Hi Mark

hello, Susheel!

how can I help you today?

I have an android app I need to build. Please let me explain the functionality .

A user will have to sign up for an account in the app's home page

and then enter another user's phone number...

the app will periodically send text messages to the recipient to ask them how they are doing...the recipient will have a chance to respond

by either hitting a pre-defined option or with a custom message

simple enough

please can you give me pointers?

pointers to... what?

on how I can go about doing this

doing... what?

So how can I store a user's info after signing up?

use a database, SharedPreferences, or a file

ok

what is the best way to implement authentication? Oauth2?

um, I can't really answer that

ok

Can I store user info on a server? Is it better to do that way?

I cannot tell you if it is "better" because I have no criteria upon which to judge that

your first step is to hire an attorney and ask your attorney about the legal issues involved with collecting and distributing phone numbers

those issues will vary by jurisdiction, and I am not an attorney, so I cannot advise you on that issue

but that needs to be the foundation of the decision as to where you store personally-identifying information

if you are writing this app on behalf of a business, take the issue to your manager, and have the manager arrange the meeting with the business' legal counsel

ok

What if I ask the user to pick a phone number from their phone contacts or store the recipient's number on their phone? That way I won't be storing any personal info. Is it possible to use shared preferences to store contact info on a phone?

well, you have two ways of going about that

one is to copy the information you need from the contact info (e.g., phone number)

the problem there is that if the contact's phone number changes, you will not know about that until/unless the user adjusts your app

the other is to store a durable Uri pointing to the contact

ok

that way, you can read in the phone number as needed and pick up updates

ok

I know that there are techniques for getting such a durable Uri, but I have never done it personally

Ok

bear in mind that any of that will require the READ_CONTACTS permission

ok

and not all users are comfortable giving that out to apps that also hold the INTERNET permission

ok

If I get the user to just enter their recipient's number and only store that info on their phone using shared preferences, that wouldn't require the app to get access to all contacts. right?

correct

If I implement this method then my app won't require the READ_CONTACTS permission anymore obviously?

correct

Great.

I guess my next question is about how to send this text message to the recipient. Can I just use the SMS API that comes with android or can I use Google Cloud Messaging? Do you know the pros and cons?

GCM has nothing to do with SMS

if you want to send an SMS, you need to send an SMS

SmsManager can do that

ok

can you tell me how I can send automated sms's at regular intervals?

use AlarmManager for the "regular intervals" part

ok

use SmsManager for sending the SMS messages

great

bear in mind that there are no guarantees here (e.g., user might have the device in airplane mode)

thanks

oh

is it possible to 'listen' to an 'sms sending failure' event?

with knowing possible reasons?

well, you can specify a PendingIntent that will be invoked when the message is sent or failed

see sendTextMessage() on SmsManager for details

ok

I have another question. When I receive an sms, is it possible to extract specific info from the body of the text given that I know the format?

I have the same question for email

for SMS, you have the possibility of viewing messages, and so it's just a string

ok

for email, you have no way to view the messages, unless you are implementing your own email client or the user elects to share the text of the email with you

ok

Is it possible to draw a 'custom route' on an android map?

given enough points, you can draw any Polyline you wish

ok

Is it possible to dynamically lookup areas of interest(on google or anywhere else) in my app's background, say restaurants or ATM's in a given location and obtain the location of these points? As opposed to hardcoding the geo-location of these places beforehand? I hope I asked the question clearly

that doesn't really have much to do with Android -- you would need to find some Web service that offers this

ok

Alternatively, if I choose to look up places using google maps in a webview can I then obtain the location from the search results by examining the html or js?

conceivably, I suppose

Great.

Do you know if there are any disadvantages of using Xamarin for android development? Do I have a cap for the number of questions I'm asking or am I good till 8:30?

I'm not a .NET guy, so I cannot comment on Xamarin

so long as nobody else is in the chat room, you're welcome to ask questions until 8:30

ok.

when there is more than one person here, I alternate between people, to ensure everyone gets a chance

great

Well thanks for all the help today Mark. Your book is really awesome!

thanks! glad you like it!