Some simple functions. Useful for displaying a progress dialog when something working in background.

BaseActivity.kt

import com.trello.rxlifecycle2.components.support.RxAppCompatActivity
import com.trello.rxlifecycle2.kotlin.bindToLifecycle
import io.reactivex.Observable
import io.reactivex.android.schedulers.AndroidSchedulers

/**
 * base activity
 * all activities should extend base activity
 * Created by icris on 2017/3/27.
 */
@Suppress("unused")
abstract class BaseActivity : RxAppCompatActivity() {

    fun <T> Observable<T>.withProgress(): Observable<T> = takeUntil(loading())
    fun <T> Observable<T>.withCancelableProgress(): Observable<T> = takeUntil(loadingCancelable())
    fun <T> Observable<T>.bindToLifecycle(): Observable<T> = bindToLifecycle(this@BaseActivity)

    fun loading(): Observable<Any> = Observable.create<Any> {
        val dialog = LoadingDialog().apply { show(supportFragmentManager, "loading") }
        it.setCancellable(dialog::dismiss)
    }.subscribeOn(AndroidSchedulers.mainThread())

    fun loadingCancelable(): Observable<Any> = Observable.create<Any> {
        val dialog = LoadingDialog(cancelable = true, onCancelListener = it::onComplete).apply {
            show(supportFragmentManager, "loading")
        }
        it.setCancellable(dialog::dismiss)
    }.subscribeOn(AndroidSchedulers.mainThread())

}

LoadingDialog.kt

import android.app.Dialog
import android.content.DialogInterface
import android.os.Bundle
import android.support.v4.app.DialogFragment
import android.view.*
import com.facebook.common.util.UriUtil
import com.facebook.drawee.backends.pipeline.Fresco
import com.facebook.drawee.drawable.ScalingUtils
import com.facebook.drawee.view.SimpleDraweeView
import org.jetbrains.anko.*
import org.jetbrains.anko.custom.ankoView

typealias OnCancelListener = () -> Unit

/**
 * loading dialog
 * Created by icris on 2017/3/27.
 */
class LoadingDialog(val cancelable: Boolean = false, val onCancelListener: OnCancelListener = {}) : DialogFragment() {

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        isCancelable = cancelable
        return super.onCreateDialog(savedInstanceState).apply {
            window?.setBackgroundDrawableResource(android.R.color.transparent)
        }
    }

    override fun onCancel(dialog: DialogInterface?) {
        super.onCancel(dialog)
        onCancelListener()
    }

    override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        return MUI().createView(AnkoContext.create(activity, this))
    }

    private class MUI : AnkoComponent<LoadingDialog> {
        override fun createView(ui: AnkoContext<LoadingDialog>): View = with(ui) {
            frameLayout {
                simpleDraweeView {
                    lparams(width = dip(80), height = dip(80))
                    imageRes = R.raw.ripple
                    hierarchy.actualImageScaleType = ScalingUtils.ScaleType.FIT_CENTER
                }
            }
        }
    }

}
inline fun ViewManager.simpleDraweeView(theme: Int = 0, init: SimpleDraweeView.() -> Unit)
        = ankoView(::SimpleDraweeView, theme) { init() }

var SimpleDraweeView.imageRes get() = 1
    set(value) {
        val controller = Fresco.newDraweeControllerBuilder()
                .setUri(UriUtil.getUriForResourceId(value))
                .setAutoPlayAnimations(true)
                .setOldController(controller)
                .build()
        setController(controller)
    }