Keep IMM#mCurRootView synchronized with the actual window focus.

Currently IMM#mCurRootView is always cleared every time when
IMM#finishInputLocked() is called.  We have been doing this since
Iad09cf5dbb7f6f156fd39ed243431432e00f8945 so as not to hold the
strong reference to a DecorView so long time (Bug 6413553).

Strictly speaking, the attached window may continue holding
input focus even after IMM#finishInputLocked() is called.
In this state IMM#focusIn() might have unexpectedly rejected
focus-in event but presumably this might not be obvious, or might
not occur at all because in some situations IMM#finishInputLocked()
has never been called even when the attached view loses input
focus.

In order to fix Issue 20820914, however, we need to call
IMM#finishInputLocked() exactly when the attached view loses
input focus.  To make it easier to diagnose any unexpected
regressions, this CL only changes the handling of
IMM#mCurRootView, while the next CL Id6afc8fc64512225578c62557b96
plumbs IMM#focusOut() to IMM#finishInputLocked().

Manually tested following scenarios.
- Repro steps in Bug 6413553.  Made sure that IMM#mCurRootView
  is cleared after switching back from the current application to
  the previous application with back key.
- Test application that calls WebView#showFindDialog(). Made sure
  that LatinIME works fine when switching text fields.  This is
  non-trivial because android.webkit.FindActionModeCallback is
  changed in this CL.
- Repro steps in Bug 21144633.  Made sure that we can enter
  recipient's name in the messaging app.

Bug: 20820914
Change-Id: I219394178e4172bc47864297f1418e677dba25e5

1 files changed, 20 insertions, 7 deletions

diff --git a/core/java/android/view/inputmethod/InputMethodManager.java b/core/java/android/view/inputmethod/InputMethodManager.java
index 568e160..824b434 100644
--- a/core/java/android/view/inputmethod/InputMethodManager.java
+++ b/core/java/android/view/inputmethod/InputMethodManager.java
@@ -1289,14 +1289,14 @@ public final class InputMethodManager {
 
     void focusInLocked(View view) {
         if (DEBUG) Log.v(TAG, "focusIn: " + view);
-        
+
         if (mCurRootView != view.getRootView()) {
             // This is a request from a window that isn't in the window with
             // IME focus, so ignore it.
             if (DEBUG) Log.v(TAG, "Not IME target window, ignoring");
             return;
         }
-        
+
         mNextServedView = view;
         scheduleCheckFocusLocked(view);
     }
@@ -1392,7 +1392,7 @@ public final class InputMethodManager {
      * Called by ViewAncestor when its window gets input focus.
      * @hide
      */
-    public void onWindowFocus(View rootView, View focusedView, int softInputMode,
+    public void onPostWindowFocus(View rootView, View focusedView, int softInputMode,
             boolean first, int windowFlags) {
         boolean forceNewFocus = false;
         synchronized (mH) {
@@ -1441,14 +1441,27 @@ public final class InputMethodManager {
             }
         }
     }
-    
+
     /** @hide */
-    public void startGettingWindowFocus(View rootView) {
+    public void onPreWindowFocus(View rootView, boolean hasWindowFocus) {
         synchronized (mH) {
-            mCurRootView = rootView;
+            if (rootView == null) {
+                mCurRootView = null;
+            } if (hasWindowFocus) {
+                mCurRootView = rootView;
+            } else if (rootView == mCurRootView) {
+                // If the mCurRootView is losing window focus, release the strong reference to it
+                // so as not to prevent it from being garbage-collected.
+                mCurRootView = null;
+            } else {
+                if (DEBUG) {
+                    Log.v(TAG, "Ignoring onPreWindowFocus()."
+                            + " mCurRootView=" + mCurRootView + " rootView=" + rootView);
+                }
+            }
         }
     }
-    
+
     /**
      * Report the current selection range.
      *