[battery] Port battery to use platform interface

[yash1200]

Description

In this PR, I have ported battery to use battery_platform_package .

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[yash1200]

Hey @ditman kindly have a look at this one :)

[ditman]

This looks great! However the current master is failing a test. I'll merge this once that gets fixed!

[yash1200]

Sounds good :) Thank you @ditman .

[ditman]

LGTM, lots of red! Let's merge this. Thanks for the contribution!

[ditman]

Tagged and published as battery: ^1.0.5

[yash1200]

Thank you sir!

[yash1200]

Hey @ditman , I had a query, I was working on it's linux version and and for that I don't need to make method call as I can get data by opening 2 files in dart only. For that to work I have to make get methods batteryLevel and onBatteryStateChanged and then override the platform functions in battery_platform_interface to get data, which means I have to rename platform functions to get that working. Am I in right direction or is there some other method to get this working?

[ditman]

@yash1200 on Linux you just need to implement the calls to the Method Channel of the battery interface in C++, similar to this:

https://github.com/flutter/plugins/blob/master/packages/url_launcher/url_launcher_linux/linux/url_launcher_plugin.cc

No need to override anything on the platform interface.

I hope that helps!

[yash1200]

Method channel can be implemented in Linux but I don't know about event channels. I couldn't find anything on it on flutter engine docs. That's why I was trying to implement it like this.

This way it can be done using Dart only, as I have to listen to file /sys/class/power_supply/BAT1/status for getting battery status and it can be done in Dart.

[ditman]

@yash1200 shared_preferences_linux seems to be written in Dart also, you might want to use it as an additional example: https://github.com/flutter/plugins/tree/master/packages/shared_preferences/shared_preferences_linux

What's the problem?

Also, do you think there's a more portable way to check the battery? it seems there can be multiple BATx devices (some blog posts I see BAT0)

[yash1200]

Thanks for the information @ditman . Just had a little confusion in it and it's resolved now. And for the BATx , there are only two versions of it. This differs with distros. I'll add a check for this in the plugin 😀. Thanks again.