From 19864ec962fe9b8d42fee5ea360a4474c550fa7e Mon Sep 17 00:00:00 2001
From: Jeff DeCew <jeffdq@google.com>
Date: Fri, 26 Feb 2021 13:53:12 -0500
Subject: Fix the vertical positioning of the text in collapsed notifications.

Test: manual / visual
Bug: 181048615
Change-Id: I57fb542a776b254a6537dbed608259e69def411f
---
 .../widget/NotificationVanishingFrameLayout.java   | 70 ++++++++++++++++++++++
 .../layout/notification_template_material_base.xml | 16 +++--
 2 files changed, 82 insertions(+), 4 deletions(-)
 create mode 100644 core/java/com/android/internal/widget/NotificationVanishingFrameLayout.java

diff --git a/core/java/com/android/internal/widget/NotificationVanishingFrameLayout.java b/core/java/com/android/internal/widget/NotificationVanishingFrameLayout.java
new file mode 100644
index 000000000000..742bdfdde756
--- /dev/null
+++ b/core/java/com/android/internal/widget/NotificationVanishingFrameLayout.java
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.internal.widget;
+
+import android.annotation.Nullable;
+import android.content.Context;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.FrameLayout;
+import android.widget.RemoteViews;
+
+/**
+ * This view will measure itself as having 0 size if all of its children are {@link #GONE}.
+ * Otherwise it acts like a normal {@link FrameLayout}.
+ */
+@RemoteViews.RemoteView
+public class NotificationVanishingFrameLayout extends FrameLayout {
+    public NotificationVanishingFrameLayout(Context context) {
+        this(context, null, 0, 0);
+    }
+
+    public NotificationVanishingFrameLayout(Context context, @Nullable AttributeSet attrs) {
+        this(context, attrs, 0, 0);
+    }
+
+    public NotificationVanishingFrameLayout(Context context, @Nullable AttributeSet attrs,
+            int defStyleAttr) {
+        this(context, attrs, defStyleAttr, 0);
+    }
+
+    public NotificationVanishingFrameLayout(Context context, AttributeSet attrs, int defStyleAttr,
+            int defStyleRes) {
+        super(context, attrs, defStyleAttr, defStyleRes);
+    }
+
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        if (allChildrenGone()) {
+            int zeroSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.EXACTLY);
+            super.onMeasure(zeroSpec, zeroSpec);
+        } else {
+            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+        }
+    }
+
+    private boolean allChildrenGone() {
+        final int childCount = getChildCount();
+        for (int i = 0; i < childCount; i++) {
+            final View child =  getChildAt(i);
+            if (child != null && child.getVisibility() != GONE) {
+                return false;
+            }
+        }
+        return true;
+    }
+}
diff --git a/core/res/res/layout/notification_template_material_base.xml b/core/res/res/layout/notification_template_material_base.xml
index fa7b1c90dfac..b83611bcc177 100644
--- a/core/res/res/layout/notification_template_material_base.xml
+++ b/core/res/res/layout/notification_template_material_base.xml
@@ -138,12 +138,20 @@
             android:orientation="vertical"
             >
 
-            <include
-                layout="@layout/notification_template_text"
+            <com.android.internal.widget.NotificationVanishingFrameLayout
                 android:layout_width="match_parent"
                 android:layout_height="@dimen/notification_headerless_line_height"
-                android:layout_marginTop="0dp"
-                />
+                >
+                <!-- This is the simplest way to keep this text vertically centered without using
+                 gravity="center_vertical" which causes jumpiness in expansion animations. -->
+                <include
+                    layout="@layout/notification_template_text"
+                    android:layout_width="match_parent"
+                    android:layout_height="@dimen/notification_text_height"
+                    android:layout_gravity="center_vertical"
+                    android:layout_marginTop="0dp"
+                    />
+            </com.android.internal.widget.NotificationVanishingFrameLayout>
 
             <include
                 layout="@layout/notification_template_progress"
-- 
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