Level selector

Getting Started Newbie Questions
#21

I will check that out after I’m done with this project Jay. Thanks for the tip!

I got a question, I have now added the level selection buttons to the screen, I’ve added them in the " createScene function "

I need to add object.id to them aswell.

object = display.newImage("btn1lvl.png") object:translate( 250, 200) screenGroup:insert ( object )

How would I go forward when adding the object.id, I tried to add it under the " display.newImage "
But I get a error when trying it in the sim.

Thanks!

EDIT:

Writing the code under “object:translate” works. I got it.

#22

Hi again guys, having some trouble with onObjectTouch

 

function scene:createScene( event ) local screenGroup = self.view image = display.newImage("BGlvl.jpg", centerX, centerY) screenGroup:insert ( image ) object = display.newImage("btn1lvl.png") object:translate( 250, 200) object.id = "level1" screenGroup:insert ( object ) object = display.newImage("btn2lvl.png") object:translate( 400, 200) object.id = "level2" screenGroup:insert ( object ) object = display.newImage("btn3lvl.png") object:translate( 550, 200) object.id = "level3" screenGroup:insert ( object )

I have that in the createScene function.

And I’m calling the objects from the enterScene function like this : 

 

function scene:enterScene( event ) local function onObjectTouch( event ) local level1 = event.target.id if event.phase == "began" then storyboard.gotoScene( "level1", "fade", 400) return true end end object:addEventListener( "touch", onObjectTouch ) print( "1: enterScene event" ) -- remove previous scene's view storyboard.purgeScene( "start" ) end

I’ve only made one touch listener, just for trying out.

Everything works OK, but when I’m in the level selection screen in the SIM.

If I try to press the image 1 to go to level1.lua, nothing happens.

If I press image 15 to go to level15.lua it works.

Do you guys have any idea what it could be ?

 

storyboard.gotoScene( "level1", "fade", 400 )

It doesn’t matter what I put in “level” if I put level1 or level 6, it’s still only allowing me to press the “level15button” to go to the next screen.

#23

you’re using the same object variable ‘object’ so only the last instance will be valid.

You need to either name your variables object1, object2 etc or better still use an array.

#24

I’m not sure how “array” works, might have to look for some tutorials. I tried changing names of the objects, but I get a error.

#25

You can reuse the same object name (although in some cases it’s not a good idea) but you’d need to format your code differently.

Here’s one option:

local function onObjectTouch(event) local goto = event.target.id if event.phase == "began" then storyboard.gotoScene( goto, {effect="fade", time=400}) return true end end local function createDisplay() local image = display.newImage("BGlvl.jpg", centerX, centerY) scene.view:insert ( image ) local startXPos = 250 for x = 1, 3 do local object = display.newImage("btn" .. x .. "lvl.png") object:translate( startXPos, 200) object.id = "level" .. x object:addEventListener( "touch", onObjectTouch ) scene.view:insert ( object ) startXPos = startXPos + 150 end end function scene:createScene( event ) local screenGroup = self.view createDisplay() end function scene:enterScene( event ) print( "1: enterScene event" ) -- remove previous scene's view storyboard.purgeScene( "start" ) end

I haven’t actually run that code, but I think it’s correct. First thing I did was pull most of the code out of the “official” scene functions – that makes reuse in the future much easier. And if you end up wanting to “restart” a level it makes it a breeze if you don’t have stuff crammed into the createScene and enterScene functions.

There’s also a loop that puts three buttons on the screen, 150 pixels apart. And I think your syntax was off in storyboard.gotoScene(). I changed it to match the docs.

See if that helps.

 Jay

#26

Thanks Jay, not happy with re-doing this, but I’ll guess I have to. I’ve made 15 buttons.                                                                                                

 

local object = display.newImage("btn" .. x .. "lvl.png") object:translate( startXPos, 200) object.id = "level" .. x object:addEventListener( "touch", onObjectTouch ) scene.view:insert ( object ) startXPos = startXPos + 150 end

How would I go about adding more buttons? do I just  add this several time, with different info ofc.

 

 

#27

No, you change the 

for x = 1, 3 do  

to

for x = 1, 15 do  

in order to do 15 buttons. If you don’t know about loops you should go dig into them. Here’s a video I made on that topic:

https://www.youtube.com/watch?v=N3lmLaywy0U

It’s the 5th in a series of using Lua, so if you need a refresher, watch them all. :slight_smile:

The main problem with moving from 3 to 15 buttons is the placement. The code I wrote assumes they’re all at the same Y coordinate and you can do that with 15 buttons – as long as they’re small. Otherwise they’ll spill off the screen.

So you could create a table of locations for the buttons, which would look something like this:

 local btnPos = { {250,200}, {400,200}, {550,200}, {250,350}, {400,350}, {550,350} } for x = 1, #btnPos do local object = display.newImage("btn" .. x .. "lvl.png") object:translate( btnPos[x][1], btnPos[x][2]) object.id = "level" .. x object:addEventListener( "touch", onObjectTouch ) scene.view:insert ( object ) startXPos = startXPos + 150 end

That btnPos is a table of button positions, the X and Y for each button. That loop shows six buttons because I didn’t want to wrap on the screen, but you could keep adding more sets of X/Y positions for as many buttons as you want.

The start of the loop now uses #btnPos to show how many times to loop – it says how many elements (sets of X/Y coordinates) are in that table.

 Jay

#28

Thanks I’ll look into that :slight_smile:

But I need to write object.id to the buttons.

how do I attach the id to each button ? 

Thanks again Jay!

#29

This line in the code above does it:

object.id = “level” … x

So you’ll end up with each button having an id that’s level1, level2, level3, etc.

That x variable that get’s concatenated is the one in the for loop that goes from 1 to however many buttons you have.

 Jay

#30

I got some issues with physics.
 

local function createDisplay() local image = display.newImage( "gameBg1.jpg", centerX, centerY ) scene.view:insert ( image ) local startXpos = 30 for x =1, 40 do local block = display.newImage("blocktest1.png") block:translate( startXpos, 600) scene.view:insert ( block ) startXpos = startXpos + 40 physics.addBody(block, "static", {friction=0.5, bounce=0.3 } ) --local startXpos = 100 local ball = display.newImage("coconut.png") ball:translate(400, 20 ) scene.view:insert (ball) physics.addBody(ball, {density = 0.6, friction = 0.6, bounce= 0.6, radius = 19}) end end

When the ball hit’s the ground, there’s suddenly (almost like a explosion) 20 balls.

 

I’m thinking it might be the code that put’s the ground. 
I wrote that code so I didn’t have to put every single block(ground) in code.

I’m not sure if that will work. Anyone had any experience with that ?

#31

Your do statement should end earlier since you are not creating 40 balls but 40 blocks only.

local function createDisplay() local image = display.newImage( "gameBg1.jpg", centerX, centerY ) scene.view:insert ( image ) local startXpos = 30 for x =1, 40 do local block = display.newImage("blocktest1.png") block:translate( startXpos, 600) scene.view:insert ( block ) startXpos = startXpos + 40 physics.addBody(block, "static", {friction=0.5, bounce=0.3 } ) end \<--------- move here --local startXpos = 100 local ball = display.newImage("coconut.png") ball:translate(400, 20 ) scene.view:insert (ball) physics.addBody(ball, {density = 0.6, friction = 0.6, bounce= 0.6, radius = 19}) end

Good Luck!

burhan

#32

I see.
 Thanks.

What would be the best option to get a ball to move, to follow the ground.

I’m currently looking at : setLinearVelocity

Do you have any tip?

#33 
local object = display.newImage( "level1.png" ) object.id = "level1" local function onObjectTouch( event ) if event.phase == "began" then storyboard.gotoScene( "level1", "fade", 400 ) end return true end object:addEventListener( "touch", onObjectTouch )

Would this be the correct way to go ? 

#34

Hi @sindrekristiansen,

You are almost there but you may add event.target.id.

try this

local object = display.newImage( "level1.png" ) object.id = "level1" local object = display.newImage( "level2.png" ) object.id = "level2" local function onObjectTouch( event ) local level = event.target.id if event.phase == "began" then storyboard.gotoScene( level, "fade", 400 ) end return true end object:addEventListener( "touch", onObjectTouch )

Good Luck!

burhan

#35

Thanks for the reply burthan.

I want multiple level’s on the " Level selector screen " 

Ex:

5 levels, if you press on picture 1 you go to level 1, picture 2 you go to level 2 etc etc

Do I need to add this multiple times ? 

 

local function onObjectTouch( event ) local level = event.target.id if event.phase == "began" then storyboard.gotoScene( level1, "fade", 400 ) local function onObjectTouch( event ) local level = event.target.id if event.phase == "began" then storyboard.gotoScene( level2, "fade", 400 )

And how does Corona / Lua know that when you press the first picture, you go to level 1 etc

There’s nothing in that function " onObjectTouch " that tells it when you press pic 1,
you go to Level.Lua

I’m sorry if I’m writing this complicated, I just want to understand this.

Thanks again!

#36

hi,

You just need to create your display objects. 5 pictures in your case.

You add the object.id to them. level1 to level5

in your onObjectTouch  function (created just once) you have

local level = event.target.id .

level will change depending on which image(display object) you clicked.

Then gotoscene will go to the level which you clicked.

burhan

#37

Hi @sindrekristiansen,

If you’re using level director (which i think your are) can you not just add 5 button objects to your scene?

In code you simply attach the onPress event handler to each button which in turn will have the code to launch each level?

#38

2rdcdig.png

I’m getting this error, what could it be ? 
I’m just trying out one button for now.

@retrofitProductions

I’m not using level director right now, I just want to learn basic lua before I jump into LD again.
It’s a verry nice software, but I need to learn the basics first I think.
 

#39

Yes learning the basics is a good idea.

I think from the screenshot it appears that newImage is failing therefore your object var is nil.

Are you sure your image is named correctly and is not in a sub folder?

#40

Yes, the image is named correctly and is not in a sub folder.    Thanks for replying