From e0809e5edae3c232fb8e121e0909c03ee7ae0c65 Mon Sep 17 00:00:00 2001
From: nielsandriesse <andriesseniels@gmail.com>
Date: Fri, 4 Jun 2021 14:21:08 +1000
Subject: [PATCH] Add swipe to reply icon

---
 .../v2/ConversationTouchHelperCallback.kt     | 46 ++++++++++++++++---
 1 file changed, 40 insertions(+), 6 deletions(-)

diff --git a/app/src/main/java/org/thoughtcrime/securesms/conversation/v2/ConversationTouchHelperCallback.kt b/app/src/main/java/org/thoughtcrime/securesms/conversation/v2/ConversationTouchHelperCallback.kt
index c1f6f8650c..83e865818e 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/conversation/v2/ConversationTouchHelperCallback.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/conversation/v2/ConversationTouchHelperCallback.kt
@@ -2,14 +2,23 @@ package org.thoughtcrime.securesms.conversation.v2
 
 import android.content.Context
 import android.graphics.Canvas
+import android.graphics.Rect
 import android.view.HapticFeedbackConstants
+import androidx.core.content.ContextCompat
 import androidx.recyclerview.widget.ItemTouchHelper
 import androidx.recyclerview.widget.RecyclerView
+import kotlinx.android.synthetic.main.view_visible_message.view.*
+import network.loki.messenger.R
+import org.thoughtcrime.securesms.conversation.v2.messages.VisibleMessageView
 import org.thoughtcrime.securesms.loki.utilities.toDp
+import org.thoughtcrime.securesms.loki.utilities.toPx
 import kotlin.math.abs
+import kotlin.math.min
+import kotlin.math.roundToInt
 
 class ConversationTouchHelperCallback(private val adapter: ConversationAdapter, private val context: Context,
     private val onSwipe: (Int) -> Unit) : ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {
+    private val background = ContextCompat.getDrawable(context, R.drawable.ic_baseline_reply_24)!!
     private var previousX: Float = 0.0f
 
     companion object {
@@ -24,16 +33,41 @@ class ConversationTouchHelperCallback(private val adapter: ConversationAdapter,
         adapter.notifyItemChanged(viewHolder.adapterPosition)
     }
 
-    override fun onChildDraw(c: Canvas, recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, dX: Float, dY: Float, actionState: Int, isCurrentlyActive: Boolean) {
-        super.onChildDraw(c, recyclerView, viewHolder, dX / 4 , dY, actionState, isCurrentlyActive)
-        val x = abs(toDp(dX, context.resources))
+    override fun onChildDraw(c: Canvas, recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder,
+        dX: Float, dY: Float, actionState: Int, isCurrentlyActive: Boolean) {
+        val adjustedDistanceInPx = dX / 4
+        super.onChildDraw(c, recyclerView, viewHolder, adjustedDistanceInPx, dY, actionState, isCurrentlyActive)
+        val absDistanceInDp = abs(toDp(dX, context.resources))
         val threshold = ConversationTouchHelperCallback.swipeToReplyThreshold
-        if (x > threshold && previousX < threshold) {
-            val view = viewHolder.itemView
+        val view = viewHolder.itemView
+        if (view !is VisibleMessageView) { return }
+        // Draw the background
+        val messageContentView = view.messageContentView
+        if (dX < 0) { // Swipe to the left
+            val alpha = min(absDistanceInDp, threshold) / threshold
+            background.alpha = (alpha * 255.0f).roundToInt()
+            val spacing = context.resources.getDimension(R.dimen.medium_spacing).toInt()
+            val itemViewTop = viewHolder.itemView.top
+            val itemViewBottom = viewHolder.itemView.bottom
+            val height = itemViewBottom - itemViewTop
+            val iconSize = toPx(24, context.resources)
+            val offset = (height - iconSize) / 2
+            background.bounds = Rect(
+                messageContentView.right + adjustedDistanceInPx.toInt() + spacing,
+                itemViewTop + offset,
+                messageContentView.right + adjustedDistanceInPx.toInt() + iconSize + spacing,
+                itemViewTop + offset + iconSize
+            )
+        } else {
+            //background.setBounds(0, 0, 0, 0)
+        }
+        background.draw(c)
+        // Perform haptic feedback and invoke onSwipe callback if threshold has been reached
+        if (absDistanceInDp > threshold && previousX < threshold) {
             view.isHapticFeedbackEnabled = true
             view.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS)
             onSwipe(viewHolder.adapterPosition)
         }
-        previousX = x
+        previousX = absDistanceInDp
     }
 }
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