My question will be really long but I encourage you to read through everything as it will be used for an honest, good cause. Or you can skip to the highlighted questions part.
Let me introduce myself first, I am an independent web application developer here in the Philippines and I work for a non-profit organization where we help less fortunate people by providing IT solutions and services for free. I have a working web application that has dynamic registration forms where users can enter their data online. I developed this application with responsive UI using bootstrap's grid system. But being here in the Philippines, there are remote areas where the target clients don't have access to the internet 24/7, and bringing laptop or desktop computers is a pain because of the terrain and rivers that we need to cross to reach these remote areas.
Now, together with my team, we are thinking of a way to use our mobile phones, mostly androids to create a mobile app version of our web application. Where it can download the registration form (html) when we are connected and then use it even without internet connection.
Ideally the situation should be:
1. Launch the app from my mobile, and while connected to the internet, download the html forms needed from our web application.
2. Travel to remote areas, use the mobile application to encode the native's information offline. (I heard its possible to save it locally to sqlite db)
3. Go back to the headquarters and sync with the online web application to pass all the information gathered and thats it.
Having said all that, I have 3 questions:
1. What should I use to create a mobile app that can display html forms downloaded from the internet?
2. How can I save the data locally (within the phone)? I heard about sqlite db but I am not sure if it will work with my situation.
3. How can I sync the locally saved data to the online web application?
This is more like a survey application. You dont need the html here. You design your question definitions in xml or json. You may have multiple types of question like Text Answer Question, Single Choice Multiple Option Question, Multiple Choice Multiple Option question, Image Question, QR Code Question, GPS Coordinate Question etc etc. You design these questions in json or xml and put them in server. For example
{
questionSetName: "Question Set 1",
question:[{
questionText: "What is your name ?",
questionType: "TextAnswer"
},
{
questionText: "Which one console below do you own ?",
questionType: "SingleChoiceMultipleOption",
options:["PS4", "XBox", "Steam Console"]
}]
}
Now for your mobile client:
When online user will want to download questions for later offline surveys. so user send a request to server for available question sets. then will pull these file from server (in case of android through some HttpClient like OkHttpClient) and put them in sd card. The server will implement rest apis for question lists and downloading individual question sets.
The application will check if files are present in a certain folder (your app designated folder) in the sdcard. The file names will be the list of the questions.It will parse the json or xml and render question windows accordingly, for example for text question a label with the question text and a text box for answer, for single choice multiple options a set of option buttons, for image questions open the mobile camera etc.
When filling up (answering) the questions you save the answers and question number and flush them in a json file. and put the answer files in another directory (you need some sort of identification).
later on upload the answer files to server.
The server side will require the following rest apis :
1. List of Question Sets of a user (from db ??)
2. An api (webservice) to download a set of questions.
3. An api to upload an answer sheet for a question.
4. user management of course.
Hope this helps.
Related
I am working on learning application. I want to add MCQ test functionality in my app. I want to load data from the server when the test started. and it will not call to the server for each question because it will slow down test process. I want to load all the question when the test starts and a new question will appear only when clicking on next question button. There will be four option in each question so at the end I want to send data to the server to verify the answer. I actually confused in what should I used to save question in internal memory. and then their answer to submit to the server.
Android developer guide has an explanatory list of available options for storage that you can leverage. Since you would want to keep this information secure. I suggest you should use one from the list below
Internal file storage: Store app-private files on the device file
system.
Databases: Store structured data in a private database.
Although a lot depends on the size of data and other specifics of your use case.
Based on the discussion in the comments. Here is a cool answer to the same, i.e serialize/deserialize the objects.
I´m creating a simple database, let´s say something like NBA players with statistics and pictures. I want to be able to edit the database in my desktop C# application and then consult it on my phone .. When there is no internet!
it is Ok to transfer files from desktop to phone manually. It is Ok to download in the app and then get to the place where there is no internet.
The question is .. what´s my best option here? one big xml? or json? a one-file database like sqllite?
I have expertise on C# but I´m new to android and the whole internet connectivity thing. So I´m specially interested on something that´s easily accesible from android phone.
What would you do ?
In my opinion, it is better that you use a single database for the 2 application using mySQL, a local network is necessary, but an internet will be optional. Android will Send & Retrieve Data in the database. Here are some links you can use( documentation, sample codes ).
I'm developing a simple Android App where the user must fill in a very complex form, for which I believe it's much easier to use an HTML form than an Android Activity with tons of TextViews.
The data collected by the form must be sent to some remote database, and the application must be able to work offline.
I thought of two alternatives, the question is: which one would be better?
Let a WebView load a remote website with an offline manifest
Let a WebView load a local website in assets folder
My second question is related to the storage when offline, and once again I have two options, and I don't know which one is better:
Using the HTML5 local storage, and let HTML + javascript send data to the server when online again
Let my Android app catch the form data, and handle everything the Android way.
Any input will be very helpful. Thanks in advance.
Regarding the first question: depends on how often will you need to update your form. An online cached form can be updated quickly, while bundled pages are only updateable together with the app, and you will need to consider that both legacy and new clients can connect to your server at the same time (users will procrastinate updating).
Another aspect is portability. Do you envision an iOS version of your app, or perhaps a mobile site? If yes, then an HTML5 solution is definitely more portable. Also, debugging an app which is entirely HTML or entirely native is usually easier than a hybrid one -- you can stay within a single debugger.
Perhaps, one drawback of using HTML local storage inside WebView is that the data you save will be in a kind of a "black box" -- you will not be able to back it up easily.
[Added later] OK -- one drawback of putting your site into assets folder is that you'll have to use file: scheme in order to access it. This can lead to some cross-origin loading access related issues if you will try to mix your bundled content with content from the web. Check these WebView settings for example: setAllowFileAccessFromFileURLs, setAllowUniversalAccessFromFileURLs, setMixedContentMode.
I'm looking for a way to create offline order entry application for Android and Apple tablets.
Application should download product list with images.
It should allow to show large product image and allow to enter ordered quantities for products.
This order entry must work also if there is no internet connection.
If internet becomes available, entered order should submitted to server.
I looked into offline Web application sample in
http://diveintohtml5.info/offline.html
and searched sourceforge and codeplex for reference applications but haven't found any.
Most difficult seems to be showing offline images. In html5 application I found two possibilities:
Store images in Indexeddb (or in other way) and use javascript to show images
in tablet browser in offline mode.
Where to find sample for this? To to convert database data to image which is displayed in tablet ?
Create manifest containing all image urls dynamically. Tablet browser probably then loads images into offline cache and allows to show them in offline mode.
Where to find framework or sample application which can be used as starting point ?
Should I use html5 + Indexeddb + jQuery + jQuery UI or is there better way ?
Server is Linux server running C# Mono ASP.NET MVC4 application which can provide data for this planned tablet offline application and receives orders from it. I can create WebAPI controller for application.
You need to persist the images in your application and control the references using a database (search for core data for iOS and greendao for Android). Anyway you will need a mechanism to download those images from server when internet connection is available to store that.
About the orders, you can store the order locally in your database and when internet is available you sync those informations with the server, that mechanism can be called whenever you want, you need to define how will be user experience.
My suggestion: Try to break your problem in small problems and try to resolve them. Your question looks more like a general architecture question.
Here is the topics that can help you to develop these apps:
Android:
Database: greendao:
http://greendao-orm.com/
Webservice/Persistence: https://github.com/koush/ion
iOS:
Database: Core Data: https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/CoreData/cdProgrammingGuide.html
Webservice/Persistence: https://github.com/AFNetworking/AFNetworking
I hope this help you to start.
I'm a Webdev beginner, have been learning some Python/PHP/Javascript and want to help a friend of mine with a project.
She's conducting a large scale survey of old houses/windows, and fills in forms (similar to Google Forms). However, she doesnt always have 3G coverage on her phone, so she wants some way of uploading the data when she gets online, and she wants to be able to upload photos and attach these to the forms.
I've found a javascript-library which makes use of html5 localstorage, but I havent understood if localstorage also accepts file uploads? Also, when you have submitted one form you would need internet access to open up the form again to submit another form.
Are there libraries or projects around that would help me with some of this, so I dont have to reinvent the wheel?
This is going to be very difficult to do with a web app. Your going to have to rely on something like AJAX to send the data and if it times out store in local storage and keep retrying every few minutes, because a web app has no access to anything like checking the wifi status etc.
Also that there is a limit to the size you can use in html5 local storage:
What is the max size of localStorage values?
, this is not going to work if you want to hold onto photos.
This would require a native or minimum a hybrid app (like phonegap) to store the data on the actual device in a file or SQLite database. This way you can store what you like, have access to the status of the internet connection and even have prompts to appear on the screen (when the app is in the background) to remind her that there are still some that need to be uploaded.
It will be much more reliable and stable this way
You can create an app which stores the data (form) in the Local DB (ie SQLite) of the App.
Once she is online (mostly wifi) she can start uploading the data.