QString fileName=QFileDialog::getOpenFileName(this,"打开文件", "/", "文本文件(*.txt);;C文件(*.c);;json文件(*.json)");

QColor c=QColorDialog::getColor(QT::blue);

bool ok;

QFont f=QFontDialog::getFont(&ok);

//文本输入

QString text=QInputDialog::getText(this, "字符串对话框", "请输入姓名：", QLineEdit::Normal, "默认值", &ok);//ok==true，点击了确定按钮，false，点击了取消按钮

//列表选择

QStringList listItem;

listItem<<"A"<<"B";

QString item=QInputDialog::getItem(this, "选择对话框", "请选择：", listItem, , false, &ok);

//int输入

int age=QInputDialog::getInt(this, "int输入对话框", "请输入年龄：", , , , , &ok);

//double输入

double score=QInputDialog::getInt(this, "int输入对话框", "请输入成绩：", , , , , &ok);

QMessageBox::question(this, "Question消息框", "是否退出程序？", QMessageBox::Ok|QMessageBox::Cancel, QMessageBox::Ok);

QMessageBox::information(this, "Information消息框", "欢迎来到三体世界");

QMessageBox::warning(this, "Warning消息框", "是否退出程序？", QMessageBox::Ok|QMessageBox::Cancel, QMessageBox::Ok);

QMessageBox::critical(this, "Critical消息框", "欢迎来到三体世界");

QMessageBox::about(this, "About消息框", "欢迎来到三体世界");

QTime time=QTime::currentTime();

QString str=time.toString("hh:mm:ss");

#include "mainwindow.h"

#include <QApplication>

#include <QPixmap>

#include <QSplashScreen>

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

{

    QApplication a(argc, argv);

    QPixmap pixmap("Qt.png");                //(a)

    QSplashScreen splash(pixmap);            //(b)

    splash.show();                            //显示此启动图片

    a.processEvents();                        //(c)

    MainWindow w;

    w.show();

    splash.finish(&w);                        //(e)

    return a.exec();

}