Simplifying Fragment newInstance() implementation

[overengineered]

I often create companion methods for Fragments that create new instance of the fragment and a helper to initialise arguments for that new instance is really helpful, e.g.:

class MyFragment : Fragment() {
    companion object {
        const val LABEL = "label"
        const val INDEX = "index"

        fun newInstance(label: String, value: Int): PostFragment {
            return MyFragment().withArguments {
                putString(LABEL, label)
                putInt(INDEX, index)
            }
        }
    }
 }

Possible implementation

inline fun <T: Fragment> T.withArguments(block: Bundle.() -> Unit): T
        = this.apply { arguments = Bundle().apply(block) }

[JakeWharton]

We aren't adding any extensions for platform fragments (#161 (comment)) and this library isn't targeted for support library fragments.