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Common forms in QT

2022-06-21 22:55:00 【Clown's stage】

Qwidget

1. brief introduction ：

QWidget Class is the base class for all user interface objects . It receives the mouse from the window system , Keyboard and other events , And draw itself on the screen .

Simultaneous inheritance ：QObject class and QPaintDevice class

QWidget： Class is the base class for all user interface objects .
QObject： It's all Qt Class base class . Provides a signal - Slot mechanism .
QPaintDevice： have access to QPainter The base class of the drawn object .

2. Constructors

 QWidget::QWidget(
    QWidget *parent = Q_NULLPTR,
    Qt::WindowFlags f = Qt::WindowFlags()
 );

parent： If it is nullptr, The widget will become a main window , Otherwise the widget will become parent When a child window in deletes its parent window , Will delete his widget .

f： Bitwise marked by any window “ or ” Value of composition .Qt::Window Flags() Is to construct a template class object. The default is Qt::Widget

3. Member functions

Moving functions ：

void move(const QPoint &) void move(int x, int y)

// Set the color （ Commonly used with color fill sets ）

void setPalette(const QPalette &)

// Color fill

void setAutoFillBackground(bool enabled)

// Set the font

void setFont(const QFont &);

// Set mouse tracking Events

void setMouseTracking(bool enable);

 // The widget 
 
     QWidget *widget=new QWidget(nullptr,Qt::Window);
     // Set the window title ：
     widget->setWindowTitle(QStringLiteral(" This is because QWidget forms "));
     //widget->setToolTip(QStringLiteral(" This is a hint "));
     // Set the icon of the window 
     widget->setWindowIcon(QIcon("F:\\qtItem\\oftenForms\\image\\11.jpg"));
     // Set the state of the window ：
     widget->setWindowState(Qt::WindowNoState);// The normal state 
     //widget->setWindowState(Qt::WindowMinimized);// Stay small 
     //widget->setWindowState(Qt::WindowMaximized);// Maximum state 
     //widget->setWindowState(Qt::WindowFullScreen);// Full screen , There are no buttons to maximize or minimize ;
     //widget->setWindowState(Qt::WindowActive);// Active window , I don't know what's the use 
     // Set window transparent reading 
     widget->setWindowOpacity(0.7);
     // Hide form ：
    // widget->hide();
     // Closing Windows 
     //widget->close();
     // Set window fixed size 
     //widget->setFixedSize(400,400);
     // Set the cursor 
     widget->setCursor(Qt::CrossCursor);
     // Display window 
     widget->show();

4. attribute ：

enabled Enable or disable widget, Enabled by default .
geometry widget Location and size of
3.sizePolicy Set up widget Horizontal and vertical scaling strategies and scaling factors , The so-called scaling strategy is actually widget treat sizeHint The strategy of ,

palette: palette

Value attribute	Meaning
Fixed	Think sizeHint Value is optimal ,widget The size cannot be changed
Minimum	Think sizeHint The value is the minimum , The size can be increased , It can't be smaller
Maximum	Think sizeHint Value is maximum , The size can be reduced , Can't get bigger
Preferred	Think sizeHint Is the appropriate value , The size can be changed , But it is not recommended to get bigger
Expanding	Think sizeHint Is the appropriate value , The size can be changed , Than Preferred Suitable for getting bigger
MinimumExpanding	Think sizeHint Is minimum , The size can be increased , It can't be smaller
Ignored	Ignore sizeHint size , The size can be changed

QFrame（ Form with border ）

brief introduction ：

1.QFrame And QWidget The difference between ：

QFrame Is the base class of the basic control ,QWidget yes QFrame Parent class .

QFrame stay QWidget Provides control of the form border based on .

Function ：

It mainly controls some border styles , for example ： Bulge , Concave , shadow , Line width ;

attribute ：

frameRect : QRect ： Draw the rectangle of the frame . By default, the entire widget . When the widget changes size , The frame rectangle adjusts automatically .
frameShadow : Shadow: Frame style frame shadow .
frameShape : Shape : Frame shape of frame style .
frameWidth : const int : The width determined by the style frame . for example ,NoFrame The frame width of the specified style is always 0, and Panel The specified style frame width is equal to lineWidth.
lineWidth : int : The width of the frame .
A frame used as a separator （HLine and VLine） Of lineWidth from frameWidth Appoint .
midLineWidth : int : The width of an extra line in the middle of the frame , It uses a third color to get a special 3D effect . Bulge only （raised） Or sunken （sunken） Of Box、HLine、VLine Draw the centerline of the frame .

type ：

1、enum QFrame::Shadow： This enumeration type definition is used to provide 3D The shadow type of the effect .

Plain： The frame and content are flush with the surroundings . Use the palette QPalette::WindowText Color painting （ There is no 3D effect ） Raised： The frame and content are raised ; Draw using the light and dark colors of the current color group 3D Raised line Sunken： The frame and content are sunken ; Draw using the light and dark colors of the current color group 3D Sag line 2、enum QFrame::Shape： This enumeration type defines the shapes of the available frames .

NoFrame： Draw nothing Box： Draw a box around its contents Panel： Draw a panel , To make the contents appear convex or concave StyledPanel： Draw a rectangular panel , Its appearance depends on the current GUI style . It can be convex or concave HLine： Draw a horizontal line , No frame （ Use as separator ） VLine： Draw a vertical line , No box （ Use as separator ） WinPanel： Draw a rectangular panel , It can look like Windows 2000 Raised or sunken like a panel in . Specifies that this shape sets the lineweight to 2 Pixels . Provide WinPanel For compatibility . about GUI Style independence , It is suggested to use it instead StyledPanel

application

     // First step ： Create a QFrame object 
     QFrame frame;
     //frame.setStyleSheet()
     // Set border width 
     frame.setLineWidth(10);
     // Set the center line 
     frame.setMidLineWidth(5);
     // Set shape 
     frame.setFrameShape(QFrame::Box);
     // Set the background color of the window 
     //frame.setStyleSheet("background-color:red");
     // Set shadow 
     frame.setFrameShadow(QFrame::Raised);
     // Set border position   Draw the rectangular size of the frame ;
     frame.setFrameRect(QRect(10,0,400,400));
     // Get the width of the border 
     qDebug()<< frame.lineWidth();
     frame.show();

QDialog（ Dialog box ）

brief introduction ：

Inherited from Qwidget, Is a container type component ;

When QWidget As a separate window when there is no parent component , When there is a parent component , Embed as a visible part into the parent component .

QDialog Cannot be embedded as a child in another container ;

QGroupBox（ Group box ）

QGroupBox Provides support for building group boxes . Group boxes usually have a border and a title bar , Used as a container part , Various window components can be arranged in it . Can be used as a container for a set of controls when laying out , But here's the thing , Layout controls must be used internally （ Such as QBoxLayout） Progressive cloth game .

attribute ：

alignment: Qt::Alignment
Alignment of group box titles . The default is Qt::AlignLeft.
- Qt::AlignLeft： Left alignment .
- Qt::AlignRight： right justify .
- Qt::AlignHCenter： align horizontal center .
checkable : bool :
Whether there is a check box in the title .
If this check box is selected , Then enable the sub items of the group box ; otherwise , They will be disabled and inaccessible .
checked : bool Whether the check box is selected .
flat : bool
Is it flattened .
A group box usually consists of a surrounding frame with a title at the top . If this property is enabled , Then most styles only draw the top of the frame ; otherwise , The entire frame will be drawn .
Be careful ： In some styles , A flat group box and a non flat group box have similar representations , And may not be as distinguishable as in other styles .
title : QString
Title Text .
If the title contains and symbols ('&') Followed by a letter , The group box title text will have keyboard shortcuts .
```
 g->setTitle("&User information");
```
In the example above ,Alt+U Move keyboard focus to group box .

usage

  // First step ：
     QHBoxLayout *box1=new QHBoxLayout(this);
     QLabel *label1=new QLabel(QStringLiteral(" male "));
     QLabel *label2=new QLabel(QStringLiteral(" Woman "));
     QCheckBox *check1=new QCheckBox;
     QCheckBox *check2=new QCheckBox;
     QHBoxLayout *box2=new QHBoxLayout;
     box2->addWidget(check1);
     box2->addWidget(label1);
     box2->addWidget(check2);
     box2->addWidget(label2);
     QGroupBox *group=new QGroupBox(QStringLiteral(" Gender "));
     group->setCheckable(true);// Sets whether the check box displays 
     group->setChecked(false);// if true, Then the group box can use , Otherwise, the group box is unavailable 
     group->setAlignment(Qt::AlignHCenter);// Set the location of the information 
     group->setLayout(box2);
     box1->addWidget(group);

QScrollArea（ Scroll area ）

brief introduction ：

QScrollArea Used as a container part , Provide a scrollable area form . When internal controls cannot be fully displayed ,QScrollArea You can scroll up and down or left and right to display . Be careful ： Use QScrollArea It's usually through setWidget Method to add a QFrame object .

attribute ：

usage ：

  // Create a child window , This sub window is given to the scrolling area 
     QWidget* pSubWidget = new QWidget();
 
     // At the window （100,100） Position display 150*150 Size scrolling area 
     QScrollArea* pScrollArea = new QScrollArea(this);
     //pScrollArea->setFixedSize(350, 150);
     // Set whether to automatically resize the part . The default is false.
     //pScrollArea->setWidgetResizable(true);
     // Format alignment 
     pScrollArea->setAlignment(Qt::AlignHCenter);
     pScrollArea->move(QPoint(100, 100));
     // Set the vertical scrolling policy 
     pScrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     // Settings settings QScrollArea（ Scroll area ） Sizing strategy for 
     pScrollArea-> setSizeAdjustPolicy(QAbstractScrollArea::AdjustToContents);
 
     // Set a vertical layout object for the child window , Add buttons dynamically , The child window will automatically resize 
     QVBoxLayout* pSubLayout = new QVBoxLayout(this);
     pSubWidget->setLayout(pSubLayout);
     for (auto i = 0; i < 10; ++i)
     {
         pSubLayout->addWidget(new QPushButton(QString("test%1").arg(i), this));
     }
     pScrollArea->setWidget(pSubWidget);

QToolBox hold-all

brief introduction ：

QToolBox Class provides a list of tabbed widget items . Inherited from Qframe;

A toolbox is a widget , It displays a list of tabs one by one , The current item is displayed below the current tab . Each tab There is an index position in each tab column . The tab item is a QWidget.

attribute ：

count : const int This property holds the number of items contained in the toolbox .

currentIndex : int This property holds the index of the current item

Method ：

// Add items to the toolbox , You can specify the text content and icon content of the item

int addItem(QWidget *widget, const QIcon &iconSet, const QString &text)

int addItem(QWidget *w, const QString &text)

// In the toolbox index Insert item at , You can specify the text content and icon content of the item int insertItem(int index, QWidget *widget, const QIcon &icon, const QString &text) int insertItem(int index, QWidget *widget, const QString &text)

// Sets whether items are available according to the index void setItemEnabled(int index, bool enabled)

// Set the icon of the item according to the index void setItemIcon(int index, const QIcon &icon)

// Set the text of the item according to the index void setItemText(int index, const QString &text)

// Set the prompt content of the item according to the index void setItemToolTip(int index, const QString &toolTip)

QTabWidget（ Label form ）

QTabWidget It is mainly used for pagination display , One interface per page , Many interfaces share a common area , Save interface size , very It is convenient to display more information for users .

Common methods

 // Add a page at the end of the label form , And set the form of the page , Tag name and tag icon 
 int addTab(QWidget *page, const QString &label)
 int addTab(QWidget *page, const QIcon &icon, const QString &label)
 // In the label form index Position inserts a page , And set the form of the page , Tag name and tag icon 
 int insertTab(int index, QWidget *page, const QString &label)
 int insertTab(int index, QWidget *page, const QIcon &icon, const QString &label)
 // Set whether the label can be moved 
 void setMovable(bool movable)
 // Set the display position of the label 
 void setTabPosition(TabPosition)
 // Set whether the label is available 
 void setTabEnabled(int index, bool enable)
 // Set whether the label can be closed 
 void setTabsClosable(bool closeable)
 // Set the current label index or form 
 void setCurrentIndex(int index)
 void setCurrentWidget(QWidget *widget)

Enumeration type ：QTabWidget::TabPosition

name	value	explain
QTabWidget::North	0	To the north
QTabWidget::South	1	Southward direction
QTabWidget::West	2	Westward
QTabWidget::East	3	To the East

QListWidget List form

QListWidget（ List form ） Is an item based （item） List form of . The parent class is QListView, Is based on Model（ model type ） List view of . QListWidget（ List form ） Contains a series of commonly used list form operation interfaces . It can meet the requirements of the general list seek . Can pass QListWidgetItem Set items .

Method list

 // Add items to the list form , You can specify the name of the item , The object of the item . Or add multiple items at once 
 void addItem(const QString &label)
 void addItem(QListWidgetItem *item)
 void addItems(const QStringList &labels)
 // Insert item 
 void insertItem(int row, QListWidgetItem *item)
 void insertItem(int row, const QString &label)
 void insertItems(int row, const QStringList &labels)
 // obtain row The item pointer of the line 
 QListWidgetItem *item(int row) const
 // Find items in the list according to their contents and related rules 
 QList<QListWidgetItem *> findItems(const QString &text, Qt::MatchFlags flags) 
 const
 // Set the currently selected row or item 
 void setCurrentItem(QListWidgetItem *item)
 void setCurrentItem(QListWidgetItem *item, QItemSelectionModel::SelectionFlags 
 command)
 void setCurrentRow(int row)
 void setCurrentRow(int row, QItemSelectionModel::SelectionFlags command)
 // Set whether items are sorted when they are added , No sort by default , Display in the order of addition . Set to true Display in ascending order . 
 void setSortingEnabled(bool enable)
 // Sort all items . The default is ascending . 
 void sortItems(Qt::SortOrder order = Qt::AscendingOrder)
 // The setting item is editable ,
 void closePersistentEditor(QListWidgetItem *item)
 // Close the editable state of the item 
 void openPersistentEditor(QListWidgetItem *item)
 // clear list 
 void clear()
 // The signal 
 // Send this signal when the selected item changes 
 void currentItemChanged(QListWidgetItem *current, QListWidgetItem *previous)
 // This signal is sent when the current line changes 
 void currentRowChanged(int currentRow)
 // Send this signal when the current item changes , The parameter is the text of the current item 
 void currentTextChanged(const QString &currentText)
 // When item This signal is sent when it is active .（ Double click the mouse or click ）
 void itemActivated(QListWidgetItem *item)
 // When item This signal is sent when the content of changes 
 void itemChanged(QListWidgetItem *item)
 // When the mouse clicks item Send the signal when 
 void itemClicked(QListWidgetItem *item)
 // When the mouse double clicks item Send the signal when 
 void itemDoubleClicked(QListWidgetItem *item)
 // When the mouse enters item Send the signal when , You have to set setMouseTracking by true
 void itemEntered(QListWidgetItem *item)
 // When the mouse goes away item Send the signal when , You have to set setMouseTracking by true
 void itemPressed(QListWidgetItem *item)
 // This signal is sent when the selected middle item changes 
 void itemSelectionChanged()

QStackedWidget Stack forms

Stack form （QStackedWidget） Can contain multiple forms , But only one form is displayed . You can set the cable To set the contents of the displayed form . Inherited from 、QFrame;

attribute

count : const int currentIndex : int

function

int addWidget(QWidget *widget)： int count() const int currentIndex() const QWidget *currentWidget() const int indexOf(QWidget *widget) const int insertWidget(int index, QWidget *widget) void removeWidget(QWidget *widget) QWidget *widget(int index) const