Add scroll to bottom button

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/ConversationActivityV2.kt

@@ -197,6 +197,10 @@ class ConversationActivityV2 : PassphraseRequiredActionBarActivity(), InputBarDe
         val attachmentOptionsContainerLayoutParams = attachmentOptionsContainer.layoutParams as RelativeLayout.LayoutParams
         attachmentOptionsContainerLayoutParams.bottomMargin = bottomMargin + attachmentButtonHeight + margin
         attachmentOptionsContainer.layoutParams = attachmentOptionsContainerLayoutParams
+        // Scroll to bottom button
+        val scrollToBottomButtonLayoutParams = scrollToBottomButton.layoutParams as RelativeLayout.LayoutParams
+        scrollToBottomButtonLayoutParams.bottomMargin = newValue + additionalContentContainer.height + toPx(12, resources)
+        scrollToBottomButton.layoutParams = scrollToBottomButtonLayoutParams
     }
 
     override fun inputBarEditTextContentChanged(newContent: CharSequence) {
@@ -313,7 +317,7 @@ class ConversationActivityV2 : PassphraseRequiredActionBarActivity(), InputBarDe
         val rawAlpha = (bottomOffset.toFloat() - scrollButtonNoVisibilityThreshold) /
             (scrollButtonFullVisibilityThreshold - scrollButtonNoVisibilityThreshold)
         val alpha = max(min(rawAlpha, 1.0f), 0.0f)
-        Log.d("Test", "$alpha")
+        scrollToBottomButton.alpha = alpha
     }
     // endregion
 

app/src/main/res/drawable/view_scroll_to_bottom_button_background.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="oval">
+    <solid android:color="@color/scroll_to_bottom_button_background" />
+    <stroke android:width="1px" android:color="@color/scroll_to_bottom_button_border" />
+</shape>

app/src/main/res/layout/activity_conversation_v2.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<RelativeLayout
-    xmlns:android="http://schemas.android.com/apk/res/android"
+<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
     android:id="@+id/contentView"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
@@ -70,6 +70,27 @@
 
     </LinearLayout>
 
+    <RelativeLayout
+        android:id="@+id/scrollToBottomButton"
+        android:layout_width="40dp"
+        android:layout_height="40dp"
+        android:layout_alignParentRight="true"
+        android:layout_alignParentBottom="true"
+        android:layout_marginRight="12dp"
+        android:layout_marginBottom="72dp"
+        android:alpha="0"
+        android:background="@drawable/view_scroll_to_bottom_button_background">
+
+        <ImageView
+            android:layout_width="16dp"
+            android:layout_height="16dp"
+            android:src="@drawable/ic_chevron_up"
+            android:layout_centerInParent="true"
+            android:rotation="180"
+            app:tint="@color/text" />
+
+    </RelativeLayout>
+
     <org.thoughtcrime.securesms.conversation.v2.input_bar.InputBarRecordingView
         android:id="@+id/inputBarRecordingView"
         android:layout_width="match_parent"

app/src/main/res/values-notnight-v21/colors.xml

@@ -29,6 +29,8 @@
     <color name="mention_candidates_view_background">#FCFCFC</color>
     <color name="mention_candidates_view_background_ripple">#DFDFDF</color>
     <color name="link_preview_background">#0F000000</color>
+    <color name="scroll_to_bottom_button_background">#FCFCFC</color>
+    <color name="scroll_to_bottom_button_border">#99000000</color>
 
     <color name="default_background_start">#ffffff</color>
     <color name="default_background_end">#fcfcfc</color>

app/src/main/res/values/colors.xml

@@ -36,6 +36,8 @@
     <color name="mention_candidates_view_background">#171717</color>
     <color name="mention_candidates_view_background_ripple">#0C0C0C</color>
     <color name="link_preview_background">#000000</color>
+    <color name="scroll_to_bottom_button_background">#171717</color>
+    <color name="scroll_to_bottom_button_border">#99FFFFFF</color>
 
     <array name="profile_picture_placeholder_colors">
         <item>#5ff8b0</item>