Implement better swipe to reply gesture

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

@@ -84,9 +84,6 @@ class ConversationActivityV2 : PassphraseRequiredActionBarActivity() {
                 adapter.changeCursor(null)
             }
         })
-        val touchHelperCallback = ConversationTouchHelperCallback(adapter, this) { reply(it) }
-        val touchHelper = ItemTouchHelper(touchHelperCallback)
-        touchHelper.attachToRecyclerView(conversationRecyclerView)
     }
 
     private fun setUpToolbar() {

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

@@ -73,11 +73,6 @@ class ConversationAdapter(context: Context, cursor: Cursor, private val onItemPr
                 view.messageTimestampTextView.isVisible = isSelected
                 val position = viewHolder.adapterPosition
                 view.bind(message, getMessageBefore(position, cursor), getMessageAfter(position, cursor))
-                view.setOnClickListener { onItemPress(message, viewHolder.adapterPosition) }
-                view.setOnLongClickListener {
-                    onItemLongPress(message, viewHolder.adapterPosition)
-                    true
-                }
             }
             is ControlMessageViewHolder -> viewHolder.view.bind(message)
         }

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

@@ -0,0 +1,40 @@
+package org.thoughtcrime.securesms.conversation.v2
+
+import android.content.Context
+import android.util.AttributeSet
+import android.view.MotionEvent
+import android.view.VelocityTracker
+import androidx.recyclerview.widget.RecyclerView
+import kotlin.math.abs
+
+class ConversationRecyclerView : RecyclerView {
+    private var velocityTracker: VelocityTracker? = null
+
+    constructor(context: Context) : super(context)
+    constructor(context: Context, attrs: AttributeSet) : super(context, attrs)
+    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr)
+
+    override fun onInterceptTouchEvent(e: MotionEvent): Boolean {
+        return false
+        /*
+        val velocityTracker = velocityTracker ?: return super.onInterceptTouchEvent(e)
+        velocityTracker.computeCurrentVelocity(1000) // Specifying 1000 gives pixels per second
+        val vx = velocityTracker.xVelocity
+        val vy = velocityTracker.yVelocity
+        // Only allow swipes to the left; allowing swipes to the right interferes with some back gestures
+        if (vx > 0) { return super.onInterceptTouchEvent(e) }
+        // Return false if abs(v.x) > abs(v.y) so that only swipes that are more horizontal than vertical
+        // get passed on to the message view
+        return abs(vx) < abs(vy)
+         */
+    }
+
+    override fun onTouchEvent(e: MotionEvent): Boolean {
+        when (e.action) {
+            MotionEvent.ACTION_DOWN -> velocityTracker = VelocityTracker.obtain()
+            MotionEvent.ACTION_UP, MotionEvent.ACTION_CANCEL -> velocityTracker = null
+        }
+        velocityTracker?.addMovement(e)
+        return super.onTouchEvent(e)
+    }
+}

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

@@ -1,72 +0,0 @@
-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 {
-        const val swipeToReplyThreshold = 200.0f // dp
-    }
-
-    override fun onMove(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, target: RecyclerView.ViewHolder): Boolean {
-        return false
-    }
-
-    override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
-        background.alpha = 0
-        adapter.notifyItemChanged(viewHolder.adapterPosition)
-    }
-
-    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
-        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
-            )
-        }
-        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 = absDistanceInDp
-    }
-}

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

@@ -25,6 +25,8 @@ import java.lang.IllegalStateException
 
 class VisibleMessageContentView : LinearLayout {
 
+    // TODO: Large emojis
+
     // region Lifecycle
     constructor(context: Context) : super(context) {
         setUpViewHierarchy()

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

@@ -1,11 +1,10 @@
 package org.thoughtcrime.securesms.conversation.v2.messages
 
 import android.content.Context
+import android.os.Build
 import android.util.AttributeSet
-import android.view.Gravity
-import android.view.LayoutInflater
-import android.view.View
-import android.view.ViewGroup
+import android.util.Log
+import android.view.*
 import android.widget.LinearLayout
 import androidx.core.view.isVisible
 import kotlinx.android.synthetic.main.view_visible_message.view.*
@@ -14,28 +13,38 @@ import org.session.libsession.messaging.contacts.Contact.ContactContext
 import org.session.libsession.utilities.ViewUtil
 import org.thoughtcrime.securesms.database.DatabaseFactory
 import org.thoughtcrime.securesms.database.model.MessageRecord
+import org.thoughtcrime.securesms.loki.utilities.toDp
 import org.thoughtcrime.securesms.util.DateUtils
 import java.util.*
+import kotlin.math.abs
 import kotlin.math.roundToInt
+import kotlin.math.sqrt
 
 class VisibleMessageView : LinearLayout {
+    private var dx = 0.0f
+    private var previousTranslationX = 0.0f
+
+    companion object {
+        const val swipeToReplyThreshold = 100.0f // dp
+    }
 
     // region Lifecycle
     constructor(context: Context) : super(context) {
-        setUpViewHierarchy()
+        initialize()
     }
 
     constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
-        setUpViewHierarchy()
+        initialize()
     }
 
     constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
-        setUpViewHierarchy()
+        initialize()
     }
 
-    private fun setUpViewHierarchy() {
+    private fun initialize() {
         LayoutInflater.from(context).inflate(R.layout.view_visible_message, this)
         layoutParams = ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)
+        isHapticFeedbackEnabled = true
     }
     // endregion
 
@@ -122,4 +131,46 @@ class VisibleMessageView : LinearLayout {
         messageContentView.recycle()
     }
     // endregion
+
+    // region Interaction
+    override fun onTouchEvent(event: MotionEvent): Boolean {
+        when (event.action) {
+            MotionEvent.ACTION_DOWN -> onDown(event)
+            MotionEvent.ACTION_MOVE -> onMove(event)
+            MotionEvent.ACTION_UP, MotionEvent.ACTION_CANCEL -> onFinish(event)
+        }
+        return true
+    }
+
+    private fun onDown(event: MotionEvent) {
+        dx = x - event.rawX
+    }
+
+    private fun onMove(event: MotionEvent) {
+        val translationX = toDp(event.rawX + dx, context.resources)
+        // The idea here is to asymptotically approach a maximum drag distance
+        val damping = 50.0f
+        val sign = -1.0f
+        val x = (damping * (sqrt(abs(translationX)) / sqrt(damping))) * sign
+        this.translationX = x
+        if (abs(x) > VisibleMessageView.swipeToReplyThreshold && abs(previousTranslationX) < VisibleMessageView.swipeToReplyThreshold) {
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+                performHapticFeedback(HapticFeedbackConstants.CONTEXT_CLICK)
+            } else {
+                performHapticFeedback(HapticFeedbackConstants.LONG_PRESS)
+            }
+        }
+        previousTranslationX = x
+    }
+
+    private fun onFinish(event: MotionEvent) {
+        if (abs(translationX) > VisibleMessageView.swipeToReplyThreshold) {
+            Log.d("Test", "Reply")
+        }
+        animate()
+            .translationX(0.0f)
+            .setDuration(150)
+            .start()
+    }
+    // endregion
 }

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

@@ -6,7 +6,7 @@
     android:layout_height="match_parent"
     android:orientation="vertical">
 
-    <androidx.recyclerview.widget.RecyclerView
+    <org.thoughtcrime.securesms.conversation.v2.ConversationRecyclerView
         android:id="@+id/conversationRecyclerView"
         android:layout_width="match_parent"
         android:layout_height="match_parent" />