Populating the Video Files Menu

Now that you have created a menu (the list field) to display your videos we will look at how to populate the menu so that it displays a list of available videos.

This lesson will introduce revTalk for the first time in the application. revTalk is the language you use in Revolution to control what the application does and how it responds to user actions.

Edit The Card Script

Edit The Card Script

So far we have discussed the Stack window, the Player and the List Field. Now we will introduce the Card object. A Stack window is made up of one or more Cards. A Card can contain multiple objects such as a Player or Field.

We are going to add the revTalk necessary to populate the List Field to the Card Script. The Card Script stores revTalk that can affect any object on the card.

To edit the Card Script choose Object > Card Script.

The Script Editor Opens

The Script Editor Opens

When you edit the script of an object you use the Script Editor. The Script Editor enables you to write revTalk that affects the behavior of your application. Notice that a tab is open in the Script Editor for the Stack window's card (1). We will begin typing revTalk into the script field (2).

The Card Script

Below you will find all of the revTalk that goes in the Card script. If you would just like to copy and paste all of the code into the Card script without worrying about what it does then you can do so. If you would like to walk through writing the revTalk that goes in the Card script then skip the next step go to the next lesson which describes the Card script in detail.

Copy and paste the following revTalk into the Card script. After pasting the revTalk into the Card script the dot in the Card's tab will turn yellow (1). Click the Compile button (2) so that Revolution applies the changes you've made to the Card's script.

Copy & Paste Into Card Script

on preOpenCard
	## Load the video list
	uiPopulateVideoList
	
	## If there is at least 1 video in the list then load the video
	if the text of field "Video Menu" is not empty then
		set the hilitedline of field "Video Menu" to 1
		uiLoadSelectedVideo
	end if
	
end preOpenCard

command uiPopulateVideoList
	## Get list of video files in Video folder
	put GetVideoFiles() into theFiles
	
	## Assign the list of files to the list field (our menu)
	set the text of field "Video Menu" to theFiles
	
end uiPopulateVideoList

function GetVideoFiles
	## Get the path to the "Video" folder on disk
	put GetPathToFolder("Videos") into theFolder
	
	## Get list of files in the folder
	put GetFilesInFolder(theFolder) into theFiles
	
	## Return list of files
	return theFiles 
end GetVideoFiles

function GetPathToFolder pFolderName
	## Retrieving paths to folders that are relative to the stack can be tricky.
	
	## Determine the location of this stack on disk
	put the filename of this stack into theFolder
	
	## Folder paths use "/" to separate each folder in the path
	## By setting the itemDelimiter to slash we can refer to 
	## individual sections of the path by the 'item' token in revTalk.
	set the itemDelimiter to slash
	
	## When you build a standalone version of this stack on OS X the stack
	## file will be located in side of an application bundle. These next few
	## lines strip the application bundle portion of the path off.
	if the platform is "MacOS" then
		if theFolder contains ".app/Contents/MacOS" then
			## Delete the last three items of the path that are specific
			## to the application bundle
			delete item -3 to -1 of theFolder
		end if
	end if
	
	## Replace the last item in theFolder with the 'pFolderName' parameter
	put pFolderName into the last item of theFolder
	
	## Return the complete path
	return theFolder
end GetPathToFolder

function GetFilesInFolder pFolder
	## This function uses the default folder to get a list of files
	
	## Store the original default folder so we can return to it later
	put the defaultfolder into theOrigDefaultFolder
	
	## Change the default folder to the folder passed into the function (pFolder)
	set the defaultfolder to pFolder
	
	## 'the files' always returns the files in the 'default folder'
	put the files into theFiles
	
	## Restore the original 'default folder' setting
	set the defaultfolder to theOrigDefaultFolder
	
	## Filter out invisible files (files that start with a "." in their name) from 'theFiles' variable
	filter theFiles without ".*"
	
	## Return the list of files to the caller of the function
	return theFiles
end GetFilesInFolder

command uiLoadSelectedVideo
	## Get the name of the video selected in the video menu
	put the selectedtext of field "Video Menu" into theVideoName
	put "Videos/" & theVideoName into theVideoFile 
	
	## Set 'the filename' property the player object to the relative video path
	## Revolution will locate the video as long as the "Videos" folder is
	## alongside the stack file or the application executable.
	set the filename of player "My Video" to theVideoFile
	
	## Reset the time of the Player object to 0
	set the currenttime of player "My Video" to 0
end uiLoadSelectedVideo

4 Comments

Rory

How do I get the code above to copy correctly? At the moment it copies all on one line and has '?' at the end of every line of code?

Hanson Schmidt-Cornelius

Hi Rory,

you can copy the code by first placing it in a text editor and the copying it from there into the LiveCode script editor. This should remove the '?' for you.

Kind Regards,

Hanson

Daniel

The list of videos in my video file doesn't appear I just get:

about.text
license agreement.txt
livecode.exe

etc....

How do I fix this?

Elanor Buchanan

Hi Daniel

It sounds like the line of code where you set the defaultFolder property is failing, these are the files in the LiveCode distribution which is what the defaultFolder is set to when LiveCode starts up so it sounds like it is not changing successfully.

Double check that line of code, and the folder path you are using there and you should be able to get it working.

Kind regards

Elanor

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