howdy, Hamish!

how can I help you today?

Hello

Apologies in advance, Mark, I'm sure you will have been asked this before.

When using the standard Task Manager on my Gingerbread device to kill running services, I see that some services, displayed in a different colour, soon "come back to life". I thought if a User task-killed a service then all the service's processes are killed and its alarms are cleared and nothing runs until the user explicitly relaunches the service herself. If that is the case, how do these services automatically restart. I am not rebooting my phone so the services cannot be being restarted from an OnBoot receiver.

what is "the standard Task Manager"?

do you mean the Settings app, where you are pressing Force Close?

or do you mean something else that your device manufacturer included with their device?

Long press middle menu button and the recent task lists popup with abutton for Task Manager this is on a Samsung Galaxy s2

OK, that is unique to that device (or other Samsungs possibly)

they are most likely using the killBackgroundProcesses() method

this does not do a Force Stop

the process is treated as if there was a low-memory condition

ah ok, so if it's a Force stop then everything is killed ?

and so the service can come back (e.g., START_STICKY)

right, Force Stop on 2.3+ nukes everything from orbit

and on 3.1+ prevents anything from running again until the user manually launches an activity

on 2.1 and earlier, there was a way for task killers to do this too

(maybe 2.2 as well -- I forget the timing)

"prevents anything from running again until the user manually launches an activity" even if it is registered for OnBoot broadcasts ?

correct

if the service is a system service can it be killed by a Task Manager?

what do you consider a "system service" to be?

A service running as system_user inside the framework?

AFAIK those are not "services" (i.e., Dalvik VM apps with a class inheriting from android.app.Service)

those are processes that we interact with via AIDL

and, no, those cannot be killed by a task manager

most cannot be stopped by Settings, either, IIRC

if you have other questions, feel free to chime in, at least until somebody else shows up :-)

howdy, Daniel!

i was thinking more of system apps? like the Alarm Clock or System Settings app ?

Hello there

Hamish: apps can be killed by task killers, subject to the limitations we discussed

Daniel: do you have a question?

Yes, I'm having issue with generating a spinner from a cursor. I have a SimpleCursorAdapter, but I think the issue I have is to do with either the projection or to paramaters. Because my spinner shows "empty" options for the number of rows I have. Example: I have 4 rows in the database, and the spinner shows 4 blank options

that sounds like an issue of binding data from the Cursor to the TextViews or other widgets

how are you doing that? overriding bindView()? using a ViewBinder? something else?

I was able to get the data to display in a ListView, but not with a spinner.

Neither of those to my knowledge. I am rather new to android, and trying to pick pieces together from many sources so might have missed something

um, well, you gotta do something :-)

are you using SimpleCursorAdapter?

Yup SimpleCursorAdapter

can you paste your SimpleCursorAdapter constructor call here?

SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, android.R.layout.simple_spinner_item, c, projection, to, 0);

projection and to should just have one value in each array -- correct?

sorry that didn't paste too well, but you get point hopefully

android.R.layout.simple_spinner_item does not have a TextView with id R.id.name_entry

oh I see

you probably had an R.id.name_entry in a custom row for your ListView

yup I did

that means either you need to create a custom row for your Spinner, or you need to adjust "to" to use the right ID

(which would be android.R.id.text1, BTW)

Ah thank you. That does work now.

who-hoo!

Hamish: do you have another question?

howdy, Nitin!

Nitin: do you have a question?

Hi Mark..

Yes

Culd you suggest me the best way to parse a JSON response?

how big is the JSON, and what versions of Android are you supporting?

It can have 50-100 of JSON objects I suppose. Android 2.2+

mainly 2.2 & 2.3 as of now

I would start with the org.json classes (JSONObject and JSONArray)

if you find that performance is an issue, consider Jackson as a third-party JAR

okay. I'll check that. How good is GSON compared to Jackson?

I suspect that they are comparable, but I do not have performance statistics handy

Okay.

note that API Level 11 added android.util.JsonReader, which is based on GSON

Noted.

Mark, if I plan to develop a web apps, what are the few things I should make sure of? Some brief idea?

that is not my area of expertise, sorry

Daniel: do you have another question?

Okay.

if anyone has a question, chime in

Is there a way to determine which Activity you entered the current Activity from? So that I can return the user to the correct one if they use the "up" navigation in the ActionBar?

not automatically

I do. Have to seen the official TED app?

you can pass that info via an extra

Nitin: no, I have not

Okay. AFAIK, how can we create a layout with multiple screens corresponding to the button at the top of every screen? Something like what Tabhost or ViewPager does.

well, what do you want that TabHost or ViewPager do not do?

with respect to the TED app, based on Google Play screenshots, that is presumably a ViewPager if it supports horizontal swiping on the body

in terms of what they are using for their tab bar, that could be a styled TabHost, or a set of ToggleButtons, or just about anything

Cool. Thank you. I liked the Interface of the app.

it does support horizontal swiping.

it is nicely polished, though I do not like the varying position of that tab bar thing

but, that's just me

I am getting what's tab bar in it? I m running that app right now. :)

I am sorry, but I did not understand that question

wait, let me check the screenshots in google play

Leave it. So a ViewPager supports both horizontal swiping and the clicks on those tabs?

ViewPager won't work with the tabs automatically, but you can arrange for it

see the JavaDocs for ViewPager for an example

using action bar tabs

Okay. I'll look into that. Your book doesn't cover it?

right now, it doesn't even cover ViewPager

though the Omnibus will cover it in a couple of weeks

Cool. I am looking forward to the pdf version.

(by "it" I mean ViewPager itself)

that is probably 3-4 weeks away

Okay. I am done for the day. Thanks for your time.

you are very welcome

Daniel: definitely chime in if you have more questions

I'm out of questions for today. I'm just getting started, but I might have some for your next Office Hours, I was just staying around to get some further insight from others questions incase they helped me later :)

no problem

Thank you for the help and for the books. Will leave now, take care.

you are very welcome!

that is a wrap for today's chat

next one is Wednesday at 7:30pm Eastern

have a pleasant day!