lua中的TextField输入为空时出错?
问题是,当txt.text为空时,我会收到错误消息lua中的TextField输入为空时出错?,lua,coronasdk,Lua,Coronasdk,问题是,当txt.text为空时,我会收到错误消息 --input text local txt = native.newTextField(160,100,300,50) --button press to get answer local btn = display.newRect(160,300,120,40) --label text to show answer local label = display.newText("answer",160,200) txt.inputTy
--input text
local txt = native.newTextField(160,100,300,50)
--button press to get answer
local btn = display.newRect(160,300,120,40)
--label text to show answer
local label = display.newText("answer",160,200)
txt.inputType = "number"
function doit(e)
-- Currency exchange (USD to any country)
label.text = txt.text * 2
-- when txt.text == empty I get error
end
btn:addEventListener("tap",doit)
我尝试使用
if-else
,但同样的问题。您只需要添加适当的if
语句。尝试:
function doit (e)
if tonumber(txt.text) then
label.text = tonumber(txt.text) * 2
end
end
代码的其余部分保持不变