[Qt Study Notes 04] Dialogs

I. Modal and Non-Modal Dialogs

In the previous section, we built a simple window and added elements such as a menu bar and toolbar.

However, the current window is only a shell, and none of its internal functionality has been implemented yet.

In this section, we will implement a feature that opens a dialog when a button is clicked.

1.1 Introduction

Dialogs fall into two categories:

• Modal dialog: After it opens, you can interact with other windows
• Non-modal dialog: After it opens, you cannot click anywhere outside the dialog (code execution is blocked)

1.2 Creating the Dialog in Code

Include the header file

#include <QDialog>`

Create the dialog

connect(ui->actionNew,&QAction::triggered,[=](){
//模态对话框 （不可以对其他窗口进行操作） 非模态对话框 （可以对其他窗口进行操作）
//模态创建 阻塞
    QDialog dlg(this);
    dlg.resize(200,100);
    dlg.exec();
    qDebug() << "模态对话框弹出了";   //需要引入#include <QDebug>


//非模态对话框
    QDialog * dlg2 = new QDialog (this);
    dlg2->resize(200,100);
    dlg2->show();
    dlg2->setAttribute(Qt::WA_DeleteOnClose);
    qDebug() << "非模态对话框弹出了";
}

II. Standard Dialogs

Qt provides many built-in dialogs:

Built-in Qt Dialog	Function
QColorDialog	Selects a color
QFileDialog	Selects a file or directory
QFontDialog	Selects a font
QInputDialog	Allows the user to enter a value and returns that value
QMessageBox	A modal dialog used to display information, ask questions, etc.
QPageSetupDialog	Provides paper-related options for a printer
QPrintDialog	Configures a printer
QPrintPreviewDialog	Displays a print preview
QProgressDialog	Displays the progress of an operation

The following example uses a message dialog.