new QToolBar(this);
 70  
 71      fileToolBar -> addAction(openAct);
 72      fileToolBar -> addAction(printAct);
 73      fileToolBar -> addAction(exitAct);
 74  
 75      addToolBar(Qt::TopToolBarArea,fileToolBar);
 76 }
 77  
 78 void ImageViewer::initConnect()
 79 {
 80     //singals and slots
 81     connect(openAct,SIGNAL(triggered),this,SLOT(open()));
 82     connect(printAct,SIGNAL(triggered),this,SLOT(print()));
 83     connect(exitAct,SIGNAL(triggered),this,SLOT(exit()));
 84     connect(zoomInAct,SIGNAL(triggered),this,SLOT(zoomIn()));
 85     connect(zoomOutAct,SIGNAL(triggered),this,SLOT(zoomOut()));
 86     connect(normalSizeAct,SIGNAL(triggered),this,SLOT(normalSize()));
 87     connect(fitToWindowAct,SIGNAL(triggered),this,SLOT(fitToWindow()));
 88     connect(aboutAct,SIGNAL(triggered),this,SLOT(about()));
 89     connect(aboutQtAct,SIGNAL(triggered),this,SLOT(aboutQt()));
 90 }
 91  
 92 //implement slot functions
 93 void ImageViewer::open()
 94 {
 95  
 96 }
 97  
 98 void ImageViewer::print()
 99 {
100  
101 }
102  
103 void ImageViewer::exit()
104 {
105  
106 }
107  
108 void ImageViewer::zoomIn()
109 {
110  
111 }
112  
113 void ImageViewer::zoomOut()
114 {
115  
116 }
117  
118 void ImageViewer::normalSize()
119 {
120  
121 }
122  
123 void ImageViewer::fitToWindow()
124 {
125  
126 }
127  
128 void ImageViewer::about()
129 {
130  
131 }
132  
133 void ImageViewer::aboutQt()
134 {
135  
136 }

介面效果如圖：