manually manage the web view in order to make sure it does not leak

Author: brindy

app/build.gradle

@@ -6,7 +6,7 @@ apply plugin: 'kotlin-kapt'
 apply from: '../versioning.gradle'
 
 ext {
-    VERSION_NAME = "4.0.8"
+    VERSION_NAME = "4.0.9"
 }
 
 android {
@@ -79,6 +79,9 @@ ext {
 
 
 dependencies {
+    debugCompile 'com.squareup.leakcanary:leakcanary-android:1.5.4'
+    releaseCompile 'com.squareup.leakcanary:leakcanary-android-no-op:1.5.4'
+
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
     implementation "com.android.support:appcompat-v7:$supportLibrary"

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

@@ -24,16 +24,19 @@ import android.arch.lifecycle.ViewModelProviders
 import android.content.Context
 import android.content.Intent
 import android.net.Uri
+import android.os.Build
 import android.os.Bundle
 import android.support.v7.widget.LinearLayoutManager
 import android.text.Editable
 import android.view.KeyEvent.KEYCODE_ENTER
 import android.view.Menu
 import android.view.MenuItem
 import android.view.View
+import android.view.View.FOCUSABLE
 import android.view.inputmethod.EditorInfo.IME_ACTION_DONE
 import android.webkit.CookieManager
 import android.webkit.WebSettings.MIXED_CONTENT_COMPATIBILITY_MODE
+import android.webkit.WebView
 import android.widget.TextView
 import android.widget.Toast
 import com.duckduckgo.app.bookmarks.ui.BookmarksActivity
@@ -79,11 +82,43 @@ class BrowserActivity : DuckDuckGoActivity() {
     private val fireMenu: MenuItem?
         get() = toolbar.menu.findItem(R.id.fire_menu_item)
 
+    private lateinit var webView: WebView
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
+
         setContentView(R.layout.activity_browser)
+
+        createWebView()
+        createPopupMenu()
+        configureObservers()
+        configureToolbar()
+        configureWebView()
+        configureOmnibarTextInput()
+        configureDummyViewTouchHandler()
+        configureAutoComplete()
+
+        if (savedInstanceState == null) {
+            consumeSharedTextExtra()
+        }
+    }
+
+    private fun createPopupMenu() {
         popupMenu = BrowserPopupMenu(layoutInflater)
+    }
 
+    // inspired by https://stackoverflow.com/a/8011027/73479
+    private fun createWebView() {
+        webView = NestedWebView(this.applicationContext)
+        webView.gone()
+        webView.isFocusableInTouchMode = true
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            webView.focusable = FOCUSABLE
+        }
+        webViewContainer.addView(webView)
+    }
+
+    private fun configureObservers() {
         viewModel.viewState.observe(this, Observer<BrowserViewModel.ViewState> {
             it?.let { render(it) }
         })
@@ -122,16 +157,6 @@ class BrowserActivity : DuckDuckGoActivity() {
                 }
             }
         })
-
-        configureToolbar()
-        configureWebView()
-        configureOmnibarTextInput()
-        configureDummyViewTouchHandler()
-        configureAutoComplete()
-
-        if (savedInstanceState == null) {
-            consumeSharedTextExtra()
-        }
     }
 
     private fun configureAutoComplete() {
@@ -435,6 +460,9 @@ class BrowserActivity : DuckDuckGoActivity() {
     }
 
     override fun onDestroy() {
+        webViewContainer.removeAllViews()
+        webView.destroy()
+
         popupMenu.dismiss()
         super.onDestroy()
     }

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

@@ -16,6 +16,7 @@
 
 package com.duckduckgo.app.browser
 
+import android.annotation.SuppressLint
 import android.content.Context
 import android.support.v4.view.NestedScrollingChild
 import android.support.v4.view.NestedScrollingChildHelper
@@ -44,6 +45,7 @@ class NestedWebView : WebView, NestedScrollingChild {
         isNestedScrollingEnabled = true
     }
 
+    @SuppressLint("ClickableViewAccessibility")
     override fun onTouchEvent(ev: MotionEvent): Boolean {
         var returnValue = false
 

app/src/main/java/com/duckduckgo/app/global/DuckDuckGoApplication.kt

@@ -24,6 +24,7 @@ import com.duckduckgo.app.di.DaggerAppComponent
 import com.duckduckgo.app.job.AppConfigurationSyncer
 import com.duckduckgo.app.migration.LegacyMigration
 import com.duckduckgo.app.trackerdetection.TrackerDataLoader
+import com.squareup.leakcanary.LeakCanary
 import dagger.android.AndroidInjector
 import dagger.android.DispatchingAndroidInjector
 import dagger.android.HasActivityInjector
@@ -56,6 +57,8 @@ class DuckDuckGoApplication : HasActivityInjector, HasServiceInjector, Applicati
     override fun onCreate() {
         super.onCreate()
 
+        if (!installLeakCanary()) return
+
         configureDependencyInjection()
         configureLogging()
         configureCrashReporting()
@@ -66,6 +69,14 @@ class DuckDuckGoApplication : HasActivityInjector, HasServiceInjector, Applicati
         migrateLegacyDb()
     }
 
+    private fun installLeakCanary(): Boolean {
+        if (LeakCanary.isInAnalyzerProcess(this)) {
+            return false;
+        }
+        LeakCanary.install(this);
+        return true
+    }
+
     private fun migrateLegacyDb() {
         doAsync {
             migration.start { favourites, searches ->

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

@@ -140,15 +140,12 @@
             android:layout_height="match_parent"
             android:focusableInTouchMode="true" />
 
-        <com.duckduckgo.app.browser.NestedWebView
-            android:id="@+id/webView"
+        <FrameLayout
+            android:id="@+id/webViewContainer"
             android:layout_width="match_parent"
             android:layout_height="match_parent"
-            android:focusable="true"
-            android:focusableInTouchMode="true"
-            android:visibility="gone"
             app:layout_behavior="@string/appbar_scrolling_view_behavior"
-            tools:visibility="visible" />
+            />
 
         <android.support.v7.widget.RecyclerView
             android:id="@+id/autoCompleteSuggestionsList"