Unhandled Exception in a simple IF statement

I have just discovered Error Reporting Application (ERA) and checked my apps.
The only report so far is one for the Battery Guesstimate App:

I seems to happen regularly, but its weird because the code is a simple IF statement

if (systemStats.charging == true && chargeNotification > 0 && systemStats.battery >= chargeNotification) {

systemStats are read by: `var systemStats = System.getSystemStats();`

and chargeNotification from the properties via `var chargeNotification = Properties.getValue("charge-notification") as Integer;`

What could go wrong with that?

Here the full code with context: github.com/.../BatteryGuesstimateApp.mc

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0 forandy over 2 years ago

Most probably chargeNotification is null in some cases, you should a check "&& chargeNotification != null &&" before.

0 Yeti II over 2 years ago in reply to forandy

would that even happen if I cast it to Integer?

because the request is

Properties.getValue("charge-notification") as Integer;

0 forandy over 2 years ago in reply to Yeti II

yep. Properties can allways be null for any reason, and null cannot be converted to int anyhow.

+1 jim_m_58 over 2 years ago in reply to forandy

You want to have Properies.getValue() in a try/catch as if the key doesn't exist, it will throw an exception and not return null.

0 SpitRider over 2 years ago

I see that chargeNotification is not a property but a setting configurable via Garmin Connect app.

GC mobile has old known bug that numeric settings are being read as a String.

Then you are making a math comparison between String and Integer via ">" operator, that causes an exception.

You need to call "toNumber()" method on each numeric setting instead of the simple cast to Integer in order to make the code working

0 jim_m_58 over 2 years ago in reply to SpitRider

In the New Developer FAQ there is a section that talks about this specifically. A simple wrapper function that uses toNumber() and will return a default in the case of a null. I've used that in all my apps for years.

It doesn't however include the code for getValue() or the try/catch, but that was easy to add..

0 Yeti II over 2 years ago in reply to jim_m_58

If the key exists, but is empty getValue seem to return null, so I need a try/catch, check for null, and then do a toNumber()

0 Yeti II over 2 years ago in reply to Yeti II

My last comment was wrong!

I think this is the correct order:

 var chargeNotification = 0;
 try {
 chargeNotification = Properties.getValue("charge-notification") as Integer;
 } catch (e) {
 // the key does not exist, nothing to do, the default is already 0
 }
 // getValue might still return a String
 chargeNotification = chargeNotification.toNumber();
 if (chargeNotification == null) {
 chargeNotification = 0;
 }

`toNumber()` on an empty string, or any string that is not convertible to Number is returning null, see developer.garmin.com/.../String.html

0 SpitRider over 2 years ago in reply to Yeti II

Don't overcomplicate things

forums.garmin.com/.../new-developer-faq