SOURCES
+=
\

main.cpp

QT
+=
widgets gui

/*应用程序抽象类*/

#include <QApplication>

/*窗口类*/

#include <QWidget>

/*按钮*/

#include <QPushButton>

int main(int argc,char *argv[])

{

    QApplication app(argc,argv);

    /*构造一个窗口*/

    QWidget w;

    /*显示窗口*/

    w.show();

    /*按钮也是一个窗口*/

    QPushButton button;

    button.setText("Button");

    /*窗口对象的父子关系，影响显示位置*/

    /*没有父窗口的窗口，我们称之为主窗口*/

    button.setParent(&w);

    button.show();

    /*QT对C++的拓展*/

    //std::bind std::function

    QObject::connect(&button, SIGNAL(clicked()), &w, SLOT(close()));

    w.setWindowTitle("Hello World");

    /*在exec中有一个消息循环*/

    return app.exec();

}

运行结果：

/*应用程序抽象类*/

#include
<QApplication>

/*窗口类*/

#include
<QWidget>

#include
<QCompleter>

#include
<QLineEdit>

int
main(int
argc,char
*argv[])

{

QApplication
app(argc,argv);

/*构造一个窗口*/

QWidget
w;

QLineEdit
edit;

edit.show();

edit.setParent(&w);

/*输入密码*/

/*

edit.setEchoMode(QLineEdit::PasswordEchoOnEdit);

edit.text();

edit.setPlaceholderText("Please
input
text:");

*/

QCompleter
completer(QStringList()
<<
"aab"
<<
"123"
<<
"998");

completer.setFilterMode(Qt::MatchContains);

edit.setCompleter(&completer);

//显示窗口

w.show();

/*QT对C++的拓展

QT对C++的拓展

std::bind
std::function

QObject::connect(&button,
SIGNAL(clicked()),
&w,
SLOT(close()));

*/

w.setWindowTitle("Hello
World");

/*在exec中有一个消息循环*/

return
app.exec();

}

运行结果：

/*应用程序抽象类*/

#include <QApplication>

/*窗口类*/

#include <QWidget>

/*按钮*/

#include <QPushButton>

int main(int argc,char *argv[])

{

    QApplication app(argc,argv);

    /*构造一个窗口*/

    QWidget w;

    /*显示窗口*/

    w.show();

    /*按钮也是个窗口*/

    QPushButton button;

    button.setText("Button");

    /*窗口对象的父子关系，影响显示位置*/

    /*没有父窗口的窗口，我们称之为主窗口*/

    button.setParent(&w);

    button.show();

    button.setGeometry(30,30,100,30);

    /* QT对C++的拓展 */

    //std::bind std::function

    QObject::connect(&button,SIGNAL(clicked()),&w,SLOT(close()));

    w.setWindowTitle("Hello World");

    /*在exec中有一个消息循环*/

    return app.exec();

}

运行结果：

/*应用程序抽象类*/

#include
<QApplication>

/*窗口类*/

#include
<QWidget>

/*按钮*/

#include
<QPushButton>

#include
<QHBoxLayout>

int
main(int
argc,char
*argv[])

{

QApplication
app(argc,argv);

/*构造一个窗口*/

QWidget
*window
=
new
QWidget;

/*
按钮也是个窗口
*/

//QPushButton
button;

//button.setText("Button");

/*
窗口对象的父子关系，影响显示位置
*/

/*
没有父窗口的窗口，我们称之为主窗口
*/

QHBoxLayout
*layout
=
new
QHBoxLayout;

QPushButton
*button1
=
new
QPushButton("One");

QPushButton
*button2
=
new
QPushButton("Two");

QPushButton
*button3
=
new
QPushButton("Three");

QPushButton
*button4
=
new
QPushButton("Four");

QPushButton
*button5
=
new
QPushButton("Five");

//弹簧，可以控制组件的显示位置

layout->addStretch(1);

layout->addWidget(button1,1);

layout->addWidget(button2,1);

layout->addWidget(button3,1);

layout->addWidget(button4,1);

layout->addWidget(button5,1);

layout->addStretch(1);

//通过下面的方法可以设置每个button的间隔距离

layout->setSpacing(50);

window->setLayout(layout);

window->show();

return
app.exec();

}

运行结果：

/*应用程序抽象类*/

#include
<QApplication>

/*窗口类*/

#include
<QWidget>

/*按钮*/

#include
<QPushButton>

#include
<QLineEdit>

#include
<QGridLayout>

int
main(int
argc,char
*argv[])

{

QApplication
app(argc,argv);

/*构造一个窗口*/

QWidget
*window
=
new
QWidget;

/*按钮也是一个窗口*/

QPushButton
button;

button.setText("Button");

button.show();

QLineEdit
edit;

edit.setParent(window);

//表格布局

QGridLayout
*layout
=
new
QGridLayout;

layout->setColumnStretch(3,1);

layout->setRowStretch(4,1);

layout->setColumnStretch(0,1);

layout->setRowStretch(0,1);

layout->addWidget(&button,1,1);

layout->addWidget(&edit,1,2);

layout->addWidget(new
QPushButton("1,0"),2,1);

layout->addWidget(new
QPushButton("1,1"),2,2);

//void
addWidget(QWidget
*,
int
row,
int
column,

//              
int
rowSpan,
int
columnSpan,
Qt::Alignment
=
0);

//行，第2列，占1行，合并2列

layout->addWidget(new
QPushButton("aaa"),3,1,1,2);

window->setLayout(layout);

window->show();

return
app.exec();

}

运行结果：

/*应用程序抽象类*/

#include
<QApplication>

/*窗口类*/

#include
<QWidget>

/*按钮*/

#include
<QPushButton>

#include
<QLineEdit>

#include
<QLabel>

#include
<QGridLayout>

int
main(int
argc,char
*argv[])

{

QApplication
app(argc,argv);

/*构造一个窗口*/

QWidget
*window
=
new
QWidget;

QGridLayout
layout;

QLineEdit*
password;

layout.setColumnStretch(3,
1);

layout.setRowStretch(4,
1);

layout.setColumnStretch(0,
1);

layout.setRowStretch(0,
1);

layout.addWidget(new
QLabel("Username:"),
1,
1);

layout.addWidget(new
QLineEdit(),
1,
2);

layout.addWidget(new
QLabel("Password:"),
2,
1);

layout.addWidget(password
=
new
QLineEdit(),
2,
2);

QHBoxLayout*
hBox;

//列

layout.addLayout(hBox
=
new
QHBoxLayout,
3,
2);

//加一个弹簧，让它向右偏移

hBox->addStretch(1);

hBox->addWidget(new
QPushButton("Login"));

window->setLayout(&layout);

window->show();

return
app.exec();

}

运行结果：