App closes without error mesasge

MIT App Inventor Help
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1

Hi there,
I'm practising a lot with lists and storage components. Here in my project I have a csv file that I want to read and then work out from this list, but in all screens that I have this file (RESULT and mostrar_datos), the app suddenly closes without showing any error message. In one screen (RESULT) I've saved all csv data in a TinyDB, in the other one (mostrar_datos) I haven't... and it still doesn't work in any of both.

Here's my aia file
BOOKS_BARCODES_copy_8.aia (44.2 KB)

Here's my csv database
BOOKS APP - Sheet1.csv (84.7 KB)

By the way, is there any way to find where my issue is by myself. For example, like when in some bocks the red cross appears meaning there's no such list, element, etc. needed.

Thanks in advance

2

you should switch screens correctly, see also

if it still does not work after fixing that, then one method to find out why you get a runtime error is to use logcat

EDIT: see also tip 1 here

Taifun

1 Like
3

Thanks for all your resources!!
I have two questions regarding the Pura Vida Tutorial.
The first one:
imagen_2023-04-12_101615595
Why is this math (blue) equal used instead of the logic (green) equal?

The second one:
I got the idea that it's better to work with layouts (visible true/false), but for the app that I already have... how can I go to another screen with start value but also closing the current screen I am at?

Thanks a lot!

4

From the documentation
http://ai2.appinventor.mit.edu/reference/blocks/logic.html#=

Acts exactly the same as the = block found in Math

Use the Open another screen with value block

Taifun

5

Yes, I used to use this block, but then the new screen opens without having closed the one I was in.
I don't know how to combine both blocks: "open another screen with value" + "close current screen", do you know what I mean?

Thanks

6

Thanks!!

7

You have a solution which uses the close screen block and the open another screen block together... now what happens, if you replace the open another screen block by open another screen with value?

Taifun

8

I would like something like this
imagen_2023-04-13_150826411

But both close screen and open another screen with start value don't allow other blocks below them, so I cannot put one and then the other one... I don't know if you get my idea...

I have now a crazy idea:
imagen_2023-04-13_150520566
Would this be possible?

Thanks

9

What about trying it?
And isn't that exactly that thing I was talking about?

Taifun