Creating a Hello World application

This guide is aimed at the complete beginner who would like to know how to develop their own applications for SHR. Taking the usual Hello World program as an example, it will use Vala as the programming language which should be familiar to Java developers.

It is assumed that the reader has already successfully built SHR using the instructions at Building SHR.

1. Creating a source folder

$ cd /path/to/shr/build
$ mkdir myfirstapp
$ cd myfirstapp

2. Writing Hello World in Vala

Create and enter a sub folder for the source:

$ mkdir src
$ cd src

Create a file called myfirstapp.vala and insert the following text:

class Demo.HelloWorld : GLib.Object
{
    public static int main(string[] args)
    {
        stdout.printf("Hello, World\n");
        return 0;
    }
}

More information about Vala can be found here:  http://live.gnome.org/Vala/Tutorial

3. Setting up autotools

Create a file called Makefile.am and insert the following text:

bin_PROGRAMS = myfirstapp

AM_CFLAGS = $(DEPS_CFLAGS)
AM_LIBS = $(DEPS_LIBS) $(DEPS_LIBS)

AM_VALAFLAGS = --pkg "gio-2.0" --pkg "glib-2.0"

myfirstapp_SOURCES = myfirstapp.vala
myfirstapp_LDADD = $(INTI_LIBS)

myfirstapp_LDFLAGS = $(AM_LIBS)

clean:
	rm -f *.c *.o *.stamp

Go back to the previous folder:

$ cd ..

Create another file called Makefile.am and insert the following text:

SUBDIRS = src

Create a file called configure.ac and insert the following text:

AC_INIT([myfirstapp],0.1)
AM_INIT_AUTOMAKE
AC_CONFIG_SRCDIR([src/myfirstapp.vala])

AC_PROG_CC
m4_pattern_allow
AM_PROG_VALAC

PKG_CHECK_MODULES([DEPS], [glib-2.0 gio-2.0])

AC_OUTPUT([Makefile src/Makefile])

Run the following commands:

$ aclocal
$ autoconf
$ touch AUTHORS NEWS README ChangeLog
$ automake --add-missing

4. Adding a bitbake recipe

Enter the third party recipes folder:

$ cd /path/to/shr/build/shr-unstable/openembedded/recipes/openmoko-3rdparty

Create a file called myfirstapp_0.1.bb and insert the following text:

DESCRIPTION = "A hello world program written in Vala"
PR = "r0"

S = "${WORKDIR}/myfirstapp"

SRC_URI = "file:///path/to/shr/build/myfirstapp"

inherit autotools vala

Note: For building from local sources you can also use "inherit srctree" as it's used in conf/local-builds.conf

5. Building a package

$ cd /path/to/shr/build/shr-unstable
$ . setup-env
$ bitbake myfirstapp

You should find that you now have an ipk package like this: /path/to/shr/build/shr-unstable/tmp/deploy/ipk/armv4t/myfirstapp_0.1-r0.6_armv4t.ipk

In order to test your program, simply install this package on your phone and run "/usr/bin/myfirstapp".

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Graphical User Interface

Once you have successfully completed the steps above, you may wish to know how to add a Graphical User Interface (GUI). This section will show you how to do this using the Elementary widget set, which is utilised by the core SHR phone applications.

1. Creating a source folder

$ cd /path/to/shr/build
$ mkdir myfirstgui
$ cd myfirstgui

2. Writing a Hello World GUI in Vala and Elementary

Create and enter a sub folder for the source:

$ mkdir src
$ cd src

Create a file called myfirstgui.vala and insert the following text:

using Elm;

private void win_del()
{
	Elm.exit();
}

class Demo.HelloWorldGui : GLib.Object
{
	public static int main(string[] args)
	{
		Elm.init(args);

		Win win = new Win(null, "hello", WinType.BASIC);
		win.title_set("Hello");
		win.smart_callback_add("delete-request", win_del);
    
		Bg bg = new Bg(win);
		bg.size_hint_weight_set(1.0, 1.0);
		win.resize_object_add(bg);
		bg.show();

		Label lb = new Label(win);
		lb.label_set("Hello World!");
		lb.size_hint_weight_set(1.0, 1.0);
		win.resize_object_add(lb);
		lb.show();

		win.show();

		Elm.run();
		Elm.shutdown();

		return 0;
	}
}

More information about Elementary can be found here:  http://trac.enlightenment.org/e/wiki/Elementary