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);

//下面的参数表示第3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;

//表示在第三行，占用2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：