In my code below, I want to make it so that the rectangle that is being dragged can only be dragged vertically in a straight line. How would I do that? Thanks!
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 | system.activate( "multitouch" ) local function onTouch( event ) local t = event.target local phase = event.phase if "began" == phase then -- Make target the top-most object local parent = t.parent parent:insert( t ) display.getCurrentStage():setFocus( t, event.id ) -- Spurious events can be sent to the target, e.g. the user presses -- elsewhere on the screen and then moves the finger over the target. -- To prevent this, we add this flag. Only when it's true will "move" -- events be sent to the target. t.isFocus = true -- Store initial position t.x0 = event.x - t.x t.y0 = event.y - t.y elseif t.isFocus then if "moved" == phase then -- Make object move (we subtract t.x0,t.y0 so that moves are -- relative to initial grab point, rather than object "snapping"). t.x = event.x - t.x0 t.y = event.y - t.y0 elseif "ended" == phase or "cancelled" == phase then display.getCurrentStage():setFocus( t, nil ) t.isFocus = false end end -- Important to return true. This tells the system that the event -- should not be propagated to listeners of any objects underneath. return true end local rectangle = display.newRect(100,100,50,50) rectangle:addEventListener("touch",onTouch) |
If thats all you want then all you have to do is remove the part that tells the rectangle to move on the x-axis.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 | system.activate( "multitouch" ) local function onTouch( event ) local t = event.target local phase = event.phase if "began" == phase then -- Make target the top-most object local parent = t.parent parent:insert( t ) display.getCurrentStage():setFocus( t, event.id ) -- Spurious events can be sent to the target, e.g. the user presses -- elsewhere on the screen and then moves the finger over the target. -- To prevent this, we add this flag. Only when it's true will "move" -- events be sent to the target. t.isFocus = true -- Store initial position t.y0 = event.y - t.y elseif t.isFocus then if "moved" == phase then -- Make object move (we subtract t.x0,t.y0 so that moves are -- relative to initial grab point, rather than object "snapping"). t.y = event.y - t.y0 elseif "ended" == phase or "cancelled" == phase then display.getCurrentStage():setFocus( t, nil ) t.isFocus = false end end -- Important to return true. This tells the system that the event -- should not be propagated to listeners of any objects underneath. return true end local rectangle = display.newRect(100,100,50,50) rectangle:addEventListener("touch",onTouch) |
views:1663 update：2011/9/28 21:38:26