lua - How to stop an object from moving past a point -

i wondering if there way stop object moving off screen. in code, have controllable character (player) , want prevent moving left when it's x coordinate < 1

i have tried in code below, however, player not stopped if hold down left arrow key.

is there way fix this? if had guess, somehow need program continuously check case player.x < 1

motionx = 0; -- variable used move character along x axis speed = 10; -- set walking speed   local function moveplayer (event)     player.x = player.x + motionx; end  runtime:addeventlistener("enterframe", moveplayer)  local function onkeyevent( event )     if ( event.phase == "down" )         if ( event.keyname == "left" ) , player.x > 1             motionx = -speed             return true         elseif ( event.keyname == "right" )             motionx = speed             return true         end     end end  runtime:addeventlistener( "key", onkeyevent ) 

you need check boundaries , set motionx zero:

local player = display.newcircle(display.contentcenterx, display.contentcentery, 10)  local motionx = 0; -- variable used move character along x axis local speed = 10; -- set walking speed  local function moveplayer( event )     player.x = player.x + motionx;     if player.x < 0         player.x = 0         motionx = 0     elseif player.x > display.contentwidth         player.x = display.contentwidth         motionx = 0     end end  runtime:addeventlistener( "enterframe", moveplayer )  local function onkeyevent( event )     if event.phase == "down"         if event.keyname == "left"             motionx = -speed             return true         elseif event.keyname == "right"             motionx = speed             return true         end     end end  runtime:addeventlistener( "key", onkeyevent )