I have a new project involving the build of an Android app for a website of a hiking club. The website has a login functionality after which the user can browse through available hikes, subscribe to a hike, view the other subscribers, contact the organizer etc.
The original site is based on a MySQL database with a front end of .asp pages. Most data is passed through the pages as GET parameters on the query string.
New to Android development, some things really puzzle me, even after reading several tutorials. I am thinking towards an architecture baes on REST webservices but there a several obstacles to overcome and chooses to be made.
Apart from using REST, some other options are available:
Call the original .asp pages from the app instead of building a dedicated Web service. This leaves me with much less code to write, the original business logic (queries e.a.) as well as the login system can be used (with the "remember me" functionality based on cookies). Downside is that the (X)HTML code in the response needs to be parsed to show in the app GUI, where the majority of the response code is useless ballast code. Also, it does not feel very good from an archtitectorial point of view.
Using a SOAP based webservice. I am totally unfamiliar with SOAP and it appears to be much too heavyweight for a mobile device.
Using REST services. I am leaning towards this option, and have made
some already working services using the SLIM framework. But there
are some problems. First, REST is stateless by definition and does
not seem to support sessions. But the "Remember me" option is
required for the app after login in for the first time, the user
needs not to login again unless he explicitly logs out.
But how can we achieve that?
First option is to designing some completely client-site login/logout system which saves the credentials locally until the user logs out. And sending the credentials with each request to the Web service as POST parameters, or somehow in the HTTP Authorization request header, though I am not familiar with that.
Second option is to deviate a bit from RESt principles and use a session mechanism anyway. After sending the credentials to the web service, a cookie is created and send to the client app. The dartabase cannot be extended so there is no option to save a token in the user table. Maybe the usernae/password can be encrypted and send as a cookie to the app, and decrypted at each subsequent request?
I am a bit lost in this, and look forward to serious suggestions!
I believe that from a long term perspective, it is important that you lean towards REST Interfaces. While JSoup and/or WebView approaches will definitely work, it is important to have the flexibility to redefine/design the mobile application in ways that are completely agnostic of the Server side. REST will help you there and you do not need to play catch up with the Server side, everytime they change the HTML pages, etc.
Going REST will also help in future with writing additional mobile applications and even on different platforms like iOS, if your roadmap contains that.
You can use jsoup to parse the html pages from your Android app and reorganize the information of the web page, this option will gives you ability to quickly develop an App, later you may think on add REST interfaces to your web site and populate data in json.
You can also use WebView to laod your web pages if you don't want to parse html pages.
I suggest you using REST architecture as you said. You can use a rest client library for Android as RESTDroid, take a look to the guide because there is a implementation example with special header needed for the particular web service used (Parse.com in this case).
Related
First, I am a newbie in Android and I was wondering what would be the best way to transfer data coming from an Android app to a web app.
(The purpose of this is to make an IOT platform for monitoring the environment, and ideally, it would be better if the data on the webpage was live, but I could deal with it if it is not possible)
I am not looking for a very detailed answer, simply some tips to get me started would be appreciated.
Thanks
Try the following guidelines:
From your android application, create a service that runs in the background.
This service will run for example every 30 seconds or however often you want it to update the remote server.
If the data you are sending to the server must be input from a user, you can perhaps store that data locally while also managing stale data
Since the service is already running in the background thread, you won't have to worry about affecting the UI thread.
Now make a HTTP POST request, which will post your data in a JSON string to your server.
When you get your data in your web application, store them to your database as usual.
Once stored, you can have a mechanism to check for new data every few seconds and display it.
There are frameworks that make it very easy to have updates without browser refreshes. Regardless of the framework, you should be able to pull that off easily!
I hope this helps you get an idea!
If you already have this web app, a simple solution would be to create an android app based in a webview, which is a basic "tool" to work with webpages, allowing your android app to function like a web browser. Until then you cannot gain advantages if comparing this with your basic mobile web browser. The advantages could showup if you produce special designed pages in your web application exactely to be used only inside your android app. For example: simplified design (less, bigger, direct texts; less images, less elements; easy and fast visualization and use) which could represent less bandwidth demand, faster and more productive experience for the user when compared with a normal browser.
I am interested in making android app like crickbuzz that will fetch live content from server and also there is option of like and comment for users for feedback. So, can anyone tell that how to implement this i.e (how to fetch data from server) how that data will fit in app(confused about this how data get fit in instagram app means profile, home, search tab)
thanks
I suggest you check out this links
Android, PHP & MySQL
Fetch Data From Server
Ok, let's break it down:
The data is obtained from the server using http requests. It is usually received in the form of JSON String, basically a ordered, human-readable data format which is easy to read and parse.
On the app side, you need to implement the layout, which is done in xml and Java. You also need some logic which will obtain the data with the aforementioned requests, parse it, turn into Java Objects and put everything into the layout.
The process is not really complex, could be completed by a single person, but you will need experience, time and good architectural decisions.
If this is your first time with Android app programming, do some tutorials (especially ones that cover networking), learn some libraries (Volley, Retrofit, org.json, RXJava, Picasso will be really useful for what you ask about) and code several small apps from start to end. After that you may be ready to tackle the app you described :-)
Im building this app (using Unity3d) for a city hall and I need to split the content from the actual app since content must be easily changeable without having to update the app itself.
I want to host the content on a server and use http get/post messages to retrieve the data. I also need to have a web editor (kinda like a CMS) so that the client can change the content himself.
In the editor I would just have a list of "rooms", where each "room" would be one of three types (i.e. text screen, slideshow or audio). Depending on what type the room is, different parameters should be visible and editable.
What language you suggest I write the server in? (the server that the app would contact in order to obtain the up-to-date content) Python i'm guessing here?
What would be the easiest way to build the browser editor? Javascript and django?
If you know Python already and don't want to have to support maintaining a web server for your client it would probably be easy to host the web portion of your app on Google's App Engine. It's relatively easy to use App Engine to serve a simple a web form where the client could edit content and upload binaries. The form could be built using Jinja or Django-style templates, and the data would be written to App Engine's datastore. (also, it's easy to restrict access to the form to app administrators to prevent accidental/malicious edits)
Then the Unity app would query a page on the App Engine server to see if there's new content using the WWW object. The server would make a quick memcache/datastore query and return a JSON response telling Unity if there's more stuff to download or not.
I've done all of this in past projects, so I'm sure it's workable, and a lot of relevant code can be found in App Engine's tutorials and via some light Googling.
I would also look at Wordpress as a CMS. You can create custom forms for different post types. Each "room" type could also be a category type and have custom fields for data to be inputed.
There are loads of plugins to get up and running without too much coding. But you can also dig in and customize with some PHP coding.
The great thing about Wordpress is that media handling, Database interface, user management, privilege and editorial controls, to hand off to a client, are all there. There are loads of tutorials and documentation to get the platform to work for your needs.
Android get connected easily with cloud server.I don't know about others. You can connect using JSON and PHP for this.
You can use .net platform as an backend server.
You could also build Webservices. On my project we work with it. You could also do it with PHP. Try this link: Androidhive.info/how-to-connect-android-with-php
I have started working on an Android app for which we need to use MySQL as database and Ruby on Rails for server side code. We will be using SQLLite too on device(will sync both DB as and when required). I searched the web and couldn't find any relevant tutorials/examples which can serve as a base to start with.
I have gone through MySQL and ROR tutorials but still has confusion on connecting Android with ROR.
Can somebody share some relevant tutorials/code snippet which can explain the complete linkage of the technologies. I mean how to send data from Android device to MySQL and vice versa. I know the concept theoretically but not sure how and where to start with.
My sincere apologies for asking such a basic question or if I sound ambiguous but I am a beginner and need to complete this task. Thanks in Anticipation..
Here is a brief overview of what you should know to accomplish your goal. I am not going to go that far into detail, especially since I have never personally used RoR. Note that some of these parts might not relate exactly to RoR, but the general idea behind it still applies. I will leave it up to you to research and figure out how to implement each individual component.
The general flow of everything is as follows:
Android App <==> Network <==> Web Service <==> MySQL
Note the double-edged arrows since data will be flowing in both directions.
The Android App is the client, and the Web Service and MySQL database are located on your Web Server. I only included the Network part for completeness, but you shouldn't have to do anything once the data has been sent onto the network.
A brief overview of each section:
Android App:
The Android App is the client that sends and retrieves data from the Web Server. I am assuming that in your app you are going to allow the user to do some tasks which in essence becomes the data that you want to send to the server at some point.
Take for example, the user should be able to enter his name and favorite animal. Lets say that there is an actual "Submit" button that the user may click. When this "Submit" button is clicked, it should wrap up the data into a proper format to be sent across the network. Two of the most common ones are JSON and XML. Once the data has been formatted properly, you will want to send the data to the server using some type of network protocol such as HTTP. In order to send the data, you of course must have some URL as the target. Lets say the target is www.example.com/webservice.php. This target is our Web Service located on the Web Server.
Once you send the data, the server will respond with some data at which point you can do whatever you want with it. Maybe display it to the user, or stick it in an SQLite database, or even both.
The key thing to remember is that there is no magic going on. Everything I have just described will be implemented in Java code that you will write in your Android Application at some point.
Key Ideas you should research more and figure out how to implement in Java code:
JSON and XML
HTTP in Java
REST and SOAP
Here is an excellent video on possible ways to set up the structure of your Android App.
Make sure that you are doing all network operations in your Android App on a different thread. An easy to use method is an Intent Service.
Web Service:
This is often the most confusing part. A Web Service is simply some entry point for clients attempting to access the Web Server. My explanation here might different slightly when using RoR, but the same idea applies. Notice above that the target URL was www.example.com/webservice.php. The web service is literally the PHP code that exists on the Web Server, called webservice.php. In your Android App, when you send data to the target URL using HTTP, the Web Service code will be executed on the server (and also have access to the data that you sent to it). Inside of your Web Service code, you will basically be extracting the data (which is in some format like JSON), grabbing the necessary parts, and then doing something with it. In this case you will most likely be querying the database. In PHP it is easy to write code that connects and queries a MySQL database that is also running on the server. When the response of the database is retrieved by the Web Server, you can send it back to the Android App. Just as before, remember, there is no magic going on. All of these ideas are implemented by writing some code.
Main ideas to research:
Ruby on Rails web service
How to access a MySQL database using Ruby on Rails
MySQL Database:
This is where you will store the data on the Web Server. I am not going to go that in depth here because this is just going to require you doing a lot of reading up on how to set up a MySQL database on a web server. It is also important that you learn how to create the appropriate queries such as SELECT, INSERT and so forth.
Main Ideas to research:
How to setup a MySQL database on a web server
If you need any clarification, let me know!
I need help figuring out the best, cross-browser compatible way to "SAVE" user input and STORE them locally(offline mod) AND on a server(online). Program will be used by Android and iOS.
I want to know the best way to track user progress while the device is online OR offline.
Hello I have been researching AJAX, JSON, XMLHttpRequest, REST, Java, and HTML5 (specifically, localStorage).
The scenario: (Read a book online/offline, save page progress)
A user logs in to a Web Service and the Web Service allows the user to download an "html webpage book" (view with HTML5 browser).
After every page turn, a REST API uses a GET request to post the Progress data to a Web Server. Simultaneously, a JSON string is created and saved in a file on the server. (let's say "ProgressData.txt")
In the background, a separate "copy" of ProgressData.txt is saved LOCALLY on the mobile device. The user then leaves the internet connection and continues to read the HTML Book.
When the user regains connectivity, the ProgressData.txt is uploaded to the server using a REST API where it will update the old server file with the NEW .txt file with all of the user ProgressData.
Possible solutions:
HTML5 localStorage solution looks good. jQuery even simplifies it:
http://plugins.jquery.com/project/html5Storage
Straight Javascript looks good for Server-Side storage, however it doesn't have access to a mobile device's physical hard-drive, thus preventing any kind of offline saving.
Java applets look possible. Plus not sure how Java runs with Android/iOS.
I don't want to have to run a localhost(PHP/Apache/Python) from a mobiledevice every time the user goes offline, however that may be where the solution lies. I did stumble on this powerful tool: http://couchdb.apache.org/
Question:
I need to know the best way to track user progress while the device is online OR offline. What is the best way to do this?
I stumbled across store.js the other day which might help solve the cross browser local storage. It was from this article about local storage.
I think your best option for tracking online/offline is to ping the server via an AJAX call when the page is turned. Always try and update the server on a page turn, but if it fails, handle the failure and store the progress locally. Each page turn will either amend the locally stored progress file or if connection is restored then simply update the server with the progress.
The issue I am thinking might occur is if a book is finished offline then there are no more clicks that would trigger the syncing, regardless of a restored connection. You may want to think about a manual sync link/button at the end of a book. Or maybe have a manual sync available at all times anyway? Give some control to the users and describe the whole offline/online reading scenario. You might find that it is easier to just let the users do the work… if they don't sync then it's their problem!
Here are 2 screencasts what will help you with your problem.
They are in Ruby on Rails but maybe you can get the idea. It is using the html5 cache manifest.
Hope it will help you!
http://railscasts.com/episodes/247-offline-apps-part-1
http://railscasts.com/episodes/248-offline-apps-part-2
some more resources (sorry i dont have experiences myself with html5 cache manifest)
http://diveintohtml5.ep.io/offline.html
http://developer.apple.com/library/safari/#documentation/iPhone/Conceptual/SafariJSDatabaseGuide/OfflineApplicationCache/OfflineApplicationCache.html
I'd suggest just using a cookie to store the current state. That way it is automatically sent to your server with every user request (so no need to build out a custom server-side API for receiving the state after a lost connection, and no need to have any custom client-side code for sending the data to the server), and still updateable even if the user has lost Internet connectivity. Also it doesn't rely on HTML5 features, so you don't need to restrict people to HTML5-capable browsers.
In any case, the best way to handle storing the current state would be to have a simple onclick handler on your "next page" link (or button, or whatever it is) that calls a function and sets the cookie value to whatever the current position is. Note that because the state is always available client-side, and sent to the server on every request, there is no need to maintain any explicit copy of the state server-side, unless you want to be able to remember the user's place even when they manually delete their cookies (which is overkill in my opinion).
You may want to look at the W3C Example Code for setting/getting cookie values in JavaScript.
Also, here's a website that demonstrates functionality similar to what you want to build. It uses cookies to keep track of a user's place when reading various webcomics. Pretty much the same as what it sounds like you want, except with comics instead of books.
It would be wise to track the progress in both a server side database and in the client's local storage if a constant internet connection is not necessary.
Evercookie is a controversial javascript api that aims to provide local storage using any means available including standard cookies, Flash shared object, Silverlight, browser history and HTML 5 storage. Data should persist when the user is offline and when the connection is restored, sync the cookie and database with whichever data has greater page number for the given book. Droid has Flash and the Flash shared object data is a "cookie" available to both desktop and web-based apps.
With great power comes great responsibility:
http://samy.pl/evercookie/