QMessageBox

QMessageBox is a class in the Qt toolkit that provides a simple way to display alert messages and dialogs to the user. It is commonly used in Qt applications to inform users about certain events or to prompt them for a decision.

Using QMessageBox

To use QMessageBox in your Qt application, you first need to include the relevant header file:

#include <QMessageBox>

Once you have included the header file, you can create an instance of QMessageBox and use it to display different types of messages:


QMessageBox msgBox;
msgBox.setText("Hello, World!");
msgBox.exec();


Types of Messages

QMessageBox supports different types of messages, such as information messages, warning messages, question messages, and critical messages. You can set the type of message using the setIcon() method:


QMessageBox msgBox;
msgBox.setText("Are you sure you want to delete this file?");
msgBox.setIcon(QMessageBox::Question);
msgBox.exec();


In this example, the message box will display a question icon along with the message.

Buttons and Responses

When displaying a QMessageBox, you can also specify the buttons that should be shown to the user. You can use the setStandardButtons() method to set the buttons:


QMessageBox msgBox;
msgBox.setText("Do you want to save your changes?");
msgBox.setIcon(QMessageBox::Information);
msgBox.setStandardButtons(QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel);
int response = msgBox.exec();


In this example, the message box will display three buttons – Save, Discard, and Cancel. The user’s response to the message box can be obtained by calling the exec() method, which returns a value indicating which button was clicked.

Conclusion

QMessageBox is a useful class in the Qt toolkit for displaying alert messages and dialogs in Qt applications. By using QMessageBox, you can easily interact with the user and prompt them for decisions or inform them about certain events.