howdy, Maria!

Just you and me again?

at the moment

people tend to come and go

I have you all to myself!

how can I help you today?

Hello

howdy, Pavan!

Greetings

Maria: you arrived first, so you get the first question

Is there a way to emulate the files storage on the sdcard in the emulator?

sure

when you create your emulator AVD, there's an option for how big of an SD card to give it

Yes, I've seen that

but how do you create a file structure on it?

Or are you supposed to create the structure via code?

it will already be formatted, if that's what you mean

just as an SD card comes formatted when you buy it from the store

What if I want to copy some files onto it?

I know how to do that on the phone, but not on the emulator

use DDMS' File Manager, or adb push from the command line

You have to use adb

exactly!

bummer. I don't think adb works for me. I'm using windows 7 on a 64 bit machine and I think I have a driver problem.

What's your question, Pavan?

there should be no drivers involved with the emulator

Ok. that does kind of make sense. when I hear adb I'm thinking "talk to the phone"

Cool.

adb is really more "talk to the 'droid" :-)

yes I see what you mean

with a phone/tablet, you need drivers on Windows

not for the emulator

I would use it to connect to the emulator instance

correct

OK, Pavan: do you have a question?

My applicaiton needs a broadcast to be sent to it whenever the signal quality reaches some threshold. I setup a service that boots on startup and has a phonestatelistener with the onsignalstrengthschanged() to send the broadcast. Is this a good way to set up what I want or is there any other way?

let's back up a step

Sure

why does your application need a broadcast to be sent to it whenever the signal quality reaches some threshold?

I need to run something if there is high signal quality

so you will be running something every millisecond of every day if I am sitting at home and have continuous high signal quality?

or is there a time component as well?

Once I receive the broadcast I will decide if I have to run or just ignore the broadcast

No time component really!

to be blunt, that stinks

the only way to do that is your current approach, with an everlasting service

users do not like those

at all

ok.

if there is a time component involved ?

let's say you wanted to do some work every hour, but only if there is good signal strength

then, you could use AlarmManager for the every-hour part, and have it start your service watching for the signal strength

once the signal strength is good, you do your work, then set the next alarm

or just have the alarm fire every hour, though you'll need to deal with the edge case of not getting good signal within the hour

Hmm! Got it!

that way, at least you're not running the service *all* the time

what you want to avoid, desperately, is getting killed with a task killer

on Android 3.1+, your code will never run again once killed, until the user manually runs an activity of yours from the launcher

Even if I have a service running all the time with the phonestatelistener on it, how much battery would it consume?

I mean the service

battery should not be an issue

RAM is an issue

and, more importantly, just existing is an issue

while your service may be awesome, plenty of them are less awesome

Hmm!

some users just start smacking down anything they do not recognize via a task killer

the less reason you can give them to smack you down, the better

Correct!

since signal strength is only relevant for voice (AFAIK), and since you can't do anything with voice from the SDK, I'm hoping you'll reconsider this capability

let me swing back to Maria, and we can follow up after she's had a chance

Maria: do you have another question?

Sure1

Of course!

I'm just a beginner so bear with me.

I would like a make a little application that receives artwork from a server.

I'm done some web programming so that's my bias

but what would you recommend?

is webview

a good component to build everything around?

um

what is "artwork" from a technical standpoint?

suppose you are studying for art history final

it would be nice to select a a group like "images for final"

and then have them appear on the phone

and maybe have a way via touch to see the

artist/year/etc

what is "artwork" **from a technical standpoint**?

stuff you must memorize

JPEG?

SVG?

yes

MP4?

no

maybe png

ok, so it's images

just images

yes

if this will all be downloaded on demand, you could skip Android entirely and just write an HTML5 Web app

or, if you want distribution through the Android Market, go with PhoneGap

it's more for myself to learn.

or, write a native Android app (e.g., Gallery of ImageViews)

I am taking the art class

well, what do you want to learn?

right so you would suggest Gallery and ImageVies

ImageViews

trying to learn android programming!

if you want to learn native development, Gallery and ImageViews would be a fine starting point

would you use the alarm component you were just talking about for timing?

I don't see where you need timing

user launches app

user taps on image collection

you download images, display them

user swipes gallery

user taps on images

you do something interesting there

I was thinking I would use the tap for display the right answer

is it hard to do a swipe for the next picture?

that would be logical

that's what Gallery is for

ok so it's easy because it's built in

great!

ok, let's switch back to Pavan for a bit

Pavan: do you have another question?

sound good to me

Naa!

OK

it's open season now, at least until somebody else shows up

either of you can fire away with any questions

So what about caching if there's no internet? would you worry about that before starting the design or would you worry about it once the basic stuff is done?

no, you need to work out your data model first

ok so worry about it later?

no, I mean worry about it first

it is substantially different to say "I'll grab the images on the fly" and "I'll have the images locally and sync them sporadically"

or "I'll have the images locally, downloaded when the user first clicks on them"

in this case, your images are the core of your data model

I was thinking I would download them on the fly and cache them and then if there's no internet, use the local copies

that can work, but you'll want to set that up from the outset

I have about a 1000 images so I think it's to many to have all at once

depending on the image size, that may be too many in general

yeah, it's fine on the server but I wouldn't want to cache that many

users may not want to dedicated hundreds of MB of storage to your app

exactly

all the more reason to work out your caching and storage strategy first

I went to Canada recently and my phone was almost a dead brick

so I'm too sensitive to the "no connection" situation

I'm using mysql to keep track of everything on the server side. Do think it might be reasonable to send/cache an sqlite version? I don't think it would take up that much space if I just limit myself to a few sets of strings and foreign keys.

I'm not a huge fan of using SQLite as a data interchange protocol

instead, create a Web service around your MySQL database

and have your Android app consume that service

So what I was thinking is that the sqlite would have names and dates and maybe an extra column for whether the image was in the cache or not

agreed

the images should be sent from the server

The db is more for use offline.

Say you want to see pictures by Manet.

You could get what was in the cache

there's nothing stopping you from downloading a SQLite database, but, again, I am not a big fan of that model

which may or may not have any manet

for starters, it only works on devices that have SQLite

which is 100% of Android and 0% of Windows Phone, for example

that's why I recommend you develop a platform-neutral Web service interface, for querying and downloading image sets

I see.

or, have the whole image roster as one big XML or JSON file that gets downloaded on first run

or something else that gives you more flexibility

I think this can't be an app for sale because I'm sure there are all kinds of copyright issues with serving up artwork.

understood

Well, I've got a lot to think about and read about.

I'm sure all be back during another office hours to give you an update and ask more questions!

Thanks for your help

no problem

glad to be useful

howdy, Marco!

Hi Mark

can I ask you a question?

we only have a few minutes left, so ask quickly! :-)

ok!

Do you know some libraries to read pdf on Android? I've only found libraries, but only with GPL license

mupdf for example.. they have also a commercial license but I think it's very expensive

not really

usually, you just fire off an ACTION_VIEW Intent for it

let the user choose a PDF viewer

Adobe Reader is free, for example

ok, but if it's possible I want to stay in my application

that's rather unusual

desktops don't "stay in the application" for viewing PDFs

Web apps don't "stay in the application" for viewing PDFs

I can think of no reason for you to "stay in the application" for viewing PDFs

yes, but my application will be a sort of ebook reader, so it's the "main" functionality

then you shouldn't be using PDF

use EPUB

I can read EPUB easily on Android?

it's just HTML

an EPUB file is a ZIPped archive with HTML, images, stylesheets, etc.

plus a few metadata files

ok

I will take a look also for this opportunity

thank you mark

running out of time -- any last questions?

no thanks for your itme

see you next time, I don't have any other question

Thanks!

have a pleasant day!