QT Basics (i)----buttons, text boxes, windows, layouts, options boxes, etc.

The explanation for each statement is placed in the function comment!

A preliminary study of QT Program, window and button creation and correlation

Application abstract Class #include<qapplication>//window class #include<qwidget>//button class #include<qpushbutton>int main (int ARGC, Char *argv[]) {    //Initialize application    qapplication app (argc, argv);    Constructs a window w    qwidget W;    Set window name    w.setwindowtitle ("hello,world!");    Constructs a button, actually the button is also a button    Qpushbutton;    Sets the text    button.settext ("button") on the button;    Put the button inside the window, create a parent-child relationship//Window object with the Window object to    affect the display position, do not establish such a parent-child relationship, there is no mutual pipe, separate    //No parent window window becomes the main window    Button.setparent (&w);    Why add the following sentence after the window becomes very small, only enough to hold a button    //button.show ();    When the button is clicked, the window is closed    //qt the extension of C + +    //The object of the first parameter is the Qobject subclass, the preceding two parameters are an object, the next two parameters are Chao    //std::bind Std::function, bind two functions together    qobject::connect (&button, SIGNAL (clicked ()), &w, SLOT (Close ()));    Display window    w.show ();    There is a message loop in Exec, the dead loop    return App.exec ();}

Operation Result:

Note: don't forget to add the following code to the pro file:

QT + = Widgets GUI

2 When the line input box and its input message prompt function and its input password when the exception input function

#include <QApplication> #include <qwidget>//input box header file #include<qlineedit>//prompt message #include< qcompleter>//#include <qdebug>int main (int argc, char *argv[]) {    qapplication app (argc, argv);    Qwidget W;    W.setwindowtitle ("hello,world!");    Add an input box    qlineedit edit;    Edit.show ();    Edit.setparent (&w);    Enter the password, yes text is not visible    //edit.setechomode (qlineedit::P assword);    Gets the input result of the password   //edit.text ();    Enter    the prompt edit.setplaceholdertext ("Please enter password:");    Message list    Qcompleter completer (qstringlist () << "Apple" << "Lin" << "Qian" << "Qin");    Set completer matching mode    completer.setfiltermode (qt::matchcontains);    Input information automatically prompt input    edit.setcompleter (&completer);    W.show ();    return app.exec ();}

Run Result: There is an input box in the interface.
3 Setting the position and size of the button

#include <QApplication> #include <qwidget>//input box header file #include<qlineedit>//prompt message #include< qcompleter>//#include <qdebug>int main (int argc, char *argv[]) {    qapplication app (argc, argv);    Qwidget W;    W.setwindowtitle ("hello,world!");    Add an input box    qlineedit edit;    Edit.show ();    Edit.setparent (&w);    Enter the password, yes text is not visible    //edit.setechomode (qlineedit::P assword);    Gets the input result of the password   //edit.text ();    Enter    the prompt edit.setplaceholdertext ("Please enter password:");    Message list    Qcompleter completer (qstringlist () << "Apple" << "Lin" << "Qian" << "Qin");    Set completer matching mode    completer.setfiltermode (qt::matchcontains);    Input information automatically prompt input    edit.setcompleter (&completer);    W.show ();    return app.exec ();} <strong></strong>

Run result: no longer as the first program in the top left of the main interface

4 Layout Management

#include <QApplication> #include <QWidget> #include <QPushButton> #include <qlineedit>//window layout, Vertical Change #include<qvboxlayout>//window layout, horizontal change #include<qhboxlayout>//lattice window #include<qgridlayout>//hint Text # include<qlabel>//#define HBOX//#define GBOX//#define LABINT Main (int argc, char *argv[]) {qapplication app (argc,    ARGV);    Qwidget W;    W.setwindowtitle ("Positon");    Qpushbutton button;    Button.settext ("UserName:");    Qpushbutton button2;    Button2.settext ("Password:");//Button.setparent (&AMP;W);    Qobject::connect (&button, SIGNAL (clicked ()), &w, SLOT (Close ()));    W.show ();    Qlineedit edit; Qlineedit *password; Edit.setparent (&w); #ifdef Hbox//layout is not a window, it is an object that actively creates a parent-child relationship with the main window//layout automatically arranges windows in the System window and changes as the window changes//Note    With layout, the SetParent function of the button and edit box can comment out the qhboxlayout layout;    On the right there is a spring layout.addstretch (1);    Layout inside add two windows, while adding the words push the button to the middle Layout.addwidget (&button); There is a slight distance between the previous button and the Next button, such as 50 pixels LAYout.addspacing (50);    Layout.addwidget (&edit);    Add a spring, the editor window does not change with the main window//the Left has a spring layout.addstretch (1); #endif #ifdef gbox qgridlayout layout;    Add button buttons to row No. 0, column No. 0 layout.addwidget (&button, 0, 0);    Layout.addwidget (&edit, 0, 1);    Layout.addwidget (New Qpushbutton ("10"), 1, 0);    Layout.addwidget (New Qpushbutton ("11"), 1, 1);    Add spring put the object on the upper left corner//Add the 2nd column of Spring Layout.setcolumnstretch (2, 1);    Add the 2nd row of Spring Layout.setrowstretch (2, 1); #endif qgridlayout layout;    Layout.setrowstretch (0,1);    Layout.setcolumnstretch (3,1);    Layout.addwidget (&button, 1, 1);    Layout.addwidget (&edit,1,2);    Layout.addwidget (&button2, 2, 1);    Layout.addwidget (password = new Qlineedit (), 2, 2);    Password->setechomode (qlineedit::P assword);    Layout is a qhboxlayout *hbox that can be nested;    Layout.addlayout (Hbox = new Qhboxlayout, 3, 2);    Hbox->addstretch (1);    Hbox->addwidget (New Qpushbutton ("Login")); Layout.addwidget (New Qpushbutton ("login"), 3, 2);    Layout.setrowstretch (4,1);    Layout.setcolumnstretch (0,1);    W.show ();    Add Layout w.setlayout (&layout) to the entire system window; App.exec ();}

Operation Result:

5 qt button, Slide box option, sub-text item and so on first create a class that adds qt + = Widgets GUI [Enter] CONFIG + = c++11 header file in Pro file Mywidget.h

#ifndef mywidget_h#define mywidget_h#include <QWidget> #include <qtextedit>class mywidget:public qwidget{    q_objectpublic:    explicit Mywidget (Qwidget *parent = 0);    qtextedit* myedit;signals:public Slots:}; #endif//Mywidget_h

Source file Mywidget.cpp

#include "mywidget.h" #include <QApplication> #include <QLabel>//display a single line of text or pictures #include<qpushbutton># Include<qlineedit>//single-line Input box #include<qcombobox>//Slide box option #include<qcheckbox>//Can tick the box #include&lt ; qradiobutton>//Radio box #include<qtextedit>//Multi-line text box, sub-text #include<qtextbrowser>//read-only text #include< qgroupbox>//Small box, containing content, used to classify the #include<qslider>//analog display value #include<qspinbox>//digital, through the button can be added to reduce the #inclu de<qdateedit> #include <QDateTimeEdit> #include <QTimeEdit> #include <QTabWidget>//Do not count controls # include<qvboxlayout> #include <QCompleter> #include <QHBoxLayout> #include <QDebug> #include <QPixmap>//Add image #include<qlcdnumber>//digital Mywidget::mywidget (Qwidget *parent) to display the LCD style: Qwidget (pare    NT) {qvboxlayout *layout = new Qvboxlayout (this);          Qlabel *label;       Display a single line of text or pictures Qcombobox *combo;    Slide Box Qpushbutton *button;    Qradiobutton *radio; QcompLeter *completer;    Qtextedit *edit;    Qgroupbox *groupbox; The label supports HTML format layout->addwidget (label = new Qlabel ("<font color = red>Operation Result:




QT Basics (i)----buttons, text boxes, windows, layouts, options boxes, etc.