Widget - Black Screen before trans. effect finishes

Getting Started Newbie Questions
#1

I have a button widget to get me out of the menu to another scene (FYI: using Composer).

Here’s the function I use to go to the new scene:

local function GongBtn (event)

  if event.phase == “ended” then

  composer.loadScene( “gong”, false, options )

  composer.gotoScene ( “gong”, { effect=“crossFade”, time=800 } )

  end

end

If I touch the widget button twice before the “crossFade” effect has finished, the new scene quickly fades to a black screen with no way of getting out except reseting the simulator.

How do I prevent this black screen?  For example, if a user accidentally touches the widgetButton a second time before the crossfade effect has finished.

#2

Sounds like you might need to code your button handler to ignore future requests while it’s processing the current one. 

Rob

#3

Thanks for the tip, Rob.  But I’m not sure how to do this.  Can you point me to a sample? 

if event.effect = true then

don’t turn the screen black

; )

I should mention I tried “return true” but it’s the same object that’s getting touched which is causing this black screen phenomenon.  It didn’t work whether I put it before or after the 1st “end”.

#4

Near the top of the scene file add:

local sceneChangeButtonAlreadyPressed

In your scene:show() do:

     if event.phase == “did” then

          sceneChangeButtonAlreadyPressed = false

          – the rest of your did phase processing

     end

then in your event function for your button:

local function GongBtn (event)

  if event.phase == “ended” then

      if sceneChangeButtonAlreadyPressed then

          return true

      end

      sceneChangeButtonAlreadyPressed = true

  composer.loadScene( “gong”, false, options )

  composer.gotoScene ( “gong”, { effect=“crossFade”, time=800 } )

  end

end

or something like that.

#5

Thanks, Rob.  That helped a lot.  Just to show for others to see I put your middle code above here:

[lua]

function scene:show( event )

      local sceneGroup = self.view

      local phase = event.phase

      if ( phase == “will” ) then

      elseif ( phase == “did” ) then

        –      INSERT code here (e.g. start timers, load audio, start listeners, etc.)

      

      if event.phase == “did” then

          sceneChangeButtonAlreadyPressed = false

     end

    end

end

[/lua]

If I removed   if event.phase == “did” then and attached it to the elseif above, it wouldn’t work.

About your last part, if the part bolded below is written without a true or false then, is it another way to say “true.”  Is that statement really saying " if sceneChangeButtonAlreadyPressed  is true then return true?  Although I set it to false near the top of the scene…  

Confused.  I’m just trying to find a way to speak these lines of code (lines 3-6 below) in English, so i can understand why you’d write them this way- plus it will help me to remember it if I can make sense of it.

[lua]

local function GongBtn (event)

  if event.phase == “ended” then

      if sceneChangeButtonAlreadyPressed then

          return true

      end

      sceneChangeButtonAlreadyPressed = true

  composer.loadScene( “gong”, false, options )

  composer.gotoScene ( “gong”, { effect=“crossFade”, time=800 } )

  end

end

[/lua]

#6

Sounds like you might need to code your button handler to ignore future requests while it’s processing the current one. 

Rob

#7

Thanks for the tip, Rob.  But I’m not sure how to do this.  Can you point me to a sample? 

if event.effect = true then

don’t turn the screen black

; )

I should mention I tried “return true” but it’s the same object that’s getting touched which is causing this black screen phenomenon.  It didn’t work whether I put it before or after the 1st “end”.

#8

Near the top of the scene file add:

local sceneChangeButtonAlreadyPressed

In your scene:show() do:

     if event.phase == “did” then

          sceneChangeButtonAlreadyPressed = false

          – the rest of your did phase processing

     end

then in your event function for your button:

local function GongBtn (event)

  if event.phase == “ended” then

      if sceneChangeButtonAlreadyPressed then

          return true

      end

      sceneChangeButtonAlreadyPressed = true

  composer.loadScene( “gong”, false, options )

  composer.gotoScene ( “gong”, { effect=“crossFade”, time=800 } )

  end

end

or something like that.

#9

Thanks, Rob.  That helped a lot.  Just to show for others to see I put your middle code above here:

[lua]

function scene:show( event )

      local sceneGroup = self.view

      local phase = event.phase

      if ( phase == “will” ) then

      elseif ( phase == “did” ) then

        –      INSERT code here (e.g. start timers, load audio, start listeners, etc.)

      

      if event.phase == “did” then

          sceneChangeButtonAlreadyPressed = false

     end

    end

end

[/lua]

If I removed   if event.phase == “did” then and attached it to the elseif above, it wouldn’t work.

About your last part, if the part bolded below is written without a true or false then, is it another way to say “true.”  Is that statement really saying " if sceneChangeButtonAlreadyPressed  is true then return true?  Although I set it to false near the top of the scene…  

Confused.  I’m just trying to find a way to speak these lines of code (lines 3-6 below) in English, so i can understand why you’d write them this way- plus it will help me to remember it if I can make sense of it.

[lua]

local function GongBtn (event)

  if event.phase == “ended” then

      if sceneChangeButtonAlreadyPressed then

          return true

      end

      sceneChangeButtonAlreadyPressed = true

  composer.loadScene( “gong”, false, options )

  composer.gotoScene ( “gong”, { effect=“crossFade”, time=800 } )

  end

end

[/lua]