5 files changed, 43 insertions, 24 deletions
diff --git a/core/java/android/view/View.java b/core/java/android/view/View.java
index cdd7098d27fe..30de74ae32dc 100644
--- a/core/java/android/view/View.java
+++ b/core/java/android/view/View.java
@@ -821,6 +821,17 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
     static boolean sTextureViewIgnoresDrawableSetters = false;
 
     /**
+     * Prior to N, some ViewGroups would not convert LayoutParams properly even though both extend
+     * MarginLayoutParams. For instance, converting LinearLayout.LayoutParams to
+     * RelativeLayout.LayoutParams would lose margin information. This is fixed on N but target API
+     * check is implemented for backwards compatibility.
+     *
+     * {@hide}
+     */
+    protected static boolean sPreserveMarginParamsInLayoutParamConversion;
+
+
+    /**
      * This view does not want keystrokes. Use with TAKES_FOCUS_MASK when
      * calling setFlags.
      */
@@ -4054,6 +4065,10 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
             // On N+, we throw, but that breaks compatibility with apps that use these methods.
             sTextureViewIgnoresDrawableSetters = targetSdkVersion <= M;
 
+            // Prior to N, we would drop margins in LayoutParam conversions. The fix triggers bugs
+            // in apps so we target check it to avoid breaking existing apps.
+            sPreserveMarginParamsInLayoutParamConversion = targetSdkVersion >= N;
+
             sCompatibilityDone = true;
         }
     }
diff --git a/core/java/android/widget/FrameLayout.java b/core/java/android/widget/FrameLayout.java
index 029313c53938..b8c74d88b580 100644
--- a/core/java/android/widget/FrameLayout.java
+++ b/core/java/android/widget/FrameLayout.java
@@ -382,13 +382,14 @@ public class FrameLayout extends ViewGroup {
 
     @Override
     protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) {
-        if (lp instanceof LayoutParams) {
-            return new LayoutParams((LayoutParams) lp);
-        } else if (lp instanceof MarginLayoutParams) {
-            return new LayoutParams((MarginLayoutParams) lp);
-        } else {
-            return new LayoutParams(lp);
+        if (sPreserveMarginParamsInLayoutParamConversion) {
+            if (lp instanceof LayoutParams) {
+                return new LayoutParams((LayoutParams) lp);
+            } else if (lp instanceof MarginLayoutParams) {
+                return new LayoutParams((MarginLayoutParams) lp);
+            }
         }
+        return new LayoutParams(lp);
     }
 
     @Override
diff --git a/core/java/android/widget/GridLayout.java b/core/java/android/widget/GridLayout.java
index 726586ee8d5f..af2852cde22a 100644
--- a/core/java/android/widget/GridLayout.java
+++ b/core/java/android/widget/GridLayout.java
@@ -868,13 +868,14 @@ public class GridLayout extends ViewGroup {
 
     @Override
     protected LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) {
-        if (lp instanceof LayoutParams) {
-            return new LayoutParams((LayoutParams) lp);
-        } else if (lp instanceof MarginLayoutParams) {
-            return new LayoutParams((MarginLayoutParams) lp);
-        } else {
-            return new LayoutParams(lp);
+        if (sPreserveMarginParamsInLayoutParamConversion) {
+            if (lp instanceof LayoutParams) {
+                return new LayoutParams((LayoutParams) lp);
+            } else if (lp instanceof MarginLayoutParams) {
+                return new LayoutParams((MarginLayoutParams) lp);
+            }
         }
+        return new LayoutParams(lp);
     }
 
     // Draw grid
diff --git a/core/java/android/widget/LinearLayout.java b/core/java/android/widget/LinearLayout.java
index 33d335a1a9aa..e2c535ca1695 100644
--- a/core/java/android/widget/LinearLayout.java
+++ b/core/java/android/widget/LinearLayout.java
@@ -1871,13 +1871,14 @@ public class LinearLayout extends ViewGroup {
 
     @Override
     protected LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) {
-        if (lp instanceof LayoutParams) {
-            return new LayoutParams((LayoutParams) lp);
-        } else if (lp instanceof MarginLayoutParams) {
-            return new LayoutParams((MarginLayoutParams) lp);
-        } else {
-            return new LayoutParams(lp);
+        if (sPreserveMarginParamsInLayoutParamConversion) {
+            if (lp instanceof LayoutParams) {
+                return new LayoutParams((LayoutParams) lp);
+            } else if (lp instanceof MarginLayoutParams) {
+                return new LayoutParams((MarginLayoutParams) lp);
+            }
         }
+        return new LayoutParams(lp);
     }
 
 
diff --git a/core/java/android/widget/RelativeLayout.java b/core/java/android/widget/RelativeLayout.java
index 0136542ef4ac..a189d3c0cc91 100644
--- a/core/java/android/widget/RelativeLayout.java
+++ b/core/java/android/widget/RelativeLayout.java
@@ -1104,13 +1104,14 @@ public class RelativeLayout extends ViewGroup {
 
     @Override
     protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) {
-        if (lp instanceof LayoutParams) {
-            return new LayoutParams((LayoutParams) lp);
-        } else if (lp instanceof MarginLayoutParams) {
-            return new LayoutParams((MarginLayoutParams) lp);
-        } else {
-            return new LayoutParams(lp);
+        if (sPreserveMarginParamsInLayoutParamConversion) {
+            if (lp instanceof LayoutParams) {
+                return new LayoutParams((LayoutParams) lp);
+            } else if (lp instanceof MarginLayoutParams) {
+                return new LayoutParams((MarginLayoutParams) lp);
+            }
         }
+        return new LayoutParams(lp);
     }
 
     /** @hide */