From 46c17ca3a46a2e8f2d7f73921f8693dfef5b7f43 Mon Sep 17 00:00:00 2001
From: Alexander Djenkov <a.djenkov90@gmail.com>
Date: Fri, 19 Jul 2019 17:09:40 +0300
Subject: [PATCH] fix(bottom-navigation): crash when tab selected with no item
 (#7527)

---
 .../org/nativescript/widgets/BottomNavigationBar.java  |  8 +++++---
 .../main/java/org/nativescript/widgets/TabLayout.java  |  8 +++++---
 .../ui/bottom-navigation/bottom-navigation.android.ts  | 10 ++++++++--
 tns-core-modules/ui/tabs/tabs.android.ts               | 10 ++++++++--
 .../android/org.nativescript.widgets.d.ts              |  2 +-
 5 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/tns-core-modules-widgets/android/widgets/src/main/java/org/nativescript/widgets/BottomNavigationBar.java b/tns-core-modules-widgets/android/widgets/src/main/java/org/nativescript/widgets/BottomNavigationBar.java
index b594cd155..29a5c0492 100644
--- a/tns-core-modules-widgets/android/widgets/src/main/java/org/nativescript/widgets/BottomNavigationBar.java
+++ b/tns-core-modules-widgets/android/widgets/src/main/java/org/nativescript/widgets/BottomNavigationBar.java
@@ -216,8 +216,9 @@ public class BottomNavigationBar extends LinearLayout {
         lp.weight = 1;
     }
 
-    public void onTap(int position) {
+    public boolean onTap(int position) {
         // to be overridden in JS
+        return true;
     }
 
     public void onSelectedPositionChange(int position, int prevPosition) {
@@ -269,8 +270,9 @@ public class BottomNavigationBar extends LinearLayout {
         public void onClick(View v) {
              for (int i = 0; i < mTabStrip.getChildCount(); i++) {
                  if (v == mTabStrip.getChildAt(i)) {
-                     onTap(i);
-                     setSelectedPosition(i);
+                     if (onTap(i)) {
+                         setSelectedPosition(i);
+                     }
                      return;
                  }
              }
diff --git a/tns-core-modules-widgets/android/widgets/src/main/java/org/nativescript/widgets/TabLayout.java b/tns-core-modules-widgets/android/widgets/src/main/java/org/nativescript/widgets/TabLayout.java
index fad929b9c..a784d5431 100644
--- a/tns-core-modules-widgets/android/widgets/src/main/java/org/nativescript/widgets/TabLayout.java
+++ b/tns-core-modules-widgets/android/widgets/src/main/java/org/nativescript/widgets/TabLayout.java
@@ -301,8 +301,9 @@ public class TabLayout extends HorizontalScrollView {
         }
     }
 
-    public void onTap(int position) {
+    public boolean onTap(int position) {
         // to be overridden in JS
+        return true;
     }
 
     public void onSelectedPositionChange(int position, int prevPosition) {
@@ -429,8 +430,9 @@ public class TabLayout extends HorizontalScrollView {
         public void onClick(View v) {
             for (int i = 0; i < mTabStrip.getChildCount(); i++) {
                 if (v == mTabStrip.getChildAt(i)) {
-                    onTap(i);
-                    mViewPager.setCurrentItem(i);
+                    if (onTap(i)) {
+                        mViewPager.setCurrentItem(i);
+                    }
                     return;
                 }
             }
diff --git a/tns-core-modules/ui/bottom-navigation/bottom-navigation.android.ts b/tns-core-modules/ui/bottom-navigation/bottom-navigation.android.ts
index b24ddbdd6..18da53cff 100644
--- a/tns-core-modules/ui/bottom-navigation/bottom-navigation.android.ts
+++ b/tns-core-modules/ui/bottom-navigation/bottom-navigation.android.ts
@@ -118,10 +118,10 @@ function initializeNativeClasses() {
             owner.selectedIndex = position;
         }
 
-        public onTap(position: number): void {
+        public onTap(position: number): boolean {
             const owner = this.owner;
             if (!owner) {
-                return;
+                return false;
             }
 
             const tabStripItems = owner.tabStrip && owner.tabStrip.items;
@@ -129,6 +129,12 @@ function initializeNativeClasses() {
             if (position >= 0 && tabStripItems[position]) {
                 tabStripItems[position]._emit(TabStripItem.tapEvent);
             }
+
+            if (!owner.items[position]) {
+                return false;
+            }
+
+            return true;
         }
     }
 
diff --git a/tns-core-modules/ui/tabs/tabs.android.ts b/tns-core-modules/ui/tabs/tabs.android.ts
index 56435aef1..c7a5e2d55 100644
--- a/tns-core-modules/ui/tabs/tabs.android.ts
+++ b/tns-core-modules/ui/tabs/tabs.android.ts
@@ -259,10 +259,10 @@ function initializeNativeClasses() {
             }
         }
 
-        public onTap(position: number): void {
+        public onTap(position: number): boolean {
             const owner = this.owner;
             if (!owner) {
-                return;
+                return false;
             }
 
             const tabStripItems = owner.tabStrip && owner.tabStrip.items;
@@ -270,6 +270,12 @@ function initializeNativeClasses() {
             if (position >= 0 && tabStripItems[position]) {
                 tabStripItems[position]._emit(TabStripItem.tapEvent);
             }
+
+            if (!owner.items[position]) {
+                return false;
+            }
+
+            return true;
         }
     }
 
diff --git a/tns-platform-declarations/android/org.nativescript.widgets.d.ts b/tns-platform-declarations/android/org.nativescript.widgets.d.ts
index e2d2b424f..33ab960a1 100644
--- a/tns-platform-declarations/android/org.nativescript.widgets.d.ts
+++ b/tns-platform-declarations/android/org.nativescript.widgets.d.ts
@@ -410,7 +410,7 @@
                 setTabTextFontSize(fontSize: number): void;
                 getTabTextFontSize(): number;
 
-                onTap(position: number): void;
+                onTap(position: number): boolean;
                 onSelectedPositionChange(position: number, prevPosition: number): void ;
                 setSelectedPosition(position: number): void;
                 setItems(items: Array<TabItemSpec>): void;