Prevent show/back operations while busy

Fixes #22

CHANGELOG.md

@@ -0,0 +1,56 @@
+## Monarch 2.7.0 [britzl released 2018-06-04]
+NEW: Added monarch.top([offset]) and monarch.bottom([offset]) to get screen id of top and bottom screens (w. optional offset)  
+NEW: Transition messages now contain `next_screen` or `previous_screen`
+
+## Monarch 2.6.1 [britzl released 2018-06-04]
+FIX: Check if screen has already been preloaded before trying to preload it again (the callback will still be invoked).
+
+## Monarch 2.6.0 [britzl released 2018-06-03]
+NEW: monarch.preload() to load but not show a screen. Useful for content heavy screens that you wish to show without delay.
+
+## Monarch 2.5.0 [britzl released 2018-06-01]
+NEW: Transitions will send a `transition_done` message to the creator of the transition to notify that the transition has finished. The `message` will contain which transition that was finished.
+
+## Monarch 2.4.0 [britzl released 2018-05-26]
+NEW: Screen transitions are remembered so that they can be replayed when the screen layout changes.
+
+## Monarch 2.3.0 [britzl released 2018-03-24]
+CHANGE: The functions in monarch.lua that previously only accepted a hash as screen id now also accepts strings (and does the conversion internally)
+
+## Monarch 2.2.0 [britzl released 2018-03-19]
+NEW: Transitions now handle layout changes (via `layout_changed` message)  
+NEW: Transitions can now be notified of changes in window size using transition.window_resize(width, height)
+
+## Monarch 2.1 [britzl released 2017-12-27]
+NEW: Added Popup on Popup flag that allows a popup to be shown on top of another popup
+
+## Monarch 2.0 [britzl released 2017-12-08]
+BREAKING CHANGE: If you are using custom screen transitions (ie your own transition functions) you need to make a change to the function. The previous function signature was ```(node, to, easing, duration, delay, url)``` where ```url``` was the URL  to where the ```transition_done``` message was supposed to be posted. The new function signature for a transition function is: ```(node, to, easing, duration, delay, cb)``` where ```cb``` is a function that should be invoked when the transition is completed.  
+  
+FIX: Fixed issues related to screen transitions.  
+FIX: Code cleanup to reduce code duplication.  
+FIX: Improved documentation regarding transitions.
+
+## Monarch 1.4 [britzl released 2017-12-06]
+FIX: Several bugfixes for specific corner cases.
+
+## Monarch 1.3 [britzl released 2017-12-01]
+FIX: monarch.back(data, cb) set the data on the previous screen not the new current screen.  
+NEW: monarch.is_top(id)  
+NEW: monarch.get_stack()  
+NEW: monarch.in_stack(id)
+
+## Monarch 1.2 [britzl released 2017-11-28]
+NEW: Message id constants exposed from the Monarch module  
+NEW: Focus lost/gained contains id of next/previous screen
+
+## Monarch 1.1 [britzl released 2017-11-22]
+FIX: Bugfixes for transitions and state under certain circumstances  
+NEW: Added 'reload' option to show() command.
+
+## Monarch 1.0 [britzl released 2017-09-28]
+First public stable release
+
+## Monarch 0.9 [britzl released 2017-09-17]
+
+

README.md

@@ -6,6 +6,7 @@
 # Monarch
 Monarch is a screen manager for the [Defold](https://www.defold.com) game engine.
 
+
 # Installation
 You can use Monarch in your own project by adding this project as a [Defold library dependency](http://www.defold.com/manuals/libraries/). Open your game.project file and in the dependencies field under project add:
 
@@ -13,9 +14,11 @@ https://github.com/britzl/monarch/archive/master.zip
 
 Or point to the ZIP file of a [specific release](https://github.com/britzl/monarch/releases).
 
+
 # Usage
 Using Monarch requires that screens are created in a certain way. Once you have one or more screens created you can start navigating between the screens.
 
+
 ## Creating screens
 Monarch screens are created in individual collections and loaded through collection proxies. The recommended setup is to create one game object per screen and per game object attach a collection proxy component and an instance of the ```screen.script``` provided by Monarch. The ```screen.script``` will take care of the setup of the screen. All you need to do is to make sure that the script properties on the ```screen.script``` are correct:
 
@@ -28,6 +31,7 @@ Monarch screens are created in individual collections and loaded through collect
 
 ![](docs/setup.png)
 
+
 ## Navigating between screens
 The navigation in Monarch is based around a stack of screens. When a screen is shown it is pushed to the top of the stack. When going back to a previous screen the topmost screen on the stack is removed. Example:
 
@@ -123,6 +127,7 @@ When a transition is completed it is up to the developer to send a ```transition
 Monarch comes with a system for setting up transitions easily in a gui_script using the ```monarch.transitions.gui``` module. Example:
 
 	local transitions = require "monarch.transitions.gui"
+	local monarch = require "monarch.monarch"
 
 	function init(self)
 		-- create transitions for the node 'root'
@@ -137,6 +142,10 @@ Monarch comes with a system for setting up transitions easily in a gui_script us
 
 	function on_message(self, message_id, message, sender)
 		self.transition.handle(message_id, message, sender)
+		-- you can also check when a transition has completed:
+		if message_id == monarch.TRANSITION.DONE and message.transition == monarch.TRANSITION.SHOW_IN then
+			print("Show in done!")
+		end
 	end
 
 ### Predefined transitions
@@ -182,6 +191,26 @@ When using dynamic screen orientation together with gui layouts or using transit
 	end
 
 
+### Screen stack info and transitions
+The transition message sent to the Transition Url specified in the screen configuration contains additional information about the transition. For the ```transition_show_in``` and ```transition_back_out``` messages the message contains the previous screen id:
+
+	function on_message(self, message_id, message, sender)
+		if message_id == hash("transition_show_in") or message_id == hash("transition_back_out") then
+			print(message.previous_screen)
+		end
+	end
+
+For the ```transition_show_out``` and ```transition_back_in``` messages the message contains the next screen id:
+
+	function on_message(self, message_id, message, sender)
+		if message_id == hash("transition_show_out") or message_id == hash("transition_back_in") then
+			print(message.next_screen)
+		end
+	end
+
+This information can be used to create dynamic transitions where the direction of the transition depends on the previous/next screen
+
+
 ## Screen focus gain/loss
 Monarch will send focus gain and focus loss messages if a Focus Url was provided when the screen was created. The focus gained message will contain the id of the previous screen and the focus loss message will contain the id of the next screen. Example:
 
@@ -195,9 +224,11 @@ Monarch will send focus gain and focus loss messages if a Focus Url was provided
 		end
 	end
 
+
 ## Callbacks
 Both the ```monarch.show()``` and ```monarch.back()``` functions take an optional callback function that will be invoked when the ```transition_show_in``` (or the ```transition_back_in``` in the case of a ```monarch.back()``` call) transition is completed. The transition is considered completed when a ```transition_done``` message has been received (see section on [transitions](#transitions) above).
 
+
 ## Monarch API
 
 ### monarch.show(screen_id, [options], [data], [callback])
@@ -214,6 +245,10 @@ The options table can contain the following fields:
 * ```clear``` (boolean) - If the clear flag is set Monarch will search the stack for the screen that is to be shown. If the screen already exists in the stack and the clear flag is set Monarch will remove all screens between the current top and the screen in question.
 * ```reload``` (boolean) - If the reload flag is set Monarch will reload the collection proxy if it's already loaded (this can happen if the previous screen was a popup).
 
+**RETURN**
+* ```success``` (boolean) - True if the process of showing the screen was started successfully. False if already busy showing/hiding a screen.
+
+
 ### monarch.back([data], [callback])
 Go back to a previous Monarch screen
 
@@ -221,6 +256,37 @@ Go back to a previous Monarch screen
 * ```data``` (table) - Optional data to associate with the screen you are going back to.  Retrieve using ```monarch.data()```.
 * ```callback``` (function) - Optional function to call when the previous screen is visible.
 
+**RETURN**
+* ```success``` (boolean) - True if the process of going back to a previous screen was started successfully. False if already busy showing/hiding a screen.
+
+
+### monarch.preload(screen_id, [callback])
+Preload a Monarch screen. This will load but not enable the screen. This is useful for content heavy screens that you wish to be able to show without having to wait for it load.
+
+**PARAMETERS**
+* ```screen_id``` (hash) - Id of the screen to preload.
+* ```callback``` (function) - Optional function to call when the new screen is preloaded.
+
+
+### monarch.top([offset])
+Get the id of the screen at the top of the stack.
+
+**PARAMETERS**
+* ```offset``` (number) - Optional offset from the top of the stack, ie -1 to get the previous screen
+
+**RETURN**
+* ```screen_id``` (hash) - Id of the requested screen
+
+
+### monarch.bottom([offset])
+Get the id of the screen at the bottom of the stack.
+
+**PARAMETERS**
+* ```offset``` (number) - Optional offset from the bottom of the stack
+
+**RETURN**
+* ```screen_id``` (hash) - Id of the requested screen
+
 
 ### monarch.data(screen_id)
 Get the data associated with a screen (from a call to ```monarch.show()``` or ```monarch.back()```).
@@ -240,3 +306,7 @@ Check if a Monarch screen exists.
 
 **RETURN**
 * ```exists``` (boolean) - True if the screen exists.
+
+
+### monarch.debug()
+Enable verbose logging of the internals of Monarch.

monarch/monarch.lua

@@ -1,9 +1,5 @@
 local M = {}
 
-local screens = {}
-
-local stack = {}
-
 local CONTEXT = hash("monarch_context")
 local PROXY_LOADED = hash("proxy_loaded")
 local PROXY_UNLOADED = hash("proxy_unloaded")
@@ -25,6 +21,15 @@ M.FOCUS = {}
 M.FOCUS.GAINED = hash("monarch_focus_gained")
 M.FOCUS.LOST = hash("monarch_focus_lost")
 
+-- all registered screens
+local screens = {}
+
+-- the current stack of screens
+local stack = {}
+
+-- true while busy showing/hiding something
+local busy = false
+
 
 local function log(...) end
 
@@ -171,10 +176,10 @@ local function async_load(screen)
 	screen.wait_for = nil
 end
 
-local function transition(screen, message_id)
+local function transition(screen, message_id, message)
 	log("transition()", screen.id)
 	screen.wait_for = M.TRANSITION.DONE
-	msg.post(screen.transition_url, message_id)
+	msg.post(screen.transition_url, message_id, message)
 	coroutine.yield()
 	screen.wait_for = nil
 end
@@ -225,6 +230,7 @@ local function show_out(screen, next_screen, cb)
 	log("show_out()", screen.id)
 	local co
 	co = coroutine.create(function()
+		busy = true
 		screen.co = co
 		change_context(screen)
 		release_input(screen)
@@ -234,10 +240,11 @@ local function show_out(screen, next_screen, cb)
 		local next_is_popup = next_screen and not next_screen.popup
 		local current_is_popup = screen.popup
 		if (next_is_popup and not current_is_popup) or (current_is_popup) then
-			transition(screen, M.TRANSITION.SHOW_OUT)
+			transition(screen, M.TRANSITION.SHOW_OUT, { next_screen = next_screen.id })
 			unload(screen)
 		end
 		screen.co = nil
+		busy = false
 		if cb then cb() end
 	end)
 	coroutine.resume(co)
@@ -247,23 +254,32 @@ local function show_in(screen, previous_screen, reload, cb)
 	log("show_in()", screen.id)
 	local co
 	co = coroutine.create(function()
+		busy = true
 		screen.co = co
 		change_context(screen)
 		if reload and screen.loaded then
 			log("show_in() reloading", screen.id)
 			unload(screen)
 		end
+		-- if the screen has been preloaded we need to enable it
+		if screen.preloaded then
+			log("show_in() screen was preloaded", screen.id)
+			msg.post(screen.proxy, ENABLE)
+			screen.loaded = true
+			screen.preloaded = false
 		-- the screen could be loaded if the previous screen was a popup
 		-- and the popup asked to show this screen again
 		-- in that case we shouldn't attempt to load it again
-		if not screen.loaded then
+		elseif not screen.loaded then
+			log("show_in() loading screen", screen.id)
 			async_load(screen)
 		end
 		stack[#stack + 1] = screen
-		transition(screen, M.TRANSITION.SHOW_IN)
+		transition(screen, M.TRANSITION.SHOW_IN, { previous_screen = previous_screen and previous_screen.id })
 		acquire_input(screen)
 		focus_gained(screen, previous_screen)
 		screen.co = nil
+		busy = false
 		if cb then cb() end
 	end)
 	coroutine.resume(co)
@@ -273,17 +289,25 @@ local function back_in(screen, previous_screen, cb)
 	log("back_in()", screen.id)
 	local co
 	co = coroutine.create(function()
+		busy = true
 		screen.co = co
 		change_context(screen)
-		if not screen.loaded then
+		if screen.preloaded then
+			log("back_in() screen was preloaded", screen.id)
+			msg.post(screen.proxy, ENABLE)
+			screen.preloaded = false
+			screen.loaded = true
+		elseif not screen.loaded then
+			log("back_in() loading screen", screen.id)
 			async_load(screen)
 		end
 		if previous_screen and not previous_screen.popup then
-			transition(screen, M.TRANSITION.BACK_IN)
+			transition(screen, M.TRANSITION.BACK_IN, { previous_screen = previous_screen.id })
 		end
 		acquire_input(screen)
 		focus_gained(screen, previous_screen)
 		screen.co = nil
+		busy = false
 		if cb then cb() end
 	end)
 	coroutine.resume(co)
@@ -293,13 +317,15 @@ local function back_out(screen, next_screen, cb)
 	log("back_out()", screen.id)
 	local co
 	co = coroutine.create(function()
+		busy = true
 		screen.co = co
 		change_context(screen)
 		release_input(screen)
 		focus_lost(screen, next_screen)
-		transition(screen, M.TRANSITION.BACK_OUT)
+		transition(screen, M.TRANSITION.BACK_OUT, { next_screen = next_screen and next_screen.id })
 		unload(screen)
 		screen.co = nil
+		busy = false
 		if cb then cb() end
 	end)
 	coroutine.resume(co)
@@ -330,11 +356,16 @@ end
 -- @param options (table) - Table with options when showing the screen (can be nil). Valid values:
 -- 		* clear - Set to true if the stack should be cleared down to an existing instance of the screen
 -- 		* reload - Set to true if screen should be reloaded if it already exists in the stack and is loaded.
---				  This would be the case if doing a show() from a popup on the screen just below the popup.
+--				   This would be the case if doing a show() from a popup on the screen just below the popup.
 -- @param data (*) - Optional data to set on the screen. Can be retrieved by the data() function
 -- @param cb (function) - Optional callback to invoke when screen is shown
+-- @return success True if screen is successfully shown, false if busy performing another operation
 function M.show(id, options, data, cb)
 	assert(id, "You must provide a screen id")
+	if busy then
+		return false
+	end
+	
 	id = tohash(id)
 	assert(screens[id], ("There is no screen registered with id %s"):format(tostring(id)))
 
@@ -379,13 +410,20 @@ function M.show(id, options, data, cb)
 
 	-- show screen
 	show_in(screen, top, options and options.reload, cb)
+
+	return true
 end
 
 
 -- Go back to the previous screen in the stack
 -- @param data (*) - Optional data to set for the previous screen
 -- @param cb (function) - Optional callback to invoke when the previous screen is visible again
+-- @return true if successfully going back, false if busy performing another operation
 function M.back(data, cb)
+	if busy then
+		return false
+	end
+
 	local screen = table.remove(stack)
 	if screen then
 		log("back()", screen.id)
@@ -411,6 +449,35 @@ function M.back(data, cb)
 	elseif cb then
 		cb()
 	end
+	return true
+end
+
+--- Preload a screen. This will load but not enable and show a screen. Useful for "heavier" screens
+-- that you wish to show without any delay.
+-- @param id (string|hash) - Id of the screen to preload
+-- @param cb (function) - Optional callback to invoke when screen is loaded
+function M.preload(id, cb)
+	assert(id, "You must provide a screen id")
+	id = tohash(id)
+	assert(screens[id], ("There is no screen registered with id %s"):format(tostring(id)))
+
+	local screen = screens[id]
+	if screen.preloaded then
+		if cb then cb() end
+		return
+	end
+	local co
+	co = coroutine.create(function()
+		screen.co = co
+		change_context(screen)
+		screen.wait_for = PROXY_LOADED
+		msg.post(screen.proxy, ASYNC_LOAD)
+		coroutine.yield()
+		screen.preloaded = true
+		screen.wait_for = nil
+		if cb then cb() end
+	end)
+	coroutine.resume(co)
 end
 
 
@@ -454,6 +521,25 @@ function M.get_stack()
 	return s
 end
 
+
+--- Get the screen on top of the stack
+-- @param offset Optional offset from the top of the stack, (eg -1 for the previous screen)
+-- @return Id of the requested screen
+function M.top(offset)
+	local screen = stack[#stack + (offset or 0)]
+	return screen and screen.id
+end
+
+
+--- Get the screen at the bottom of the stack
+-- @param offset Optional offset from the bottom of the stack
+-- @return Id of the requested screen
+function M.bottom(offset)
+	local screen = stack[1 + (offset or 0)]
+	return screen and screen.id
+end
+
+
 function M.dump_stack()
 	local s = ""
 	for i, screen in ipairs(stack) do

monarch/transitions/gui.lua

@@ -96,6 +96,8 @@ function M.create(node)
 
 	local transitions = {}
 
+	local current_transition = nil
+	
 	local initial_data = {}
 	initial_data.pos = gui.get_position(node)
 	initial_data.scale = gui.get_scale(node)
@@ -108,19 +110,28 @@ function M.create(node)
 			delay = delay,
 			in_progress = false,
 			urls = {},
+			id = nil
 		}
 	end
 
-	local function start_transition(transition, url)
+	local function finish_transition(transition)
+		transition.in_progress = false
+		local message = { transition = transition.id }
+		while #transition.urls > 0 do
+			local url = table.remove(transition.urls)
+			msg.post(url, monarch.TRANSITION.DONE, message)
+		end
+	end
+
+	local function start_transition(transition, transition_id, url)
 		table.insert(transition.urls, url)
 		if not transition.in_progress then
+			table.insert(transition.urls, msg.url())
 			transition.in_progress = true
+			transition.id = transition_id
+			current_transition = transition
 			transition.fn(node, initial_data, transition.easing, transition.duration, transition.delay or 0, function()
-				transition.in_progress = false
+				finish_transition(transition)
-				while #transition.urls > 0 do
-					local url = table.remove(transition.urls)
-					msg.post(url, monarch.TRANSITION.DONE)
-				end
 			end)
 		end
 	end
@@ -129,10 +140,19 @@ function M.create(node)
 	function instance.handle(message_id, message, sender)
 		if message_id == LAYOUT_CHANGED then
 			initial_data.pos = gui.get_position(node)
+			-- replay the current transition if the layout changes
+			-- this will ensure that things are still hidden if they
+			-- were transitioned out
+			if current_transition then
+				current_transition.fn(node, initial_data, current_transition.easing, 0, 0)
+				if current_transition.in_progress then
+					finish_transition(current_transition)
+				end
+			end
 		else
 			local transition = transitions[message_id]
 			if transition then
-				start_transition(transition, sender)
+				start_transition(transition, message_id, sender)
 			end
 		end
 	end

test/test_monarch.lua

@@ -1,6 +1,7 @@
 local cowait = require "test.cowait"
 local monarch = require "monarch.monarch"
 
+local SCREEN1_STR = hash("screen1")
 local SCREEN1 = hash(SCREEN1_STR)
 local SCREEN2 = hash("screen2")
 local POPUP1 = hash("popup1")
@@ -147,6 +148,23 @@ return function()
 		end)
 
 		
+		it("should prevent further operations while hiding/showing a screen", function()
+			assert(monarch.show(SCREEN1) == true)
+			assert(monarch.show(SCREEN2) == false)
+			assert(wait_until_shown(SCREEN1), "Screen1 was never shown")
+			assert_stack({ SCREEN1 })
+
+			assert(monarch.show(SCREEN2) == true)
+			assert(wait_until_shown(SCREEN2), "Screen1 was never shown")
+			assert_stack({ SCREEN1, SCREEN2 })
+
+			assert(monarch.back() == true)
+			assert(monarch.back() == false)
+			assert(wait_until_shown(SCREEN1), "Screen1 was never shown")
+			assert_stack({ SCREEN1 })
+		end)
+		
+		
 		it("should close any open popups when showing a popup without the Popup On Popup flag", function()
 			monarch.show(SCREEN1)
 			assert(wait_until_shown(SCREEN1), "Screen1 was never shown")
@@ -174,6 +192,31 @@ return function()
 			assert(wait_until_shown(SCREEN2), "Popup2 was never shown")
 			assert_stack({ SCREEN1, SCREEN2 })
 		end)
-										
+
+
+		it("should be able to get the id of the screen at the top and bottom of the stack", function()
+			assert(monarch.top() == nil)
+			assert(monarch.bottom() == nil)
+			assert(monarch.top(1) == nil)
+			assert(monarch.bottom(-1) == nil)
+						
+			monarch.show(SCREEN1)
+			assert(wait_until_shown(SCREEN1), "Screen1 was never shown")
+			assert(monarch.top() == SCREEN1)
+			assert(monarch.top(0) == SCREEN1)
+			assert(monarch.top(1) == nil)
+			assert(monarch.bottom() == SCREEN1)
+			assert(monarch.bottom(0) == SCREEN1)
+			assert(monarch.bottom(-1) == nil)
+									
+			monarch.show(SCREEN2)
+			assert(wait_until_hidden(SCREEN1), "Screen1 was never hidden")
+			assert(wait_until_shown(SCREEN2), "Screen2 was never shown")
+			assert_stack({ SCREEN1, SCREEN2 })
+			assert(monarch.top(0) == SCREEN2)
+			assert(monarch.top(-1) == SCREEN1)
+			assert(monarch.bottom(0) == SCREEN1)
+			assert(monarch.bottom(1) == SCREEN2)
+		end)
 	end)
 end