feat(android): add support for mediaType option for android devices

[xuhcc]

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
• All existing tests are passing
• Tests for the changes are included

What is the current behavior?

mediaType option only works on iOS.

What is the new behavior?

mediaType option supported on Android too.

Implements #175.

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[xuhcc]

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[tgpetrov]

@xuhcc
Thank you for your PR. However, the demo app, currently crashes with Cannot read property 'Image' of undefined error. It seem like the ImagePickerMediaType enumeration is not recognised in the imagepicker.android.ts file. Can you check?

[xuhcc]

Hi @tgpetrov

I just tried both npm run demo.android and npm run demo.ng.android and they are working fine for me.

[xuhcc]

I also merged latest commits from master into this branch. Unfortunately npm run demo.ng.android started to crash after that, but it does not seem to be caused by my commit:

Exception in thread "main" java.lang.RuntimeException: Class not found!
	at org.nativescript.staticbindinggenerator.generating.parsing.classes.hierarchy.generics.impl.GenericsAwareClassHierarchyParserImpl.getJavaClassFromCache(GenericsAwareClassHierarchyParserImpl.java:320)
	at org.nativescript.staticbindinggenerator.generating.parsing.classes.hierarchy.generics.impl.GenericsAwareClassHierarchyParserImpl.getClassHierarchyRecursively(GenericsAwareClassHierarchyParserImpl.java:137)
	at org.nativescript.staticbindinggenerator.generating.parsing.classes.hierarchy.generics.impl.GenericsAwareClassHierarchyParserImpl.getClassHierarchy(GenericsAwareClassHierarchyParserImpl.java:54)
	at org.nativescript.staticbindinggenerator.Generator.createExtendedClassGenericHierarchyView(Generator.java:314)
	at org.nativescript.staticbindinggenerator.Generator.writeBinding(Generator.java:290)
	at org.nativescript.staticbindinggenerator.Generator.generateBinding(Generator.java:171)
	at org.nativescript.staticbindinggenerator.Generator.processRows(Generator.java:234)
	at org.nativescript.staticbindinggenerator.Generator.generateBindings(Generator.java:121)
	at org.nativescript.staticbindinggenerator.Generator.writeBindings(Generator.java:97)
	at org.nativescript.staticbindinggenerator.Main.main(Main.java:48)

[tgpetrov]

@xuhcc It seems like the issue I was hitting was related to a braking change in NativeScript CLI 6.0, so I had to include the ImagePickerMediaType in a ts file (and not only d.ts as until now). When I applied your changes, the checks were successful. Thank you for your contribution!
P.S. Due to a limitation, our checks never pass when a PR is created from fork, so I'm going to merge the PR I created and close this one.

[xuhcc]

OK, thank you!