# While/When function on screen start?

**URL:** https://community.thunkable.com/t/while-when-function-on-screen-start/61518
**Category:** Questions about Thunkable X
**Created:** [December 20, 2018, 6:48pm UTC](https://community.thunkable.com/t/while-when-function-on-screen-start/61518 "2018-12-20T18:48:49Z")
**Posts on this page:** 6
**Page:** 1

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### Author: ![Cian\_O\_Sullivan](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/cian_o_sullivan/32/34494_2.png) [@Cian\_O\_Sullivan](https://community.thunkable.com/u/Cian_O_Sullivan)
#### Post date: [December 20, 2018, 6:48pm UTC](https://community.thunkable.com/t/while-when-function-on-screen-start/61518/1 "2018-12-20T18:48:49Z")

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Hello,

I am trying to have a function that waits until a variable does not = 0 and then it triggers.

When variable =\>1 do API call etc…

Any advice?

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### Author: ![darren](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/darren/32/69854_2.png) [@darren](https://community.thunkable.com/u/darren)
#### Post date: [December 20, 2018, 7:12pm UTC](https://community.thunkable.com/t/while-when-function-on-screen-start/61518/2 "2018-12-20T19:12:59Z")

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My first thought is to check if the variable does not = 0 whenever you change it. If it is \> 0, then call your function.

Would something like this work for you?

 ![checkVariable](https://us1.discourse-cdn.com/flex015/uploads/thunkable/original/3X/0/e/0ec2c9df7d54bce0a7170f6f6d5b1c834a0e3c63.png)

Thanks,  
[Darren](https://www.youtube.com/channel/UCHDDjy-6nbgwdrJpSZIfCOA)

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### Author: ![Cian\_O\_Sullivan](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/cian_o_sullivan/32/34494_2.png) [@Cian\_O\_Sullivan](https://community.thunkable.com/u/Cian_O_Sullivan)
#### Post date: [December 20, 2018, 7:24pm UTC](https://community.thunkable.com/t/while-when-function-on-screen-start/61518/3 "2018-12-20T19:24:30Z")

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Very interesting approach. I am going to tinker with something like that. Thanks for that.

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### Author: ![Dennis](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/dennis/32/30148_2.png) [@Dennis](https://community.thunkable.com/u/Dennis)
#### Post date: [December 20, 2018, 7:42pm UTC](https://community.thunkable.com/t/while-when-function-on-screen-start/61518/4 "2018-12-20T19:42:19Z")

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You could also use the clock component for this. Fire every (1 or 2 seconds) and check your variable then.  
Hope this helps

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### Author: ![Mark](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/mark/32/18133_2.png) [@Mark](https://community.thunkable.com/u/Mark)
#### Post date: [December 21, 2018, 10:31pm UTC](https://community.thunkable.com/t/while-when-function-on-screen-start/61518/5 "2018-12-21T22:31:34Z")

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Just so you know, the next release of Thunkable ✕ will have a ‘when’ block which will execute when a ‘stored’ or ‘app’ variable changes value (or initializes). There is currently such a block for ‘cloud’ variables.

The next version of Thunkable ✕ will be probably be released so after the new year.

-Mark

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### Author: ![ioannis](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/ioannis/32/146956_2.png) [@ioannis](https://community.thunkable.com/u/ioannis)
#### Post date: [November 8, 2024, 11:52am UTC](https://community.thunkable.com/t/while-when-function-on-screen-start/61518/6 "2024-11-08T11:52:18Z")

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