Hi Mark

hello, Susheel!

how can I help you today?

I have a raw audio file. Can I play it at a certain frequency in android?

maybe via AudioTrack, where you are pushing in raw PCM data

otherwise, I doubt it, but that's outside my depth in the audio space

no just like an mp3 or something like that

Ok I have another question. As part of a text message I want to put a link to start my app. How can I do that? I mean launch mainactivity by clicking a link in the text. Is that possible?

that depends on your requirements

the problem is that there are N text messaging clients

you have no control over whether they make things be links

your most likely case for them making some piece of your text message be a link, is if that link is an HTTP URL

you can add an <intent-filter> on the activity to advertise that you support such URLs

there's coverage of that in the book

however, bear in mind two things:

in custom urls section?

1. the user will *also* be given browser(s) as options in a chooser

2. not all SMS clients will necessarily make URLs be clickable

ok

and, yes, that sounds about right in terms of where it is in the book

great

Just to make sure I asked my question clearly, I will give you an example. Say I am sending a text to my friend 'Test this'. When my friends receives it, he should be able to launch my app (already installed on his phone) when he clicks 'Test'. I hope this is what you understood my question to be in the first place.

well, that's not possible

text messages do not support HTML in general

there is nothing that will cause SMS clients to magically make "Test" clickable at all, let alone to launch anything in particular

ok

If I remember intercepting text messages using SMS manager is not available for android 4.4, am I right?

not smsmanager, broadcast receiver

you can intercept text messages via their broadcast, but you cannot prevent the user's chosen SMS client from receiving the message as well

Oh I get it

Can I ask you questions about serial port programming in android?

you can ask them, but I can't answer them :-)

Haha

Well thanks for your help Mark.

you are very welcome

hello, EGHDK!

how can I help you today?

Hey Mark, so another simple question. I'm working through my Head First Java book. But right on the cover it says "Java is pass by value". You said it's pass by reference the last time I brought this question up. So For primitives its pass by value, and for objects its by reference?

well, it depends on how you define "pass by value"

I'm pretty sure we went over this already

technically, Java is always pass by value... however the "value" of an object is what in C/C++ you would consider a "pointer"

the net effect, from the standpoint of simple analysis, is that Java behaves like pass-by-reference for objects

however, language purists (e.g., http://javadude.com/articles/passbyvalue.htm) will stick with the "it's pass-by-value, with values being pointers" description

Interesting...

I've never worked with c/c++ so I'm not sure what a pointer is.

and *that's* why it is usually simpler to just think of Java as pass-by-reference

to understand why it is technically pass-by-value, you need experience in lower-level programming languages, like C/C++

there are lots of Java developers in the same boat as you

Hmm. Okay. Well I'm glad that it "is" technically "pass by value" but that value just happens to be a reference.

C seems simple enough to learn.

like many programming languages, C is not that hard to write, but very hard to write well

c++ on the other hand is really weird, because I tried to get into it but I had a hard time because I had to seemingly use microsoft visual studio. then I had questions that I asked, and people had no idea why I was importing certain things, but apparently they are needed for windows. i don't understand why the same exact code wont work across different os's

it can, so long as you don't want to do anything that is OS-specific

which, in C/C++, means "so long as you only want trivial programs that run at the command prompt"

even trying to implement a server is likely to get you into OS-specific stuff, let alone a desktop GUI

Is that why java is so popular?

the Java class library helps insulate you more from the OS

that has its pros and its cons

the popularity of Java is more based on where and how it got used: server-side "enterprise class" Web apps, plus Android

Gotcha. All the books I've read about how popular it got mention servers. But that doesn't really make any sense to me. Forgive me for my lack of knowledge on how java made server side easier.

it didn't make it easier

at least, not on an absolute scale

it was easier than some things, and probably harder than others

asking why Java succeeded on the server is akin to asking why kangaroos exist

if you believe in the theory of evolution, kangaroos exist because of a series of evolutionary steps, that eventually wound up with kangaroos

kangaroos aren't the fastest, the most lethal, the cutest, the highest fliers, etc.

but, they filled some ecological niche

in other words, kangaroos exist because, well, something had to exist, and we gave it the name "kangaroo", perhaps because we were running out of simpler animal names

similarly, something had to create Web apps

lots of things were tried

some stuck around for a short while (Perl and CGI), to be replaced by alternatives that were clearly superior

some stuck around for a long time, and in parallel to other solutions (e.g., PHP and Java)

PHP and Java each filled a niche

Really interesting. Thanks.

Last question for today. This will actually be on Android development. In 4.0 in multi tasking you get a little screenshot of your app. Do you think its possible to set that screenshot programatically? I have tried to override onPause, and set the background color of the window before I call super.onPause(), but somehow I see the color change really quickly, but when I look in the multitasking it doesn't have the color change. Any ideas?

override onCreateThumbnail(), IIRC

and that's a wrap for today's chat

the next one is Thursday at 10am US Eastern Time

Great. Thanks.

this chat's transcript will be archived at http://commonsware.com/office-hours/ shortly

have a pleasant day!