Closes mozilla-mobile#1079: Adding find in page feature component.

.buildconfig.yml

@@ -72,6 +72,10 @@ projects:
     path: components/feature/prompts
     description: 'Feature that will subscribe to the selected session and will handle all the common prompt dialogs from web content.'
     publish: true
+  feature-findinpage:
+      path: components/feature/findinpage
+      description: 'Feature that will subscribe to the selected session and shows a UI based on the data Session.findResults.'
+      publish: true
   browser-awesomebar:
     path: components/browser/awesomebar
     description: 'A customizable awesomebar component for browsers.'

README.md

@@ -124,6 +124,8 @@ _Combined components to implement feature-specific use cases._
 
 * 🔴 [**Prompts**](components/feature/prompts/README.md) - A component that will handle all the common prompt dialogs from web content.
 
+* 🔴 [**Find In Page**](components/feature/findinpage/README.md) - A component that provides an UI widget for [find in page functionality](https://support.mozilla.org/en-US/kb/search-contents-current-page-text-or-links).
+
 ## UI
 
 _Generic low-level UI components for building apps._

components/feature/findinpage/README.md

@@ -0,0 +1,68 @@
+# [Android Components](../../../README.md) > Feature > Prompts
+
+A feature that provides an UI widget for [find in page functionality](https://support.mozilla.org/en-US/kb/search-contents-current-page-text-or-links).
+
+## Usage
+
+### Setting up the dependency
+Use Gradle to download the library from [maven.mozilla.org](https://maven.mozilla.org/) ([Setup repository](../../../README.md#maven-repository)):
+
+```Groovy
+implementation "org.mozilla.components:feature-findinpage:{latest-version}"
+```
+
+### Adding feature find in page.
+To use feature find in page you have to do two things:
+
+**1. Add the `FindInPageView` widget to you layout.**
+
+By default, it has a`GONE` visibility, and to make it visible just call `show()`.
+```xml
+        <mozilla.components.feature.findinpage.FindInPageView
+                android:id="@+id/find_in_page"
+                android:layout_width="match_parent"
+                android:background="#FFFFFFFF"
+                android:elevation="10dp"
+                android:layout_height="56dp"
+                android:padding="4dp" />
+```
+
+These are the properties that you can customize of this widget.
+```xml
+        <attr name="findInPageQueryTextColor" format="reference|color"/>
+        <attr name="findInPageQueryHintTextColor" format="reference|color"/>
+        <attr name="findInPageQueryTextSize" format="dimension"/>
+        <attr name="findInPageResultCountTextColor" format="reference|color"/>
+        <attr name="findInPageResultCountTextSize" format="dimension"/>
+        <attr name="findInPageButtonsTint" format="reference|color"/>
+```
+
+**2. Start the `FindInPageFeature` in you activity/fragment.**
+
+```kotlin
+     val findInPageView = layout.findViewById<FindInPageView>(R.id.find_in_page)
+
+     val  findInPageFeature = FindInPageFeature(
+            sessionManager = sessionManager,
+            findInPageView = findInPageView
+        )
+
+        lifecycle.addObservers( findInPageFeature)
+
+       // To make it visible
+       findInPageView.show()
+
+       // Optional
+       findInPageView.onCloseButtonPressListener = {
+         // Do something.
+        }
+
+```
+
+🦊 A practical example of using feature find in page can be found in [Sample Browser](https://github.com/mozilla-mobile/android-components/tree/master/samples/browser).
+
+## License
+
+    This Source Code Form is subject to the terms of the Mozilla Public
+    License, v. 2.0. If a copy of the MPL was not distributed with this
+    file, You can obtain one at http://mozilla.org/MPL/2.0/

components/feature/findinpage/build.gradle

@@ -0,0 +1,41 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
+
+android {
+    compileSdkVersion config.compileSdkVersion
+
+    defaultConfig {
+        minSdkVersion config.minSdkVersion
+        targetSdkVersion config.targetSdkVersion
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+}
+
+dependencies {
+    implementation project(':browser-session')
+    implementation project(':concept-engine')
+    implementation project(':support-ktx')
+    implementation project(':ui-icons')
+
+    implementation Dependencies.kotlin_stdlib
+    implementation Dependencies.support_constraintlayout
+
+    testImplementation Dependencies.androidx_test_core
+    testImplementation Dependencies.testing_junit
+    testImplementation Dependencies.testing_robolectric
+    testImplementation Dependencies.testing_mockito
+    testImplementation project(':support-test')
+}
+
+apply from: '../../../publish.gradle'
+ext.configurePublish(config.componentsGroupId, archivesBaseName, project.ext.description)

components/feature/findinpage/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

components/feature/findinpage/src/main/AndroidManifest.xml

@@ -0,0 +1,5 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="mozilla.components.feature.findinpage" />

components/feature/findinpage/src/main/java/mozilla/components/feature/findinpage/FindInPageFeature.kt

@@ -0,0 +1,83 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package mozilla.components.feature.findinpage
+
+import android.support.annotation.CallSuper
+import android.support.annotation.VisibleForTesting
+import android.support.annotation.VisibleForTesting.PRIVATE
+import mozilla.components.browser.session.SelectionAwareSessionObserver
+import mozilla.components.browser.session.Session
+import mozilla.components.browser.session.SessionManager
+import mozilla.components.support.base.feature.LifecycleAwareFeature
+
+/**
+ * This feature will subscribe to the currently selected [Session] and when started will forward
+ * [Session.Observer.onFindResult] calls to the [findInPageView] ui widget.
+ *
+ * @property sessionManager The [SessionManager] instance in order to subscribe to the selected [Session].
+ * @property findInPageView The [FindInPageView] instance that will capture user interactions, and new calls
+ *  of [Session.Observer.onFindResult] will be delegated.
+ */
+
+class FindInPageFeature(
+    private val sessionManager: SessionManager,
+    private val findInPageView: FindInPageView
+) : LifecycleAwareFeature {
+
+    private val observer = FindInPageRequestObserver(sessionManager, feature = this)
+
+    /**
+     * Start observing the selected session and forwarding events to the [findInPageView] widget.
+     */
+    override fun start() {
+        observer.observeSelected()
+        val selectedSession = sessionManager.selectedSession ?: return
+        val engineSession = sessionManager.getEngineSession(selectedSession) ?: return
+        findInPageView.sessionEngine = engineSession
+    }
+
+    /**
+     * Stop observing the selected session and forwarding events to the [findInPageView] widget.
+     */
+    override fun stop() {
+        observer.stop()
+    }
+
+    /**
+     * Informs the [findInPageView] widget that the back button has been pressed.
+     *
+     * @return true if the event was handled, otherwise false.
+     */
+    fun onBackPressed(): Boolean {
+        return if (findInPageView.isActive()) {
+            findInPageView.onCloseButtonClicked()
+            true
+        } else {
+            false
+        }
+    }
+
+    @VisibleForTesting(otherwise = PRIVATE)
+    internal fun onFindResult(session: Session, result: Session.FindResult) {
+        findInPageView.onFindResultReceived(result)
+    }
+
+    internal class FindInPageRequestObserver(
+        private val sessionManager: SessionManager,
+        private val feature: FindInPageFeature
+    ) : SelectionAwareSessionObserver(sessionManager) {
+
+        override fun onFindResult(session: Session, result: Session.FindResult) {
+            feature.onFindResult(session, result)
+        }
+
+        @CallSuper
+        override fun onSessionSelected(session: Session) {
+            super.onSessionSelected(session)
+            val engineSession = sessionManager.getEngineSession(session) ?: return
+            feature.findInPageView.sessionEngine = engineSession
+        }
+    }
+}