My First "Google Glass App"

I made what my friends consider a poor purchasing decision - and what I hope will pay itself off in the long run. I bought an explorer edition of Google Glass.

The purpose, of course, was to start developing for them. I'm a programmer at heart and programming is what I want to do. It took about a week before I finally got around to making my first app, and of course being an Android developer I wanted to play with the newly released "Glass Development Kit" or GDK - the API on top of Android specifically for Google Glass Apps - not the mirror api cards. So I took apart one of Google's samples, as I'd never worked with Services or RemoteViews before.

It says "Meow" (on the card) when you trigger it using the voice command "OK Glass, Meow."

To do this, I had to create a few things: MeowService - the service running in the background that controls the LiveCard, meow_card.xml - the layout file that simply says "meow", MenuActivity - the required intent when interacting with the live card (yes, required!), and voice_trigger_start - a trigger with the text to launch the app, and of course AndroidManifest.xml, but that's barely important.

	<?xml version="1.0" encoding="utf-8"?>
	<!-- Copyright (C) 2013 The Android Open Source Project
	Licensed under the Apache License, Version 2.0 (the "License");
	you may not use this file except in compliance with the License.
	You may obtain a copy of the License at
	http://www.apache.org/licenses/LICENSE-2.0
	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
	-->
	<manifest xmlns:android="http://schemas.android.com/apk/res/android"
	package="me.navarr.app.meow"
	android:versionCode="1"
	android:versionName="1.0" >
	<uses-sdk
	android:minSdkVersion="15"
	android:targetSdkVersion="15" />
	<application
	android:allowBackup="true"
	android:icon="@drawable/ic_lap"
	android:label="@string/app_name" >
	<activity
	android:name="me.navarr.app.meow.MenuActivity"
	android:label="@string/app_name"
	android:theme="@style/MenuTheme"
	android:enabled="true" >
	</activity>
	<service
	android:name="me.navarr.app.meow.MeowService"
	android:icon="@drawable/ic_lap"
	android:label="@string/app_name"
	android:enabled="true"
	android:exported="true">
	<intent-filter>
	<action android:name="com.google.android.glass.action.VOICE_TRIGGER" />
	</intent-filter>
	<meta-data
	android:name="com.google.android.glass.VoiceTrigger"
	android:resource="@xml/voice_trigger_start" />
	</service>
	</application>
	</manifest>

view raw AndroidManifest.xml hosted with ❤ by GitHub

	buildscript {
	repositories {
	mavenCentral()
	}
	dependencies {
	classpath 'com.android.tools.build:gradle:0.6.+'
	}
	}
	apply plugin: 'android'
	repositories {
	mavenCentral()
	}
	android {
	compileSdkVersion "Google Inc.:Glass Development Kit Sneak Peek:15"
	buildToolsVersion "18.1.1"
	defaultConfig {
	minSdkVersion 15
	targetSdkVersion 15
	}
	buildTypes {
	release {
	runProguard true
	proguardFile getDefaultProguardFile('proguard-android-optimize.txt')
	}
	}
	productFlavors {
	defaultFlavor {
	proguardFile 'proguard-rules.txt'
	}
	}
	}
	dependencies {
	}

view raw build.gradle hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<FrameLayout
	xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	android:background="@color/black" >
	<TextView
	android:id="@+id/seconds_view"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	android:layout_gravity="center"
	android:layout_marginTop="-10px"
	android:text="@string/meow"
	android:textSize="140sp"
	android:gravity="center" />
	</FrameLayout>

view raw card_meow.xml hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<!-- Copyright (C) 2013 The Android Open Source Project
	Licensed under the Apache License, Version 2.0 (the "License");
	you may not use this file except in compliance with the License.
	You may obtain a copy of the License at
	http://www.apache.org/licenses/LICENSE-2.0
	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
	-->
	<menu xmlns:android="http://schemas.android.com/apk/res/android">
	<item
	android:id="@+id/stop"
	android:title="@string/stop"
	android:icon="@drawable/ic_stop" />
	</menu>

view raw menu.xml hosted with ❤ by GitHub

	package me.navarr.app.meow;
	import android.app.Activity;
	import android.content.Intent;
	import android.os.Bundle;
	import android.view.Menu;
	import android.view.MenuInflater;
	import android.view.MenuItem;
	/**
	* Activity showing the options menu.
	*/
	public class MenuActivity extends Activity {
	@Override
	protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	}
	@Override
	public void onResume() {
	super.onResume();
	openOptionsMenu();
	}
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
	MenuInflater inflater = getMenuInflater();
	inflater.inflate(R.menu.menu, menu);
	return true;
	}
	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
	// Handle item selection.
	switch (item.getItemId()) {
	case R.id.stop:
	stopService(new Intent(this, MeowService.class));
	return true;
	default:
	return super.onOptionsItemSelected(item);
	}
	}
	@Override
	public void onOptionsMenuClosed(Menu menu) {
	// Nothing else to do, closing the Activity.
	finish();
	}
	}

view raw MenuActivity.java hosted with ❤ by GitHub

	package me.navarr.app.meow;
	import android.app.PendingIntent;
	import android.app.Service;
	import android.content.Intent;
	import android.os.IBinder;
	import android.util.Log;
	import android.widget.RemoteViews;
	import com.google.android.glass.timeline.LiveCard;
	import com.google.android.glass.timeline.TimelineManager;
	public class MeowService extends Service {
	private static final String TAG = "MeowService";
	private static final String LIVE_CARD_ID = "meow_card";
	private TimelineManager mTimelineManager;
	private LiveCard mLiveCard;
	@Override
	public void onCreate() {
	super.onCreate();
	/**
	* TimelineManager is the object to, well, manage the Timeline.
	* If you're unfamiliar with the terminology, the timeline is the list
	* of cards that appear on Glass. The cards to the right of the homescreen
	* are cards from the past (notifications, emails, texts). Cards to the left of the
	* homescreen are cards happening right now or in the future (LiveCards and Google Now)
	*/
	mTimelineManager = TimelineManager.from(this);
	}
	@Override
	public int onStartCommand(Intent intent, int flags, int startId) {
	/**
	* For obvious reasons, you will probably only ever want ONE version of your
	* LiveCard running
	*/
	if (mLiveCard == null) {
	Log.d(TAG, "Publishing LiveCard");
	mLiveCard = mTimelineManager.getLiveCard(LIVE_CARD_ID);
	/**
	* LiveCard.setViews is how we give it the low-frequency layout. For higher
	* frequency rendering (real-time rendering) you will need to use
	* LiveCard.enableDirectRendering and attach your rendering to LiveCard.getSurfaceHolder
	*/
	mLiveCard.setViews(new RemoteViews(this.getPackageName(), R.layout.card_meow));
	/**
	* Setting the LiveCard as non-silent means that we will be taken to the Timeline as
	* soon as the card is published, rather than it just appearing in the background.
	*
	* If you are not doing anything else in the foreground, you definitely want to do this.
	*/
	mLiveCard.setNonSilent(true);
	/**
	* An action intent IS REQUIRED. After all, the user should have a way to stop your app
	* or interact with it if there are other actions. Here we set the action as a
	* PendingIntent to call up the MenuActivity.
	*/
	Intent menuIntent = new Intent(this, MenuActivity.class);
	mLiveCard.setAction(PendingIntent.getActivity(this, 0, menuIntent, 0));
	/**
	* This immediately publishes the live card, and with setNonSilent as true, we're
	* immediately taken to it.
	*/
	mLiveCard.publish();
	Log.d(TAG, "Done publishing LiveCard");
	}
	return START_STICKY;
	}
	@Override
	public void onDestroy() {
	if (mLiveCard != null && mLiveCard.isPublished()) {
	// I think you can figure out what we're doing here.
	Log.d(TAG, "Unpublishing LiveCard");
	mLiveCard.unpublish();
	mLiveCard = null;
	}
	super.onDestroy();
	}
	@Override
	public IBinder onBind(Intent intent) {
	return null;
	}
	}

view raw MeowService.java hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<!-- Copyright (C) 2013 The Android Open Source Project
	Licensed under the Apache License, Version 2.0 (the "License");
	you may not use this file except in compliance with the License.
	You may obtain a copy of the License at
	http://www.apache.org/licenses/LICENSE-2.0
	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
	-->
	<resources>
	<string name="app_name">Meow</string>
	<string name="stop">Stop</string>
	<string name="open">Meow</string>
	<string name="meow">ニャン</string>
	</resources>

view raw strings.xml hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<!-- Copyright (C) 2013 The Android Open Source Project
	Licensed under the Apache License, Version 2.0 (the "License");
	you may not use this file except in compliance with the License.
	You may obtain a copy of the License at
	http://www.apache.org/licenses/LICENSE-2.0
	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
	-->
	<trigger keyword="@string/open" />

view raw voice_trigger_start.xml hosted with ❤ by GitHub