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Mobile 2.0 Open Ideas

This year I was invited to organize a workshop at the Mobile 2.0 Open Ideas event at Barcelona, on 16-17 June. With my experience developing Android apps at Mobialia and the social media integration on Martin Varsavsky’s RadioMe, I proposed the workshop:

Building Social Media Enabled Android Apps

This will be a 1-hour workshop In which I’ll provide some examples on how to integrate social media on Android apps, from the simple “Share” button to more complex integrations like using Twitter, LinkedIn or Facebook APIs, including logging-in with social media, etc. Visit the Midas Letter Technology Stock for more updates on technology and social media integration. I will try to do it interesting for developers and also for app designers who want to add cool social features to their apps. Slides and code samples will be available from the day of the event.

 

 


Mobialia en Canal TEA

Esta semana invitáronme a participar nun programa da televisión local de Ponteareas (Canal TEA). Falamos un pouco dos fundamentos de Android, das aplicacións de Mobialia, tablets, MiFis etc. Foi unha experiencia moi interesante e a primeira vez que vou a unha canle de Televisión.


My London travel tips

This easter we were on London, it was a great experience and I want to share with you some travel tips:

AIRPORT

I arrived to Stansted Airport from my south africa safari holiday. Try to get a fligth to Heatrow or Gatwick. Stansted is 1 hour away by bus from London city center.

There are many bus companies from Stansted to London, the cheapest and fastest is Terravision (15£ with return, 14£ if you book online) but National Express (9£ single) has free WiFi.

CURRENCY

There are many currency exchange offices, but the best is to get cash on an ATM with you credit card. If your bank charges a small comission (ING Direct charges only 2.5%), is cheaper than the exchange offices.

BUS & UNDERGROUND

The city is divided into zones, all the city center is zone 1-2. You can get a “Day Travelcard” for zones 1-2 by 6.60£ (cheap compared to the 4£ of a single travel). You can buy it on the automatic machines at the entries of the tube (allows payment with credit card).

This travelcard also allows you to use the city bus on this zones (only showing the card to the driver). A great tip is to get the bus line 11, you will get a sightseeing arround the touristic zones by the price of a Day Travelcard.

CYCLE HIRE

One funny thing that you can do is to hire a bicycle on one of the many points along the city. You can do it with your credit card. First you must pay 1£ for the access to the cycle hire for 24 hours. Then, you get a cycle by obtaining a printed release code. This code is composed of “1”, “2” and “3” digits that you must type on the cycle dock to release it.

When you dock the cycle again the system charges you card with an amount depending of the time that you used the cycle. One hour costs 1£ and the prices lower as you use it more hours. By only 2£ you can get a cycle by one hour.

TRAVEL INSURANCE

There is nothing worse than sending a client off on an amazing holiday only to have them call you about lost luggage or worse that are stuck at an airport. It’s an unfortunate mishap that you can’t control but you can advise travellers to take precautions. What is travel insurance?, it is an insurance that is intended to cover medical expenses, trip cancellation, lost luggage, flight accident and other losses incurred while traveling.

Travel insurance can usually be arranged at the time of the booking of a trip to cover exactly the duration of that trip, or a “multi-trip” policy can cover an unlimited number of trips within a set time frame. Some policies offer lower and higher medical-expense options.
MUSEUMS

The British Museum and other public museums are free so don’t miss them. Quite curious that you can’t take photos with flash on the underground but the British Museum is full of unconscious tourists taking photos with flash and touching pieces from the ancient Egypt.

WIFI

It’s quite hard to find free WiFis on London, but there are lot of BT-FON spots, my advice is to became a FON member before traveling to London, buy “La Fonera” by only 39€ at http://www.fon.com and share your home ADSL. As a FON member you can use this WiFis for free.

ANDROID

As I cound’t find free WiFis (and at the moment I’m not a FON member), I dindn’t used a lot my phone. As now Google Maps has local cache, try to view maps of London City Center when online, they willl remain cached when offline.

HOTELS

We were on a Easyhotel room but I can only say that it was cheap. Quick tip: never rent a hotel room just for the cheap price. Because just like it’s cheap price, the quality will most likely be cheap as well. The Easyhotel room we stayed at had bed bugs, which got into my wife’s hair. We quickly visited http://www.deadpestz.com/bed-bugs-hair/ to learn more about it and then talked with the hotel receptionist and manager. Now, I wont say that you can’t find bed bugs in a 4 star hotel, but just try and investigate the hotel before you book a any room. Easyhotel thinks that a “room with window” is an underground room with a window to a corridor without natural light. It’s also quite surprising to make fit a bed and a bathroom on 6m2.

My trip to London was phenomenal. It was amazing and I had a fine time. I met a friend there who I adored the most. Her name is Lisa and she lives in London and she is very ecstatic. She told me about this New York City Non-Surgical treatments that she got when she was venturing United States. And most of the time I was on this trip I was with her.


SobrosoParty 2011

Hoxe sábado ás 18 horas repetimos o laboratorio de Android “A Miña Primera Aplicación Android” na SobrosoParty no Pavillón Municipal de Ponteareas. Neste taller usaremos como exemplo a aplicación WikiPlaces para explicar cales son os pasos da creación dunha aplicación Android, dende a instalación do SDK e a configuración do Eclipse ata a súa publicación no Android Market.

Esta aplicación ten moitos exemplos de cousas típicas na programación de Android:

  • Deseño de layouts
  • Obte-la ubicación
  • Amosar un mapa e usar overlays para representar información sobre él
  • Amosar unha lista utilizando adapters
  • Obter datos de servidores externos
  • Usar intents para lanzar outras aplicacións dende a nosa
  • Introducción de Anuncios de AdMob

Tentaremos condensa-lo taller en dúas horas que é pouco tempo, xa que no último LabAndroid en Málaga seis horas non chegaron para moito, pero como creo que non vai haber nen enchufes nen ordenadores para todos tentaremos facelo un pouco máis xeral.

Para asistir a este taller non fai falta estar incribito na SobrosoParty (que ten só 300 plazas), con dicirlle a persoa de seguridade que se vai asistir ó taller de Android non debería haber problema en pasar.

Notas de prensa:


Using styles on Android layouts

A very cool feature of Android that many developers do not know (at least me 6 months ago) is the possibility of using “styles” on Android XML layouts. This thing is similar to CCS on HTML and provides a method to simplify the XML design.

First, let’s see an example of a XML layout without styles, you can notice the need to repeat attributes and the difficulty of reading the XML:

<LinearLayout
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:orientation="vertical">
 <TextView
  android:text="@string/text1"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:textStyle="bold"
  android:textColor="@color/white"
 />
 <TextView
  android:text="@string/text2"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:textStyle="bold"
  android:textColor="@color/red"
 />
</LinearLayout>

But we can define styles grouping this attributes on the file res/values/styles.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <style name="VerticalLinearLayout">
  <item name="android:layout_width">wrap_content</item>
  <item name="android:layout_height">wrap_content</item>
  <item name="android:orientation">vertical</item>
 </style>
 <style name="WhiteText">
  <item name="android:layout_width">wrap_content</item>
  <item name="android:layout_height">wrap_content</item>
  <item name="android:orientation">vertical</item>
  <item name="android:textStyle">bold</item>
  <item name="android:textColor">@color/white</item>
 </style>
 <style name="RedText" parent="@style/WhiteText">
  <item name="android:textColor">@color/red</item>
 </style>
</resources>

Note te possibility of  inheriting styles, in this example “RedText” is inherited from the “WhiteText” style changing only the text color.

Our XML layout, with styles, gets reduced to:

<LinearLayout style="@style/VerticalLinearLayout"/>
 <TextView style="@style/WhiteText"
  android:text="@string/text1"
 />
 <TextView style="@style/RedText"
  android:text="@string/text2"
 />
</LinearLayout>

Finally,  you can see that I’m using colors (@color/white and @color/red) which must be defined on the file res/values/colors.xml (in a similar way to strings):

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <color name="white">#ffffffff</color>
 <color name="red">#ffff0000</color>
</resources>

My Firefox 4 setup

After two weeks since the  Firefox 4 (FF4)  release, I decided to switch back again to Firefox from Google’s Chrome. But I miss Chrome a lot, so I configured FF4 almost like a Chrome… ¿how? using those themes and plugins:

  • FXChrome Theme: this theme claims to work only on Windows, but I’m using it on Linux without any problem
  • Movable Firefox Button: Converts the FF4 menu to a button that you can place on your navigation tab (to the right, like on Chrome)
  • Omnibar: Joins the address box and the search box in only one box
  • Titlebar Tweaker Plus: Hides title bar on Linux, on Windows you can use better options like “Hide Caption Titlebar Plus”, but on FF4 this last doesn’t work on Linux
  • Close Button: Without the title bar, I need a button to close FF4, I put it to the right of the tabs, (If using the  “Hide Caption Titlebar Plus” you don’t need this)
  • Barlesque: the new FF4 addon bar occupies all the window bottom, this extension collapses this bar on the bottom right (configurable), having much more space for browsing

And I also recommend this plugins:

  • AdBlock Plus: Removes ads from web pages
  • Speed Dial: Shows your favourite site on dials like Opera
  • FaviconizeTab: Adds a contextual menu on tabs to show only the favicon instead of the title on the tabs
  • Download Statusbar: Shows the downloads on the status bar
  • Echofon: a small twitter client, I miss the TweetDeck Chome app, but it seems that soon will be avaiable for FF4
  • Cutyfox URL Shortener: I use it to fast-shorten URLs with bit.ly
  • DownloadHelper: to download videos from Youtube and a lot of video sites
  • User Agent Switcher: some apps (Ok, JDEdwards) need to change the User-Agent header to work properly, also a good tool to test mobile web browsing

That’s the result:


A small problem with the facebook Android SDK

At Mobialia the lasts weeks I was involved on the development of a social app using, among other social networks APIs, the facebook API. The event was really beneficial to me as I even met some SEO and marketing experts from The Marketing Heaven, and learnt quite a lot from them. 

For me it was easier to implement Twitter API access using only the signpost library, for facebook they recommend to download their Android SDK, and I did so. First we need a class attribute with the Facebook object:

Facebook fb = new Facebook(appId);

The problem is during the autentication process: we must call the fb.authorize method…

fb.authorize(this, PERMISSIONS, ACTIVITY_CODE, this);

And wait for the result of this called activity on our onActivityResult method

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    fb.authorizeCallback(requestCode, resultCode, data);
}

But, here is the problem, under heavy memory requierements (like testing on a old HTC Magic) the caller activity may be killed, and the status of the Facebook object is not maintained so the call to authorizeCallback is going to fail.

Then I need a method to mantain the Facebook object status, and here comes the hack. I added this method to the Facebook object:

public void setStatus(int mAuthActivityCode, DialogListener mAuthDialogListener){
    this.mAuthActivityCode = mAuthActivityCode;
    this.mAuthDialogListener = mAuthDialogListener;
}

And I call this method on my onActivityResult:

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    fb.setStatus(ACTIVITY_CODE, this);
    fb.authorizeCallback(requestCode, resultCode, data);
}

Note that the DialogListener is the same Activity. Other solution may be to avoid killing of the caller activity, but I don’t figure how…


Using two location providers on Android


Android has two kinds of accuracy on location:

  • Fine: provided by the GPS, needs some time to be obtained
  • Coarse: location determined with the cell of the mobile network

This location methods can be enabled or disabled by the user on the preferences or with some widgets.

Initially on our apps we used only one LocationProvider with “Fine” accuracy:

  • If the GPS was disabled it used automatically network-based location
  • But if GPS was enabled, the location used it needing some time to be determined

As the data couldn’t be obtained until the location is determined, the app didn’t showed data, receiving this kind of error reports from some users.

The best solution that I found is to mantain two separated providers, with different precisions and receive location updates using both.

LocationManager manager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(false);
criteria.setPowerRequirement(Criteria.POWER_LOW);       

criteria.setAccuracy(Criteria.ACCURACY_FINE);
String providerFine = manager.getBestProvider(criteria, true);

criteria.setAccuracy(Criteria.ACCURACY_COARSE);
String providerCoarse = manager.getBestProvider(criteria, true);

if (providerCoarse != null) {
    manager.requestLocationUpdates(providerCoarse, 5*60000, 100, this);
}
if (providerFine != null) {
    manager.requestLocationUpdates(providerFine, 5*60000, 100, this);
}

You can also check if providerFine and providerCoarse are the same provider. When receiving location, the one received from providerFine must take precedence over the one from providerCoarse. Location’s provider can be obtained with location.getProvider():

public void onLocationChanged(Location location) {
     if (location.getProvider().equals(providerFine)) {
     ...

This is a trick that we are using on our Gas Stations Spain app and also on Wikiplaces (open sourced).


Mobialia at LabAndroid

This week I was speaking at LabAndroid, a spanish initiative about Android devices, apps and development.

I developed a special app for this event called “Wikiplaces” and I made the code avaiable as open source on Google Code.

This app shows on a map or on a list places from Wikipedia near your location. I tried to include on it small code snippets for common things like styles on layouts, obtaining location, launching Google Maps Navigation, etc.


Dealing with the “Bitmap Size Exceeds VM Budget” error

One of the most common errors that I found developing Android Apps is the “java.lang.OutOfMemoryError: Bitmap Size Exceeds VM Budget” error. I found this error frecuently on activities using lots of bitmaps after changing orientation: the Activity is destroyed, created again and the layouts are “inflated” from the XML consuming the VM memory avaiable for bitmaps.

Bitmaps on the previous activity layout are not properly deallocated by the garbage collector because they have crossed references to their activity. After many experiments and consulting with the cost of an ecommerce website, I found a quite good solution for this problem.

First, set the “id” attribute on the parent view of your XML layout:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
 android:id="@+id/RootView"
>
...

Then, on the onDestroy()  method of your Activity, call the unbindDrawables() method passing a refence to the parent View and then do a System.gc()

@Override
protected void onDestroy() {
	super.onDestroy();

	unbindDrawables(findViewById(R.id.RootView));
	System.gc();
}

private void unbindDrawables(View view) {
	if (view.getBackground() != null) {
		view.getBackground().setCallback(null);
	}
	if (view instanceof ViewGroup) {
		for (int i = 0; i < ((ViewGroup) view).getChildCount(); i++) {
			unbindDrawables(((ViewGroup) view).getChildAt(i));
		}
		((ViewGroup) view).removeAllViews();
	}
}

This unbindDrawables() method explores the view tree recursively and:

  • Removes callbacks on all the background drawables
  • Removes childs on every viewgroup

This solved the problem on many of our Mobialia apps.

UPDATE 2011-03-30:

Today @luiskap from SpartanBits told me another good solution: if you don’t need different layouts for portrait and landscape modes, you can make your activity react to orientation changes (avoiding activity destroy) adding to your activity’s manifest: android:configChanges="keyboardHidden|orientation" and overriding the onConfigurationChanged method, calling setContentView reusing the already created views. There is a good explanation on StackOverflow.