Enable swipe-to-refresh for browser tabs

app/build.gradle

@@ -99,6 +99,7 @@ android {
 ext {
     androidX = "1.2.0-beta01"
     materialDesign = "1.2.0-alpha05"
+    swipeRefreshLayout = "1.0.0"
     architectureComponents = "1.1.1"
     architectureComponentsExtensions = "1.1.1"
     androidKtxCore = "1.2.0"
@@ -146,6 +147,7 @@ dependencies {
     implementation "androidx.appcompat:appcompat:$androidX"
     implementation "com.google.android.material:material:$materialDesign"
     implementation "androidx.constraintlayout:constraintlayout:$constraintLayout"
+    implementation "androidx.swiperefreshlayout:swiperefreshlayout:$swipeRefreshLayout"
     implementation "androidx.webkit:webkit:$webkit"
     implementation "com.squareup.okhttp3:okhttp:$okHttp"
     implementation "com.squareup.retrofit2:retrofit:$retrofit"

app/src/main/java/com/duckduckgo/app/browser/BrowserTabFragment.kt

@@ -287,6 +287,7 @@ class BrowserTabFragment : Fragment(), FindListener, CoroutineScope, DaxDialogLi
         configureObservers()
         configurePrivacyGrade()
         configureWebView()
+        configureSwipeRefresh()
         viewModel.registerWebViewListener(webViewClient, webChromeClient)
         configureOmnibarTextInput()
         configureFindInPage()
@@ -842,6 +843,21 @@ class BrowserTabFragment : Fragment(), FindListener, CoroutineScope, DaxDialogLi
         }
     }
 
+    private fun configureSwipeRefresh() {
+        swipeRefreshContainer.setColorSchemeColors(ContextCompat.getColor(requireContext(), R.color.cornflowerBlue))
+
+        swipeRefreshContainer.setOnRefreshListener {
+            onRefreshRequested()
+        }
+
+        swipeRefreshContainer.setCanChildScrollUpCallback {
+            webView?.canScrollVertically(-1) ?: false
+        }
+
+        // avoids progressView from showing under toolbar
+        swipeRefreshContainer.progressViewStartOffset = swipeRefreshContainer.progressViewStartOffset - 15
+    }
+
     /**
      * Explicitly disable database to try protect against Magellan WebSQL/SQLite vulnerability
      */
@@ -1451,6 +1467,10 @@ class BrowserTabFragment : Fragment(), FindListener, CoroutineScope, DaxDialogLi
                         createTrackersAnimation()
                     }
                 }
+
+                if (!viewState.isLoading) {
+                    swipeRefreshContainer.isRefreshing = false
+                }
             }
         }
 

app/src/main/java/com/duckduckgo/app/browser/DuckDuckGoWebView.kt

@@ -83,7 +83,10 @@ class DuckDuckGoWebView : WebView, NestedScrollingChild {
 
                 returnValue = super.onTouchEvent(event)
 
-                if (dispatchNestedScroll(0, scrollOffset[1], 0, deltaY, scrollOffset)) {
+                if (scrollY == 0) {
+                    // Give parents control (required for SwipeRefreshLayout to work)
+                    stopNestedScroll()
+                } else if (dispatchNestedScroll(0, scrollOffset[1], 0, deltaY, scrollOffset)) {
                     event.offsetLocation(0f, scrollOffset[1].toFloat())
                     nestedOffsetY += scrollOffset[1]
                     lastY -= scrollOffset[1]

app/src/main/java/com/duckduckgo/app/browser/ui/ScrollAwareRefreshLayout.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2020 DuckDuckGo
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.duckduckgo.app.browser.ui
+
+import android.content.Context
+import android.util.AttributeSet
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
+
+class ScrollAwareRefreshLayout(context: Context, attrs: AttributeSet?) : SwipeRefreshLayout(context, attrs) {
+
+    private var canChildScrollUpCallback: (() -> Boolean)? = null
+
+    fun setProgressViewStartOffset(start: Int) {
+        mOriginalOffsetTop = start
+    }
+
+    override fun canChildScrollUp(): Boolean {
+        return canChildScrollUpCallback?.invoke() ?: super.canChildScrollUp()
+    }
+
+    fun setCanChildScrollUpCallback(callback: () -> Boolean) {
+        canChildScrollUpCallback = callback
+    }
+}

app/src/main/res/layout/fragment_browser_tab.xml

@@ -71,16 +71,23 @@
         app:layout_behavior="@string/appbar_scrolling_view_behavior"
         tools:context="com.duckduckgo.app.browser.BrowserActivity">
 
-        <FrameLayout
-            android:id="@+id/webViewContainer"
-            android:layout_width="0dp"
-            android:layout_height="0dp"
-            app:layout_behavior="@string/appbar_scrolling_view_behavior"
-            app:layout_constraintBottom_toBottomOf="parent"
-            app:layout_constraintEnd_toEndOf="parent"
-            app:layout_constraintStart_toStartOf="parent"
-            app:layout_constraintTop_toTopOf="parent"
-            tools:background="#4F00" />
+        <com.duckduckgo.app.browser.ui.ScrollAwareRefreshLayout
+            android:id="@+id/swipeRefreshContainer"
+            android:layout_width="match_parent"
+            android:layout_height="match_parent">
+
+                <FrameLayout
+                    android:id="@+id/webViewContainer"
+                    android:layout_width="0dp"
+                    android:layout_height="0dp"
+                    app:layout_behavior="@string/appbar_scrolling_view_behavior"
+                    app:layout_constraintBottom_toBottomOf="parent"
+                    app:layout_constraintEnd_toEndOf="parent"
+                    app:layout_constraintStart_toStartOf="parent"
+                    app:layout_constraintTop_toTopOf="parent"
+                    tools:background="#4F00" />
+
+        </com.duckduckgo.app.browser.ui.ScrollAwareRefreshLayout>
 
         <View
             android:id="@+id/focusDummy"