From d179e74026c8d7979e88ee17a2e2cf39dfd0d4bd Mon Sep 17 00:00:00 2001
From: Constantine <kostyaxxx8@gmail.com>
Date: Sun, 10 Feb 2019 23:09:59 +0300
Subject: [PATCH] Fix problem with jumping of backLayout

---
 .../backdrop/BackdropBehavior.kt              | 47 +++++++++++++------
 .../semper_viventem/backdrop/BackdropUtils.kt |  2 +-
 2 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/backdrop/src/main/kotlin/ru/semper_viventem/backdrop/BackdropBehavior.kt b/backdrop/src/main/kotlin/ru/semper_viventem/backdrop/BackdropBehavior.kt
index 93d24b8..08b3f88 100644
--- a/backdrop/src/main/kotlin/ru/semper_viventem/backdrop/BackdropBehavior.kt
+++ b/backdrop/src/main/kotlin/ru/semper_viventem/backdrop/BackdropBehavior.kt
@@ -45,6 +45,8 @@ class BackdropBehavior : CoordinatorLayout.Behavior<View> {
 
     private var dropState: DropState = DEFAULT_DROP_STATE
 
+    private var needToInitializing = true
+
     private var dropListeners = mutableListOf<OnDropListener>()
 
     constructor() : super()
@@ -91,7 +93,7 @@ class BackdropBehavior : CoordinatorLayout.Behavior<View> {
             }
         }
 
-        if (toolbar != null && frontLayout != null && backLayout != null) {
+        if (toolbar != null && frontLayout != null && backLayout != null && needToInitializing) {
             initViews(parent, frontLayout!!, toolbar!!, backLayout!!)
         }
 
@@ -142,7 +144,7 @@ class BackdropBehavior : CoordinatorLayout.Behavior<View> {
     } else {
         dropState = DropState.OPEN
         if (backLayout != null && toolbar != null && frontLayout != null) {
-            drawDropState(backLayout!!, toolbar!!, frontLayout!!, withAnimation)
+            drawDropState(frontLayout!!, toolbar!!, backLayout!!, withAnimation)
         } else {
             throw IllegalArgumentException("Toolbar and backContainer must be initialized")
         }
@@ -155,7 +157,7 @@ class BackdropBehavior : CoordinatorLayout.Behavior<View> {
     } else {
         dropState = DropState.CLOSE
         if (backLayout != null && toolbar != null && frontLayout != null) {
-            drawDropState(backLayout!!, toolbar!!, frontLayout!!, withAnimation)
+            drawDropState(frontLayout!!, toolbar!!, backLayout!!, withAnimation)
         } else {
             throw IllegalArgumentException("Toolbar and backContainer must be initialized")
         }
@@ -165,12 +167,14 @@ class BackdropBehavior : CoordinatorLayout.Behavior<View> {
 
     private fun initViews(parent: CoordinatorLayout, frontLayout: View, toolbar: Toolbar, backLayout: View) {
 
-        // TODO (next release): remove this conditional
+        // TODO (next release): remove this block
         if (toolbarId != null) {
             backLayout.y = toolbar.y + toolbar.height
+            frontLayout.layoutParams.height = parent.height - toolbar.height
+        } else {
+            frontLayout.layoutParams.height = parent.height - (backLayout.y.toInt() + toolbar.y.toInt() + toolbar.height)
         }
 
-        frontLayout.layoutParams.height = parent.height - (toolbar.y.toInt() + toolbar.height)
         drawDropState(frontLayout, toolbar, backLayout, false)
 
         with(toolbar) {
@@ -183,33 +187,48 @@ class BackdropBehavior : CoordinatorLayout.Behavior<View> {
                 notifyListeners(true)
             }
         }
+
+        needToInitializing = false
     }
 
-    private fun drawDropState(child: View, toolbar: Toolbar, backContainer: View, withAnimation: Boolean = true) {
+    private fun drawDropState(frontLayout: View, toolbar: Toolbar, backContainer: View, withAnimation: Boolean = true) {
         when (dropState) {
             DropState.CLOSE -> {
-                drawClosedState(child, backContainer, withAnimation)
+                drawClosedState(frontLayout, backContainer, toolbar, withAnimation)
                 toolbar.setNavigationIcon(closedIconId)
             }
             DropState.OPEN -> {
-                drawOpenedState(child, backContainer, withAnimation)
+                drawOpenedState(frontLayout, backContainer, withAnimation)
                 toolbar.setNavigationIcon(openedIconRes)
             }
         }
     }
 
-    private fun drawClosedState(child: View, backContainer: View, withAnimation: Boolean = true) {
-        val position = backContainer.y
+    private fun drawClosedState(frontLayout: View, backLayout: View, toolbar: Toolbar, withAnimation: Boolean = true) {
+        val position = calculateTopPosition(backLayout, toolbar)
         val duration = if (withAnimation) DEFAULT_DURATION else WITHOUT_DURATION
 
-        child.animate().y(position).setDuration(duration).start()
+        frontLayout.animate().y(position).setDuration(duration).start()
     }
 
-    private fun drawOpenedState(child: View, backContainer: View, withAnimation: Boolean = true) {
-        val position = backContainer.y + backContainer.height
+    private fun drawOpenedState(frontLayout: View, backLayout: View, withAnimation: Boolean = true) {
+        val position = calculateBottomPosition(backLayout)
         val duration = if (withAnimation) DEFAULT_DURATION else WITHOUT_DURATION
 
-        child.animate().y(position).setDuration(duration).start()
+        frontLayout.animate().y(position).setDuration(duration).start()
+    }
+
+    private fun calculateTopPosition(backLayout: View, toolbar: Toolbar): Float {
+        // TODO (next release): remove this block
+        return if (toolbarId != null) {
+            backLayout.y
+        } else {
+            (backLayout.y + toolbar.y + toolbar.height)
+        }
+    }
+
+    private fun calculateBottomPosition(backLayout: View): Float {
+        return backLayout.y + backLayout.height
     }
 
     private fun notifyListeners(fromUser: Boolean) {
diff --git a/backdrop/src/main/kotlin/ru/semper_viventem/backdrop/BackdropUtils.kt b/backdrop/src/main/kotlin/ru/semper_viventem/backdrop/BackdropUtils.kt
index 94f008d..f69d5f5 100644
--- a/backdrop/src/main/kotlin/ru/semper_viventem/backdrop/BackdropUtils.kt
+++ b/backdrop/src/main/kotlin/ru/semper_viventem/backdrop/BackdropUtils.kt
@@ -3,7 +3,7 @@ package ru.semper_viventem.backdrop
 import android.view.ViewGroup
 import androidx.appcompat.widget.Toolbar
 
-class BackdropUtils {
+internal class BackdropUtils {
 
     fun findToolbar(viewGroup: ViewGroup): Toolbar? {
         for (chileId in 0..viewGroup.childCount) {