A thread that automatically pops up a modal dialog box with a progress bar and cancel button while it's busy running. More...

#include <juce_ThreadWithProgressWindow.h>

Inheritance diagram for juce::ThreadWithProgressWindow:

[legend]

Collaboration diagram for juce::ThreadWithProgressWindow:

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Public Types
enum	{ realtimeAudioPriority = -1 }
	Special realtime audio thread priority. More...

using	ThreadID = void *
	A value type used for thread IDs. More...

Public Member Functions
	ThreadWithProgressWindow (const String &windowTitle, bool hasProgressBar, bool hasCancelButton, int timeOutMsWhenCancelling=10000, const String &cancelButtonText=String(), Component *componentToCentreAround=nullptr)
	Creates the thread. More...

	~ThreadWithProgressWindow () override
	Destructor. More...

void	addListener (Listener *)
	Add a listener to this thread which will receive a callback when signalThreadShouldExit was called on this thread. More...

AlertWindow *	getAlertWindow () const noexcept
	Returns the AlertWindow that is being used. More...

ThreadID	getThreadId () const noexcept
	Returns the ID of this thread. More...

const String &	getThreadName () const noexcept
	Returns the name of the thread. More...

bool	isThreadRunning () const
	Returns true if the thread is currently active. More...

void	launchThread (int priority=5)
	Starts the thread and returns. More...

void	notify () const
	Wakes up the thread. More...

void	removeListener (Listener *)
	Removes a listener added with addListener. More...

virtual void	run ()=0
	Must be implemented to perform the thread's actual code. More...

bool	runThread (int priority=5)
	Starts the thread and waits for it to finish. More...

void	setAffinityMask (uint32 affinityMask)
	Sets the affinity mask for the thread. More...

bool	setPriority (int priority)
	Changes the thread's priority. More...

void	setProgress (double newProgress)
	The thread should call this periodically to update the position of the progress bar. More...

void	setStatusMessage (const String &newStatusMessage)
	The thread can call this to change the message that's displayed in the dialog box. More...

void	signalThreadShouldExit ()
	Sets a flag to tell the thread it should stop. More...

void	startThread ()
	Starts the thread running. More...

void	startThread (int priority)
	Starts the thread with a given priority. More...

bool	stopThread (int timeOutMilliseconds)
	Attempts to stop the thread running. More...

virtual void	threadComplete (bool userPressedCancel)
	This method is called (on the message thread) when the operation has finished. More...

bool	threadShouldExit () const
	Checks whether the thread has been told to stop running. More...

bool	wait (int timeOutMilliseconds) const
	Suspends the execution of this thread until either the specified timeout period has elapsed, or another thread calls the notify() method to wake it up. More...

bool	waitForThreadToExit (int timeOutMilliseconds) const
	Waits for the thread to stop. More...

Static Public Member Functions
static bool	currentThreadShouldExit ()
	Checks whether the current thread has been told to stop running. More...

static Thread *	getCurrentThread ()
	Finds the thread object that is currently running. More...

static ThreadID	getCurrentThreadId ()
	Returns an id that identifies the caller thread. More...

static void	initialiseJUCE (void jniEnv, void jContext)
	Initialises the JUCE subsystem for projects not created by the Projucer. More...

static void	launch (std::function< void()> functionToRun)
	Invokes a lambda or function on its own thread. More...

static void	setCurrentThreadAffinityMask (uint32 affinityMask)
	Changes the affinity mask for the caller thread. More...

static void	setCurrentThreadName (const String &newThreadName)
	Changes the name of the caller thread. More...

static bool	setCurrentThreadPriority (int priority)
	Changes the priority of the caller thread. More...

static void	sleep (int milliseconds)
	Suspends the execution of the current thread until the specified timeout period has elapsed (note that this may not be exact). More...

static void	yield ()
	Yields the current thread's CPU time-slot and allows a new thread to run. More...

Private Member Functions
int	getTimerInterval () const noexcept
	Returns the timer's interval. More...

bool	isTimerRunning () const noexcept
	Returns true if the timer is currently running. More...

void	startTimer (int intervalInMilliseconds) noexcept
	Starts the timer and sets the length of interval required. More...

void	startTimerHz (int timerFrequencyHz) noexcept
	Starts the timer with an interval specified in Hertz. More...

void	stopTimer () noexcept
	Stops the timer. More...

void	timerCallback () override
	The user-defined callback routine that actually gets called periodically. More...

Static Private Member Functions
static void	callAfterDelay (int milliseconds, std::function< void()> functionToCall)
	Invokes a lambda after a given number of milliseconds. More...

static void	callPendingTimersSynchronously ()
	For internal use only: invokes any timers that need callbacks. More...

Private Attributes
std::unique_ptr< AlertWindow >	alertWindow

String	message

CriticalSection	messageLock

double	progress

const int	timeOutMsWhenCancelling

bool	wasCancelledByUser

Detailed Description

A thread that automatically pops up a modal dialog box with a progress bar and cancel button while it's busy running.

These are handy for performing some sort of task while giving the user feedback about how long there is to go, etc.

E.g.

class MyTask  : public ThreadWithProgressWindow
{
public:
    MyTask()    : ThreadWithProgressWindow ("busy...", true, true)
    {
    }
    void run()
    {
        for (int i = 0; i < thingsToDo; ++i)
        {
            // must check this as often as possible, because this is
            // how we know if the user's pressed 'cancel'
            if (threadShouldExit())
                break;
            // this will update the progress bar on the dialog box
            setProgress (i / (double) thingsToDo);
            //   ... do the business here...
        }
    }
};
void doTheTask()
{
    MyTask m;
    if (m.runThread())
    {
        // thread finished normally..
    }
    else
    {
        // user pressed the cancel button..
    }
}

See also: Thread, AlertWindow

{GUI}

Member Typedef Documentation

◆ ThreadID

using juce::Thread::ThreadID = void*

inherited

A value type used for thread IDs.

See also: getCurrentThreadId(), getThreadId()

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

inherited

Special realtime audio thread priority.

This priority will create a high-priority thread which is best suited for realtime audio processing.

Currently, this priority is identical to priority 9, except when building for Android with OpenSL/Oboe support.

In this case, JUCE will ask OpenSL/Oboe to construct a super high priority thread specifically for realtime audio processing.

Note that this priority can only be set before the thread has started. Switching to this priority, or from this priority to a different priority, is not supported under Android and will assert.

For best performance this thread should yield at regular intervals and not call any blocking APIs.

See also: startThread, setPriority, sleep, WaitableEvent

Enumerator
realtimeAudioPriority

Constructor & Destructor Documentation

◆ ThreadWithProgressWindow()

juce::ThreadWithProgressWindow::ThreadWithProgressWindow	(	const String &	windowTitle,
		bool	hasProgressBar,
		bool	hasCancelButton,
		int	timeOutMsWhenCancelling = `10000`,
		const String &	cancelButtonText = `String()`,
		Component *	componentToCentreAround = `nullptr`
	)

Creates the thread.

Initially, the dialog box won't be visible, it'll only appear when the runThread() method is called.

Parameters

windowTitle	the title to go at the top of the dialog box
hasProgressBar	whether the dialog box should have a progress bar (see setProgress() )
hasCancelButton	whether the dialog box should have a cancel button
timeOutMsWhenCancelling	when 'cancel' is pressed, this is how long to wait for the thread to stop before killing it forcibly (see Thread::stopThread() )
cancelButtonText	the text that should be shown in the cancel button (if it has one). Leave this empty for the default "Cancel"
componentToCentreAround	if this is non-null, the window will be positioned so that it's centred around this component.

◆ ~ThreadWithProgressWindow()

juce::ThreadWithProgressWindow::~ThreadWithProgressWindow ( )

override

Destructor.

Member Function Documentation

◆ addListener()

void juce::Thread::addListener ( Listener * )

inherited

Add a listener to this thread which will receive a callback when signalThreadShouldExit was called on this thread.

See also: signalThreadShouldExit, removeListener

◆ callAfterDelay()

static void juce::Timer::callAfterDelay	(	int	milliseconds,
		std::function< void()>	functionToCall
	)

staticinherited

Invokes a lambda after a given number of milliseconds.

◆ callPendingTimersSynchronously()

static void juce::Timer::callPendingTimersSynchronously ( )

staticinherited

For internal use only: invokes any timers that need callbacks.

Don't call this unless you really know what you're doing!

◆ currentThreadShouldExit()

static bool juce::Thread::currentThreadShouldExit ( )

staticinherited

Checks whether the current thread has been told to stop running.

On the message thread, this will always return false, otherwise it will return threadShouldExit() called on the current thread.

See also: threadShouldExit

◆ getAlertWindow()

AlertWindow* juce::ThreadWithProgressWindow::getAlertWindow ( ) const

inlinenoexcept

Returns the AlertWindow that is being used.

◆ getCurrentThread()

static Thread* juce::Thread::getCurrentThread ( )

staticinherited

Finds the thread object that is currently running.

Note that the main UI thread (or other non-JUCE threads) don't have a Thread object associated with them, so this will return nullptr.

◆ getCurrentThreadId()

Thread::ThreadID juce::Thread::getCurrentThreadId ( )

staticinherited

Returns an id that identifies the caller thread.

To find the ID of a particular thread object, use getThreadId().

Returns: a unique identifier that identifies the calling thread.

See also: getThreadId

Referenced by juce::ThreadLocalValue< Type >::get(), and juce::ThreadLocalValue< Type >::releaseCurrentThreadStorage().

◆ getThreadId()

ThreadID juce::Thread::getThreadId ( ) const

noexceptinherited

Returns the ID of this thread.

That means the ID of this thread object - not of the thread that's calling the method. This can change when the thread is started and stopped, and will be invalid if the thread's not actually running.

See also: getCurrentThreadId

◆ getThreadName()

const String& juce::Thread::getThreadName ( ) const

inlinenoexceptinherited

Returns the name of the thread.

This is the name that gets set in the constructor.

References JUCE_CALLTYPE.

◆ getTimerInterval()

int juce::Timer::getTimerInterval ( ) const

inlinenoexceptinherited

Returns the timer's interval.

Returns: the timer's interval in milliseconds if it's running, or 0 if it's not.

References JUCE_CALLTYPE.

Referenced by juce::CarbonViewWrapperComponent::setOurSizeToEmbeddedViewSize().

◆ initialiseJUCE()

static void juce::Thread::initialiseJUCE	(	void *	jniEnv,
		void *	jContext
	)

staticinherited

Initialises the JUCE subsystem for projects not created by the Projucer.

On Android, JUCE needs to be initialised once before it is used. The Projucer will automatically generate the necessary java code to do this. However, if you are using JUCE without the Projucer or are creating a library made with JUCE intended for use in non-JUCE apks, then you must call this method manually once on apk startup.

You can call this method from C++ or directly from java by calling the following java method:

com.roli.juce.Java.initialiseJUCE (myContext);

Note that the above java method is only available in Android Studio projects created by the Projucer. If you need to call this from another type of project then you need to add the following java file to your project:

package com.roli.juce;
public class Java
{
    static { System.loadLibrary ("juce_jni"); }
    public native static void initialiseJUCE (Context context);
}

Parameters

jniEnv	this is a pointer to JNI's JNIEnv variable. Any callback from Java into C++ will have this passed in as it's first parameter.
jContext	this is a jobject referring to your app/service/receiver/ provider's Context. JUCE needs this for many of it's internal functions.

◆ isThreadRunning()

bool juce::Thread::isThreadRunning ( ) const

inherited

Returns true if the thread is currently active.

◆ isTimerRunning()

bool juce::Timer::isTimerRunning ( ) const

inlinenoexceptinherited

Returns true if the timer is currently running.

◆ launch()

static void juce::Thread::launch ( std::function< void()> functionToRun )

staticinherited

Invokes a lambda or function on its own thread.

This will spin up a Thread object which calls the function and then exits. Bear in mind that starting and stopping a thread can be a fairly heavyweight operation, so you might prefer to use a ThreadPool if you're kicking off a lot of short background tasks.

Also note that using an anonymous thread makes it very difficult to interrupt the function when you need to stop it, e.g. when your app quits. So it's up to you to deal with situations where the function may fail to stop in time.

◆ launchThread()

void juce::ThreadWithProgressWindow::launchThread ( int priority = 5 )

Starts the thread and returns.

This will start the thread and make the dialog box appear in a modal state. When the thread finishes normally, or the cancel button is pressed, the window will be hidden and the threadComplete() method will be called.

Parameters

priority the priority to use when starting the thread - see Thread::startThread() for values

◆ notify()

void juce::Thread::notify ( ) const

inherited

Wakes up the thread.

If the thread has called the wait() method, this will wake it up.

See also: wait

◆ removeListener()

void juce::Thread::removeListener ( Listener * )

inherited

Removes a listener added with addListener.

◆ run()

virtual void juce::Thread::run ( )

pure virtualinherited

Must be implemented to perform the thread's actual code.

Remember that the thread must regularly check the threadShouldExit() method whilst running, and if this returns true it should return from the run() method as soon as possible to avoid being forcibly killed.

See also: threadShouldExit, startThread

Implemented in juce::ThreadedAnalyticsDestination::EventDispatcher, juce::MidiOutput, juce::NetworkServiceDiscovery::AvailableServiceList, juce::InterprocessConnectionServer, and juce::NetworkServiceDiscovery::Advertiser.

◆ runThread()

bool juce::ThreadWithProgressWindow::runThread ( int priority = 5 )

Starts the thread and waits for it to finish.

This will start the thread, make the dialog box appear, and wait until either the thread finishes normally, or until the cancel button is pressed.

Before returning, the dialog box will be hidden.

Parameters

priority the priority to use when starting the thread - see Thread::startThread() for values

Returns: true if the thread finished normally; false if the user pressed cancel

◆ setAffinityMask()

void juce::Thread::setAffinityMask ( uint32 affinityMask )

inherited

Sets the affinity mask for the thread.

This will only have an effect next time the thread is started - i.e. if the thread is already running when called, it'll have no effect.

See also: setCurrentThreadAffinityMask

◆ setCurrentThreadAffinityMask()

void juce::Thread::setCurrentThreadAffinityMask ( uint32 affinityMask )

staticinherited

Changes the affinity mask for the caller thread.

This will change the affinity mask for the thread that calls this static method.

See also: setAffinityMask

References juce::ignoreUnused(), and jassertfalse.

◆ setCurrentThreadName()

void juce::Thread::setCurrentThreadName ( const String & newThreadName )

staticinherited

Changes the name of the caller thread.

Different OSes may place different length or content limits on this name.

References JUCE_AUTORELEASEPOOL, juce::juceStringToNS(), juce::BlocksProtocol::setName, and juce::String::toRawUTF8().

◆ setCurrentThreadPriority()

static bool juce::Thread::setCurrentThreadPriority ( int priority )

staticinherited

Changes the priority of the caller thread.

Similar to setPriority(), but this static method acts on the caller thread. May return false if for some reason the priority can't be changed.

See also: setPriority

◆ setPriority()

bool juce::Thread::setPriority ( int priority )

inherited

Changes the thread's priority.

May return false if for some reason the priority can't be changed.

Parameters

priority the new priority, in the range 0 (lowest) to 10 (highest). A priority of 5 is normal.

See also: realtimeAudioPriority

◆ setProgress()

void juce::ThreadWithProgressWindow::setProgress ( double newProgress )

The thread should call this periodically to update the position of the progress bar.

Parameters

newProgress the progress, from 0.0 to 1.0

See also: setStatusMessage

◆ setStatusMessage()

void juce::ThreadWithProgressWindow::setStatusMessage ( const String & newStatusMessage )

The thread can call this to change the message that's displayed in the dialog box.

◆ signalThreadShouldExit()

void juce::Thread::signalThreadShouldExit ( )

inherited

Sets a flag to tell the thread it should stop.

Calling this means that the threadShouldExit() method will then return true. The thread should be regularly checking this to see whether it should exit.

If your thread makes use of wait(), you might want to call notify() after calling this method, to interrupt any waits that might be in progress, and allow it to reach a point where it can exit.

See also: threadShouldExit, waitForThreadToExit

◆ sleep()

void juce::Thread::sleep ( int milliseconds )

staticinherited

Suspends the execution of the current thread until the specified timeout period has elapsed (note that this may not be exact).

The timeout period must not be negative and whilst sleeping the thread cannot be woken up so it should only be used for short periods of time and when other methods such as using a WaitableEvent or CriticalSection are not possible.

Referenced by juce::OpenGLContext::NativeContext::initialiseOnRenderThread(), and juce::OpenGLContext::NativeContext::swapBuffers().

◆ startThread() [1/2]

void juce::Thread::startThread ( )

inherited

Starts the thread running.

This will cause the thread's run() method to be called by a new thread. If this thread is already running, startThread() won't do anything.

See also: stopThread

◆ startThread() [2/2]

void juce::Thread::startThread ( int priority )

inherited

Starts the thread with a given priority.

Launches the thread with a given priority, where 0 = lowest, 10 = highest. If the thread is already running, its priority will be changed.

See also: startThread, setPriority, realtimeAudioPriority

◆ startTimer()

void juce::Timer::startTimer ( int intervalInMilliseconds )

noexceptinherited

Starts the timer and sets the length of interval required.

If the timer is already started, this will reset it, so the time between calling this method and the next timer callback will not be less than the interval length passed in.

Parameters

intervalInMilliseconds the interval to use (any value less than 1 will be rounded up to 1)

Referenced by juce::StandalonePluginHolder::init(), and juce::CarbonViewWrapperComponent::setOurSizeToEmbeddedViewSize().

◆ startTimerHz()

void juce::Timer::startTimerHz ( int timerFrequencyHz )

noexceptinherited

Starts the timer with an interval specified in Hertz.

This is effectively the same as calling startTimer (1000 / timerFrequencyHz).

Referenced by juce::AnimatedPosition< Behaviour >::endDrag(), juce::AnimatedPosition< Behaviour >::nudge(), and juce::AnimatedPosition< Behaviour >::timerCallback().

◆ stopThread()

bool juce::Thread::stopThread ( int timeOutMilliseconds )

inherited

Attempts to stop the thread running.

This method will cause the threadShouldExit() method to return true and call notify() in case the thread is currently waiting.

Hopefully the thread will then respond to this by exiting cleanly, and the stopThread method will wait for a given time-period for this to happen.

If the thread is stuck and fails to respond after the timeout, it gets forcibly killed, which is a very bad thing to happen, as it could still be holding locks, etc. which are needed by other parts of your program.

Parameters

timeOutMilliseconds The number of milliseconds to wait for the thread to finish before killing it by force. A negative value in here will wait forever.

Returns: true if the thread was cleanly stopped before the timeout, or false if it had to be killed by force.

See also: signalThreadShouldExit, threadShouldExit, waitForThreadToExit, isThreadRunning

◆ stopTimer()

void juce::Timer::stopTimer ( )

noexceptinherited

Stops the timer.

No more timer callbacks will be triggered after this method returns.

Note that if you call this from a background thread while the message-thread is already in the middle of your callback, then this method will cancel any future timer callbacks, but it will return without waiting for the current one to finish. The current callback will continue, possibly still running some of your timer code after this method has returned.

Referenced by juce::AnimatedPosition< Behaviour >::beginDrag(), juce::CarbonViewWrapperComponent::setOurSizeToEmbeddedViewSize(), juce::AnimatedPosition< Behaviour >::setPosition(), juce::AnimatedPosition< Behaviour >::timerCallback(), and juce::StandalonePluginHolder::~StandalonePluginHolder().

◆ threadComplete()

virtual void juce::ThreadWithProgressWindow::threadComplete ( bool userPressedCancel )

virtual

This method is called (on the message thread) when the operation has finished.

You may choose to use this callback to delete the ThreadWithProgressWindow object.

◆ threadShouldExit()

bool juce::Thread::threadShouldExit ( ) const

inherited

Checks whether the thread has been told to stop running.

Threads need to check this regularly, and if it returns true, they should return from their run() method at the first possible opportunity.

See also: signalThreadShouldExit, currentThreadShouldExit

◆ timerCallback()

void juce::ThreadWithProgressWindow::timerCallback ( )

overrideprivatevirtual

The user-defined callback routine that actually gets called periodically.

It's perfectly ok to call startTimer() or stopTimer() from within this callback to change the subsequent intervals.

Implements juce::Timer.

◆ wait()

bool juce::Thread::wait ( int timeOutMilliseconds ) const

inherited

Suspends the execution of this thread until either the specified timeout period has elapsed, or another thread calls the notify() method to wake it up.

A negative timeout value means that the method will wait indefinitely.

Returns: true if the event has been signalled, false if the timeout expires.

◆ waitForThreadToExit()

bool juce::Thread::waitForThreadToExit ( int timeOutMilliseconds ) const

inherited

Waits for the thread to stop.

This will wait until isThreadRunning() is false or until a timeout expires.

Parameters

timeOutMilliseconds the time to wait, in milliseconds. If this value is less than zero, it will wait forever.

Returns: true if the thread exits, or false if the timeout expires first.

◆ yield()

void juce::Thread::yield ( )

staticinherited

Yields the current thread's CPU time-slot and allows a new thread to run.

If there are no other threads of equal or higher priority currently running then this will return immediately and the current thread will continue to run.

Member Data Documentation

◆ alertWindow

std::unique_ptr<AlertWindow> juce::ThreadWithProgressWindow::alertWindow

private

◆ message

String juce::ThreadWithProgressWindow::message

private

◆ messageLock

CriticalSection juce::ThreadWithProgressWindow::messageLock

private

◆ progress

double juce::ThreadWithProgressWindow::progress

private

◆ timeOutMsWhenCancelling

const int juce::ThreadWithProgressWindow::timeOutMsWhenCancelling

private

◆ wasCancelledByUser

bool juce::ThreadWithProgressWindow::wasCancelledByUser

private

The documentation for this class was generated from the following file:

juce_ThreadWithProgressWindow.h

Public Types

Public Member Functions

Static Public Member Functions

Private Member Functions

Static Private Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

◆ ThreadID

Member Enumeration Documentation

◆ anonymous enum

Constructor & Destructor Documentation

◆ ThreadWithProgressWindow()

◆ ~ThreadWithProgressWindow()

Member Function Documentation

◆ addListener()

◆ callAfterDelay()

◆ callPendingTimersSynchronously()

◆ currentThreadShouldExit()

◆ getAlertWindow()

◆ getCurrentThread()

◆ getCurrentThreadId()

◆ getThreadId()

◆ getThreadName()

◆ getTimerInterval()

◆ initialiseJUCE()

◆ isThreadRunning()

◆ isTimerRunning()

◆ launch()

◆ launchThread()

◆ notify()

◆ removeListener()

◆ run()

◆ runThread()

◆ setAffinityMask()

◆ setCurrentThreadAffinityMask()

◆ setCurrentThreadName()

◆ setCurrentThreadPriority()

◆ setPriority()

◆ setProgress()

◆ setStatusMessage()

◆ signalThreadShouldExit()

◆ sleep()

◆ startThread() [1/2]

◆ startThread() [2/2]

◆ startTimer()

◆ startTimerHz()

◆ stopThread()

◆ stopTimer()

◆ threadComplete()

◆ threadShouldExit()

◆ timerCallback()

◆ wait()

◆ waitForThreadToExit()

◆ yield()

Member Data Documentation

◆ alertWindow

◆ message

◆ messageLock

◆ progress

◆ timeOutMsWhenCancelling

◆ wasCancelledByUser