Can I use backgound touch listener for an object?

[dodi_games]

 --create local bg = display.newRect( centerX, centerY, 768, 1024 ) bg.fill = data.greenWood sceneGroup:insert( bg ) bg:addEventListener( "touch", moveRect)

Up my background created in the scene:create.

I already uploaded my first app and now I’m trying to make my first game. In which I need to use a touch listener in the background image to move a rectangle. I’m doing my first game based on the Corona game example “Star Explorer” in which a touch listener is used to move the ship when you touch the ship, I want to use the background touch listener to move my rectangle when the uses move his finger in the screen.

The problem is that I am moving the background when I touch the screen. How can I move the “rect” using a touch listener in the background?

Here is the function code, basically identical to the “Star Explorer”

local function moveRect( event ) local rect= event.target local phase = event.phase if ( "began" == phase ) then -- Set touch focus on the rect display.currentStage:setFocus( rect ) -- Store initial offset position rect.touchOffsetX = event.x - rect.x elseif ( "moved" == phase ) then -- Move the rect to the new touch position rect.x = event.x - rect.touchOffsetX elseif ( "ended" == phase or "cancelled" == phase ) then -- Release touch focus on the rect display.currentStage:setFocus( nil ) end return true -- Prevents touch propagation to underlying objects end

[sporkfin]

The touch listener is attached to bg.

It’s confusing because in moveRect( ) , event.target is called rect but it is moving the bg because that is the event.target.

1. Put the touch listener on the actual rectangle.  

2. Change the name of rect in moveRect( ) to something like “target” to avoid confusion.

[sporkfin]

Or if your rectangle is named “rect” then just get rid of 

[lua]

local rect = event.target

[/lua]

Then rect will refer to the rectangle and not the local “rect” which is actually “bg” (the event.target) and then you can use the background as your touch listener.  I think that is what you were asking for but I’m not quite sure.

[dodi_games]

thanks for the response @sporkfin…it’s confusing, I get rid off

local rect = event.target

but nothing move, neither the background nor the rect.

I just want to move the rectangle using the background touch listener. As if the background were the touchpad of the rectangle. The rectangle is very small, I do not want the user to lose sight of the rectangle by putting his finger on the screen.

[roaminggamer]

I say this all the time, but SSK has a solution for this.

1. Use SSK as per instructions: https://roaminggamer.github.io/RGDocs/pages/SSK2/#installing-ssk2

2. In your scene’s create() method add this code:

   function scene:create( event ) local sceneGroup = self.view ssk.easyInputs.oneTouch.create( sceneGroup )

3. Add this code to the top of the file where you make your ‘player’ object

   local function onOneTouch( self, event ) if(event.phase == “began”) self.x0 = self.x self.y0 = self.y else local dx = event.x - event.xStart local dy = event.y - event.yStart self.x = self.x0 + dx self.y = self.y0 + dy end end

4. When you create the player object do this
    

   local player = … your create code player.onOneTouch = onOneTouch listen( “onOneTouch”, player ) function player.finalize( self ) ignoreList( { “onOneTouch” }, self ) end; player:addEventListener(“finalize”)

Any typos in my code may result in bugs, you should  debug them on your own, just follow the clues in the console messages.

[roaminggamer]

One final note:

I can think of about a half-dozen ways to do this.  You simply need to understand:

• touch listeners
• scope

Then you’re good to go.

[roaminggamer]

I downloaded a copy of the star explorer code from here:

https://github.com/coronalabs/GettingStarted03

Then I modified it to allow dragging/tapping on the background to move the ship and fire.

Download this: 

https://github.com/roaminggamer/RG_FreeStuff/raw/master/AskEd/2018/08/GettingStarted03-master.zip

In the file you’ll see two folders:

• original
• modified

Diff them to see what I changed.

[sporkfin]

The touch listener is attached to bg.

It’s confusing because in moveRect( ) , event.target is called rect but it is moving the bg because that is the event.target.

1. Put the touch listener on the actual rectangle.  

2. Change the name of rect in moveRect( ) to something like “target” to avoid confusion.

[sporkfin]

Or if your rectangle is named “rect” then just get rid of 

[lua]

local rect = event.target

[/lua]

Then rect will refer to the rectangle and not the local “rect” which is actually “bg” (the event.target) and then you can use the background as your touch listener.  I think that is what you were asking for but I’m not quite sure.

[dodi_games]

thanks for the response @sporkfin…it’s confusing, I get rid off

local rect = event.target

but nothing move, neither the background nor the rect.

I just want to move the rectangle using the background touch listener. As if the background were the touchpad of the rectangle. The rectangle is very small, I do not want the user to lose sight of the rectangle by putting his finger on the screen.

[roaminggamer]

I say this all the time, but SSK has a solution for this.

1. Use SSK as per instructions: https://roaminggamer.github.io/RGDocs/pages/SSK2/#installing-ssk2

2. In your scene’s create() method add this code:

   function scene:create( event ) local sceneGroup = self.view ssk.easyInputs.oneTouch.create( sceneGroup )

3. Add this code to the top of the file where you make your ‘player’ object

   local function onOneTouch( self, event ) if(event.phase == “began”) self.x0 = self.x self.y0 = self.y else local dx = event.x - event.xStart local dy = event.y - event.yStart self.x = self.x0 + dx self.y = self.y0 + dy end end

4. When you create the player object do this
    

   local player = … your create code player.onOneTouch = onOneTouch listen( “onOneTouch”, player ) function player.finalize( self ) ignoreList( { “onOneTouch” }, self ) end; player:addEventListener(“finalize”)

Any typos in my code may result in bugs, you should  debug them on your own, just follow the clues in the console messages.

[roaminggamer]

One final note:

I can think of about a half-dozen ways to do this.  You simply need to understand:

• touch listeners
• scope

Then you’re good to go.

[roaminggamer]

I downloaded a copy of the star explorer code from here:

https://github.com/coronalabs/GettingStarted03

Then I modified it to allow dragging/tapping on the background to move the ship and fire.

Download this: 

https://github.com/roaminggamer/RG_FreeStuff/raw/master/AskEd/2018/08/GettingStarted03-master.zip

In the file you’ll see two folders:

• original
• modified

Diff them to see what I changed.