- Add the “android:debuggable” attribute to your application element in the AndroidManifest.xml, and set it up to true

android:debuggable="true"

- If you are running it in a device also check in you phone settings/Application/Development that Debug mode is active in the handset.

That is it, now your are ready to start setting up breakpoints and eclipse will stop when one is reached.

In the talk I did a quick introduction about the Android platform and Android SDK, going from the basics to the key elements you need to understand to get your hands on Android development. Also I presented the new service 0x1f that I developed for my company Innerfunction. 0x1f is a URL shortening and QR tag generation service developed with nodejs and using couchdb as database. This service will be a key component in a number of mobile web projects we will be working on over the next year.

The experience was great, and that is not all. I’ve also proposed them some ideas about possible QR tags applications they may be interested in develop and give them freedom to choose their own application idea to be complete as part of the course assignment.

I will keep you informed about where all this is going, in the meantime I want to include here the slices I prepared for the talk even when I’m not a big fun of releasing slides as learning resource – they are intended to be a complement of a talk and contain a minimal information enougth to keep me talking for an hour or more, but they are not a good learning resource for somebody who is new in the area and may find a book or even the Android doc much more interesting.

Anyway I leave them here :

Android-Dev-Presentation@Trinity College

We want to ensure that the server is up and running 24/7 right? Maybe also to get email notifications about when a crash happen, or even monitor if the machine is running out of memory…

Monit is a tool that can be very useful to monitor UNIX process and have actions or alerts send triggered when something happens in our server. This is how I setup monit to restart nodejs scripts:

Create a script like in /etc/init.d/0x1f to start and stop your service, in this case the service name is 0x1f, here is the script I’m using:

#!/bin/bash
# Start and stops 0x1f

case "$1" in
start)
echo $$
sudo echo $$ > /var/run/0x1f.pid
exec sudo /usr/local/bin/node /home/javier/0x1f/0x1f.js >> /var/log/0x1f.log
;;

;;
status)
status 0x1f
;;
restart)
$0 stop
$0 start
;;
*)
echo "Usage $0 {start|stop|restart|status}"
exit 1
esac


Then install and setup monit to monitor your service and restart them when they go down, to do that I added the next to /etc/monit/monitrc:

check host 0x1f with address 127.0.0.1
start program = "/etc/init.d/0x1f start"
stop program = "/etc/init.d/0x1f stop"
if failed port 3000 protocol HTTP
request /
with timeout 20 seconds
then restart
if 5 restarts within 5 cycles then timeout


That will monitor when a HTTP connection can not be done to port 3000 and then restart the script. If you also want to setup monit to send emails with alert then add the next lines to you monitrc:


set alert admin@if.com #
set mailserver smtp.emailsrvr.com port 25
username "bar@foo.com" password "xxxxx"
with timeout 15 seconds
using hostname "smtp.emails.com"


With this conf monit sends all alert messages to email admin@if.com using SMTP server “smtp.emails.com” with those credentials.

Then you can setup monit to send you alerts at your convenience, I use the next to get alerted when a the service goes down:


if failed port 3000 protocol HTTP
request /
with timeout 20 seconds
then alert


And you will get monit emails when bad things happens, and the services will restart automatically.

Monit, Your faithful employee.

The child element for the ScrollView has to be a single element, usually a LinearLayout can do the trick, but you could use other views always bearing in mind that ListViews and TextView have their own scrolling already so they don’t need an additional ScrollView.

If you want to have a set of views centered inside a ScrollView you can think that would be enought with setting the params “layout_width” and “layout_high” to “fill_parent” and then set the property center in the LinearLayout, but that is not enougth because the scroll view doesn’t stech to fill parent as expected.

The solution is to set the ScrollView property “fillViewPort” to true, and that it will work. See the example below.


<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:fillViewport="true"
android:background="@drawable/backgroud">

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android >
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center">

<!-- Your set of views : buttons, editText, textViews... -->

</LinearLayout>
</ScrollView>

The scrolling doesn’t appears in the horizontal view but when the users change device orientation to vertical the user can scroll between the view elements. Observe the scrolling bar on the right side.

I’d recommend to use a scroll view as a pattern in all your activities, this way you won’t run in the problem of a screen where the user can not reach some of the elements. e.g: User cannot click on buttons so it makes the activity completely unusable.

Some commands you will need

// Start an emulator
$ emulator -avd $emulator
// Install apk in emulator
$ adv -e install your-app.apk


And then you can start your app from the emulator.

This way we can send intents between different applications, for example if we want to scan a barcode we can call the barcode scaner app from our own. This could be done like:


Intent intent = new Intent("com.google.zxing.client.android.SCAN");
intent.putExtra("SCAN_MODE", "QR_CODE_MODE");
startActivityForResult(intent, 0);


Then we can override the onActivtyResult() method in the class that was starting the event and process the result from barcode scanner like:


public void onActivityResult(int requestCode, int resultCode, Intent intent) {
if (requestCode == 0) {
if (resultCode == RESULT_OK) {
String contents = intent.getStringExtra("SCAN_RESULT");
String format = intent.getStringExtra("SCAN_RESULT_FORMAT");
// Handle successful scan
} else if (resultCode == RESULT_CANCELED) {
// Handle cancel
}
}
}


Android uses intent filter to handle events. Event filters are defined in the androidManifiest file and you can create your own filters or use existing ones. When you create the intent you have to specify the view ACTION and some data to be pass to the action.


ACTION_VIEW content://contacts/people/1
Intent myIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("content://contacts/people/1"));


This code display infomation about the person with id 1. There are a number of standard actions in Android (ACTION_VIEW, ACTION_EDIT, ACTION_DIAL, ACTION_MAIN… see the Android intents doc) or you can create your own actions adding them to the AndroidManifiest file and the caller and the handler can use them.


<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<scheme android:name="http" />
<scheme android:name="https" />
<scheme android:name="file" />
</intent-filter>


That eventFilter will catch the next event:

Intent myIntent = new Intent(Intent.VIEW_ACTION, Uri.parse("http://www.google.com"));

For more info about Android indent see the Intent official doc.

ANDROID INTENTS

Android intents are used to navigate between activities – an android Activity is normally a screen – so if we have an activity call ProgramDetailActivity and we want to open it we just have to create an intent and call the startActivity method. There are several ways to create an intent:


// Using the constructor and passing the context and the activity class
Intent openDetail = new Intent(v.getContext(),ProgramDetailActivity.class );

// or using setClassName method explicit application package name and class name.
Intent openDetail = new Intent();
openDetail.setClassName("com.innerfunction.android.telia",
"com.innerfunction.android.telia.ProgramDetailActivity");


Then we can call the startActivity method to start the activity:

startActivity(openDetail);


More about Intents to come in next posts…

I just edited the Eclipse.ini file in : /Applications/eclipse/Eclipse.app/Contents/MacOS and added the next line :

-vm System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Commands/java


I also located more memory for Eclipse:

-Xms128m
-Xmx1024m


To make a call with iPhone you have to use the next code :

NSString *phoneToCall = @"tel: 00468215890,324661#,*241557#";
NSString *phoneToCallEncoded = [phoneToCall stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding];
NSURL *url = [[NSURL alloc] initWithString:phoneToCallEncoded];
[[UIApplication sharedApplication] openURL:url];

Calling international number with #:

Also I needed o call intenrational numbers with special characters as pauses or #.  e.x: 00468215890,324661#,*241557#

I have find out that with iPhone you can not use # charaters in the URL  due to security issues, while that is allowed in Android. On iOS the only  possible work arround I’ve found is to  save the number in a new contact and then bring the user to that contact to make a call. It’s not an ideal solution but may make the trick.

UPDATE : In iOS the user has to exit the app and manually go to the contact if he needs to call it. Navigate from you app to the contact don’t allow to call complex phone numbers including #. Apple said they did it for security reasons, but this seems to be very restrictive. A user should be able to see the contact with the phone number and then choose if he wants to call the number.

Android uses a less restrictive but efficient security mechanism, instead of don’t allow any call to special numbers like the iPhone it allows them but advise you about the functionality when you install the application with a msg staying that the application can directly call phone numbers and services that cost money. Is up to the user to trust the app or not they not limit the functionality like the Apple guys do. How are we suppose to develop conference application for iPhone if we cannot call those numbers???

you just need to use the next code:

startActivity(new Intent(Intent.ACTION_CALL, Uri.parse("tel:" + "001230012")));


And we also have to setup the permision in the AndroidManifiest.xml file adding the next line:

<uses-permission android:name="android.permission.CALL_PHONE" />