From fdd76d7100ba5b152b3330eddb90d4de712b5e36 Mon Sep 17 00:00:00 2001
From: Liam DeBeasi <liamdebeasi@icloud.com>
Date: Wed, 17 Feb 2021 12:15:09 -0500
Subject: [PATCH 1/2] do not incorrectly show toolbar when refreshing

---
 core/src/components/header/header.tsx      |  2 +-
 core/src/components/header/header.utils.ts | 13 +++++++++----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/core/src/components/header/header.tsx b/core/src/components/header/header.tsx
index eaee37f9eaa..93f0e0c512b 100644
--- a/core/src/components/header/header.tsx
+++ b/core/src/components/header/header.tsx
@@ -120,7 +120,7 @@ export class Header implements ComponentInterface {
      * as well as progressively showing/hiding the main header
      * border as the top-most toolbar collapses or expands.
      */
-    const toolbarIntersection = (ev: any) => { handleToolbarIntersection(ev, mainHeaderIndex, scrollHeaderIndex); };
+    const toolbarIntersection = (ev: any) => { handleToolbarIntersection(ev, mainHeaderIndex, scrollHeaderIndex, this.scrollEl!); };
 
     this.intersectionObserver = new IntersectionObserver(toolbarIntersection, { root: contentEl, threshold: [0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1] });
     this.intersectionObserver.observe(scrollHeaderIndex.toolbars[scrollHeaderIndex.toolbars.length - 1].el);
diff --git a/core/src/components/header/header.utils.ts b/core/src/components/header/header.utils.ts
index dd6a66d2081..58c15a05d78 100644
--- a/core/src/components/header/header.utils.ts
+++ b/core/src/components/header/header.utils.ts
@@ -72,7 +72,7 @@ export const setToolbarBackgroundOpacity = (toolbar: ToolbarIndex, opacity?: num
   }
 };
 
-const handleToolbarBorderIntersection = (ev: any, mainHeaderIndex: HeaderIndex) => {
+const handleToolbarBorderIntersection = (ev: any, mainHeaderIndex: HeaderIndex, scrollTop: number) => {
   if (!ev[0].isIntersecting) { return; }
 
   /**
@@ -80,8 +80,13 @@ const handleToolbarBorderIntersection = (ev: any, mainHeaderIndex: HeaderIndex)
    * does not always reset the scrollTop position to 0 when letting go. It will
    * set to 1 once the rubber band effect has ended. This causes the background to
    * appear slightly on certain app setups.
+   *
+   * Additionally, we check if user is rubber banding (scrolling is negative)
+   * as this can mean they are using pull to refresh. Once the refresher starts,
+   * the content is transformed which can cause the intersection observer to erroneously
+   * fire here as well.
    */
-  const scale = (ev[0].intersectionRatio > 0.9) ? 0 : ((1 - ev[0].intersectionRatio) * 100) / 75;
+  const scale = (ev[0].intersectionRatio > 0.9 || scrollTop <= 0) ? 0 : ((1 - ev[0].intersectionRatio) * 100) / 75;
 
   mainHeaderIndex.toolbars.forEach(toolbar => {
     setToolbarBackgroundOpacity(toolbar, (scale === 1) ? undefined : scale);
@@ -93,9 +98,9 @@ const handleToolbarBorderIntersection = (ev: any, mainHeaderIndex: HeaderIndex)
  * and show the primary toolbar content. If the toolbars are not intersecting,
  * hide the primary toolbar content and show the scrollable toolbar content
  */
-export const handleToolbarIntersection = (ev: any, mainHeaderIndex: HeaderIndex, scrollHeaderIndex: HeaderIndex) => {
+export const handleToolbarIntersection = (ev: any, mainHeaderIndex: HeaderIndex, scrollHeaderIndex: HeaderIndex, scrollEl: HTMLElement) => {
   writeTask(() => {
-    handleToolbarBorderIntersection(ev, mainHeaderIndex);
+    handleToolbarBorderIntersection(ev, mainHeaderIndex, scrollEl.scrollTop);
 
     const event = ev[0];
 

From 927031083a099b54edfe37c80ea985d4d2ed3ac7 Mon Sep 17 00:00:00 2001
From: Liam DeBeasi <liamdebeasi@icloud.com>
Date: Wed, 17 Feb 2021 12:38:37 -0500
Subject: [PATCH 2/2] one more bug fix

---
 core/src/components/header/header.utils.ts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/core/src/components/header/header.utils.ts b/core/src/components/header/header.utils.ts
index 58c15a05d78..2df31003b82 100644
--- a/core/src/components/header/header.utils.ts
+++ b/core/src/components/header/header.utils.ts
@@ -100,7 +100,8 @@ const handleToolbarBorderIntersection = (ev: any, mainHeaderIndex: HeaderIndex,
  */
 export const handleToolbarIntersection = (ev: any, mainHeaderIndex: HeaderIndex, scrollHeaderIndex: HeaderIndex, scrollEl: HTMLElement) => {
   writeTask(() => {
-    handleToolbarBorderIntersection(ev, mainHeaderIndex, scrollEl.scrollTop);
+    const scrollTop = scrollEl.scrollTop;
+    handleToolbarBorderIntersection(ev, mainHeaderIndex, scrollTop);
 
     const event = ev[0];
 
@@ -132,7 +133,7 @@ export const handleToolbarIntersection = (ev: any, mainHeaderIndex: HeaderIndex,
 
       const hasValidIntersection = (intersection.x === 0 && intersection.y === 0) || (intersection.width !== 0 && intersection.height !== 0);
 
-      if (hasValidIntersection) {
+      if (hasValidIntersection && scrollTop > 0) {
         setHeaderActive(mainHeaderIndex);
         setHeaderActive(scrollHeaderIndex, false);
         setToolbarBackgroundOpacity(mainHeaderIndex.toolbars[0]);