Animation Sample:Demonstration of AnimatedSwitcher

[farheen21]

Made an animation sample by using AnimatedSwticher

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[farheen21]

@redbrogdon @kwalrath @johnpryan Needs your reviews here.

[farheen21]

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@googlebot i signed it!

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[johnpryan]

Hi @farheen21, thanks for the pull request. Did you know we also have an AnimatedSwitcher example in the docs? https://api.flutter.dev/flutter/widgets/AnimatedSwitcher-class.html

@redbrogdon @gspencergoog do you know if the AnimatedSwitcher example in the docs will get a DartPad version?

[gspencergoog]

Well, there weren't any plans for it, but it was easy enough, so I did: see flutter/flutter#52547

[johnpryan]

@farheen21 Thanks for making a PR. We are generally looking for contributions to be "fixes and necessary improvements". This is looks like of a technique to create a toggle-switch widget using an AnimatedPositioned with an AnimatedSwitcher. Also, this isn't one of the basic building blocks and patterns we want to cover in the basics section, so I'm going to close the issue. Filing issues before submitting pull requests can help validate contribution ideas first.

Thanks!