Quit Installer Example | Qt Installer Framework Manual

Qt Installer Framework Manual | Qt Installer Framework Examples | Quit Installer Example

# Quit Installer Example

Quit Installer illustrates how to use the `Component()` function to display a message box to end users for quitting the installation if some requirements for the installation are not met.

## Configuring the Example Installer

The installer configuration file, config.xml, in the `config` directory specifies the text and default values used in the installer:

- The `<Name>` element specifies the application name that is added to the page name and introduction text.
- The `<Version>` element specifies the application version number.
- The `<Title>` element specifies the installer name displayed on the title bar.
- The `<Publisher>` element specifies the publisher of the software (as shown in the Windows Control Panel, for example).
- The `<StartMenuDir>` element specifies the name of the default program group for the product in the Windows Start menu.
- The `<TargetDir>` element specifies that the default target directory is located in the `IfwExamples` directory in the home directory of the current user (because the predefined variable`@HomeDir@` is used as a part of the value). For more information, see Predefined Variables.

      <?xml version="1.0" encoding="UTF-8"?>
      <Installer>
          <Name>Quit Installer Example</Name>
          <Version>1.0.0</Version>
          <Title>Quit Installer Example</Title>
          <Publisher>Qt-Project</Publisher>
          <StartMenuDir>Qt IFW Examples</StartMenuDir>
          <TargetDir>@HomeDir@/IfwExamples/quitinstaller</TargetDir>
      </Installer>

## Creating the Example Package Information File

The installer package information file, package.xml, in the `meta` directory specifies the components that are available for installation:

- The `<DisplayName>` element specifies the human-readable name of the component.
- The `<Description>` element specifies the human-readable description of the component.
- The `<Version>` element specifies the version number of the component.
- The `<ReleaseDate>` element specifies the date when this component version was released.

- The `<Default>` element is set to `true` to preselect the component in the installer.
- The `<Script>` element specifies the file name of the JavaScript file that is loaded to perform operations.

      <?xml version="1.0"?>
      <Package>
          <DisplayName>Quit an installer</DisplayName>
          <Description>Quits the installer in a nice way, if there is something missing</Description>
          <Version>1.0.1</Version>
          <ReleaseDate>2013-02-27</ReleaseDate>
          <Default>true</Default>
          <Script>installscript.js</Script>
      </Package>

## Quitting the Installation

In installscript.js, we use the `Component()` function to display a message box for quitting the installer to end users:

      function Component()
      {
          var result = QMessageBox["question"]("test.quit", "Installer", "Do you want to quit the installer?<br>" +
              "This message box was created using JavaScript.", QMessageBox.Ok | QMessageBox.Cancel);

If end users select OK, we use the `installer::setValue()` function to display a message and the `installer.setDefaultPageVisible()` function to hide the subsequent installer pages:

          if (result == QMessageBox.Ok) {
              installer.setValue("FinishedText", "<font color='red' size=3>The installer was quit.</font>");
              installer.setDefaultPageVisible(QInstaller.TargetDirectory, false);
              installer.setDefaultPageVisible(QInstaller.ReadyForInstallation, false);
              installer.setDefaultPageVisible(QInstaller.ComponentSelection, false);
              installer.setDefaultPageVisible(QInstaller.StartMenuSelection, false);
              installer.setDefaultPageVisible(QInstaller.PerformInstallation, false);
              installer.setDefaultPageVisible(QInstaller.LicenseCheck, false);
              gui.clickButton(buttons.NextButton);

If end users select Cancel, we display the default installer pages and use the `installer::setValue()` function to display another message on the last installer page:

          } else {
              installer.setValue("FinishedText",
                  "<font color='green' size=3>The installer was not quit by JavaScript.</font>");
          }
      }

## Generating the Example Installer

To create the example installer, switch to the example source directory on the command line and enter the following command:

- On Windows:

        ..\..\bin\binarycreator.exe -c config\config.xml -p packages installer.exe

- On Linux or OS X:

        ../../bin/binarycreator -c config/config.xml -p packages installer

The installer is created in the current directory.

Files:

- quitinstaller/config/config.xml
- quitinstaller/packages/org.qtproject.ifw.example.quitinstaller/meta/installscript.js
- quitinstaller/packages/org.qtproject.ifw.example.quitinstaller/meta/package.xml
- quitinstaller/quitinstaller.pro