Anko Fragments v3

FragmentView.kt

import android.app.Activity
import android.app.Fragment
import android.content.Context
import android.view.View
import android.view.ViewManager
import android.widget.RelativeLayout
import org.jetbrains.anko.custom.ankoView

/**
 * @property childFragment The Fragment which this view should contain. Setting this value will destroy previous fragments and commit the new one.
 * @constructor Creates a new FragmentView.
 */
class FragmentView(ctx: Context) : RelativeLayout(ctx) {
    var childFragment: Fragment? = null
        get() = field
        set(value) {
            // Destroy the existing fragment if there is one
            if (childFragment != null) (context as Activity).fragmentManager.beginTransaction().remove(childFragment).commit()

            // Create and commit the new fragment
            field = value
            if (field == null) { return }
            (context as Activity).fragmentManager.beginTransaction().add(id, field).commit()
        }

    init {
        // Get an ID
        this.id = View.generateViewId()
    }
}

// Anko support
inline fun ViewManager.fragmentView(theme: Int = 0) = fragmentView(theme) {}
inline fun ViewManager.fragmentView(theme: Int = 0, init: FragmentView.() -> Unit) = ankoView({ FragmentView(it) }, theme, init)