QT5 basic operation (1)

  Description: Above the code box is the description of the operation, the specific operation inside the code box

Incomplete display of interface fonts during runtime (resolution problem)

//解决办法：在主函数(main.cpp)的QApplication a(argc,argv)前加入一行：
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

Code way to build components

在.h文件中private 声明指针，在.cpp文件中new实例化对象，后可在cpp中以指针方式使用

Layout of components in code (in fact, this step can be done in qt designer)

1.定义QGridLayout/水平/竖直对象a
2.a->addWidget(部件名,0,0) //添加组件，后面是对应组件x,y坐标，都从0开始

QTextEdit sets text storage format

    QTextEdit *textLeft = new QTextEdit();
    textLeft->setAlignment(Qt::AlignCenter);
    /*
     * setAlignment为设置中文字对齐方式
     * 包括AlignLeft 左对齐
     *      AlignRight 右对齐
     *      AlignCenter 中心对齐
     *      AlignUp 文字与顶部对齐
     *      AlignBottom 文字与底部对齐
     */

Window display drag bar

  QSplitter *splitterRight = new QSplitter();
  splitterRight->setOpaqueResize(false); //用于显示拖拽条，flase不显示，true显示

Set the title of the current window (actually, without tr, double quotes are fine. A is the object name of the current interface)

A->setWindowTitle(tr("Splitter"));

Display the current window (A is the object name of the current interface)

A->show();

Close the current window (A is the object name of the current interface, if it is used in your own CPP file, you can use this)

A->close();;

Set up a movable window

    QDockWidget *dock = new QDockWidget(tr("DockWindow1"), this);
    //可移动
    dock->setFeatures(QDockWidget ::DockWidgetMovable);
    dock->setAllowedAreas(Qt::LeftDockWidgetArea|Qt::RightDockWidgetArea);

Set Label to mosaic type

OtherLabel->setFrameStyle(QFrame::Panel|QFrame::Sunken);//设置控件的风格，镶嵌阴影型

Reference images as controls (such as photos)

    HeadIconLabel = new QLabel;
    QPixmap icon("123.jpg");//引用图像时可放置于build目录下
    HeadIconLabel->setPixmap(icon);

Code to adjust the size of the control (a is any control object)

a->resize(x,y);

If you need to display the drawer effect, each drawer is divided into N buttons (such as QQ chat list)

QToolBox

Various parameter settings of setToolButtonStyle in QToolButton

    /*
     * setToolButtonStyle用来设置图标和文字的位置
     * 包括：
     * ToolButtonIconOnly 只显示图标
     * ToolButtonTextOnly 只显示文字
     * ToolButtonTextBesidesIcon 文字在图标旁边
     * ToolButtonTextUnderIcon 文字在图标下面
     */
    toolBtn1_1->setToolButtonStyle(Qt::ToolButtonTextBesideIcon);

Design a progress box (like the progress bar under windows when deleting large files)

QProgressDialog

Set the window to the top (A is the name of the interface object)

A->setWindowFlags(Qt::FramelessWindowHint);

Set window transparency (A is the name of the interface object)

    //设置透明度为0.5
A->setWindowOpacity(0.5);

Mouse movement event

//调用时鼠标移动使用的应该是->buttons（）而不是->button
//以下两个函授完成时钟随着鼠标移动的功能
void DigiClock::mousePressEvent(QMouseEvent *event)
{
    
    
    if (event->buttons() == Qt::LeftButton)
    {
    
    
        //以左上角为标准计算拖动距离
        //globalPos代表全局坐标，以整个屏幕为界面显示
        dragPosition = event->globalPos()-frameGeometry().topLeft();
        event->accept();
    }
    if (event->buttons() == Qt::RightButton)
    {
    
    
        close();
    }
}

void DigiClock::mouseMoveEvent(QMouseEvent *event)
{
    
    
    if (event->buttons() & Qt::LeftButton)
    {
    
    
        move(event->globalPos()-dragPosition);
        event->accept();
    }
}

Button: Press to change color, and restore after release (implemented using QTime)

//（注意：基本思想是修改样式表的背景，所以要保证前后字体大小统一。样式表的话推荐选择border-image,background的图案会显示不全）
    this->ui->P_back->setStyleSheet("QPushButton{border-image: url(:/tubiao/14.png);color: rgb(255, 255, 255);font: 14pt 楷体;}");
    //使用等待效果，让图标变换有显示
    QTime dieTime= QTime::currentTime().addMSecs(300);
    while (QTime::currentTime() < dieTime)
        QCoreApplication::processEvents(QEventLoop::AllEvents, 100);
    this->close();
    this->ui->P_back->setStyleSheet("QPushButton{border-image: url(:/tubiao/10.png);color: rgb(255, 255, 255);font: 14pt 楷体;}");

Read the data in the TXT file

  int i = 1;
    QFile file("xxx.txt");    //文件路径,最好是绝对路径
     if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
     {
    
    
          qDebug()<<"Can't open the file!";
          return;
     }
     QTextStream in(&file);  //文件流
     QString line = in.readLine() ;   //读取一行
     while (!line.isNull())
     {
    
    
         line = in.readLine();
         a[i] = line.toFloat();
         i = i+1;
     }

Current clock, dynamic change

  //主函数
    QTimer *timer = new QTimer();
    connect(timer,SIGNAL(timeout()),this,SLOT(showtime_1()));
    timer->start(1000);//1s改变一次

    //槽函数showtime_1
    QDateTime *datatime = new QDateTime(QDateTime::currentDateTime());
    QString str = datatime->toString("yyyy-MM-dd hh:mm:ss ddd");
    ui->D_time->setText(str);