Merge pull request #13 from CentauriSoldier/master

Added State Change Callback Functions

loveframes/libraries/utils.lua

@@ -5,19 +5,75 @@
 
 return function(loveframes)
 ---------- module start ----------
-
 -- util library
 --local util = {}
 
+local statecallbacks = {};
+
 --[[---------------------------------------------------------
 	- func: SetState(name)
 	- desc: sets the current state
 --]]---------------------------------------------------------
 function loveframes.SetState(name)
 
+	if (loveframes.state ~= name) then
+
+		--fire the closing function of the soon-to-be-closed state
+		if (type(statecallbacks[loveframes.state]) == "table" and
+			type(statecallbacks[loveframes.state].onclose) == "function") then
+			--callback must accept the name of the current state and soon-to-be-opened state as args
+			statecallbacks[loveframes.state].onclose(loveframes.state, name);
+		end
+
+		local oldstate = loveframes.state;
 		loveframes.state = name
 		loveframes.base.state = name
 
+		--fire the opening function of the newly-opened state
+		if (type(statecallbacks[loveframes.state]) == "table" and
+			type(statecallbacks[loveframes.state].onopen) == "function") then
+			--callback must accept the name of the current state and previous state as args
+			statecallbacks[loveframes.state].onopen(name, oldstate);
+		end
+
+	end
+
+end
+
+--[[---------------------------------------------------------
+	- func: SetStateOnOpenCallback(name, func)
+	- desc: sets a state's opening callback function
+--]]---------------------------------------------------------
+function loveframes.SetStateOnOpenCallback(name, func)
+
+	if (type(name) == "string" and name:gsub("%s", '') ~= '' and
+		type(func) == "function") then
+
+		if (not (statecallbacks[name])) then
+			statecallbacks[name] = {};
+		end
+
+		statecallbacks[name].onopen = func;
+	end
+
+end
+
+--[[---------------------------------------------------------
+	- func: SetStateOnOpenCallback(name, func)
+	- desc: sets a state's closing callback function
+--]]---------------------------------------------------------
+function loveframes.SetStateOnCloseCallback(name, func)
+
+	if (type(name) == "string" and name:gsub("%s", '') ~= '' and
+		type(func) == "function") then
+
+		if (not (statecallbacks[name])) then
+			statecallbacks[name] = {};
+		end
+
+		statecallbacks[name].onclose = func;
+	end
+
 end
 
 --[[---------------------------------------------------------