原生Android 4.0来电按钮消失的问题

Google原生Android 4.0有个bug:来电时，如果用户进行一定操作，来电按钮会消失掉，以致用户无法接听电话.
在我们的项目中,对该问题的修复是通过修改以下几个文件来完成的：
packages/apps/Phone/src/com/android/phone/InCallScreen.java
packages/apps/Phone/src/com/android/phone/InCallTouchUi.java
packages/apps/Phone/src/com/android/phone/RespondViaSmsManager.java

InCallTouchUi.java文件的修改如下：

@@ -226,12 +226,19 @@ public class InCallTouchUi extends FrameLayout
         View.OnTouchListener smallerHitTargetTouchListener = new SmallerHitTarg
         mEndButton.setOnTouchListener(smallerHitTargetTouchListener);
     }
+    /**
+     * Updates the visibility and/or state of our UI elements, based on
+     * the current state of the phone.
+     */
+    final void updateState(CallManager cm) {
+        updateState(cm,false);
+    }
 

/**
      * Updates the visibility and/or state of our UI elements, based on
      * the current state of the phone.
      */
-    void updateState(CallManager cm) {
+    void updateState(CallManager cm, boolean force) {
         if (mInCallScreen == null) {
             log("- updateState: mInCallScreen has been destroyed; bailing out..")
             return;
@@ -270,7 +277,7 @@ public class InCallTouchUi extends FrameLayout
             // within the last 500 msec, *don't* show the incoming call
             // UI even if the phone is still in the RINGING state.
             long now = SystemClock.uptimeMillis();
-            if (now < mLastIncomingCallActionTime + 500) {
+            if ((!force) && (now < mLastIncomingCallActionTime + 500)) {
                 log("updateState: Too soon after last action; not drawing!");
                 showIncomingCallControls = false;
             }

InCallScreen.java文件的主要修改如下：

@@ -156,8 +156,9 @@ public class InCallScreen extends Activity
     private static final int EVENT_PAUSE_DIALOG_COMPLETE = 120;
     private static final int EVENT_HIDE_PROVIDER_OVERLAY = 121;  // Time to rem
     private static final int REQUEST_UPDATE_SCREEN = 122;
-    private static final int PHONE_INCOMING_RING = 123;
-    private static final int PHONE_NEW_RINGING_CONNECTION = 124;
+    private static final int REQUEST_FORCE_UPDATE_SCREEN = 123;
+    private static final int PHONE_INCOMING_RING = 124;
+    private static final int PHONE_NEW_RINGING_CONNECTION = 125;
 

// When InCallScreenMode is UNDEFINED set the default action
     // to ACTION_UNDEFINED so if we are resumed the activity will
@@ -417,6 +418,9 @@ public class InCallScreen extends Activity
                     updateScreen();
                     break;

+                case REQUEST_FORCE_UPDATE_SCREEN:
+                    updateScreen(true);
+                    break;
                 case PHONE_INCOMING_RING:
                     onIncomingRing();
                     break;
@@ -2172,7 +2176,21 @@ public class InCallScreen extends Activity