Develop Reference

using geofencing in android or ios

I want to know that is it possible to use geofencing feature without any app installed? is there some cloud or something which you can register your geofencing area so anyone with the location on can see your notifications??

I don't know about Android, but for iOS you can use Apple Wallet Passes. You can attach up to 10 locations (geo points) to your passes, and when the device that installed the pass is near one of those locations, the pass will appear on the lock screen.
Relevance Information Displays Passes on the Lock Screen
Passes let your users take some action in the real world, so accessing them needs to be easy and fast. Wallet makes relevant passes immediately accessible by integrating them with the lock screen. To take advantage of this feature, add >information about where and when your pass is relevant. A pass’s relevancy can be based either on the time or the place where the user can actually utilize it. For example, a gym membership is relevant at the gym, while a boarding pass is relevant at the time the flight begins boarding.
Inside the pass, you provide a point in time and points in space. Wallet then determines whether the pass should appear on the lock screen based on these settings. It calculates when the user is close enough to the specified time and locations based on the pass’s style. Don’t try to manipulate the pass’s presence on the lock screen by providing inaccurate relevance information.
Of course, integrating with Apple Wallet requires your own web server, and is not a simple task. However, It doesn't require any app installed, which is what you asked about.

Security of an Android application

I am developing an Android application and I am planning to release this build in “Open Beta” on the Google Play Store.
I want to implement the app security logic which can ensure that the beta build won't work after certain date dd/MM/YYYY.
Currently, I can think of two approaches for this logic:
Retrieve current date from the device (using Android code to retrieve system’s time)
Issue: User can change the device date to hack the security system
Use time server to check the current date

Issue: My application don’t need internet connection and hence it will be bad user experience if I am asking for internet connection at the start of the app
I have following questions:
What alternate approaches (other then checking dates) can be used to ensure that the app won’t work after date dd/MM/YYYY?
How can I detect that the user has changed device date manually?
Other approaches to find current date even if device is offline?
EDIT:
The beta build has all the premium features free and hence I don't want beta build to work after date dd/MM/YYYY.
NEW QUESTION:
I have implemented the code to check the real date using time server at the start of the application. What possible hacks can be done by users to access app after the date dd/MM/YYYY?
Thank you in advance.

Agreed you don't wish the device to be dependent on the internet. At some point however, the device will be online (A human will never leave his/her device offline since the installation of your app). At that point you check the time stamp and proceed from there. You could disable the app or perform any action. Many apps exhibit this behavior to run an action when and only when the net is connected.
Other than the net and device clock the only other final solution you have is to run a background timer from the moment the app is installed. Good luck

The new Permissions model includes "Internet" as default (you don't need to request it specifically anymore).

If you don't want to use internet you can use following idea. Get current timestamp when running application first time and save it preferences or in external storage. check current time stamp with saved timestamp every time user launches application. please check for negative values to prevent user setting previous dates.

You can check the date, and at the time that the date exceeds the deadline, you can save a variable in preferences, so that when you enter the application, even if they change the date, the application will detect that date been exceeded.

Android Geofencing sample app only works if another app is open using GPS

I am working with the Geofence API Sample application I've got it running and seems to work alright. I did make the modifications to it to use BroadcastReceiver instead of the IntentService.
But I will only get the notifications if I have some other app open that is using GPS such as Maps, or GPS Tester app.
If I don't have one of those apps open and I walk into the geofence zone nothing happens. But as soon as I launch one of them I will get the notification within a few seconds.

I ended up creating a service that forces the GPS to stay active by requesting location updates on a relatively quick interval.
While this is admittedly a poor work around for a "real" application. It worked for my purposes. In which I needed to be able to present a working proof of concept to an audience, which impeded my ability to use a geo points which were further spread out.

Even I too had a struggle with getting Geofence notification as soon I entered Geofence or Exit the one.There were always delays in notifications until I found a really nice Location Library called little-fluffy-location-library which serves my purpose.Location updates will be broadcast to your app periodically.
According the Documentation it says that:
The library works by using Froyo's passive location listener (only possible with Android 2.2 and up, hence why it works best with it), which listens to location updates requested by other apps on your phone. The most accurate location is broadcast to your app approximately every 15 minutes. If a location update hasn't been received from another app for an hour, the library forces a location update of its own.
I think you should give a try with this Library and Let me know if it works for you!!

Design of website pushing info to the app, or app retrieving from website

I have a design question about Android app and I am not sure if I can ask it here (If not please advise when I can ask).
I want to make an app where it gets information from a website (or actually make the website push locations to the app). Imagine a webform that has 3 fields (3 trucks locations). I want that everytime I put those values and click submit, The android app on the devices will show the location of the trucks on the map. I am familiar with the google maps so I know how to show 3 dots on the map given the location. I also know how to write HTML code that would do POST/GET upon press of a submit button But the communication and how to initiate this trigger on the app is what I am confused about. So it is more of an architecture design question. I need a starting point to know where to start looking. I hope I delivered my point here.
sooo Any help ?:)

Your talking about setting up push notifications, look at http://parse.com/products/push

This may be a use case for using Google Cloud Messaging (GCM). I have not worked with GCM yet but this is one option.
Another idea is to setup an AlarmManager to schedule the fetching for data. One draw back I can think of is if you set the AlarmManager to be frequent (ex: every 10 minutes) then all those network requests are going to drain the battery quickly.
Another alternative and similar to the polling, is to have a button within the application where the user manually presses to get the latest data.

Appinventor data triggered by GPS location

I want to create an app in appinventor which will be using gps coordinates to show some data. What I mean is that I want to make an app which will show a message whenever you go to an exact position. I already got the GPS coding that needs to be done but I'm not sure if I can save the data to somehow inside the gps. Im new at this so don't be too harsh with me! Is it even possible to do something like that in appinventor?

Unfortunately what you're describing is a service, in which your program runs in the background waiting for the GPS to hit a trigger location. App Inventor at his time does not have the capability to let you program a service.

You have to open your app manually and have it run in the background. As long as all permissions are enabled, it can then send push notifications using the appropriate block. I personally haven't experimented with what they display, but when properly done, it can show an image and text at the same time, one, or the other.
This means you could call the GPS when you reach a certain location, send a push notification with said text/image, which you can then view by the pulldown bar.
You could also have the app send yourself information via a text, replacing this with the push notification block, whenever you reach a certain latitude and longitude.