ThreadWithProgressWindow Class Reference

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 ThreadWithProgressWindow:

Public Member Functions
	ThreadWithProgressWindow (const String &windowTitle, bool hasProgressBar, bool hasCancelButton, int timeOutMsWhenCancelling=10000, const String &cancelButtonText=String(), Component *componentToCentreAround=nullptr)
	Creates the thread.
	~ThreadWithProgressWindow () override
	Destructor.
bool	runThread (Priority priority=Priority::normal)
	Starts the thread and waits for it to finish.
void	launchThread (Priority priority=Priority::normal)
	Starts the thread and returns.
void	setProgress (double newProgress)
	The thread should call this periodically to update the position of the progress bar.
void	setStatusMessage (const String &newStatusMessage)
	The thread can call this to change the message that's displayed in the dialog box.
AlertWindow *	getAlertWindow () const noexcept
	Returns the AlertWindow that is being used.
virtual void	threadComplete (bool userPressedCancel)
	This method is called (on the message thread) when the operation has finished.
Public Member Functions inherited from Thread
	Thread (const String &threadName, size_t threadStackSize=osDefaultStackSize)
	Creates a thread.
virtual	~Thread ()
	Destructor.
virtual void	run ()=0
	Must be implemented to perform the thread's actual code.
bool	startThread ()
	Attempts to start a new thread with default ('Priority::normal') priority.
bool	startThread (Priority newPriority)
	Attempts to start a new thread with a given priority.
bool	startRealtimeThread (const RealtimeOptions &options)
	Starts the thread with realtime performance characteristics on platforms that support it.
bool	stopThread (int timeOutMilliseconds)
	Attempts to stop the thread running.
bool	isThreadRunning () const
	Returns true if the thread is currently active.
void	signalThreadShouldExit ()
	Sets a flag to tell the thread it should stop.
bool	threadShouldExit () const
	Checks whether the thread has been told to stop running.
bool	waitForThreadToExit (int timeOutMilliseconds) const
	Waits for the thread to stop.
void	addListener (Listener *)
	Add a listener to this thread which will receive a callback when signalThreadShouldExit was called on this thread.
void	removeListener (Listener *)
	Removes a listener added with addListener.
bool	isRealtime () const
	Returns true if this Thread represents a realtime thread.
void	setAffinityMask (uint32 affinityMask)
	Sets the affinity mask for the thread.
bool	wait (double 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.
void	notify () const
	Wakes up the thread.
ThreadID	getThreadId () const noexcept
	Returns the ID of this thread.
const String &	getThreadName () const noexcept
	Returns the name of the thread.

Additional Inherited Members
Public Types inherited from Thread
enum class	Priority {   highest = 2 , high = 1 , normal = 0 , low = -1 ,   background = -2 }
	The different runtime priorities of non-realtime threads. More...
using	ThreadID = void*
	A value type used for thread IDs.
Static Public Member Functions inherited from Thread
static bool	launch (std::function< void()> functionToRun)
	Invokes a lambda or function on its own thread with the default priority.
static bool	launch (Priority priority, std::function< void()> functionToRun)
	Invokes a lambda or function on its own thread with a custom priority.
static bool	currentThreadShouldExit ()
	Checks whether the current thread has been told to stop running.
static void JUCE_CALLTYPE	setCurrentThreadAffinityMask (uint32 affinityMask)
	Changes the affinity mask for the caller thread.
static void JUCE_CALLTYPE	sleep (int milliseconds)
	Suspends the execution of the current thread until the specified timeout period has elapsed (note that this may not be exact).
static void JUCE_CALLTYPE	yield ()
	Yields the current thread's CPU time-slot and allows a new thread to run.
static ThreadID JUCE_CALLTYPE	getCurrentThreadId ()
	Returns an id that identifies the caller thread.
static Thread *JUCE_CALLTYPE	getCurrentThread ()
	Finds the thread object that is currently running.
static void JUCE_CALLTYPE	setCurrentThreadName (const String &newThreadName)
	Changes the name of the caller thread.
static void	initialiseJUCE (void *jniEnv, void *jContext)
	Initialises the JUCE subsystem for projects not created by the Projucer.
Static Public Attributes inherited from Thread
static constexpr size_t	osDefaultStackSize { 0 }
Protected Member Functions inherited from Thread
Priority	getPriority () const
	Returns the current priority of this thread.
bool	setPriority (Priority newPriority)
	Attempts to set the priority for this thread.

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

Constructor & Destructor Documentation

ThreadWithProgressWindow()

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()

ThreadWithProgressWindow::~ThreadWithProgressWindow ( )

override

Destructor.

Member Function Documentation

runThread()

bool ThreadWithProgressWindow::runThread

(

Priority

priority = Priority::normal

)

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::Priority for values

Returns

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

launchThread()

void ThreadWithProgressWindow::launchThread

(

Priority

priority = Priority::normal

)

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::Priority for values

setProgress()

void 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 ThreadWithProgressWindow::setStatusMessage

(

const String &

newStatusMessage

)

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

getAlertWindow()

AlertWindow * ThreadWithProgressWindow::getAlertWindow ( ) const

noexcept

Returns the AlertWindow that is being used.

threadComplete()

virtual void 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.

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

• juce_ThreadWithProgressWindow.h