fix calculating size of child view, for view with size match_parent (#450)

flexbox/src/androidTest/java/com/google/android/flexbox/FlexboxHelperTest.kt

@@ -17,6 +17,7 @@
 package com.google.android.flexbox
 
 import android.view.View
+import android.view.ViewGroup
 import android.widget.CheckBox
 import android.widget.TextView
 import androidx.core.widget.CompoundButtonCompat
@@ -167,6 +168,84 @@ class FlexboxHelperTest {
         assertEquals(3, thirdLine.mLastIndex)
     }
 
+    @Test
+    @Throws(Throwable::class)
+    fun testCalculateVertical_flexWrap_wrap_flexDirection_column_viewSize_match_parent() {
+        val activity = activityRule.activity
+        val lp1 = FlexboxLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 490)
+        val view1 = View(activity)
+        view1.layoutParams = lp1
+
+        val lp2 = FlexboxLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 500)
+        val view2 = View(activity)
+        view2.layoutParams = lp2
+
+        val lp3 = FlexboxLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 500)
+        val view3 = View(activity)
+        view3.layoutParams = lp3
+
+        val lp4 = FlexboxLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 700)
+        val view4 = View(activity)
+        view4.layoutParams = lp4
+
+        val lp5 = FlexboxLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 300)
+        val view5 = View(activity)
+        view5.layoutParams = lp5
+
+        val lp6 = FlexboxLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 100)
+        val view6 = View(activity)
+        view6.layoutParams = lp6
+
+        flexContainer.addView(view1)
+        flexContainer.addView(view2)
+        flexContainer.addView(view3)
+        flexContainer.addView(view4)
+        flexContainer.addView(view5)
+        flexContainer.addView(view6)
+        flexContainer.flexWrap = FlexWrap.WRAP
+        flexContainer.flexDirection = FlexDirection.COLUMN
+        val widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(500, View.MeasureSpec.EXACTLY)
+        val heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(1000, View.MeasureSpec.EXACTLY)
+
+        flexboxHelper.ensureIndexToFlexLine(flexContainer.flexItemCount)
+        val result = FlexboxHelper.FlexLinesResult()
+        flexboxHelper.calculateVerticalFlexLines(result, widthMeasureSpec, heightMeasureSpec)
+
+
+        assertEquals(4, result.mFlexLines.size)
+        assertEquals(990, result.mFlexLines[0].mainSize)
+        assertEquals(500, result.mFlexLines[1].mainSize)
+        assertEquals(1000, result.mFlexLines[2].mainSize)
+        assertEquals(100, result.mFlexLines[3].mainSize)
+        assertEquals(500, result.mFlexLines[0].crossSize)
+        //they don't show yet
+        assertEquals(0, result.mFlexLines[1].crossSize)
+        assertEquals(0, result.mFlexLines[2].crossSize)
+        assertEquals(0, result.mFlexLines[3].crossSize)
+
+        assertNotNull(flexboxHelper.mIndexToFlexLine)
+        assertEquals(0, flexboxHelper.mIndexToFlexLine!![0])
+        assertEquals(0, flexboxHelper.mIndexToFlexLine!![1])
+        assertEquals(1, flexboxHelper.mIndexToFlexLine!![2])
+        assertEquals(2, flexboxHelper.mIndexToFlexLine!![3])
+        assertEquals(2, flexboxHelper.mIndexToFlexLine!![4])
+        assertEquals(3, flexboxHelper.mIndexToFlexLine!![5])
+
+        val firstLine = result.mFlexLines[0]
+        assertEquals(0, firstLine.mFirstIndex)
+        assertEquals(1, firstLine.mLastIndex)
+        val secondLine = result.mFlexLines[1]
+        assertEquals(2, secondLine.mFirstIndex)
+        assertEquals(2, secondLine.mLastIndex)
+        val thirdLine = result.mFlexLines[2]
+        assertEquals(3, thirdLine.mFirstIndex)
+        assertEquals(4, thirdLine.mLastIndex)
+        val fourthLine = result.mFlexLines[3]
+        assertEquals(5, fourthLine.mFirstIndex)
+        assertEquals(5, fourthLine.mLastIndex)
+
+    }
+
     @Test
     @Throws(Throwable::class)
     fun testDetermineMainSize_direction_row_flexGrowSet() {

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

@@ -540,11 +540,12 @@ void calculateFlexLines(FlexLinesResult result, int mainMeasureSpec,
                         // so far into account. In that case, the width of the child needs to be
                         // measured again note that we don't need to judge if the wrapping occurs
                         // because it doesn't change the size along the main axis.
+                        int padding = mFlexContainer.getPaddingLeft() + mFlexContainer.getPaddingRight()
+                                + flexItem.getMarginLeft() + flexItem.getMarginRight()
+                                + sumCrossSize;
                         childCrossMeasureSpec = mFlexContainer.getChildWidthMeasureSpec(
                                 crossMeasureSpec,
-                                mFlexContainer.getPaddingLeft() + mFlexContainer.getPaddingRight()
-                                        + flexItem.getMarginLeft()
-                                        + flexItem.getMarginRight() + sumCrossSize,
+                                padding,
                                 flexItem.getWidth());
                         child.measure(childCrossMeasureSpec, childMainMeasureSpec);
                         checkSizeConstraints(child, i);

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

@@ -481,13 +481,39 @@ public void onNewFlexLineAdded(FlexLine flexLine) {
 
     @Override
     public int getChildWidthMeasureSpec(int widthSpec, int padding, int childDimension) {
-        return getChildMeasureSpec(getWidth(), getWidthMode(), padding, childDimension,
+        /*
+        The main idea that FlexboxHelper, counting size of the view
+        with dimension MATCH_PARENT with the idea, that new View should take place that we have on the screen.
+        For example screenWidth = 1080, firstFlexLineWidth = 1000. So this view will be 80
+        It sounds logic, but we have a problem, when we already take all 1080px by first flexline.
+        FlexboxHelper don't know about size of Recycler, so it can't manage it.
+        So good point to check size is this place
+        But are we have a permission to decide this?
+         */
+        int recyclerWidth = getWidth();
+        if (childDimension == LayoutParams.MATCH_PARENT && padding == recyclerWidth) {
+            childDimension = recyclerWidth;
+        }
+        return getChildMeasureSpec(recyclerWidth, getWidthMode(), padding, childDimension,
                 canScrollHorizontally());
     }
 
     @Override
     public int getChildHeightMeasureSpec(int heightSpec, int padding, int childDimension) {
-        return getChildMeasureSpec(getHeight(), getHeightMode(), padding, childDimension,
+        /*
+        The main idea that FlexboxHelper, counting size of the view
+        with dimension MATCH_PARENT with the idea, that new View should take place that we have on the screen.
+        For example screenWidth = 1080, firstFlexLineWidth = 1000. So this view will be 80
+        It sounds logic, but we have a problem, when we already take all 1080px by first flexline.
+        FlexboxHelper don't know about size of Recycler, so it can't manage it.
+        So good point to check size is this place
+        But are we have a permission to decide this?
+         */
+        int recyclerHeight = getHeight();
+        if (childDimension == LayoutParams.MATCH_PARENT && padding == recyclerHeight) {
+            childDimension = recyclerHeight;
+        }
+        return getChildMeasureSpec(recyclerHeight, getHeightMode(), padding, childDimension,
                 canScrollVertically());
     }