Dabbling in writing cell phone apps

[Roedy Green]

Do you need anything other than the free MIDP2 download from sun and
an MIDP2 Cell phone to experiment with cell phone apps?

 

[Rune Berge]

Do you need anything other than the free MIDP2 download from sun and
an MIDP2 Cell phone to experiment with cell phone apps?

You need some way to download the classes to the cell phone. This is typically either a
direct interface with the computer (USB, BlueTooth etc.) or a web server that is properly
configured to recognize .jad and .jar files. See
http://java.sun.com/j2me/docs/wtk2.1/user_html/testapps.html#wp21062
A direct interface is preferable as downloading stuff to a cell phone from the web usually
costs money...

Disclaimer: I've only tried MIDP1.0.

Rune

 

[Roedy Green]

You need some way to download the classes to the cell phone. This is typically either a
direct interface with the computer (USB, BlueTooth etc.) or a web server that is properly
configured to recognize .jad and .jar files. See
http://java.sun.com/j2me/docs/wtk2.1/user_html/testapps.html#wp21062
A direct interface is preferable as downloading stuff to a cell phone from the web usually
costs money...

So cellphone don't get their software by downloading from http servers
on the web? or it is just this is too expensive a way to debug since
you would pay connect charges.

 

[JScoobyCed]

So cellphone don't get their software by downloading from http servers
on the web? or it is just this is too expensive a way to debug since
you would pay connect charges.

Hi,

I started J2ME last month (during my lunch breaks or so) to developp on
my MIDP2 phone. It has Bluetooth and infrared. I use Bluetooth to send my
..jad and .jar to my phone (which receives it as SMS, and opening one of the
two files will start the installer and install both files). I triied IR too
and it works the same except for the speed (if you have pictures or heavy
stuff you might be concerned, but usually .jar a less than 100 Kb, so it
doesn't matter).
It is of course a better way than to upload them on website and use WAP or
GPRS to download them on your phone. Cheaper, faster, especially for
development. I have downloaded some .jar and .jad from the web from my PC
and installed them the same way to my phone.

JScoobyCed
-------------

 

[Rune Berge]

So cellphone don't get their software by downloading from http servers
on the web? or it is just this is too expensive a way to debug since
you would pay connect charges.

Yes, if you download the app a lot of times during debug it will soon become cheaper to
just by a USB cable. This is off course depending on what GPRS/WAP rates your cell phone
has. Otherwise there is no problem with http download (except that the web server has to
be configured for it, which probably excludes most public servers).

Rune

 

[Roedy Green]

It is of course a better way than to upload them on website and use WAP or
GPRS to download them on your phone

Do you have any estimates on bytes per second for
blue tooth, USB, IR, WAP ?


see http://mindprod.com/jgloss/cellphone.html

I am collecting together the basics one needs to get started.

 

[Roedy Green]

Yes, if you download the app a lot of times during debug it will soon become cheaper to
just by a USB cable. This is off course depending on what GPRS/WAP rates your cell phone
has. Otherwise there is no problem with http download (except that the web server has to
be configured for it, which probably excludes most public servers).

on the server, is this just a matter of MIME types or do the
cellphones use some protocol other than HTTP?

 

[Rune Berge]

on the server, is this just a matter of MIME types or do the
cellphones use some protocol other than HTTP?

Just MIME types. New cell phones can browse regular web pages (though they usually don't
display very well on such a small screen).

Rune

 

[JScoobyCed]

Do you have any estimates on bytes per second for
blue tooth, USB, IR, WAP ?

I don't have my Bluetooth and IR dongles here, but I can check it when I get
back home. I'll test 10Kb, 50Kb and 100Kb files on BT and IR (I didn't
registered a WAP account as I am developping. I'll do so when I'll need to
deploy).

JScoobyCed

 

[JScoobyCed]

Do you have any estimates on bytes per second for
blue tooth, USB, IR, WAP ?

On BlueTooth, I got a 28 Kbps transfert rate on a 1Mb file
It seems my IR dongle is not working well, I couldn't transfert file.

JScoobyCed
-------------

 

[Roedy Green]

On BlueTooth, I got a 28 Kbps transfert rate on a 1Mb file
It seems my IR dongle is not working well, I couldn't transfer file.

so this is slower than you would get with dialup modem? My goodness!
I read BlueTooth was supposed to be around 721KBps.

 

[JScoobyCed]

so this is slower than you would get with dialup modem? My goodness!
I read BlueTooth was supposed to be around 721KBps.

Yes, there is also some specification that say BT can go up to 10 Mbps
(wow... sounds great).
But I think what is slowing down the transfert is the writing of data on the
phone. I have seen some post on nokia newsgroup about this (it was
especially for memory stick, but maybe writing on the phone internal memory
is also slow)