ProgressManager Class

class Core::ProgressManager

The ProgressManager class is used to show a user interface for running tasks in Qt Creator. More...

Header: #include <coreplugin/progressmanager/progressmanager.h>
Inherits: QObject

Public Types

enum ProgressFlag { KeepOnFinish, ShowInApplicationIcon }
flags ProgressFlags

Public Slots

void cancelTasks(Utils::Id type)

Signals

void allTasksFinished(Utils::Id type)
void taskStarted(Utils::Id type)

Static Public Members

Core::FutureProgress *addTask(const QFuture<void> &future, const QString &title, Utils::Id type, Core::ProgressManager::ProgressFlags flags = {})
Core::FutureProgress *addTimedTask(const QFutureInterface<void> &futureInterface, const QString &title, Utils::Id type, int expectedSeconds, Core::ProgressManager::ProgressFlags flags = {})
Core::ProgressManager *instance()
void setApplicationLabel(const QString &text)

Detailed Description

The progress manager tracks the progress of a task that it is told about, and shows a progress indicator in the lower right corner of Qt Creator's main window to the user. The progress indicator also allows the user to cancel the task.

You get the single instance of this class via the ProgressManager::instance() function.

Registering a task

The ProgressManager API uses QtConcurrent as the basis for defining tasks. A task consists of the following properties:

PropertyTypeDescription
Task abstractionQFuture<void>A QFuture object that represents the task which is responsible for reporting the state of the task. See below for coding patterns how to create this object for your specific task.
TitleQStringA very short title describing your task. This is shown as a title over the progress bar.
TypeQStringA string identifier that is used to group different tasks that belong together. For example, all the search operations use the same type identifier.
FlagsProgressManager::ProgressFlagsAdditional flags that specify how the progress bar should be presented to the user.

To register a task you create your QFuture<void> object, and call addTask(). This function returns a FutureProgress object that you can use to further customize the progress bar's appearance. See the FutureProgress documentation for details.

In the following you will learn about two common patterns how to create the QFuture<void> object for your task.

Create a threaded task with QtConcurrent

The first option is to directly use QtConcurrent to actually start a task concurrently in a different thread. QtConcurrent has several different functions to run e.g. a class function in a different thread. Qt Creator itself adds a few more in src/libs/qtconcurrent/runextensions.h. The QtConcurrent functions to run a concurrent task return a QFuture object. This is what you want to give the ProgressManager in the addTask() function.

Have a look at e.g Core::ILocatorFilter. Locator filters implement a function refresh() which takes a QFutureInterface object as a parameter. These functions look something like:

void Filter::refresh(QFutureInterface<void> &future) {
    future.setProgressRange(0, MAX);
    ...
    while (!future.isCanceled()) {
        // Do a part of the long stuff
        ...
        future.setProgressValue(currentProgress);
        ...
    }
}

The actual refresh, which calls all the filters' refresh functions in a different thread, looks like this:

QFuture<void> task = Utils::map(filters, &ILocatorFilter::refresh);
Core::FutureProgress *progress = Core::ProgressManager::addTask(task, tr("Indexing"),
                                                                Locator::Constants::TASK_INDEX);

First, we to start an asynchronous operation which calls all the filters' refresh function. After that we register the returned QFuture object with the ProgressManager.

Manually create QtConcurrent objects for your thread

If your task has its own means to create and run a thread, you need to create the necessary objects yourselves, and report the start/stop state.

// We are already running in a different thread here
QFutureInterface<void> *progressObject = new QFutureInterface<void>;
progressObject->setProgressRange(0, MAX);
Core::ProgressManager::addTask(progressObject->future(), tr("DoIt"), MYTASKTYPE);
progressObject->reportStarted();
// Do something
...
progressObject->setProgressValue(currentProgress);
...
// We have done what we needed to do
progressObject->reportFinished();
delete progressObject;

In the first line we create the QFutureInterface object that will be our way for reporting the task's state. The first thing we report is the expected range of the progress values. We register the task with the ProgressManager, using the internal QFuture object that has been created for our QFutureInterface object. Next we report that the task has begun and start doing our actual work, regularly reporting the progress via the functions in QFutureInterface. After the long taking operation has finished, we report so through the QFutureInterface object, and delete it afterwards.

Customizing progress appearance

You can set a custom widget to show below the progress bar itself, using the FutureProgress object returned by the addTask() function. Also use this object to get notified when the user clicks on the progress indicator.

Member Type Documentation

enum ProgressManager::ProgressFlag
flags ProgressManager::ProgressFlags

Additional flags that specify details in behavior. The default for a task is to not have any of these flags set.

ConstantValueDescription
Core::ProgressManager::KeepOnFinish0x01The progress indicator stays visible after the task has finished.
Core::ProgressManager::ShowInApplicationIcon0x02The progress indicator for this task is additionally shown in the application icon in the system's task bar or dock, on platforms that support that (at the moment Windows 7 and Mac OS X).

The ProgressFlags type is a typedef for QFlags<ProgressFlag>. It stores an OR combination of ProgressFlag values.

Member Function Documentation

[signal] void ProgressManager::allTasksFinished(Utils::Id type)

Sent when all tasks of a type have finished.

[static slot] void ProgressManager::cancelTasks(Utils::Id type)

Schedules the cancellation of all running tasks of the given type. The cancellation functionality depends on the running task actually checking the QFuture::isCanceled property.

[signal] void ProgressManager::taskStarted(Utils::Id type)

Sent whenever a task of a given type is started.

[static] Core::FutureProgress *ProgressManager::addTask(const QFuture<void> &future, const QString &title, Utils::Id type, Core::ProgressManager::ProgressFlags flags = {})

Shows a progress indicator for the task given by the QFuture object future.

The progress indicator shows the specified title along with the progress bar. The type of a task will specify a logical grouping with other running tasks. Via the flags parameter you can e.g. let the progress indicator stay visible after the task has finished.

Returns an object that represents the created progress indicator, which can be used to further customize. The FutureProgress object's life is managed by the ProgressManager and is guaranteed to live only until the next event loop cycle, or until the next call of addTask.

If you want to use the returned FutureProgress later than directly after calling this function, you will need to use protective functions (like wrapping the returned object in QPointer and checking for 0 whenever you use it).

[static] Core::FutureProgress *ProgressManager::addTimedTask(const QFutureInterface<void> &futureInterface, const QString &title, Utils::Id type, int expectedSeconds, Core::ProgressManager::ProgressFlags flags = {})

Shows a progress indicator for task given by the QFutureInterface object futureInterface. The progress indicator shows the specified title along with the progress bar. The progress indicator will increase monotonically with time, at expectedSeconds it will reach about 80%, and continue to increase with a decreasingly slower rate.

The type of a task will specify a logical grouping with other running tasks. Via the flags parameter you can e.g. let the progress indicator stay visible after the task has finished.

See also addTask.

[static] Core::ProgressManager *ProgressManager::instance()

Returns a single progress manager instance.

[static] void ProgressManager::setApplicationLabel(const QString &text)

Shows the given text in a platform dependent way in the application icon in the system's task bar or dock. This is used to show the number of build errors on Windows 7 and macOS.

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