QT learning 19 standard dialog box in QT (top)

Qt Study 19 Qt Standard dialog boxes in （ On ）

Standard dialog box

• Qt Provides some for developers Reusable Dialog type
• Qt Reusable dialog provided The whole country does not inherit from QDialog class

• Qt Standard dialog boxes in Follow the same usage

//  Define dialog objects 
DialogType dlg(this);
//  Set dialog properties 
dlg.setPropertyXXX(value);
if(dlg.exec() == DialogType::Value) {
    
    //  Get dialog data 
    Type v = dlg.getDialogValue();
    //  Process dialog data 
    // ....
}

Message dialog

• Message dialog It's in the application The most common interface element
• The message dialog box is mainly used for ：
  • For the user Prompt important information
  • Force users Make operation selection

• How to use the message dialog

//  Construct message dialog object 
QMessageBox msg(this);
//  Set the relevant properties of the message dialog 
msg.setWindowTitle("Message Title");
msg.setText("This is message content!");
msg.setIcon(QMessageBox::Information);
msg.setStandardButtons(QMessageBox::Ok | QMessageBox::Cancel);
if (msg.exec() == QMessageBox::Ok) {
    
    qDebug() << "Ok button is clicked!";
}

File dialog

• File dialog boxes are often used in the following situations

  Open Mode

  • In the application You need to open an external file

  Save Mode

  • In the application The current content needs to be stored in the external file specified by the user

• How to use the file dialog

QFileDialog fd(this);
// 
fd.setAcceptMode(QFileDialog::AcceptOpen);
fd.setFileMode(QFileDialog::ExistingFile);
if (fd.exec() == QFileDialog::Accepted) {
    
    QStringList fs = fd.selectedFiles();
}

• file type filter

  • In the file dialog box, you can Define filters through file suffixes

  • Filter definition rules ：

    Display name ( *. suffix 1 *. suffix 2 … *. suffix N )

  example ：“Image ( *.png *.xpm *.jpg )”

  ​ “Text ( *.txt )”

  ​ “All ( *.* )”

• QFileDialog Using functions in

  • QFileDialog::getOpenFileName
  • QFileDialog::getOpenFileNames
  • QFileDialog::getSaveFileName

Code experiments

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QPushButton>

class Widget : public QWidget
{
    
    Q_OBJECT
private:
    QPushButton SimpleMsgBtn;
    QPushButton CustomMsgBtn;
    QPushButton OpenFileBtn;
    QPushButton SaveFileBtn;

private slots:
    void SimpleMsgBtn_Clicked();
    void CustomMsgBtn_Clicked();
    void OpenFileBtn_Clicked();
    void SaveFileBtn_Clicked();

public:
    Widget(QWidget *parent = 0);
    ~Widget();
};

#endif // WIDGET_H

#include "Widget.h"
#include <QDebug>
#include <QMessageBox>
#include <QFileDialog>

Widget::Widget(QWidget *parent) : QWidget(parent),
    SimpleMsgBtn(this), CustomMsgBtn(this), OpenFileBtn(this), SaveFileBtn(this)
{
    
    SimpleMsgBtn.setText("Simple Message Dialog");
    SimpleMsgBtn.move(20, 20);
    SimpleMsgBtn.resize(160, 30);

    CustomMsgBtn.setText("Custom Message Dialog");
    CustomMsgBtn.move(20, 70);
    CustomMsgBtn.resize(160, 30);

    OpenFileBtn.setText("Open File Dialog");
    OpenFileBtn.move(20, 120);
    OpenFileBtn.resize(160, 30);

    SaveFileBtn.setText("Save File Dialog");
    SaveFileBtn.move(20, 170);
    SaveFileBtn.resize(160, 30);

    resize(200, 220);

    connect(&SimpleMsgBtn, SIGNAL(clicked()), this, SLOT(SimpleMsgBtn_Clicked()));
    connect(&CustomMsgBtn, SIGNAL(clicked()), this, SLOT(CustomMsgBtn_Clicked()));
    connect(&OpenFileBtn, SIGNAL(clicked()), this, SLOT(OpenFileBtn_Clicked()));
    connect(&SaveFileBtn, SIGNAL(clicked()), this, SLOT(SaveFileBtn_Clicked()));
}

Widget::~Widget()
{
    

}

void Widget::SimpleMsgBtn_Clicked()
{
    
    QMessageBox msg(this);
    msg.setText("This is a message dialog!");
    msg.exec();
}

void Widget::CustomMsgBtn_Clicked()
{
    
    QMessageBox msg(this);
    msg.setWindowTitle("Window Title");
    msg.setText("This is a detail message dialog!");
    msg.setIcon(QMessageBox::Information);
    msg.setStandardButtons(QMessageBox::Ok | QMessageBox::Cancel | QMessageBox::YesToAll);
    if (msg.exec() == QMessageBox::Ok) {
    
        qDebug() << "Ok button is clicked!";
    }
    //  Simple usage 
    QMessageBox::information(this, "Window Title", "This is a detail message dialog!", QMessageBox::Ok|QMessageBox::Cancel|QMessageBox::YesToAll);
    QMessageBox::question(this, "Question", "This is a question dialog!", QMessageBox::Yes|QMessageBox::No|QMessageBox::Cancel);
    QMessageBox::warning(this, "Warning", "This is a warning dialog", QMessageBox::Ok);
    QMessageBox::critical(this, "Warning", "This is a warning dialog!", QMessageBox::Ok);
    QMessageBox::about(this, "About", "This is a about dialog!");
}

void Widget::OpenFileBtn_Clicked()
{
    
    QFileDialog dlg(this);
    dlg.setAcceptMode(QFileDialog::AcceptOpen);
    dlg.setFileMode(QFileDialog::ExistingFiles);

    if (dlg.exec() == QFileDialog::Accepted) {
    
        QStringList fs = dlg.selectedFiles();
        for (int i = 0; i < fs.count(); i++) {
    
            qDebug() << fs[i];
        }
    }
    //  Simple usage 
    QFileDialog::getOpenFileName(this, tr("Open File"), "./", tr("Images (*.png *.xpm *.jpg)"));
    QFileDialog::getOpenFileNames(this, "Select one or more files to open", "./", "Images (*.png *.xpm *.jpg)");
}

void Widget::SaveFileBtn_Clicked()
{
    
    QFileDialog dlg(this);
    dlg.setAcceptMode(QFileDialog::AcceptSave);
    if (dlg.exec() == QFileDialog::Accepted) {
    
        QStringList fs = dlg.selectedFiles();
        for (int i = 0; i < fs.count(); i++) {
    
            qDebug() << fs[i];
        }
    }
    //  Simple usage 
    QFileDialog::getSaveFileName(this, tr("Save File"), "./untitled.png", tr("Images (*.png *.xpm *.jpg)"));
}

#include "Widget.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    
    QApplication a(argc, argv);
    Widget w;
    w.show();

    return a.exec();
}

Summary

• Qt More than one Reusable Dialog type
  • Inherited from QDialog type
  • follow identical Usage mode
• QMessageBox Used to prompt important program information
• QFileDialog Used to get the file path in the system