Hello

hello, Jacek!

how can I help you today?

I have a question regarding Cursor and RecyclerView. Is there anything against the idea to use them together?

no

in my RecyclerView chapter, I have an example of creating a RecyclerView.Adapter that uses a Cursor as a data model

there's nothing "built in" for cursors, as an equivalent of CursorAdapter, but it's not too tough to write

the only tricky thing is that a Cursor has internal state of what row the Cursor is "pointing" at

so you need to make sure that you always move the cursor to the proper row before trying to read stuff from it

Okay, thanks for answear. Actually I've already written it, and it works quite well

My next question is about design patterns

go ahead, though I may or may not be able to help with it

In toolbar I have Spinner which shows some options and has influence on Fragment's content

But Toolbar belongs to Activity

How can I keep loose coupling in such situations?

Should toolbar be modified by fragment or activity?

off the cuff, knowing nothing more than what you have written here, I would say that the activity is the one that literally manages the Toolbar, but the fragment is the one driving the work

where you have an API between the fragment and the activity for this coordination

so, the fragment calls some setAvailableOptions() method it calls on the activity

today, the activity happens to populate this Spinner

but, perhaps in the future, you do something else (e.g., put those options in a nav drawer)

the fragment provides high-level abstractions of the requirement ("the user should be able to choose among these things"), and the activity implements it

the activity would sink the selection events from the Spinner and let the fragment know about them

So activity should implement some interface probably to fulfil fragment requirements

if there's a chance that more than one activity might host the fragment, definitely

it's less critical when there's only one possible hosting activity, though you might prefer the interfaces for cleanliness

Thanks for explanation, unfortunately those design overthinking usually kills my work :)

So thanks for your time and have a nice day

you are very welcome

Hello

hello, Bryan!

how can I help you today?

I have 3 questions (probably more)

hopefully they're short -- we don't have a lot of time left in the chat

but, fire away!

1) I just found out that you can decompile APK's fairly easily and see a lot of the code. I looked through your book but I didn't see anything about how to keep sensitive data (like api keys, etc) secure

any pointers?

don't put them on the device

by definition, if your code can use the data, somebody can get the data

so if you need your app to get information from your server without or before a user authenticates, how do you do that?

however you would normally do it

bearing in mind that the API key may be compromised

this is no different than hitting a Web server using an API key from JavaScript in the browser

you can use stuff like DexGuard to make it more difficult to get the API key

wow, ok. In a tutorial online about in app purchases, they give the key you need to use but tell you to create it from different strings to help "secure" it

do you know what they mean?

and how it helps?

squirrel the API key in a few pieces in various spots in your app, then use string concatenation or similar algorithms to combine them

akin to DexGuard, it adds a small amount of challenge to the API key retrieval process

Ok

it won't stop a determined attacker

very interesting, ok, thank you!

2) To create a "lock screen" app, are those basically apps that put an activity on top of all other screens and have their own "unlock" features

I have no idea

I avoid the topic like the plague

lol, can you tell me why?

that will help inform my report

as far as I am concerned, they are all malware

at best, they weaken security

cool, thanks

3) What is an SDK vs a Library

in terms of developing one

whether marketing got involved in the naming process

ha

usually, an SDK *is* a library

though there may be accompanying tools or something

I saw one difference is that an SDK has example code, etc in it as opposed to a library

true?

no

ah, ok, can you give me an example of what an accompanying tool would look like?

like all the ones in the Android SDK

ok, cool

lastly, are you going to be at the Big Android BBQ?

no (either Austin or the Netherlands)

What is the Austin one?

that's the original BBQ

they extended to Europe this year

very cooll, are they having one in Austin this year too?

though, now that I think about it, more recently the Texas one has been in the Dallas area

it started in Austin IIRC

Yeah, it is in Hurst this hyear

ahhh

yeah, it's been in Hurst for ~3 years

sorry, short on sleep

no problem. So you are not going to be there in Oct?

just curuious

and curious

no

I attended the first Hurst one, 3(?) years ago

ahh well, thanks for the answers! Have a great day

you are very welcome

oh, I had one more, have you tried Project Fi?

no

Alright, thanks again!!

and that's a wrap for today's chat

the transcript will be posted to https://commonsware.com/office-hours/ shortly

have a pleasant day!