Enhancement/fragment interface (#564)

* Begin fragment interfaces and themable contracts

* Prepare swiperefresh interface

* Snapshot

* Add compilable version

* Revamp once more

* Finalize layouts

* Cleanup

7 files changed, 160 insertions, 346 deletions

diff --git a/app/src/main/kotlin/com/pitchedapps/frost/web/FrostChromeClients.kt b/app/src/main/kotlin/com/pitchedapps/frost/web/FrostChromeClients.kt
index 2fa80830..344fcb27 100644
--- a/app/src/main/kotlin/com/pitchedapps/frost/web/FrostChromeClients.kt
+++ b/app/src/main/kotlin/com/pitchedapps/frost/web/FrostChromeClients.kt
@@ -5,9 +5,10 @@ import android.webkit.*
 import ca.allanwang.kau.permissions.PERMISSION_ACCESS_FINE_LOCATION
 import ca.allanwang.kau.permissions.kauRequestPermissions
 import com.pitchedapps.frost.R
-import com.pitchedapps.frost.contracts.ActivityWebContract
+import com.pitchedapps.frost.contracts.ActivityContract
 import com.pitchedapps.frost.utils.L
 import com.pitchedapps.frost.utils.frostSnackbar
+import com.pitchedapps.frost.views.FrostWebView
 import io.reactivex.subjects.BehaviorSubject
 import io.reactivex.subjects.Subject
 
@@ -45,12 +46,12 @@ class HeadlessChromeClient : WebChromeClient() {
 /**
  * The default chrome client
  */
-class FrostChromeClient(webCore: FrostWebViewCore) : WebChromeClient() {
+class FrostChromeClient(web: FrostWebView) : WebChromeClient() {
 
-    val progressObservable: Subject<Int> = webCore.progressObservable
-    val titleObservable: BehaviorSubject<String> = webCore.titleObservable
-    val activityContract = (webCore.context as? ActivityWebContract)
-    val context = webCore.context!!
+    private val progress: Subject<Int> = web.parent.progressObservable
+    private val title: BehaviorSubject<String> = web.parent.titleObservable
+    private val activity = (web.context as? ActivityContract)
+    private val context = web.context!!
 
     override fun onConsoleMessage(consoleMessage: ConsoleMessage): Boolean {
         if (consoleBlacklist.any { consoleMessage.message().contains(it) }) return true
@@ -60,18 +61,18 @@ class FrostChromeClient(webCore: FrostWebViewCore) : WebChromeClient() {
 
     override fun onReceivedTitle(view: WebView, title: String) {
         super.onReceivedTitle(view, title)
-        if (title.contains("http") || titleObservable.value == title) return
-        titleObservable.onNext(title)
+        if (title.contains("http") || this.title.value == title) return
+        this.title.onNext(title)
     }
 
     override fun onProgressChanged(view: WebView, newProgress: Int) {
         super.onProgressChanged(view, newProgress)
-        progressObservable.onNext(newProgress)
+        progress.onNext(newProgress)
     }
 
     override fun onShowFileChooser(webView: WebView, filePathCallback: ValueCallback<Array<Uri>?>, fileChooserParams: FileChooserParams): Boolean {
-        activityContract?.openFileChooser(filePathCallback, fileChooserParams) ?: webView.frostSnackbar(R.string.file_chooser_not_found)
-        return activityContract != null
+        activity?.openFileChooser(filePathCallback, fileChooserParams) ?: webView.frostSnackbar(R.string.file_chooser_not_found)
+        return activity != null
     }
 
     override fun onGeolocationPermissionsShowPrompt(origin: String, callback: GeolocationPermissions.Callback) {
diff --git a/app/src/main/kotlin/com/pitchedapps/frost/web/FrostJSI.kt b/app/src/main/kotlin/com/pitchedapps/frost/web/FrostJSI.kt
index 6bdb459e..e8135f5b 100644
--- a/app/src/main/kotlin/com/pitchedapps/frost/web/FrostJSI.kt
+++ b/app/src/main/kotlin/com/pitchedapps/frost/web/FrostJSI.kt
@@ -1,31 +1,24 @@
 package com.pitchedapps.frost.web
 
-import android.content.Context
 import android.support.v4.widget.SwipeRefreshLayout
 import android.webkit.JavascriptInterface
 import com.pitchedapps.frost.activities.MainActivity
 import com.pitchedapps.frost.contracts.VideoViewHolder
-import com.pitchedapps.frost.dbflow.CookieModel
 import com.pitchedapps.frost.facebook.FbCookie
 import com.pitchedapps.frost.utils.*
+import com.pitchedapps.frost.views.FrostWebView
 import io.reactivex.subjects.Subject
 
 
 /**
  * Created by Allan Wang on 2017-06-01.
  */
-class FrostJSI(val webView: FrostWebViewCore) {
+class FrostJSI(val web: FrostWebView) {
 
-    val context: Context
-        get() = webView.context
-
-    val activity: MainActivity?
-        get() = (context as? MainActivity)
-
-    val headerObservable: Subject<String>? = activity?.headerBadgeObservable
-
-    val cookies: ArrayList<CookieModel>
-        get() = activity?.cookies() ?: arrayListOf()
+    private val context = web.context
+    private val activity = context as? MainActivity
+    private val header: Subject<String>? = activity?.headerBadgeObservable
+    private val cookies = activity?.cookies() ?: arrayListOf()
 
     /**
      * Attempts to load the url in an overlay
@@ -34,12 +27,12 @@ class FrostJSI(val webView: FrostWebViewCore) {
      */
     @JavascriptInterface
     fun loadUrl(url: String?): Boolean
-            = if (url == null) false else webView.requestWebOverlay(url)
+            = if (url == null) false else web.requestWebOverlay(url)
 
     @JavascriptInterface
     fun loadVideo(url: String?, isGif: Boolean) {
         if (url != null)
-            webView.post {
+            web.post {
                 (context as? VideoViewHolder)?.showVideo(url, isGif)
                         ?: L.d("Could not load video; contract not implemented")
             }
@@ -48,9 +41,9 @@ class FrostJSI(val webView: FrostWebViewCore) {
     @JavascriptInterface
     fun reloadBaseUrl(animate: Boolean) {
         L.d("FrostJSI reload")
-        webView.post {
-            webView.stopLoading()
-            webView.loadBaseUrl(animate)
+        web.post {
+            web.stopLoading()
+            web.reloadBase(animate)
         }
     }
 
@@ -58,7 +51,7 @@ class FrostJSI(val webView: FrostWebViewCore) {
     fun contextMenu(url: String, text: String?) {
         if (!text.isIndependent) return
         //url will be formatted through webcontext
-        webView.post { context.showWebContextMenu(WebContext(url, text)) }
+        web.post { context.showWebContextMenu(WebContext(url, text)) }
     }
 
     /**
@@ -75,7 +68,7 @@ class FrostJSI(val webView: FrostWebViewCore) {
      */
     @JavascriptInterface
     fun disableSwipeRefresh(disable: Boolean) {
-        webView.post { (webView.parent as? SwipeRefreshLayout)?.isEnabled = !disable }
+        web.post { (web.parent as? SwipeRefreshLayout)?.isEnabled = !disable }
     }
 
     @JavascriptInterface
@@ -93,19 +86,19 @@ class FrostJSI(val webView: FrostWebViewCore) {
 
     @JavascriptInterface
     fun emit(flag: Int) {
-        webView.post { webView.frostWebClient.emit(flag) }
+        web.post { web.frostWebClient.emit(flag) }
     }
 
     @JavascriptInterface
     fun handleHtml(html: String?) {
         html ?: return
-        webView.post { webView.frostWebClient.handleHtml(html) }
+        web.post { web.frostWebClient.handleHtml(html) }
     }
 
     @JavascriptInterface
     fun handleHeader(html: String?) {
         html ?: return
-        headerObservable?.onNext(html)
+        header?.onNext(html)
     }
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/pitchedapps/frost/web/FrostUrlOverlayValidator.kt b/app/src/main/kotlin/com/pitchedapps/frost/web/FrostUrlOverlayValidator.kt
index d1f144a6..9255b5bb 100644
--- a/app/src/main/kotlin/com/pitchedapps/frost/web/FrostUrlOverlayValidator.kt
+++ b/app/src/main/kotlin/com/pitchedapps/frost/web/FrostUrlOverlayValidator.kt
@@ -9,6 +9,7 @@ import com.pitchedapps.frost.facebook.FbItem
 import com.pitchedapps.frost.facebook.USER_AGENT_BASIC
 import com.pitchedapps.frost.facebook.formattedFbUrl
 import com.pitchedapps.frost.utils.*
+import com.pitchedapps.frost.views.FrostWebView
 import org.jetbrains.anko.runOnUiThread
 
 /**
@@ -27,7 +28,7 @@ import org.jetbrains.anko.runOnUiThread
  * whether the user agent string should be changed. All propagated results will return false,
  * as we have no need of sending a new intent to the same activity
  */
-fun FrostWebViewCore.requestWebOverlay(url: String): Boolean {
+fun FrostWebView.requestWebOverlay(url: String): Boolean {
     if (url == "#" || !url.isIndependent) {
         L.i("Forbid overlay switch", url)
         return false
diff --git a/app/src/main/kotlin/com/pitchedapps/frost/web/FrostWebView.kt b/app/src/main/kotlin/com/pitchedapps/frost/web/FrostWebView.kt
deleted file mode 100644
index f6d64ab7..00000000
--- a/app/src/main/kotlin/com/pitchedapps/frost/web/FrostWebView.kt
+++ /dev/null
@@ -1,92 +0,0 @@
-package com.pitchedapps.frost.web
-
-import android.annotation.SuppressLint
-import android.content.Context
-import android.graphics.Color
-import android.os.Build
-import android.support.v4.widget.SwipeRefreshLayout
-import android.util.AttributeSet
-import android.view.View
-import android.widget.FrameLayout
-import android.widget.ProgressBar
-import ca.allanwang.kau.utils.*
-import com.pitchedapps.frost.R
-import com.pitchedapps.frost.facebook.FbItem
-import com.pitchedapps.frost.facebook.USER_AGENT_BASIC
-import com.pitchedapps.frost.utils.Prefs
-import com.pitchedapps.frost.utils.frostDownload
-import io.reactivex.android.schedulers.AndroidSchedulers
-
-/**
- * Created by Allan Wang on 2017-06-01.
- */
-class FrostWebView @JvmOverloads constructor(
-        context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0, defStyleRes: Int = 0
-) : FrameLayout(context, attrs, defStyleAttr, defStyleRes), SwipeRefreshLayout.OnRefreshListener {
-
-    val refresh: SwipeRefreshLayout by bindView(R.id.swipe_refresh)
-    val web: FrostWebViewCore by bindView(R.id.frost_webview_core)
-    val progress: ProgressBar by bindView(R.id.progress_bar)
-
-    init {
-        inflate(getContext(), R.layout.swipe_webview, this)
-        progress.tint(Prefs.textColor.withAlpha(180))
-        refresh.setColorSchemeColors(Prefs.iconColor)
-        refresh.setProgressBackgroundColorSchemeColor(Prefs.headerColor.withAlpha(255))
-        web.progressObservable.observeOn(AndroidSchedulers.mainThread()).subscribe {
-            progress.invisibleIf(it == 100)
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) progress.setProgress(it, true)
-            else progress.progress = it
-        }
-        web.refreshObservable.observeOn(AndroidSchedulers.mainThread()).subscribe {
-            refresh.isRefreshing = it
-            refresh.isEnabled = true
-        }
-        refresh.setOnRefreshListener(this)
-        addOnAttachStateChangeListener(object : OnAttachStateChangeListener {
-            override fun onViewDetachedFromWindow(v: View) {
-                web.visible()
-            }
-
-            override fun onViewAttachedToWindow(v: View) {}
-        })
-    }
-
-    @SuppressLint("SetJavaScriptEnabled")
-    fun setupWebview(url: String, enum: FbItem? = null) {
-        with(web) {
-            baseUrl = url
-            baseEnum = enum
-            with(settings) {
-                javaScriptEnabled = true
-                if (url.shouldUseBasicAgent)
-                    userAgentString = USER_AGENT_BASIC
-                allowFileAccess = true
-                textZoom = Prefs.webTextScaling
-            }
-            setLayerType(View.LAYER_TYPE_HARDWARE, null)
-            frostWebClient = baseEnum?.webClient?.invoke(this) ?: FrostWebViewClient(this)
-            webViewClient = frostWebClient
-            webChromeClient = FrostChromeClient(this)
-            addJavascriptInterface(FrostJSI(this), "Frost")
-            setBackgroundColor(Color.TRANSPARENT)
-            setDownloadListener(context::frostDownload)
-        }
-    }
-
-    //Some urls have postJavascript injections so make sure we load the base url
-    override fun onRefresh() {
-        when (web.baseUrl) {
-            FbItem.MENU.url -> web.loadBaseUrl(true)
-            else -> web.reload(true)
-        }
-    }
-
-    fun onBackPressed(): Boolean {
-        if (web.canGoBack()) {
-            web.goBack()
-            return true
-        }
-        return false
-    }
-}
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/pitchedapps/frost/web/FrostWebViewClients.kt b/app/src/main/kotlin/com/pitchedapps/frost/web/FrostWebViewClients.kt
index 5fc1ab27..71c71b66 100644
--- a/app/src/main/kotlin/com/pitchedapps/frost/web/FrostWebViewClients.kt
+++ b/app/src/main/kotlin/com/pitchedapps/frost/web/FrostWebViewClients.kt
@@ -15,6 +15,7 @@ import com.pitchedapps.frost.facebook.FbItem
 import com.pitchedapps.frost.injectors.*
 import com.pitchedapps.frost.utils.*
 import com.pitchedapps.frost.utils.iab.IS_FROST_PRO
+import com.pitchedapps.frost.views.FrostWebView
 import io.reactivex.subjects.Subject
 import org.jetbrains.anko.withAlpha
 
@@ -38,16 +39,16 @@ open class BaseWebViewClient : WebViewClient() {
 /**
  * The default webview client
  */
-open class FrostWebViewClient(val webCore: FrostWebViewCore) : BaseWebViewClient() {
+open class FrostWebViewClient(val web: FrostWebView) : BaseWebViewClient() {
 
-    val refreshObservable: Subject<Boolean> = webCore.refreshObservable
-    val isMain = webCore.baseEnum != null
+    private val refresh: Subject<Boolean> = web.parent.refreshObservable
+    private val isMain = web.parent.baseEnum != null
 
     override fun onPageStarted(view: WebView, url: String?, favicon: Bitmap?) {
         super.onPageStarted(view, url, favicon)
         if (url == null) return
         L.d("FWV Loading", url)
-        refreshObservable.onNext(true)
+        refresh.onNext(true)
     }
 
     fun launchLogin(c: Context) {
@@ -58,10 +59,10 @@ open class FrostWebViewClient(val webCore: FrostWebViewCore) : BaseWebViewClient
     }
 
     private fun injectBackgroundColor() {
-        webCore.setBackgroundColor(
+        web.setBackgroundColor(
                 when {
                     isMain -> Color.TRANSPARENT
-                    webCore.url.isFacebookUrl -> Prefs.bgColor.withAlpha(255)
+                    web.url.isFacebookUrl -> Prefs.bgColor.withAlpha(255)
                     else -> Color.WHITE
                 }
         )
@@ -80,7 +81,7 @@ open class FrostWebViewClient(val webCore: FrostWebViewCore) : BaseWebViewClient
                     CssHider.PEOPLE_YOU_MAY_KNOW.maybe(!Prefs.showSuggestedFriends && IS_FROST_PRO),
                     CssHider.SUGGESTED_GROUPS.maybe(!Prefs.showSuggestedGroups && IS_FROST_PRO),
                     Prefs.themeInjector,
-                    CssHider.NON_RECENT.maybe((webCore.url?.contains("?sk=h_chr") ?: false)
+                    CssHider.NON_RECENT.maybe((web.url?.contains("?sk=h_chr") ?: false)
                             && Prefs.aggressiveRecents))
     }
 
@@ -88,7 +89,7 @@ open class FrostWebViewClient(val webCore: FrostWebViewCore) : BaseWebViewClient
         url ?: return
         L.d("Page finished", url)
         if (!url.isFacebookUrl) {
-            refreshObservable.onNext(false)
+            refresh.onNext(false)
             return
         }
         onPageFinishedActions(url)
@@ -96,22 +97,22 @@ open class FrostWebViewClient(val webCore: FrostWebViewCore) : BaseWebViewClient
 
     open internal fun onPageFinishedActions(url: String) {
         if (url.startsWith("${FbItem.MESSAGES.url}/read/") && Prefs.messageScrollToBottom)
-            webCore.pageDown(true)
+            web.pageDown(true)
         injectAndFinish()
     }
 
     internal fun injectAndFinish() {
         L.d("Page finished reveal")
-        refreshObservable.onNext(false)
+        refresh.onNext(false)
         injectBackgroundColor()
-        webCore.jsInject(
+        web.jsInject(
                 JsActions.LOGIN_CHECK,
                 JsAssets.CLICK_A,
                 JsAssets.TEXTAREA_LISTENER,
                 CssHider.ADS.maybe(!Prefs.showFacebookAds && IS_FROST_PRO),
                 JsAssets.CONTEXT_A,
                 JsAssets.MEDIA,
-                JsAssets.HEADER_BADGES.maybe(webCore.baseEnum != null)
+                JsAssets.HEADER_BADGES.maybe(web.parent.baseEnum != null)
         )
     }
 
@@ -130,13 +131,13 @@ open class FrostWebViewClient(val webCore: FrostWebViewCore) : BaseWebViewClient
      */
     private fun launchRequest(request: WebResourceRequest): Boolean {
         L.d("Launching Url", request.url?.toString() ?: "null")
-        return webCore.requestWebOverlay(request.url.toString())
+        return web.requestWebOverlay(request.url.toString())
     }
 
     private fun launchImage(url: String, text: String? = null): Boolean {
         L.d("Launching Image", url)
-        webCore.context.launchImageActivity(url, text)
-        if (webCore.canGoBack()) webCore.goBack()
+        web.context.launchImageActivity(url, text)
+        if (web.canGoBack()) web.goBack()
         return true
     }
 
@@ -161,7 +162,7 @@ open class FrostWebViewClient(val webCore: FrostWebViewCore) : BaseWebViewClient
 /**
  * Client variant for the menu view
  */
-class FrostWebViewClientMenu(webCore: FrostWebViewCore) : FrostWebViewClient(webCore) {
+class FrostWebViewClientMenu(web: FrostWebView) : FrostWebViewClient(web) {
 
     private val String.shouldInjectMenu
         get() = when (removePrefix(FB_URL_BASE)) {
diff --git a/app/src/main/kotlin/com/pitchedapps/frost/web/FrostWebViewCore.kt b/app/src/main/kotlin/com/pitchedapps/frost/web/FrostWebViewCore.kt
deleted file mode 100644
index 15383a50..00000000
--- a/app/src/main/kotlin/com/pitchedapps/frost/web/FrostWebViewCore.kt
+++ /dev/null
@@ -1,203 +0,0 @@
-package com.pitchedapps.frost.web
-
-import android.animation.ValueAnimator
-import android.annotation.SuppressLint
-import android.content.Context
-import android.support.v4.view.NestedScrollingChild
-import android.support.v4.view.NestedScrollingChildHelper
-import android.support.v4.view.ViewCompat
-import android.util.AttributeSet
-import android.view.MotionEvent
-import android.view.animation.DecelerateInterpolator
-import android.webkit.WebView
-import ca.allanwang.kau.utils.circularReveal
-import ca.allanwang.kau.utils.fadeIn
-import ca.allanwang.kau.utils.fadeOut
-import ca.allanwang.kau.utils.isVisible
-import com.pitchedapps.frost.facebook.FbItem
-import com.pitchedapps.frost.utils.Prefs
-import io.reactivex.Scheduler
-import io.reactivex.android.schedulers.AndroidSchedulers
-import io.reactivex.disposables.Disposable
-import io.reactivex.subjects.BehaviorSubject
-import io.reactivex.subjects.PublishSubject
-
-/**
- * Created by Allan Wang on 2017-05-29.
- *
- */
-class FrostWebViewCore @JvmOverloads constructor(
-        context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
-) : WebView(context, attrs, defStyleAttr), NestedScrollingChild {
-
-    private val childHelper = NestedScrollingChildHelper(this)
-    private var lastY: Int = 0
-    private val scrollOffset = IntArray(2)
-    private val scrollConsumed = IntArray(2)
-    private var nestedOffsetY: Int = 0
-    val progressObservable: PublishSubject<Int>     // Keeps track of every progress change
-    val refreshObservable: PublishSubject<Boolean>  // Only emits on page loads
-    val titleObservable: BehaviorSubject<String>    // Only emits on different non http titles
-
-
-    var baseUrl: String? = null
-    var baseEnum: FbItem? = null //only viewpager items should pass the base enum
-    internal lateinit var frostWebClient: FrostWebViewClient
-
-    /**
-     * Wrapper to the main userAgentString to cache it.
-     * This decouples it from the UiThread
-     *
-     * Note that this defaults to null, but the main purpose is to
-     * check if we've set our own agent.
-     *
-     * A null value may be interpreted as the default value
-     */
-    var userAgentString: String? = null
-        get() = field
-        set(value) {
-            field = value
-            settings.userAgentString = value
-        }
-
-    init {
-        isNestedScrollingEnabled = true
-        progressObservable = PublishSubject.create<Int>()
-        refreshObservable = PublishSubject.create<Boolean>()
-        titleObservable = BehaviorSubject.create<String>()
-    }
-
-    fun loadUrl(url: String?, animate: Boolean) {
-        if (url == null) return
-        registerTransition(animate)
-        super.loadUrl(url)
-    }
-
-    fun reload(animate: Boolean) {
-        registerTransition(animate)
-        super.reload()
-    }
-
-    /**
-     * Hook onto the refresh observable for one cycle
-     * Animate toggles between the fancy ripple and the basic fade
-     * The cycle only starts on the first load since there may have been another process when this is registered
-     */
-    fun registerTransition(animate: Boolean) {
-        var dispose: Disposable? = null
-        var loading = false
-        dispose = refreshObservable.subscribeOn(AndroidSchedulers.mainThread()).subscribe {
-            if (it) {
-                loading = true
-                if (isVisible) fadeOut(duration = 200L)
-            } else if (loading) {
-                dispose?.dispose()
-                if (animate && Prefs.animate) circularReveal(offset = WEB_LOAD_DELAY)
-                else fadeIn(duration = 100L)
-            }
-        }
-    }
-
-    fun loadBaseUrl(animate: Boolean = true) {
-        loadUrl(baseUrl, animate)
-    }
-
-    fun addTitleListener(subscriber: (title: String) -> Unit, scheduler: Scheduler = AndroidSchedulers.mainThread()): Disposable
-            = titleObservable.observeOn(scheduler).subscribe(subscriber)
-
-    /**
-     * Handle nested scrolling against SwipeRecyclerView
-     * Courtesy of takahirom
-     *
-     * https://github.com/takahirom/webview-in-coordinatorlayout/blob/master/app/src/main/java/com/github/takahirom/webview_in_coodinator_layout/NestedWebView.java
-     */
-    @SuppressLint("ClickableViewAccessibility")
-    override fun onTouchEvent(ev: MotionEvent): Boolean {
-        val event = MotionEvent.obtain(ev)
-        val action = event.action
-        if (action == MotionEvent.ACTION_DOWN)
-            nestedOffsetY = 0
-        val eventY = event.y.toInt()
-        event.offsetLocation(0f, nestedOffsetY.toFloat())
-        val returnValue: Boolean
-        when (action) {
-            MotionEvent.ACTION_MOVE -> {
-                var deltaY = lastY - eventY
-                // NestedPreScroll
-                if (dispatchNestedPreScroll(0, deltaY, scrollConsumed, scrollOffset)) {
-                    deltaY -= scrollConsumed[1]
-                    event.offsetLocation(0f, -scrollOffset[1].toFloat())
-                    nestedOffsetY += scrollOffset[1]
-                }
-                lastY = eventY - scrollOffset[1]
-                returnValue = super.onTouchEvent(event)
-                // NestedScroll
-                if (dispatchNestedScroll(0, scrollOffset[1], 0, deltaY, scrollOffset)) {
-                    event.offsetLocation(0f, scrollOffset[1].toFloat())
-                    nestedOffsetY += scrollOffset[1]
-                    lastY -= scrollOffset[1]
-                }
-            }
-            MotionEvent.ACTION_DOWN -> {
-                returnValue = super.onTouchEvent(event)
-                lastY = eventY
-                startNestedScroll(ViewCompat.SCROLL_AXIS_VERTICAL)
-            }
-            MotionEvent.ACTION_UP, MotionEvent.ACTION_CANCEL -> {
-                returnValue = super.onTouchEvent(event)
-                stopNestedScroll()
-            }
-            else -> return false
-        }
-        return returnValue
-    }
-
-    /**
-     * If webview is already at the top, refresh
-     * Otherwise scroll to top
-     */
-    fun scrollOrRefresh() {
-        if (scrollY < 5) loadBaseUrl()
-        else scrollToTop()
-    }
-
-    fun scrollToTop() {
-        flingScroll(0, 0) // stop fling
-        if (scrollY > 10000) {
-            scrollTo(0, 0)
-        } else {
-            ValueAnimator.ofInt(scrollY, 0).apply {
-                duration = Math.min(scrollY, 500).toLong()
-                interpolator = DecelerateInterpolator()
-                addUpdateListener { scrollY = it.animatedValue as Int }
-                start()
-            }
-        }
-    }
-
-    // Nested Scroll implements
-    override fun setNestedScrollingEnabled(enabled: Boolean) {
-        childHelper.isNestedScrollingEnabled = enabled
-    }
-
-    override fun isNestedScrollingEnabled() = childHelper.isNestedScrollingEnabled
-
-    override fun startNestedScroll(axes: Int) = childHelper.startNestedScroll(axes)
-
-    override fun stopNestedScroll() = childHelper.stopNestedScroll()
-
-    override fun hasNestedScrollingParent() = childHelper.hasNestedScrollingParent()
-
-    override fun dispatchNestedScroll(dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, offsetInWindow: IntArray?)
-            = childHelper.dispatchNestedScroll(dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed, offsetInWindow)
-
-    override fun dispatchNestedPreScroll(dx: Int, dy: Int, consumed: IntArray?, offsetInWindow: IntArray?)
-            = childHelper.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow)
-
-    override fun dispatchNestedFling(velocityX: Float, velocityY: Float, consumed: Boolean)
-            = childHelper.dispatchNestedFling(velocityX, velocityY, consumed)
-
-    override fun dispatchNestedPreFling(velocityX: Float, velocityY: Float)
-            = childHelper.dispatchNestedPreFling(velocityX, velocityY)
-
-}
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/pitchedapps/frost/web/NestedWebView.kt b/app/src/main/kotlin/com/pitchedapps/frost/web/NestedWebView.kt
new file mode 100644
index 00000000..f0bb6137
--- /dev/null
+++ b/app/src/main/kotlin/com/pitchedapps/frost/web/NestedWebView.kt
@@ -0,0 +1,113 @@
+package com.pitchedapps.frost.web
+
+import android.annotation.SuppressLint
+import android.content.Context
+import android.support.v4.view.NestedScrollingChild
+import android.support.v4.view.NestedScrollingChildHelper
+import android.support.v4.view.ViewCompat
+import android.util.AttributeSet
+import android.view.MotionEvent
+import android.webkit.WebView
+
+
+/**
+ * Created by Allan Wang on 20/12/17.
+ *
+ * Webview extension that handles nested scrolls
+ */
+open class NestedWebView @JvmOverloads constructor(
+        context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
+) : WebView(context, attrs, defStyleAttr), NestedScrollingChild {
+
+    private lateinit var childHelper: NestedScrollingChildHelper
+    private var lastY: Int = 0
+    private val scrollOffset = IntArray(2)
+    private val scrollConsumed = IntArray(2)
+    private var nestedOffsetY: Int = 0
+
+    init {
+        init()
+    }
+
+    fun init() {
+        // To avoid leaking constructor
+        childHelper = NestedScrollingChildHelper(this)
+    }
+
+    /**
+     * Handle nested scrolling against SwipeRecyclerView
+     * Courtesy of takahirom
+     *
+     * https://github.com/takahirom/webview-in-coordinatorlayout/blob/master/app/src/main/java/com/github/takahirom/webview_in_coodinator_layout/NestedWebView.java
+     */
+    @SuppressLint("ClickableViewAccessibility")
+    override final fun onTouchEvent(ev: MotionEvent): Boolean {
+        val event = MotionEvent.obtain(ev)
+        val action = event.action
+        if (action == MotionEvent.ACTION_DOWN)
+            nestedOffsetY = 0
+        val eventY = event.y.toInt()
+        event.offsetLocation(0f, nestedOffsetY.toFloat())
+        val returnValue: Boolean
+        when (action) {
+            MotionEvent.ACTION_MOVE -> {
+                var deltaY = lastY - eventY
+                // NestedPreScroll
+                if (dispatchNestedPreScroll(0, deltaY, scrollConsumed, scrollOffset)) {
+                    deltaY -= scrollConsumed[1]
+                    event.offsetLocation(0f, -scrollOffset[1].toFloat())
+                    nestedOffsetY += scrollOffset[1]
+                }
+                lastY = eventY - scrollOffset[1]
+                returnValue = super.onTouchEvent(event)
+                // NestedScroll
+                if (dispatchNestedScroll(0, scrollOffset[1], 0, deltaY, scrollOffset)) {
+                    event.offsetLocation(0f, scrollOffset[1].toFloat())
+                    nestedOffsetY += scrollOffset[1]
+                    lastY -= scrollOffset[1]
+                }
+            }
+            MotionEvent.ACTION_DOWN -> {
+                returnValue = super.onTouchEvent(event)
+                lastY = eventY
+                startNestedScroll(ViewCompat.SCROLL_AXIS_VERTICAL)
+            }
+            MotionEvent.ACTION_UP, MotionEvent.ACTION_CANCEL -> {
+                returnValue = super.onTouchEvent(event)
+                stopNestedScroll()
+            }
+            else -> return false
+        }
+        return returnValue
+    }
+
+    /*
+     * ---------------------------------------------
+     * Nested Scrolling Content
+     * ---------------------------------------------
+     */
+
+    override final fun setNestedScrollingEnabled(enabled: Boolean) {
+        childHelper.isNestedScrollingEnabled = enabled
+    }
+
+    override final fun isNestedScrollingEnabled() = childHelper.isNestedScrollingEnabled
+
+    override final fun startNestedScroll(axes: Int) = childHelper.startNestedScroll(axes)
+
+    override final fun stopNestedScroll() = childHelper.stopNestedScroll()
+
+    override final fun hasNestedScrollingParent() = childHelper.hasNestedScrollingParent()
+
+    override final fun dispatchNestedScroll(dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, offsetInWindow: IntArray?)
+            = childHelper.dispatchNestedScroll(dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed, offsetInWindow)
+
+    override final fun dispatchNestedPreScroll(dx: Int, dy: Int, consumed: IntArray?, offsetInWindow: IntArray?)
+            = childHelper.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow)
+
+    override final fun dispatchNestedFling(velocityX: Float, velocityY: Float, consumed: Boolean)
+            = childHelper.dispatchNestedFling(velocityX, velocityY, consumed)
+
+    override final fun dispatchNestedPreFling(velocityX: Float, velocityY: Float)
+            = childHelper.dispatchNestedPreFling(velocityX, velocityY)
+}
\ No newline at end of file