Deleting Text - But, I promise, I have searched everywhere and I am still lost.

[dalekirkwood]

Hi All

I hope I can explain this ok.

I have an app, when I change scenes I want it to delete everything, but the text stays.

• Because text cannot be added to a group like an image, it doesn’t adhere to normal rules and as such needs to be removed manually and always sits on top

So, I get it, I can’t insert to a group and I have to remove it manually.

local function gotohome() if (ranknum) then ranknum:removeSelf() ranknum = nil end composer.gotoScene("menu", {time = 600, effect = "slideRight"}) end 

but, this is displaying a table, so the variable ‘ranknum’ has been used several time in a do…while loop. So this just removes the last text added, not all the text.

Please see the loop below

local function loadday() display.remove (today) display.remove (week) display.remove (month) for i = 1, #feedstable do if (feedstable[i]) then local yPos = 150 + (i \* 56) print (feedstable[i].dateday) print ("i"..i) print ("legnth"..#feedstable) local headertext = display.newText("Date Time ml FeedType", display.contentCenterX-300,display.contentCenterY-400,native.systemFont,36) headertext.anchorX = 0 headertext:setFillColor(0,0,0) local datetime = os.date ("\*t") --get date and time and store in a table if (feedstable[i].dateyear == datetime.year and feedstable[i].datemonth == datetime.month and feedstable[i].dateday == datetime.day ) then ranknum = display.newText(i, display.contentCenterX-320, yPos,"Arial", 36) ranknum:setFillColor (0.8) ranknum.anchorX = 1 local thisscore = display.newText(feedstable[i].dateday..".".. feedstable[i].datemonth.. "."..feedstable[i].dateyear.. " "..feedstable[i].timehour.. ":"..feedstable[i].timemin.. " "..feedstable[i].feedammount.. " "..feedstable[i].feedtype, display.contentCenterX-300, yPos, native.systemFont, 36) thisscore.anchorX = 0 thisscore:setFillColor (0,0,0) end end end end  

 I have attached an image where you can see the text has been removed, but 2 & 3 are still there.

And of course, that makes sense. How would Corona know to remove them also, they are no longer the ranknum variable.

So my question is, how, in the simplest way possible, can I clear the screen. In other scenes I do not have this issue with text, but here I do.

Please someone help me. I spent 2 or 3 hours Googling this, I am not the only one who has had this problem but it was never the exact same.

All the code below, if it helps

local composer = require( "composer" ) local scene = composer.newScene() -- ----------------------------------------------------------------------------------- -- Code outside of the scene event functions below will only be executed ONCE unless -- the scene is removed entirely (not recycled) via "composer.removeScene()" -- ----------------------------------------------------------------------------------- -- ----------------------------------------------------------------------------------- -- Scene event functions -- ----------------------------------------------------------------------------------- -- create() local today local week local month local ranknum local function gotohome() if (ranknum) then ranknum:removeSelf() ranknum = nil end composer.gotoScene("menu", {time = 600, effect = "slideRight"}) end local function addfeed() composer.gotoScene("AddFeed",{time=600,effect = "crossFade"}) end local function gotocalc() composer.gotoScene("calculator",{time=400, effect ="crossFade"}) end local function gotoabout() composer.gotoScene("about",{time=400, effect ="crossFade"}) end local json = require ("json") local filePath = system.pathForFile ("feeds.json",system.DocumentsDirectory) local file = io.open (filePath, "r") --open file as read only local contents = file:read("\*a") -- load contents into variable 'contents' io.close(file) -- closes the file feedstable = json.decode (contents) -- decode the file into LUA table local function loadday() display.remove (today) display.remove (week) display.remove (month) for i = 1, #feedstable do if (feedstable[i]) then local yPos = 150 + (i \* 56) print (feedstable[i].dateday) print ("i"..i) print ("legnth"..#feedstable) local headertext = display.newText("Date Time ml FeedType", display.contentCenterX-300,display.contentCenterY-400,native.systemFont,36) headertext.anchorX = 0 headertext:setFillColor(0,0,0) local datetime = os.date ("\*t") --get date and time and store in a table if (feedstable[i].dateyear == datetime.year and feedstable[i].datemonth == datetime.month and feedstable[i].dateday == datetime.day ) then ranknum = display.newText(i, display.contentCenterX-320, yPos,"Arial", 36) ranknum:setFillColor (0.8) ranknum.anchorX = 1 local thisscore = display.newText(feedstable[i].dateday..".".. feedstable[i].datemonth.. "."..feedstable[i].dateyear.. " "..feedstable[i].timehour.. ":"..feedstable[i].timemin.. " "..feedstable[i].feedammount.. " "..feedstable[i].feedtype, display.contentCenterX-300, yPos, native.systemFont, 36) thisscore.anchorX = 0 thisscore:setFillColor (0,0,0) end end end end function scene:create( event ) local sceneGroup = self.view local ranknum local background = display.newImageRect (sceneGroup, "Background.png",800,1400) background.x = display.contentCenterX background.y = display.contentCenterY local footer = display.newImageRect(sceneGroup,"Footer.png",793,120) footer.x = display.contentCenterX footer.y = 1150 local header = display.newImageRect(sceneGroup,"Header.png",794,140) header.x = display.contentCenterX header.y = -100 local mainbutton = display.newImageRect (sceneGroup, "Button.png",120,120) mainbutton.x = display.contentCenterX mainbutton.y = 1080 local logo = display.newImageRect(sceneGroup,"pumpit.png",282,122) logo.x = display.contentCenterX logo.y = -50 local circle = display.newImageRect (sceneGroup, "circle.png",95,95) circle.x = 232 circle.y = 1140 local homebutton = display.newImageRect (sceneGroup,"home.png",69,69) homebutton.x = 70 homebutton.y = 1140 local feeds = display.newImageRect (sceneGroup,"feeds.png",69,69) feeds.x = 230 feeds.y = 1140 local calc = display.newImageRect (sceneGroup,"calculator.png",69,69) calc.x = 550 calc.y = 1140 local info = display.newImageRect (sceneGroup,"info.png",69,69) info.x = 700 info.y = 1140 today = display.newImageRect (sceneGroup,"today.png",598,158) today.x = display.contentCenterX today.y = 300 week = display.newImageRect (sceneGroup,"week.png",598,158) week.x = display.contentCenterX week.y = 500 month = display.newImageRect (sceneGroup,"month.png",598,158) month.x = display.contentCenterX month.y = 700 homebutton:addEventListener ("tap", gotohome) mainbutton:addEventListener ("tap", addfeed) calc:addEventListener("tap", gotocalc) info:addEventListener("tap", gotoabout) today:addEventListener("tap", loadday) -- Code here runs when the scene is first created but has not yet appeared on screen end -- show() function scene:show( event ) local sceneGroup = self.view local phase = event.phase if ( phase == "will" ) then -- Code here runs when the scene is still off screen (but is about to come on screen) elseif ( phase == "did" ) then -- Code here runs when the scene is entirely on screen end end -- hide() function scene:hide( event ) local sceneGroup = self.view local phase = event.phase if ( phase == "will" ) then -- Code here runs when the scene is on screen (but is about to go off screen) composer.removeScene("viewfeeds") elseif ( phase == "did" ) then composer.removeScene("viewfeeds") end end -- destroy() function scene:destroy( event ) local sceneGroup = self.view -- Code here runs prior to the removal of scene's view end -- ----------------------------------------------------------------------------------- -- Scene event function listeners -- ----------------------------------------------------------------------------------- scene:addEventListener( "create", scene ) scene:addEventListener( "show", scene ) scene:addEventListener( "hide", scene ) scene:addEventListener( "destroy", scene ) -- ----------------------------------------------------------------------------------- return scene

Thanks in advanced 

Dale

[anaqim]

Hi,

Text objects can be added to display groups just like any other display objects.

local dg=display.newGroup()

local mytext=display.newText(blablabl)

dg:insert(mytext) – insert the text object into the display group

to get rid of the display group and all objects inside it:

display.remove(dg)

dg=nil

and just as easily to get rid of a text object:

display.remove(mytext)

mytext=nil

it is in general better to use display.remove() instead of object:removeSelf()

if you use the same variable in a loop to create objects, you will lose control over them (unless you also add them to a display group!

its would then be better create a table to hold those loop objects like this:

myobjects={}

for n=1,10 do

   myobjects[n]=display.newText(/blablabla)

end

this way you can reference each of the looped objects directly, unless you put all in a parent display group of course, which makes things very often much simpler.

hope this gives some hints

[nick_sherman]

Yes, think there may be some confusion with native.newTextField objects, which must be removed manually, and display.newText objects which can be added to the scene group and will be removed automaticallly along with everything else.

But still worth reading up on scope and tables. As Anaqim says, if you want to later access objects created in a loop, add them to a table.

[dalekirkwood]

Wow, Thanks for the fast replies everyone.

@anaqim - yes, I agree, a table would be better. I am going to refine the code

@nick_sherman - I also thought this, I understand native.newTextField can only be removed manually but I was having an issue adding display.newText to a group.

I managed to fix this yesterday. After hours of trying, I actually found I couldn’t add any display.newText to sceneGroup while it is nested so deeply. Local Function > For - Do > If > If. 

What I did, was create a new scene, added the code there and it works perfectly.

In my search I found this forum post which I think explains it better what my problem is https://forums.coronalabs.com/topic/48540-scenegroup-a-nil-valuehow-is-that-possible/

Anyway, Thank you so much again for your fast replies.

[nick_sherman]

I don’t think the nesting will be the issue. The only thing to be aware of is you must add it to sceneGroup while you have the reference to it…i.e, in the same scope, immediately after it is created.

If it were nesting this would have cropped up in the 8-9 years the framework has been available. That post just shows you can’t add an object that isn’t a display object to a scene group.

If your text object was out of scope and you tried to add it, then it would be nil and the effect would be similar to what that poster saw.

Make liberal use of print statements while developing. At each stage confirm that variables, objects etc. are what you think they are.

[dalekirkwood]

local mldaytext = 1

local mlperfeedtext = 1

sceneGroup:insert (mldaytext)

sceneGroup:insert (mlperfeedtext)

So for example, this should work?

[nick_sherman]

No, because those aren’t display objects. They are ordinary variables that just happen to have the word text in them.

[dalekirkwood]

I think the penny has dropped.

So, I take a variable such as mldaytext=display.newText (“Text”) , and then add that to a display group which I can then remove but I can’t add the variable to the display group before, I must add it once it is already a text object.

Thank you for your help in understanding this

[nick_sherman]

You would use the variable mldaytext within your call to display.newText. Then add the display.newText to sceneGroup, or another display group that is itself added to sceneGroup.

EDIT: I see you edited your post, we’re on the same page.

[anaqim]

Hi,

Text objects can be added to display groups just like any other display objects.

local dg=display.newGroup()

local mytext=display.newText(blablabl)

dg:insert(mytext) – insert the text object into the display group

to get rid of the display group and all objects inside it:

display.remove(dg)

dg=nil

and just as easily to get rid of a text object:

display.remove(mytext)

mytext=nil

it is in general better to use display.remove() instead of object:removeSelf()

if you use the same variable in a loop to create objects, you will lose control over them (unless you also add them to a display group!

its would then be better create a table to hold those loop objects like this:

myobjects={}

for n=1,10 do

   myobjects[n]=display.newText(/blablabla)

end

this way you can reference each of the looped objects directly, unless you put all in a parent display group of course, which makes things very often much simpler.

hope this gives some hints

[nick_sherman]

Yes, think there may be some confusion with native.newTextField objects, which must be removed manually, and display.newText objects which can be added to the scene group and will be removed automaticallly along with everything else.

But still worth reading up on scope and tables. As Anaqim says, if you want to later access objects created in a loop, add them to a table.

[dalekirkwood]

Wow, Thanks for the fast replies everyone.

@anaqim - yes, I agree, a table would be better. I am going to refine the code

@nick_sherman - I also thought this, I understand native.newTextField can only be removed manually but I was having an issue adding display.newText to a group.

I managed to fix this yesterday. After hours of trying, I actually found I couldn’t add any display.newText to sceneGroup while it is nested so deeply. Local Function > For - Do > If > If. 

What I did, was create a new scene, added the code there and it works perfectly.

In my search I found this forum post which I think explains it better what my problem is https://forums.coronalabs.com/topic/48540-scenegroup-a-nil-valuehow-is-that-possible/

Anyway, Thank you so much again for your fast replies.

[nick_sherman]

I don’t think the nesting will be the issue. The only thing to be aware of is you must add it to sceneGroup while you have the reference to it…i.e, in the same scope, immediately after it is created.

If it were nesting this would have cropped up in the 8-9 years the framework has been available. That post just shows you can’t add an object that isn’t a display object to a scene group.

If your text object was out of scope and you tried to add it, then it would be nil and the effect would be similar to what that poster saw.

Make liberal use of print statements while developing. At each stage confirm that variables, objects etc. are what you think they are.

[dalekirkwood]

local mldaytext = 1

local mlperfeedtext = 1

sceneGroup:insert (mldaytext)

sceneGroup:insert (mlperfeedtext)

So for example, this should work?

[nick_sherman]

No, because those aren’t display objects. They are ordinary variables that just happen to have the word text in them.

[dalekirkwood]

I think the penny has dropped.

So, I take a variable such as mldaytext=display.newText (“Text”) , and then add that to a display group which I can then remove but I can’t add the variable to the display group before, I must add it once it is already a text object.

Thank you for your help in understanding this

[nick_sherman]

You would use the variable mldaytext within your call to display.newText. Then add the display.newText to sceneGroup, or another display group that is itself added to sceneGroup.

EDIT: I see you edited your post, we’re on the same page.