Add max line attribute to specify the maximum number of flex lines.

Fixes #156
google · May 14, 2018 · 1870940 · 1870940 · Pradeepa-precious · Jun 27, 2018
1 parent b397060
commit 1870940
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Showing 5 changed files with 68 additions and 5 deletions.
diff --git a/flexbox/src/androidTest/java/com/google/android/flexbox/FakeFlexContainer.kt b/flexbox/src/androidTest/java/com/google/android/flexbox/FakeFlexContainer.kt
@@ -18,6 +18,7 @@ package com.google.android.flexbox
 
 import android.view.View
 import android.view.ViewGroup
+import com.google.android.flexbox.FlexContainer.NOT_SET
 
 /**
  * Fake implementation of [FlexContainer].
@@ -43,6 +44,8 @@ internal class FakeFlexContainer : FlexContainer {
     @AlignContent
     private var alignContent = AlignContent.STRETCH
 
+    private var maxLine = -1
+
     override fun getFlexItemCount() = views.size
 
     override fun getFlexItemAt(index: Int) = views[index]
@@ -95,6 +98,12 @@ internal class FakeFlexContainer : FlexContainer {
         this.alignItems = alignItems
     }
 
+    override fun getMaxLine(): Int = this.maxLine
+
+    override fun setMaxLine(maxLine: Int) {
+        this.maxLine = maxLine
+    }
+
     override fun getFlexLines() = flexLines
 
     override fun isMainAxisDirectionHorizontal(): Boolean {

diff --git a/flexbox/src/androidTest/java/com/google/android/flexbox/test/FlexboxAndroidTest.kt b/flexbox/src/androidTest/java/com/google/android/flexbox/test/FlexboxAndroidTest.kt
@@ -3967,6 +3967,28 @@ class FlexboxAndroidTest {
         assertThat(view2.right, `is`(240))
     }
 
+    @Test
+    @FlakyTest
+    @Throws(Throwable::class)
+    fun testMaxLines() {
+        val activity = activityRule.activity
+        val flexboxLayout = createFlexboxLayout(R.layout.activity_empty_children,
+                object : Configuration {
+                    override fun apply(flexboxLayout: FlexboxLayout) {
+                        flexboxLayout.maxLine = 3
+                        for (i in 1..50) {
+                            val textView = createTextView(activity, i.toString(), 0)
+                            val lp = FlexboxLayout.LayoutParams(100, 100)
+                            lp.flexShrink = 0f
+                            textView.layoutParams = lp
+                            flexboxLayout.addView(textView)
+                        }
+                    }
+                })
+        assertThat(flexboxLayout.childCount, `is`(50))
+        assertThat(flexboxLayout.flexLines.size, `is`(3))
+    }
+
     @Throws(Throwable::class)
     private fun createFlexboxLayout(@LayoutRes activityLayoutResId: Int,
                                     configuration: Configuration = Configuration.EMPTY): FlexboxLayout {

diff --git a/flexbox/src/androidTest/java/com/google/android/flexbox/test/FlexboxLayoutManagerTest.kt b/flexbox/src/androidTest/java/com/google/android/flexbox/test/FlexboxLayoutManagerTest.kt
@@ -3310,6 +3310,30 @@ class FlexboxLayoutManagerTest {
         assertThat(layoutManager.getChildAt(0).top, `is`(0))
     }
 
+    @Test
+    @FlakyTest
+    @Throws(Throwable::class)
+    fun testMaxLine() {
+        val activity = activityRule.activity
+        val layoutManager = FlexboxLayoutManager(activity)
+        val adapter = TestAdapter()
+        activityRule.runOnUiThread {
+            activity.setContentView(R.layout.recyclerview)
+            val recyclerView = activity.findViewById<RecyclerView>(R.id.recyclerview)
+            layoutManager.flexDirection = FlexDirection.ROW
+            layoutManager.maxLine = 3
+            recyclerView.layoutManager = layoutManager
+            recyclerView.adapter = adapter
+            for (i in 1..50) {
+                val lp = createLayoutParams(activity, 100, 70)
+                lp.flexShrink = 0f
+                adapter.addItem(lp)
+            }
+        }
+        InstrumentationRegistry.getInstrumentation().waitForIdleSync()
+        assertThat(layoutManager.flexLines.size, `is`(3))
+    }
+
     /**
      * Creates a new flex item.
      *

diff --git a/flexbox/src/main/java/com/google/android/flexbox/FlexContainer.java b/flexbox/src/main/java/com/google/android/flexbox/FlexContainer.java
@@ -273,13 +273,14 @@ interface FlexContainer {
     void setFlexLines(List<FlexLine> flexLines);
 
     /**
-     *
+     * @return the current value of the maximum number of flex lines. If not set, {@link #NOT_SET}
+     * is returned.
      */
     int getMaxLine();
 
     /**
      *
-     * @param maxLine the int value, which specifies the maximum number of lines
+     * @param maxLine the int value, which specifies the maximum number of flex lines
      */
     void setMaxLine(int maxLine);
 

diff --git a/flexbox/src/main/java/com/google/android/flexbox/FlexboxHelper.java b/flexbox/src/main/java/com/google/android/flexbox/FlexboxHelper.java
@@ -499,7 +499,7 @@ void calculateFlexLines(FlexLinesResult result, int mainMeasureSpec,
                     getViewMeasuredSizeMain(child, isMainHorizontal)
                             + getFlexItemMarginStartMain(flexItem, isMainHorizontal) +
                             getFlexItemMarginEndMain(flexItem, isMainHorizontal),
-                    flexItem, i, indexInFlexLine)) {
+                    flexItem, i, indexInFlexLine, flexLines.size())) {
                 if (flexLine.getItemCountNotGone() > 0) {
                     addFlexLine(flexLines, flexLine, i > 0 ? i - 1 : 0, sumCrossSize);
                     sumCrossSize += flexLine.mCrossSize;
@@ -824,12 +824,15 @@ private int getFlexItemMarginEndCross(FlexItem flexItem, boolean isMainHorizonta
      * @param childLength   the length of a child view which is to be collected to the flex line
      * @param flexItem      the LayoutParams for the view being determined whether a new flex line
      *                      is needed
+     * @param index         the index of the view being added within the entire flex container
+     * @param indexInFlexLine the index of the view being added within the current flex line
+     * @param flexLinesSize the number of the existing flexlines size
      * @return {@code true} if a wrap is required, {@code false} otherwise
      * @see FlexContainer#getFlexWrap()
      * @see FlexContainer#setFlexWrap(int)
      */
     private boolean isWrapRequired(View view, int mode, int maxSize, int currentLength,
-            int childLength, FlexItem flexItem, int index, int indexInFlexLine) {
+            int childLength, FlexItem flexItem, int index, int indexInFlexLine, int flexLinesSize) {
         if (mFlexContainer.getFlexWrap() == FlexWrap.NOWRAP) {
             return false;
         }
@@ -840,7 +843,11 @@ private boolean isWrapRequired(View view, int mode, int maxSize, int currentLeng
             return false;
         }
         int maxLine = mFlexContainer.getMaxLine();
-        if (maxLine != NOT_SET && maxLine <= )
+        // Judge the condition by adding 1 to the current flexLinesSize because the flex line
+        // being computed isn't added to the flexLinesSize.
+        if (maxLine != NOT_SET && maxLine <= flexLinesSize + 1) {
+            return false;
+        }
         int decorationLength =
                 mFlexContainer.getDecorationLengthMainAxis(view, index, indexInFlexLine);
         if (decorationLength > 0) {