Allow monarch.post() to loaded screens

Fixes #98

README_API.md

@@ -212,12 +212,14 @@ IMPORTANT! You must call `monarch.on_message(message_id, message, sender)` from
 * `fn` (function) - The function to call screen focus changes
 
 
-## monarch.on_post(screen_id, fn)
+## monarch.on_post(screen_id, fn_or_url)
-Set a function to be called when `msg.post()` is called on a specific screen. IMPORTANT! You must call `monarch.on_message(message_id, message, sender)` from the same script as this function was called.
+Set either a function to be called when `msg.post()` is called on a specific screen or a URL where the message is sent.
+
+IMPORTANT! If you provide a function you must also make sure to call `monarch.on_message(message_id, message, sender)` from the same script as this function was called.
 
 **PARAMETERS**
 * `screen_id` (string|hash) - Id of the screen
-* `fn` (function) - The function to call when the screen receives a message using `msg.post`
+* `fn_or_url` (function) - The function to call or URL to send message to
 
 
 ## monarch.debug()

monarch/monarch.lua

@@ -228,6 +228,17 @@ function M.is_visible(id)
 end
 
 
+--- Check if a screen is loaded
+-- @param id (string|hash)
+-- @return true if the screen is loaded
+function M.is_loaded(id)
+	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)))
+	return screens[id].loaded
+end
+
+
 --- Check if a screen is a popup
 -- @param id Screen id
 -- @return true if the screen is a popup
@@ -988,12 +999,12 @@ function M.back(options, data, cb)
 		local screen = table.remove(stack)
 		if screen then
 			log("back()", screen.id)
-			local back_cb = callbacks.track()
 			local top = stack[#stack]
 			-- if we go back to the same screen we need to first hide it
 			-- and wait until it is hidden before we show it again
 			local same_screen = top and top.id == screen.id
 			if same_screen or (options and options.sequential) then
+				local back_cb = callbacks.track()
 				back_out(screen, top, WAIT_FOR_TRANSITION, function()
 					if data then
 						top.data = data
@@ -1178,8 +1189,8 @@ end
 -- @return error (string|nil) Error message if unable to send message
 function M.post(id, message_id, message)
 	assert(id, "You must provide a screen id")
-	if not M.is_visible(id) then
+	if not M.is_loaded(id) then
-		return false, "Unable to post message to screen if it isn't visible"
+		return false, "Unable to post message to screen if it isn't loaded"
 	end
 
 	assert(message_id, "You must provide a message_id")
@@ -1331,20 +1342,30 @@ function M.on_focus_changed(id, fn)
 end
 
 ---
--- Set a function to call when a screen is sent a message using monarch.post()
+-- Set either a function to be called when msg.post() is called on a specific
--- The function will receive (message_id, message, sender)
+-- screen or a URL where the message is sent.
--- IMPORTANT! You must call monarch.on_message() from the same script as
+-- IMPORTANT! If you provide a function you must also make sure to call
--- this function was called
+-- monarch.on_message(message_id, message, sender) from the same script as
+-- this function was called.
 -- @param id Screen id to associate the message listener function with
--- @param fn Message listener function
+-- @param fn_or_url The function to call or URL to send message to
-function M.on_post(id, fn)
+function M.on_post(id, fn_or_url)
 	assert(id, "You must provide a screen id")
-	assert(fn, "You must provide a post receiver function")
 	id = tohash(id)
 	assert(screens[id], ("There is no screen registered with id %s"):format(tostring(id)))
 	local screen = screens[id]
-	screen.receiver_url = msg.url()
+
-	screen.receiver_fn = fn
+	local t = type(fn_or_url)
+	if t == "function" then
+		screen.receiver_fn = fn_or_url
+		screen.receiver_url = msg.url()
+	elseif t == "userdata" or t == "string" then
+		screen.receiver_fn = nil
+		screen.receiver_url = fn_or_url
+	else
+		screen.receiver_fn = nil
+		screen.receiver_url = msg.url()
+	end
 end
 
 local function url_to_key(url)

test/test_monarch.lua

@@ -81,7 +81,7 @@ return function()
 			monarch.when_preloaded(screen_id, done)
 		end)
 	end
-		
+
 	describe("monarch", function()
 		before(function()
 			mock_msg.mock()
@@ -142,12 +142,12 @@ return function()
 			monarch.show(SCREEN1)
 			assert(wait_until_stack({ SCREEN1 }))
 			assert(wait_until_visible(SCREEN1))
-			
+
 			monarch.show(SCREEN2)
 			assert(wait_until_stack({ SCREEN1, SCREEN2 }))
 			assert(wait_until_hidden(SCREEN1))
 			assert(wait_until_visible(SCREEN2))
-			
+
 			monarch.show(POPUP1)
 			assert(wait_until_stack({ SCREEN1, SCREEN2, POPUP1 }))
 			assert(wait_until_hidden(SCREEN1))
@@ -155,6 +155,17 @@ return function()
 			assert(wait_until_visible(POPUP1))
 		end)
 
+		it("should be able to tell if a screen is loaded or not", function()
+			assert(not monarch.is_loaded(SCREEN1))
+			monarch.show(SCREEN1)
+			assert(wait_until_visible(SCREEN1))
+			assert(monarch.is_loaded(SCREEN1))
+			
+			monarch.hide(SCREEN1)
+			assert(wait_until_hidden(SCREEN1))
+			assert(not monarch.is_loaded(SCREEN1))
+		end)
+		
 		it("should be able to show a screen without adding it to the stack", function()
 			monarch.show(BACKGROUND, { no_stack = true })
 			assert(wait_until_visible(BACKGROUND), "Background was never shown")
@@ -415,7 +426,7 @@ return function()
 			assert(mock_msg.messages(URL1)[2].message.screen == SCREEN1)
 			assert(mock_msg.messages(URL2)[2].message_id == monarch.SCREEN_TRANSITION_IN_FINISHED)
 			assert(mock_msg.messages(URL2)[2].message.screen == SCREEN1)
-												
+
 			monarch.remove_listener(URL2)
 			monarch.show(SCREEN2)
 			assert(wait_until_not_busy())
@@ -424,10 +435,10 @@ return function()
 			assert(#mock_msg.messages(URL2) == 2)
 			assert(mock_msg.messages(URL1)[3].message_id == monarch.SCREEN_TRANSITION_IN_STARTED)
 			assert(mock_msg.messages(URL1)[3].message.screen == SCREEN2)
-			assert(mock_msg.messages(URL1)[4].message_id == monarch.SCREEN_TRANSITION_IN_FINISHED)
+			assert(mock_msg.messages(URL1)[4].message_id == monarch.SCREEN_TRANSITION_OUT_STARTED)
-			assert(mock_msg.messages(URL1)[4].message.screen == SCREEN2)
+			assert(mock_msg.messages(URL1)[4].message.screen == SCREEN1)
-			assert(mock_msg.messages(URL1)[5].message_id == monarch.SCREEN_TRANSITION_OUT_STARTED)
+			assert(mock_msg.messages(URL1)[5].message_id == monarch.SCREEN_TRANSITION_IN_FINISHED)
-			assert(mock_msg.messages(URL1)[5].message.screen == SCREEN1)
+			assert(mock_msg.messages(URL1)[5].message.screen == SCREEN2)
 			assert(mock_msg.messages(URL1)[6].message_id == monarch.SCREEN_TRANSITION_OUT_FINISHED)
 			assert(mock_msg.messages(URL1)[6].message.screen == SCREEN1)
 
@@ -438,10 +449,10 @@ return function()
 			assert(#mock_msg.messages(URL2) == 2)
 			assert(mock_msg.messages(URL1)[7].message_id == monarch.SCREEN_TRANSITION_IN_STARTED)
 			assert(mock_msg.messages(URL1)[7].message.screen == SCREEN1)
-			assert(mock_msg.messages(URL1)[8].message_id == monarch.SCREEN_TRANSITION_IN_FINISHED)
+			assert(mock_msg.messages(URL1)[8].message_id == monarch.SCREEN_TRANSITION_OUT_STARTED)
-			assert(mock_msg.messages(URL1)[8].message.screen == SCREEN1)
+			assert(mock_msg.messages(URL1)[8].message.screen == SCREEN2)
-			assert(mock_msg.messages(URL1)[9].message_id == monarch.SCREEN_TRANSITION_OUT_STARTED)
+			assert(mock_msg.messages(URL1)[9].message_id == monarch.SCREEN_TRANSITION_IN_FINISHED)
-			assert(mock_msg.messages(URL1)[9].message.screen == SCREEN2)
+			assert(mock_msg.messages(URL1)[9].message.screen == SCREEN1)
 			assert(mock_msg.messages(URL1)[10].message_id == monarch.SCREEN_TRANSITION_OUT_FINISHED)
 			assert(mock_msg.messages(URL1)[10].message.screen == SCREEN2)
 		end)