MVP implementation

BasePresenter.kt

/**
 * @since 2017
 * @author Anton Vlasov - whalemare
 */
interface BasePresenter<in V : BaseView, R> {
    fun attachView(view: V)
    fun detachView()

    fun attachRouter(router: R?)
    fun detachRouter()
}

BaseView.kt

/**
 * @since 2017
 * @author Anton Vlasov - whalemare
 */
interface BaseView {
    fun showError(text: String)
}

MvpController.kt

/**
 * @since 2017
 * @author Anton Vlasov - whalemare
 */
abstract class MvpController<
        V : BaseView, 
        P : BasePresenter<V, R>,
        R : BaseRouter>(bundle: Bundle)
    : BaseController(bundle), BaseView {

    @field:javax.inject.Inject
    protected lateinit var presenter: P

    protected abstract fun getMvpRouter(): R?
    protected abstract fun getMvpView(): V

    override fun onAttach(view: android.view.View) {
        super.onAttach(view)
        presenter.attachView(getMvpView())
        presenter.attachRouter(getMvpRouter())
    }

    override fun onDetach(view: android.view.View) {
        super.onDetach(view)
        presenter.detachView()
        presenter.detachRouter()
    }

    override fun showError(text: String) {
        activity?.message(text)
    }
}

MvpPresenter.kt

/**
 * @since 2017
 * @author Anton Vlasov - whalemare
 */
abstract class MvpPresenter<V : BaseView, R : BaseRouter> : BasePresenter<V, R> {

    private var viewRef: WeakReference<V>? = null
    private var routerRef: WeakReference<R>? = null

    abstract fun onViewAttached()

    open fun onRouterAttached() {}

    override fun attachView(view: V) {
        viewRef = WeakReference(view)

        onViewAttached()
    }

    override fun attachRouter(router: R?) {
        if(router != null) {
            routerRef = WeakReference(router)
            onRouterAttached()
        }
    }

    override fun detachRouter() {
        routerRef?.clear()
        routerRef = null
    }

    override fun detachView() {
        viewRef?.clear()
        viewRef = null
    }

    protected fun getView(): V? {
        return viewRef?.get()
    }

    protected fun isViewAttached(): Boolean {
        return viewRef?.get() != null
    }

    protected fun isActive(body: (v: V) -> Unit) {
        if (isViewAttached()) {
            tryOnUiThread({
                body.invoke(getView()!!)
            })
        }
    }

    protected fun showError(error: Throwable) {
        Timber.e(error, "error: \n")
        isActive { it.showError(error.localizedMessage) }
    }

    fun tryOnUiThread(body: () -> Unit) {
        if (Looper.myLooper() == Looper.getMainLooper()) {
            body.invoke()
        } else {
            throw IllegalThreadStateException(
                    "You can`t access to view from not UI thread. Current thread = ${Thread.currentThread()}"
            )
        }
    }
}