Google Glass Live Card菜单操作导致崩溃

Question

I'm having some nullPointerException trouble with a Live Card Menu Activity on Google Glass.

I want to:

1. Pull up the menu via touch pad. (This works)
2. Be able to select something in the menu. (This works)
3. Have that selection carry out the action. (This doesn't work)

The action to be performed is simply changing the boolean value of a variable located in my LiveCardService class.

My LiveCardMenuActivity code looks like this -

public class LiveCardMenuActivity extends Activity {

LiveCardService liveCard; // call in the livecardservice class

// ... STANDARD MENU STUFF ... //

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.action_stop:
            // Stop the service which will unpublish the live card.
            stopService(new Intent(this, LiveCardService.class));
            return true;
        case R.id.action_ttoro:
            liveCard.resetWaypoints(); // THIS IS WHERE IT CRASHES
            return true;
        default:
            return super.onOptionsItemSelected(item);
    }
}
...
}

In this case, when the program attempts to carry out "livecard.resetWaypoints()" , the program crashes with a nullPointerException .

The "resetWaypoints()" function in the LiveCardService looks like this (nothing special) -

public void resetWaypoints() {
    ttoroActive = false;
    bgbukActive = false;
    lassyActive = false;
    dployActive = false;
}

The monster logcat complaint looks like this -

E/InputEventSender﹕ Exception dispatching finished signal.
E/MessageQueue-JNI﹕ Exception in MessageQueue callback: handleReceiveCallback
E/MessageQueue-JNI﹕ java.lang.NullPointerException
        at [...].LiveCardMenuActivity.resetWaypoints(LiveCardMenuActivity.java:57)
        at [...].LiveCardMenuActivity.onOptionsItemSelected(LiveCardMenuActivity.java:42)
        at android.app.Activity.onMenuItemSelected(Activity.java:2604)
        at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:1054)
        at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:765)
        at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:157)
        at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:908)
        at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:898)
        at com.google.android.glass.menu.SliderMenuView$1.onItemClick(SliderMenuView.java:81)
        at com.google.android.glass.widget.CardScrollView.onTap(CardScrollView.java:1453)
        at com.google.android.glass.widget.CardScrollView.access$2000(CardScrollView.java:94)
        at com.google.android.glass.widget.CardScrollView$3.onGesture(CardScrollView.java:383)
        at com.google.android.glass.touchpad.CombinedListener.onGesture(CombinedListener.java:185)
        at com.google.android.glass.touchpad.OneFingerState.onEvent(OneFingerState.java:49)
        at com.google.android.glass.touchpad.StateMachine.onEvent(StateMachine.java:100)
        at com.google.android.glass.touchpad.GestureDetector.onMotionEvent(GestureDetector.java:283)
        at com.google.android.glass.widget.CardScrollView.dispatchGenericFocusedEvent(CardScrollView.java:2103)
        at android.view.View.dispatchGenericMotionEvent(View.java:7778)
        at android.view.ViewGroup.dispatchGenericFocusedEvent(ViewGroup.java:1798)
        at android.view.View.dispatchGenericMotionEvent(View.java:7778)
        at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchGenericMotionEvent(PhoneWindow.java:2154)
        at android.view.ViewRootImpl$ViewPostImeInputStage.processGenericMotionEvent(ViewRootImpl.java:3995)
        at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3859)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3421)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3471)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3440)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3547)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3448)
        at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3604)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3421)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3471)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3440)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3448)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3421)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3471)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3440)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3580)
        at android.view.ViewRootImpl$ImeInputStage.onFinishedInputEvent(ViewRootImpl.java:3740)
        at android.view.inputmethod.InputMethodManager$PendingEvent.run(InputMethodManager.java:2010)
        at android.view.inputmethod.InputMethodManager.invokeFinishedInputEventCallback(InputMethodManager.java:1704)
        at android.view.inputmethod.InputMethodManager.finishedInputEvent(InputMethodManager.java:1695)
        at android.view.inputmethod.InputMethodManager$ImeInputEventSender.onInputEventFinished(InputMethodManager.java:1987)
        at android.view.InputEventSender.dispatchInputEventFinished(InputEventSender.java:141)
        at android.os.MessageQueue.nativePollOnce(Native Method)
        at android.os.MessageQueue.next(MessageQueue.java:138)
        at android.os.Looper.loop(Looper.java:131)
        at android.app.ActivityThread.main(ActivityThread.java:5045)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.

The action I would like to do seems pretty straightforward. I have looked at Google's documentation, as far as I have found, they just offer a very simple example of the menu.

This liveCardMenuActivity is registered in the Manifest.

Any tips would be much appreciated.

EDIT: Just to be clear, I want with a touch of a button to be able to change the values of those four boolean variables that are located in my LiveCardService class by calling a function I created in the LiveCardService class that does so. This is what the LiveCardService class looks like when starting the LiveCard

@Override
public int onStartCommand(Intent intent, int flags, int startId) {

    if (mLiveCard == null) { //WHEN ACTIVITY STARTS, LIVECARD IS NULL
        // Create live card object
        mLiveCard = new LiveCard(this, TAG);
        // Set rendering view of the live card
        remoteViews = new RemoteViews(getPackageName(), R.layout.live_card02);
        // Can contain TextView, ImageView, etc
        mLiveCard.setViews(remoteViews);

        // Display the options MENU when the live card is tapped.
        Intent menuIntent = new Intent(this, LiveCardMenuActivity.class);
        mLiveCard.setAction(PendingIntent.getActivity(this, 100, menuIntent, 0));
        mLiveCard.publish(PublishMode.REVEAL);

        // Runs this live card every xxxx milliseconds
        mHandler = new Handler();
        mHandler.postDelayed(runnable, 1000);
    }
    else {
        mLiveCard.navigate();
        Log.d(TAG, "Livecard is not null");

    }
    return START_STICKY;
}

Answer 1

You definitely shouldn't keep this LiveCardService instance.
You should rather talk to your Service unsing intent:

Intent intent = new Intent(this, LiveCardService.class);
intent .setAction("RESET");
startService(intent);

and then, inside your Service:

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    if("RESET".equals(intent.getAction()) {
        // do the reset here
        resetWaypoints();
    }

}