Merge "Don't allow 0-sized views to be focused."
diff --git a/core/java/android/view/View.java b/core/java/android/view/View.java
index e36a298..19ce43f 100644
--- a/core/java/android/view/View.java
+++ b/core/java/android/view/View.java
@@ -4163,6 +4163,11 @@
      */
     private static boolean sUseDefaultFocusHighlight;
 
+    /**
+     * True if zero-sized views can be focused.
+     */
+    private static boolean sCanFocusZeroSized;
+
     private String mTransitionName;
 
     static class TintInfo {
@@ -4745,6 +4750,8 @@
             sUseDefaultFocusHighlight = context.getResources().getBoolean(
                     com.android.internal.R.bool.config_useDefaultFocusHighlight);
 
+            sCanFocusZeroSized = targetSdkVersion < Build.VERSION_CODES.P;
+
             sCompatibilityDone = true;
         }
     }
@@ -6952,6 +6959,7 @@
     void clearFocusInternal(View focused, boolean propagate, boolean refocus) {
         if ((mPrivateFlags & PFLAG_FOCUSED) != 0) {
             mPrivateFlags &= ~PFLAG_FOCUSED;
+            clearParentsWantFocus();
 
             if (propagate && mParent != null) {
                 mParent.clearChildFocus(this);
@@ -10933,8 +10941,9 @@
      * descendants.
      *
      * A view will not actually take focus if it is not focusable ({@link #isFocusable} returns
-     * false), or if it is focusable and it is not focusable in touch mode
-     * ({@link #isFocusableInTouchMode}) while the device is in touch mode.
+     * false), or if it can't be focused due to other conditions (not focusable in touch mode
+     * ({@link #isFocusableInTouchMode}) while the device is in touch mode, not visible, not
+     * enabled, or has no size).
      *
      * See also {@link #focusSearch(int)}, which is what you call to say that you
      * have focus, and you want your parent to look for the next one.
@@ -10972,17 +10981,17 @@
      */
     @TestApi
     public boolean restoreFocusNotInCluster() {
-        return requestFocus(View.FOCUS_DOWN);
+        return requestFocus();
     }
 
     /**
      * Gives focus to the default-focus view in the view hierarchy that has this view as a root.
-     * If the default-focus view cannot be found, falls back to calling {@link #requestFocus(int)}.
+     * If the default-focus view cannot be found, falls back to calling {@link #requestFocus()}.
      *
      * @return Whether this view or one of its descendants actually took focus
      */
     public boolean restoreDefaultFocus() {
-        return requestFocus(View.FOCUS_DOWN);
+        return requestFocus();
     }
 
     /**
@@ -11041,9 +11050,7 @@
 
     private boolean requestFocusNoSearch(int direction, Rect previouslyFocusedRect) {
         // need to be focusable
-        if ((mViewFlags & FOCUSABLE) != FOCUSABLE
-                || (mViewFlags & VISIBILITY_MASK) != VISIBLE
-                || (mViewFlags & ENABLED_MASK) != ENABLED) {
+        if (!canTakeFocus()) {
             return false;
         }
 
@@ -11058,10 +11065,21 @@
             return false;
         }
 
+        if (!isLaidOut()) {
+            mPrivateFlags |= PFLAG_WANTS_FOCUS;
+        }
+
         handleFocusGainInternal(direction, previouslyFocusedRect);
         return true;
     }
 
+    void clearParentsWantFocus() {
+        if (mParent instanceof View) {
+            ((View) mParent).mPrivateFlags &= ~PFLAG_WANTS_FOCUS;
+            ((View) mParent).clearParentsWantFocus();
+        }
+    }
+
     /**
      * Call this to try to give focus to a specific view or to one of its descendants. This is a
      * special variant of {@link #requestFocus() } that will allow views that are not focusable in
@@ -13433,6 +13451,13 @@
         mAttachInfo.mUnbufferedDispatchRequested = true;
     }
 
+    private boolean canTakeFocus() {
+        return ((mViewFlags & VISIBILITY_MASK) == VISIBLE)
+                && ((mViewFlags & FOCUSABLE) == FOCUSABLE)
+                && ((mViewFlags & ENABLED_MASK) == ENABLED)
+                && (sCanFocusZeroSized || !isLaidOut() || (mBottom > mTop) && (mRight > mLeft));
+    }
+
     /**
      * Set flags controlling behavior of this view.
      *
@@ -13452,6 +13477,7 @@
             return;
         }
         int privateFlags = mPrivateFlags;
+        boolean shouldNotifyFocusableAvailable = false;
 
         // If focusable is auto, update the FOCUSABLE bit.
         int focusableChangedByAuto = 0;
@@ -13490,7 +13516,7 @@
                             || focusableChangedByAuto == 0
                             || viewRootImpl == null
                             || viewRootImpl.mThread == Thread.currentThread()) {
-                        mParent.focusableViewAvailable(this);
+                        shouldNotifyFocusableAvailable = true;
                     }
                 }
             }
@@ -13513,10 +13539,7 @@
                 // about in case nothing has focus.  even if this specific view
                 // isn't focusable, it may contain something that is, so let
                 // the root view try to give this focus if nothing else does.
-                if ((mParent != null) && ((mViewFlags & ENABLED_MASK) == ENABLED)
-                        && (mBottom > mTop) && (mRight > mLeft)) {
-                    mParent.focusableViewAvailable(this);
-                }
+                shouldNotifyFocusableAvailable = true;
             }
         }
 
@@ -13525,17 +13548,18 @@
                 // a view becoming enabled should notify the parent as long as the view is also
                 // visible and the parent wasn't already notified by becoming visible during this
                 // setFlags invocation.
-                if ((mViewFlags & VISIBILITY_MASK) == VISIBLE
-                        && ((changed & VISIBILITY_MASK) == 0)) {
-                    if ((mParent != null) && (mViewFlags & ENABLED_MASK) == ENABLED) {
-                        mParent.focusableViewAvailable(this);
-                    }
-                }
+                shouldNotifyFocusableAvailable = true;
             } else {
                 if (hasFocus()) clearFocus();
             }
         }
 
+        if (shouldNotifyFocusableAvailable) {
+            if (mParent != null && canTakeFocus()) {
+                mParent.focusableViewAvailable(this);
+            }
+        }
+
         /* Check if the GONE bit has changed */
         if ((changed & GONE) != 0) {
             needGlobalAttributesUpdate(false);
@@ -20034,15 +20058,58 @@
             }
         }
 
+        final boolean wasLaidOut = isLaidOut();
+
         mPrivateFlags &= ~PFLAG_FORCE_LAYOUT;
         mPrivateFlags3 |= PFLAG3_IS_LAID_OUT;
 
+        if (!wasLaidOut && isFocused()) {
+            mPrivateFlags &= ~PFLAG_WANTS_FOCUS;
+            if (canTakeFocus()) {
+                // We have a robust focus, so parents should no longer be wanting focus.
+                clearParentsWantFocus();
+            } else if (!getViewRootImpl().isInLayout()) {
+                // This is a weird case. Most-likely the user, rather than ViewRootImpl, called
+                // layout. In this case, there's no guarantee that parent layouts will be evaluated
+                // and thus the safest action is to clear focus here.
+                clearFocusInternal(null, /* propagate */ true, /* refocus */ false);
+                clearParentsWantFocus();
+            } else if (!hasParentWantsFocus()) {
+                // original requestFocus was likely on this view directly, so just clear focus
+                clearFocusInternal(null, /* propagate */ true, /* refocus */ false);
+            }
+            // otherwise, we let parents handle re-assigning focus during their layout passes.
+        } else if ((mPrivateFlags & PFLAG_WANTS_FOCUS) != 0) {
+            mPrivateFlags &= ~PFLAG_WANTS_FOCUS;
+            View focused = findFocus();
+            if (focused != null) {
+                // Try to restore focus as close as possible to our starting focus.
+                if (!restoreDefaultFocus() && !hasParentWantsFocus()) {
+                    // Give up and clear focus once we've reached the top-most parent which wants
+                    // focus.
+                    focused.clearFocusInternal(null, /* propagate */ true, /* refocus */ false);
+                }
+            }
+        }
+
         if ((mPrivateFlags3 & PFLAG3_NOTIFY_AUTOFILL_ENTER_ON_LAYOUT) != 0) {
             mPrivateFlags3 &= ~PFLAG3_NOTIFY_AUTOFILL_ENTER_ON_LAYOUT;
             notifyEnterOrExitForAutoFillIfNeeded(true);
         }
     }
 
+    private boolean hasParentWantsFocus() {
+        ViewParent parent = mParent;
+        while (parent instanceof ViewGroup) {
+            ViewGroup pv = (ViewGroup) parent;
+            if ((pv.mPrivateFlags & PFLAG_WANTS_FOCUS) != 0) {
+                return true;
+            }
+            parent = pv.mParent;
+        }
+        return false;
+    }
+
     /**
      * Called from layout when this view should
      * assign a size and position to each of its children.
@@ -20149,6 +20216,23 @@
             mOverlay.getOverlayView().setRight(newWidth);
             mOverlay.getOverlayView().setBottom(newHeight);
         }
+        // If this isn't laid out yet, focus assignment will be handled during the "deferment/
+        // backtracking" of requestFocus during layout, so don't touch focus here.
+        if (!sCanFocusZeroSized && isLaidOut()) {
+            if (newWidth <= 0 || newHeight <= 0) {
+                if (hasFocus()) {
+                    clearFocus();
+                    if (mParent instanceof ViewGroup) {
+                        ((ViewGroup) mParent).clearFocusedInCluster();
+                    }
+                }
+                clearAccessibilityFocus();
+            } else if (oldWidth <= 0 || oldHeight <= 0) {
+                if (mParent != null && canTakeFocus()) {
+                    mParent.focusableViewAvailable(this);
+                }
+            }
+        }
         rebuildOutline();
     }
 
diff --git a/core/java/android/view/ViewGroup.java b/core/java/android/view/ViewGroup.java
index 929beae..d0fcc5d 100644
--- a/core/java/android/view/ViewGroup.java
+++ b/core/java/android/view/ViewGroup.java
@@ -3215,22 +3215,31 @@
         }
         int descendantFocusability = getDescendantFocusability();
 
+        boolean result;
         switch (descendantFocusability) {
             case FOCUS_BLOCK_DESCENDANTS:
-                return super.requestFocus(direction, previouslyFocusedRect);
+                result = super.requestFocus(direction, previouslyFocusedRect);
+                break;
             case FOCUS_BEFORE_DESCENDANTS: {
                 final boolean took = super.requestFocus(direction, previouslyFocusedRect);
-                return took ? took : onRequestFocusInDescendants(direction, previouslyFocusedRect);
+                result = took ? took : onRequestFocusInDescendants(direction,
+                        previouslyFocusedRect);
+                break;
             }
             case FOCUS_AFTER_DESCENDANTS: {
                 final boolean took = onRequestFocusInDescendants(direction, previouslyFocusedRect);
-                return took ? took : super.requestFocus(direction, previouslyFocusedRect);
+                result = took ? took : super.requestFocus(direction, previouslyFocusedRect);
+                break;
             }
             default:
                 throw new IllegalStateException("descendant focusability must be "
                         + "one of FOCUS_BEFORE_DESCENDANTS, FOCUS_AFTER_DESCENDANTS, FOCUS_BLOCK_DESCENDANTS "
                         + "but is " + descendantFocusability);
         }
+        if (result && !isLaidOut() && ((mPrivateFlags & PFLAG_WANTS_FOCUS) == 0)) {
+            mPrivateFlags |= PFLAG_WANTS_FOCUS;
+        }
+        return result;
     }
 
     /**