Variable survive

Question

Hi,

Suppose we create a couple of different pages (GUI components)  and in case we want to keep a variable from one page to other, for example a set value in a slider must kept same when return to the same page from another. How can i do this?

BR

Answer 1

Hi,

if you want to keep different data within one class (e.g. a kind of settings class) you can make an autoobject and access it from everywhere within your application. Please see chapter autoobject for more details.

If you want to access values that correspond to real values of your underlying system, then let me refer to the document device class and device driver, which explains all aspects of device integration.

Hope this helps...

Comments

Hi Manfred,

There is 2 cases where i must store some variables.

1. User make a choice betwen pages and this values must kept regard only GUI enviroment for example item in a list.

2. User make a "permanent" choice for example language set or brightness of lcd panel in case of power cycle.

Questions arises with this problems is if there is a way to store variables within EmWi enviroment (direct write and read to an external EEPROM -not in flash) or EmWi must passed to device a variable, store it in external media  and then the opposite ?

Regard to Autoobject and correct me if i am rong i make a seperate unit for each page with its own components. Is this the right way for a multipage menu or i must create a GUI component (page) within root application as one file so i can create an autoobject and work with it?

BR

Paul.

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Hi Paul,

concerning the organisation of variables in autoobjects: You can create several classes each containing a set of dedicated values - or you can create one huge settings class, containing all settings of your UI application. This depends completely on your application and your software design.

Concerning the persistence: There is no automatism for storing data within a filesystem or a EEPROM - this is something that you should provide within your underlying middleware or device drivers. Please consider, that this is something completely application / target specific and not related directly to the UI application.

I hope this answers your question.

Best regards,

Manfred.