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Update UI: progress, apply and restart#

AUpdater exposes everything the UI needs as one property, AUpdater::status. It holds one of the statuses AUpdater::StatusIdle, AUpdater::StatusCheckingForUpdates, AUpdater::StatusDownloading, AUpdater::StatusWaitingForApplyAndRestart or AUpdater::StatusNotAvailable (or your own type) in a std::any. It is updated in the UI thread only.

Status-driven view#

Project the status into views with readProjected: each time the status changes, the view is rebuilt. The downloading status carries a progress property that can be bound directly to AProgressBar; the bar then updates without rebuilding.

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CustomLayout {} & mUpdater->status.readProjected([&updater = mUpdater](const std::any& status) -> _<AView> {
    if (std::any_cast<AUpdater::StatusIdle>(&status)) {
        return _new<AButton>("Check for updates").connect(&AView::clicked, AUI_SLOT(updater)::checkForUpdates);
    }
    if (std::any_cast<AUpdater::StatusCheckingForUpdates>(&status)) {
        return Label { "Checking for updates..." };
    }
    if (auto downloading = std::any_cast<AUpdater::StatusDownloading>(&status)) {
        return Vertical {
            Label { "Downloading..." },
            _new<AProgressBar>() & downloading->progress,
        };
    }
    if (std::any_cast<AUpdater::StatusWaitingForApplyAndRestart>(&status)) {
        return _new<AButton>("Apply update and restart")
            .connect(&AView::clicked, AUI_SLOT(updater)::applyUpdateAndRestart);
    }
    return nullptr;
}),

The buttons call checkForUpdates and applyUpdateAndRestart. applyUpdateAndRestart terminates the process, so save the user's data before calling it.

Custom statuses#

status is AProperty<std::any>, so you may assign your own struct, for example to display an error after a failed download. The updater does not interpret unknown types.

struct StatusFailed {
    AString reason;
};
updater->status = StatusFailed { "No internet connection" };

Reset the status to AUpdater::StatusIdle when the user dismisses the error, otherwise checkForUpdates stays unavailable (it requires StatusIdle).

Choosing the workflow#

Whether to ask the user at every step or to download silently is up to you. See "Updater workflows" in updater. When downloading silently, call downloadUpdate() at the end of checkForUpdatesImpl, and show only a "Restart to update" button for StatusWaitingForApplyAndRestart. Avoid modal message boxes unless the user explicitly asked for the check.

After the update#

On the first start of the updated application handleStartup removes the downloaded files. If the deployment failed, the old version is launched with --aui-updater-failed and the reason is available from AUpdater::getLastDeploymentError(), which you can show in the UI. See Testing and debugging AUpdater for debugging.