Use FLAG_LONG_PRESS for headset long press interactions.

Handle canceled key events correctly and don't synthesize
key events in that case.

Unfortunately, the state machine was confused by some sequences
of key events that it might receive from the input dispatcher
when new activities take focus during a long-press on the headset key.
The audio service may receive a cancel event intended for the old
window, followed by a repeated down and finally an up for the new window.
Simplified this down to just two booleans.

Bug: 6484717
Change-Id: I9587d0a5e282419ef4d7c17665940682aacea96a

Author: Jeff Brown

media/java/android/media/AudioService.java

@@ -3699,38 +3699,15 @@ private void dispatchMediaKeyEvent(KeyEvent keyEvent, boolean needWakeLock) {
     }
 
     /**
-     * The minimum duration during which a user must press to trigger voice-based interactions
-     */
-    private final static int MEDIABUTTON_LONG_PRESS_DURATION_MS = 300;
-    /**
-     * The different states of the state machine to handle the launch of voice-based interactions,
-     * stored in mVoiceButtonState.
-     */
-    private final static int VOICEBUTTON_STATE_IDLE = 0;
-    private final static int VOICEBUTTON_STATE_DOWN = 1;
-    private final static int VOICEBUTTON_STATE_DOWN_IGNORE_NEW = 2;
-    /**
-     * The different actions after state transitions on mVoiceButtonState.
+     * The different actions performed in response to a voice button key event.
      */
     private final static int VOICEBUTTON_ACTION_DISCARD_CURRENT_KEY_PRESS = 1;
     private final static int VOICEBUTTON_ACTION_START_VOICE_INPUT = 2;
     private final static int VOICEBUTTON_ACTION_SIMULATE_KEY_PRESS = 3;
 
     private final Object mVoiceEventLock = new Object();
-    private int mVoiceButtonState = VOICEBUTTON_STATE_IDLE;
-    private long mVoiceButtonDownTime = 0;
-
-    /**
-     * Log an error when an unexpected action is encountered in the state machine to filter
-     * key events.
-     * @param keyAction the unexpected action of the key event being filtered
-     * @param stateName the string corresponding to the state in which the error occurred
-     */
-    private static void logErrorForKeyAction(int keyAction, String stateName) {
-        Log.e(TAG, "unexpected action "
-                + KeyEvent.actionToString(keyAction)
-                + " in " + stateName + " state");
-    }
+    private boolean mVoiceButtonDown;
+    private boolean mVoiceButtonHandled;
 
     /**
      * Filter key events that may be used for voice-based interactions
@@ -3740,67 +3717,32 @@ private static void logErrorForKeyAction(int keyAction, String stateName) {
      *     is dispatched.
      */
     private void filterVoiceInputKeyEvent(KeyEvent keyEvent, boolean needWakeLock) {
+        if (DEBUG_RC) {
+            Log.v(TAG, "voice input key event: " + keyEvent + ", needWakeLock=" + needWakeLock);
+        }
+
         int voiceButtonAction = VOICEBUTTON_ACTION_DISCARD_CURRENT_KEY_PRESS;
         int keyAction = keyEvent.getAction();
         synchronized (mVoiceEventLock) {
-            // state machine on mVoiceButtonState
-            switch (mVoiceButtonState) {
-
-                case VOICEBUTTON_STATE_IDLE:
-                    if (keyAction == KeyEvent.ACTION_DOWN) {
-                        mVoiceButtonDownTime = keyEvent.getDownTime();
-                        // valid state transition
-                        mVoiceButtonState = VOICEBUTTON_STATE_DOWN;
-                    } else if (keyAction == KeyEvent.ACTION_UP) {
-                        // no state transition
-                        // action is still VOICEBUTTON_ACTION_DISCARD_CURRENT_KEY_PRESS
-                    } else {
-                        logErrorForKeyAction(keyAction, "VOICEBUTTON_STATE_IDLE");
-                    }
-                    break;
-
-                case VOICEBUTTON_STATE_DOWN:
-                    if ((keyEvent.getEventTime() - mVoiceButtonDownTime)
-                            >= MEDIABUTTON_LONG_PRESS_DURATION_MS) {
-                        // press was long enough, start voice-based interactions, regardless of
-                        //   whether this was a DOWN or UP key event
-                        voiceButtonAction = VOICEBUTTON_ACTION_START_VOICE_INPUT;
-                        if (keyAction == KeyEvent.ACTION_UP) {
-                            // done tracking the key press, so transition back to idle state
-                            mVoiceButtonState = VOICEBUTTON_STATE_IDLE;
-                        } else if (keyAction == KeyEvent.ACTION_DOWN) {
-                            // no need to observe the upcoming key events
-                            mVoiceButtonState = VOICEBUTTON_STATE_DOWN_IGNORE_NEW;
-                        } else {
-                            logErrorForKeyAction(keyAction, "VOICEBUTTON_STATE_DOWN");
-                        }
-                    } else {
-                        if (keyAction == KeyEvent.ACTION_UP) {
-                            // press wasn't long enough, simulate complete key press
-                            voiceButtonAction = VOICEBUTTON_ACTION_SIMULATE_KEY_PRESS;
-                            // not tracking the key press anymore, so transition back to idle state
-                            mVoiceButtonState = VOICEBUTTON_STATE_IDLE;
-                        } else if (keyAction == KeyEvent.ACTION_DOWN) {
-                            // no state transition
-                            // action is still VOICEBUTTON_ACTION_DISCARD_CURRENT_KEY_PRESS
-                        } else {
-                            logErrorForKeyAction(keyAction, "VOICEBUTTON_STATE_DOWN");
-                        }
-                    }
-                    break;
-
-                case VOICEBUTTON_STATE_DOWN_IGNORE_NEW:
-                    if (keyAction == KeyEvent.ACTION_UP) {
-                        // done tracking the key press, so transition back to idle state
-                        mVoiceButtonState = VOICEBUTTON_STATE_IDLE;
-                        // action is still VOICEBUTTON_ACTION_DISCARD_CURRENT_KEY_PRESS
-                    } else if (keyAction == KeyEvent.ACTION_DOWN) {
-                        // no state transition: we've already launched voice-based interactions
-                        // action is still VOICEBUTTON_ACTION_DISCARD_CURRENT_KEY_PRESS
-                    } else  {
-                        logErrorForKeyAction(keyAction, "VOICEBUTTON_STATE_DOWN_IGNORE_NEW");
+            if (keyAction == KeyEvent.ACTION_DOWN) {
+                if (keyEvent.getRepeatCount() == 0) {
+                    // initial down
+                    mVoiceButtonDown = true;
+                    mVoiceButtonHandled = false;
+                } else if (mVoiceButtonDown && !mVoiceButtonHandled
+                        && (keyEvent.getFlags() & KeyEvent.FLAG_LONG_PRESS) != 0) {
+                    // long-press, start voice-based interactions
+                    mVoiceButtonHandled = true;
+                    voiceButtonAction = VOICEBUTTON_ACTION_START_VOICE_INPUT;
+                }
+            } else if (keyAction == KeyEvent.ACTION_UP) {
+                if (mVoiceButtonDown) {
+                    // voice button up
+                    mVoiceButtonDown = false;
+                    if (!mVoiceButtonHandled && !keyEvent.isCanceled()) {
+                        voiceButtonAction = VOICEBUTTON_ACTION_SIMULATE_KEY_PRESS;
                     }
-                    break;
+                }
             }
         }//synchronized (mVoiceEventLock)