howdy, Aro

er, Aron

Hello!

Hello

howdy, Ben

Is it just to write out the question here or is there some sort of turn system?

Aron: do you have a question

Sure do! 1 sec

I got a question regarding the calendar on Android. As of version 4.0 there is a calender provider API that allows one to perform query, insert and update on calendars/events/etc.

I am planning to use this API for a "room booking app", which will be used on a tablet outside of meetingrooms.

One of the things this app needs to do is to see if the room is currently booked or not. As people can book the room over the web (Google Apps) I need to continuously check if the room is available or not and update the status accordingly.

The implementation I have think about implementing is to have a service running that checks against the calendar every 5 seconds (and the calender uses push-notifications automatically by Android if I'm not mistaken).

My question to you is simply, is there any way to see when there has been an update to an event/calendar without having to check every few seconds. For example is there some sort of "broadcast message" sent out by the calendar everytime it syncs(gets info pushed to it)?

Appreciate any thought on this. :) Thanks for a great service.

register a ContentObserver

Could you elaborate a little bit, I'm still kind of a newbie on Android. I can use contentobserver to see when the calendar has been updated?

yes

(sorry, I'm on an emergency phone call right now)

No problems, you can write here when you got the time! (i will read the API for contentobserver meanwhile)

OK, call over for now

you can register a ContentObserver to be notified when there is a change to some piece of content, represented by a Uir

er, Uri

okay. So I can be told for example if a database has been updated

right

which URI should I use for the calendar?

um, I don't know

the one you are querying on, presumably

or, the one for an individual event, if you want it scoped to a single event

the catch with a ContentObserver is that you have to be running

it's not like AlarmManager, which works even when your app is not running

Ah

personally, I would not "continuously check", but rather check only while the app is running

unless you are trying to implement some sort of alert mechanism

in which case, polling is pretty much your only option that I can see

that would tell you about changes to which calendars are subscribed

it might tell you about changes within those calendars, but I cannot be sure

you may need the Uri for a specific calendar, the one containing the room bookings that you are monitoring

does it tell me what changes or just that "there are changes"?

just that the data was changed

you would query the ContentProvider to get the updated information, then determine if the change is something that matters to you

Ah!

That's perfect then, will probably work much better than polling all the time

let me take a question from Ben, and I'll be back with you shortly

Ben: do you have a question?

Yes, I am using an AlarmManager with you WakefulIntentService

Can I have multiple subclasses and alarms?

you should not need multiple subclasses

you can certainly have multiple alarms

So in order to tell which alarm is triggering I can add extras to the intent?

that's a likely solution

Ok

make sure you use unique request codes when you create your PendingIntents

(second parameter on getBroadcast(), etc.)

Ok

you'd use one PendingIntent per distinct alarm, routed to your BroadcastReceiver

right

the receiver would turn around and use the same Intent for sendWakefulWork(), to pass along the extras

Aron: do you have another question?

I think I'm good for now. Still unsure about how the classes work but that is my own job to learn. :) Thanks for the help!

OK

Ben: do you have another question?

howdy, EGHDK!

EGHDK: do you have a question?

I don't have another question right now, I'm just going to hang out

Ben: OK, no problem

Hey Mark, I'm trying to get an imageView to move from it's location (bottom of the screen) towards the top on the screen, while holding down on a button. So when the button is being pressed down, it moves up and will stop at the top, but if you let go, it slowly moves back down to it's original position. I'm just kinda stuck on how to go about this. I've successfully gotten a button press that moves an image view up, but I don't know how to move the posiition up while the button is being pressed. As of right now, it just goes up one it's clicked. Sorry if it's a bit confusing.

I guess I

er

I guess I'm not sure what your specific question is

Well now it goes onClick move up this much.

you'd need to manage low-level touch events on the button for this, as there is no concept of "button being pressed" in Android

onClick() will not help you for your problem

in fact, a Button may not be the right solution

onLongClick?

lol

How about an imageview that "behaves" like a button? And reacts to "onTouch"?

probably you will need to create your own custom subclass of something, where you handle the onTouchEvent() call, as you may need to manage the background states yourself

onTouch move x amount up.

something like that, yes

Okay, so that sounds reasonable. How do I handle "notOnTouch" move x amount down?

use an animation, presumably

Well, I've been using animation to move the imageView up right now.

right

you'd run a separate animation to move it down

where "down" would be "all the way", presumably

How would the separate down animation be started?

It should ideally be started when you remove your finger from the "button"

hence, when onTouchEvent() indicates that the user has lifted their finger, start the down animation

bear in mind that I haven't done anything much like what you're describing, so I am taking educated guesses -- more or less what I'd start trying if I had to do it

Yes, but your educated guess is worth a lot more to me than my educated guess. heh

Okay, so stupid question. Is there any tutorial on reading documentation?

I'm still pretty new to java (IMO) so when I go to read android docs, I get confused more than anything else.

um

well

not really

I mean, the "right" answer is for you to get more comfortable with Java, JavaDocs, etc., whether inside or outside of Android

but we still haven't invented the microSD->brain interface

so you can't just put the Java card behind your right ear and absorb it

nor do we have Matrix-style "I know kung fu" technology

:-)

Not yet.

So let me use this example. Because it's had me stuck for the longest.

Let's say I wanted to perform a toast message.

I go to d.android.com

I type in toast, and see android.widget.toast. I click on that. And I go down to...

Public Methods

and I see "Make a standard toast that just contains a text view."

So I figure, this is what I want to use. But then I start to create the toast. Toast.makeText(this, "myToast", LENGTH_LONG);

But length long doesn't work.

that is a static data member on the Toast class

It has to be Toast.LENGTH_LONG. But I don't see that anywhere.

LENGTH_LONG is defined on that very page

(or, use Ctrl+F to search within the page in your Web browser)

Exactly! It says "Show the view or text notification for a long period of time."

public static final int LENGTH_LONG

I guess to all comes down to me still not fully understanding "static"

and that's a fairly fundamental Java construct

with corollaries in most major OO programming languages

that blog post lists a number of Java topics that Android developers need to know

fifth bullet down is "Static and instance scope", pointing here: http://en.wikibooks.org/wiki/Java_Programming/U...

I've got another question

Ben: go ahead

I have this code:

do I add the extras to the Intent i?

um

is SkootCommandService supposed to be the WakefulIntentService?

yes

then you're using WakefulIntentService wrong

Ok

for WakefulIntentService, you need to use a *broadcast* PendingIntent, routing to a BroadcastReceiver that can turn around and call sendWakefulWork() on WakefulIntentService

this is covered in the book in the chapter on AlarmManager

it is also covered in the README to the cwac-wakeful GitHub repo

EGHDK: back to you, if you have another question or a follow-up on your earlier one

if anyone has any questions, chime in

I've changed the getService to getBroadcast and mirrored your example from the book

Where do I add the extras?

you have two choices

1. add them in the BroadcastReceiver

2. add them to the Intent used in the getBroadcast() PendingIntent, in which case you need your BroadcastReceiver to pass those same extras along to the service

so the intent won't automatically keep the extras

?

I just need to pass in the same intent right

one flavor of sendWakefulWork() takes an Intent

that Intent needs to have the extras

how the extras get there is up to you

I see

for example, in my option #2, you could use the copy constructor to create an Intent for use with sendWakefulWork()

If I place the extras in the intent used in getBroadcast(), that intent will return in onReceive, and I can just pass in that intent to sendWakefulWork?

or possibly just use the original Intent passed to onReceive(), without copying it

the Intent for sendWakefulWork() needs to identify the service

your Intent received in onReceive() identifies the BroadcastReceiver

so, you'd need to call setComponent() to change it

Ok

Is there anything else I need to do?

that is difficult for me to answer

Ok

at the end of the day, the Intent passed to sendWakefulWork() must identify the service that is your WakefulIntentService and contain whatever extras you want

how you get to that point is up to you

k thanks for your time1

any last questions?

Thanks for the resources. I will have some work cut out for me this weekend. Can't believe I never stumbled upon your blog posts. Thanks. I'm outta here. Have a good night. I don't think the storm is supposed to hit you too hard right Mark? I'm in NJ, way too many emergency alert text messages. hahaha

6-8 inches here, I think

no, 6-12

Stay warm. See ya at the next office hours

which are tomorrow at 10am Eastern

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

this concludes today's chat -- have a pleasant day, all!