Fix the baseline calculation above API Level 24+ (#342)

Author: thagikura

flexbox/src/androidTest/java/com/google/android/flexbox/test/FlexboxAndroidTest.java

@@ -2262,6 +2262,27 @@ public void testAlignItems_baseline() throws Throwable {
         assertThat(topPluBaseline2, is(topPluBaseline3));
     }
 
+    @Test
+    @FlakyTest
+    public void testAlignItems_baseline_wrapContent() throws Throwable {
+        // This test verifies the issue that baseline calculation is broken on API level +24
+        // https://github.com/google/flexbox-layout/issues/341
+        final FlexboxTestActivity activity = mActivityRule.getActivity();
+        FlexboxLayout layout =
+                createFlexboxLayout(R.layout.activity_align_items_baseline_wrap_content);
+        TextView textView1 = activity.findViewById(R.id.text1);
+        TextView textView2 = activity.findViewById(R.id.text2);
+        TextView textView3 = activity.findViewById(R.id.text3);
+        int topPluBaseline1 = textView1.getTop() + textView1.getBaseline();
+        int topPluBaseline2 = textView2.getTop() + textView2.getBaseline();
+        int topPluBaseline3 = textView3.getTop() + textView3.getBaseline();
+
+        assertThat(topPluBaseline1, is(topPluBaseline2));
+        assertThat(topPluBaseline2, is(topPluBaseline3));
+        assertThat(layout.getFlexLines().size(), is(1));
+        assertTrue(layout.getFlexLines().get(0).getCrossSize() > textView1.getHeight());
+    }
+
     @Test
     @FlakyTest
     public void testAlignItems_baseline_wrapReverse() throws Throwable {

flexbox/src/androidTest/res/layout/activity_align_items_baseline_wrap_content.xml

@@ -0,0 +1,46 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+  Copyright 2017 Google Inc. All rights reserved.
+
+  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.
+  -->
+<com.google.android.flexbox.FlexboxLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:id="@+id/flexbox_layout"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    app:flexDirection="row"
+    app:flexWrap="wrap"
+    app:alignItems="baseline">
+
+    <TextView
+        android:id="@+id/text1"
+        android:layout_width="30dp"
+        android:layout_height="80dp"
+        android:text="1"
+        android:gravity="bottom" />
+
+    <TextView
+        android:id="@+id/text2"
+        android:layout_width="30dp"
+        android:layout_height="80dp"
+        android:text="2"
+        android:gravity="top" />
+
+    <TextView
+        android:id="@+id/text3"
+        android:layout_width="30dp"
+        android:layout_height="80dp"
+        android:text="3"
+        android:paddingTop="20dp"
+        android:gravity="center" />
+</com.google.android.flexbox.FlexboxLayout>

flexbox/src/main/java/com/google/android/flexbox/FlexboxLayout.java

@@ -349,28 +349,30 @@ private void measureHorizontal(int widthMeasureSpec, int heightMeasureSpec) {
 
         // TODO: Consider the case any individual child's mAlignSelf is set to ALIGN_SELF_BASELINE
         if (mAlignItems == AlignItems.BASELINE) {
-            int viewIndex = 0;
             for (FlexLine flexLine : mFlexLines) {
                 // The largest height value that also take the baseline shift into account
                 int largestHeightInLine = Integer.MIN_VALUE;
-                for (int i = viewIndex; i < viewIndex + flexLine.mItemCount; i++) {
-                    View child = getReorderedChildAt(i);
+                for (int i = 0; i < flexLine.mItemCount; i++) {
+                    int viewIndex = flexLine.mFirstIndex + i;
+                    View child = getReorderedChildAt(viewIndex);
+                    if (child == null || child.getVisibility() == View.GONE) {
+                        continue;
+                    }
                     LayoutParams lp = (LayoutParams) child.getLayoutParams();
                     if (mFlexWrap != FlexWrap.WRAP_REVERSE) {
                         int marginTop = flexLine.mMaxBaseline - child.getBaseline();
                         marginTop = Math.max(marginTop, lp.topMargin);
                         largestHeightInLine = Math.max(largestHeightInLine,
-                                child.getHeight() + marginTop + lp.bottomMargin);
+                                child.getMeasuredHeight() + marginTop + lp.bottomMargin);
                     } else {
                         int marginBottom = flexLine.mMaxBaseline - child.getMeasuredHeight() +
                                 child.getBaseline();
                         marginBottom = Math.max(marginBottom, lp.bottomMargin);
                         largestHeightInLine = Math.max(largestHeightInLine,
-                                child.getHeight() + lp.topMargin + marginBottom);
+                                child.getMeasuredHeight() + lp.topMargin + marginBottom);
                     }
                 }
                 flexLine.mCrossSize = largestHeightInLine;
-                viewIndex += flexLine.mItemCount;
             }
         }