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Commit f4ac547f authored by Chet Haase's avatar Chet Haase
Browse files

Fix NPE with display lists when view not attached 

There was logic in ViewGroup that assumed that an accelerated
view must always be able to get a display list for any child
that it was drawing. One situation occurred, however, that
caused a problem with this - a contacts activity was started
and not yet attached, but was being asked to render into an
accelerated canvas. We assumed that the child would have a display
list and simply called getDisplayList(). But since that call
returned null, we later deref'd the null object.

The fix is to check whether a child can have a display list
instead of assuming that it can just because the container view
is accelerated.

Change-Id: I7de62fd597ad50720c9585d621bec02e77c171df
parent e38ba4ac

core/java/android/view/View.java

+16 −1
Original line number Diff line number Diff line
@@ -8228,6 +8228,21 @@ public class View implements Drawable.Callback, KeyEvent.Callback, Accessibility 
     */

    protected void dispatchGetDisplayList() {}



    /**

     * A view that is not attached or hardware accelerated cannot create a display list.

     * This method checks these conditions and returns the appropriate result.

     *

     * @return true if view has the ability to create a display list, false otherwise.

     *

     * @hide

     */

    public boolean canHaveDisplayList() {

        if (mAttachInfo == null || mAttachInfo.mHardwareRenderer == null) {

            return false;

        }

        return true;

    }

    

    /**

     * <p>Returns a display list that can be used to draw this view again

     * without executing its draw method.</p>
@@ -8237,7 +8252,7 @@ public class View implements Drawable.Callback, KeyEvent.Callback, Accessibility 
     * @hide

     */

    public DisplayList getDisplayList() {

        if (mAttachInfo == null || mAttachInfo.mHardwareRenderer == null) {

        if (!canHaveDisplayList()) {

            return null;

        }

core/java/android/view/ViewGroup.java

+1 −1
Original line number Diff line number Diff line
@@ -2381,7 +2381,7 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager 
                } else if (layerType == LAYER_TYPE_NONE) {

                    // Delay getting the display list until animation-driven alpha values are

                    // set up and possibly passed on to the view

                    hasDisplayList = true;

                    hasDisplayList = child.canHaveDisplayList();

                }

            }

        }