QT学习记录(1)-控件 QPushButton, QLineEdit, QLabel, QHBoxLayout, QGridLayout

1.一个简单的QT程序(QPushButton)

/* 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();

    /* 设置按钮的坐标位置 */
    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();
}

PS：需要在.pro文件中声明

SOURCES += 
    qgridlayoutdemo.cpp

QT += gui widgets

才能正常运行。

运行结果：

2.QLineEdit, QLabel, QGridLayout, QHBoxLayout的用法

#include <QApplication>
#include <QWidget>
#include <QGridLayout>
#include <QLabel>
#include <QLineEdit>
#include <QTextEdit>
#include <QHBoxLayout>
#include <QPushButton>


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

    QApplication app(argc, argv);
    QWidget w;


    QGridLayout *layout = new QGridLayout;
    layout->setColumnStretch(0, 1);
    layout->setColumnStretch(1, 4);
    layout->setColumnStretch(2, 1);
    layout->setColumnStretch(3, 1);
    layout->setColumnStretch(4, 4);


    QLabel *lb_first_name = new QLabel("First Name:");
    QLineEdit *ed_first_name = new QLineEdit;
    QLabel *lb_last_name = new QLabel("Last Name:");
    QLineEdit *et_last_name = new QLineEdit;
    QLabel *lb_sex = new QLabel("Sex:");
    QLineEdit *et_sex = new QLineEdit;
    QLabel *lb_birthday = new QLabel("Birthday:");
    QLineEdit *et_birthday = new QLineEdit;
    QLabel *lb_address = new QLabel("Address:");
    QTextEdit *te_edit = new QTextEdit;


    layout->addWidget(lb_first_name, 0, 0);
    layout->addWidget(ed_first_name, 0, 1);
    layout->addWidget(lb_last_name, 0, 3);
    layout->addWidget(et_last_name, 0, 4);
    layout->addWidget(lb_sex, 1, 0);
    layout->addWidget(et_sex, 1, 1);
    layout->addWidget(lb_birthday, 1, 3);
    layout->addWidget(et_birthday, 1, 4);
    layout->addWidget(lb_address, 2, 0);
    layout->addWidget(te_edit, 3, 0, 1, 5);


//    QGridLayout layout;
//    QLineEdit *pwd;

//    layout.setColumnStretch(0, 1);
//    layout.setColumnStretch(3, 1);
//    layout.setRowStretch(0, 1);
//    layout.setRowStretch(4, 1);

//    layout.addWidget(new QLabel("UserName:"), 1, 1);
//    layout.addWidget(new QLineEdit(), 1, 2);
//    layout.addWidget(new QLabel("Password"), 2, 1);
//    layout.addWidget(pwd = new QLineEdit(), 2, 2);

//    QHBoxLayout *hBoxLayout;
//    layout.addLayout(hBoxLayout = new QHBoxLayout(), 3, 2);
//    hBoxLayout->addStretch(1);
//    hBoxLayout->addWidget(new QPushButton("Login"));

//    pwd->setEchoMode(QLineEdit::Password);

    w.setLayout(layout);
    w.setWindowTitle("QGridLayoutDemo");
    w.show();

    return app.exec();
}

运行结果：