I've made a quiz app and it's working fine.
I have used an ArrayList to 'store' all the questions I made up myself. Right now it contains 60 questions. I eventually want to expand this to ~300 questions. It looks like this right now:
questions = new ArrayList<>();
Question question0 = new Question(R.drawable.piano, "Welke coureur verkoos een carrière als coureur boven een carrière als pianist?", "Max Verstappen", "Fernando Alonso", "Jean Alesi", "Adrian Sutil", 3);
questions.add(question0);
And I have done this 60 times now. At first I thought I could use a for-loop to add all the questions like :
for (int i=0; i<questions.size(); i++){
questions.add(i);
}
But this is not possible, because the size of the questions is still 0 in the beginning. Now I have a lot of the same code, and I was wondering how to solve it. I could use a database, but I still have to create colums/rows and have to add all the questions. Which takes even more time, right?
I would like to get some advice on what to use and why.
Thanks.
Is it necessary to use a database in my case?
No. However, depending upon what you want from the quiz, a database may be the way to go. If you are just going to present a quiz, the same quiz with the same questions and answers then the App may then no need.
However, if you ventured into storing results, displaying a subset of the questions (e.g. those not attempted or those not answered correctly etc) then you are moving into the realms of the database being desirable perhaps even needed.
I could use a database, but I still have to create colums/rows and have to add all the questions.
Rows would be created by adding the questions.
Which takes even more time, right?
Perhaps not with one of the available SQLite tools, the database could be created using such a tool and then copied into the App (typically as an asset) (more work to implement copying the asset). Of course should the App develop then this could save time (if implemented well).
Related
I am trying to create an Addin which will copy certain attributes of a chart from First PowerPoint and read it to an Temporary Excel, which then can be used by a second chart in Second PowerPoint. Sounds simple enough, but the problem is, the attributes that I am reading happens to be a multidimensional array, which can't be written to an excel. So I have hit a roadblock as to how to tackle this situation.
On searching through internet, I came across something called localstorage and most of the answer seems to be surrounding javascript which I don't know, so didn't really understand much.
Because this strikes to me like a common problem which others might have also faced at some point in their life, so really hoping to take away some pointers from here.
I have been developing some things and you know during early prototyping types and tables change quickly... it would be nice to cleanup the old data and start again in certain meshes.
For now I was using the example HTTP server so I deleted data.json; but I forgot the localStorage in the browser also needs to be cleared.
One might suppose you could put(null)
I asked on gitter and got
https://github.com/amark/gun/wiki/delete
except for deletes , lol, our excuse is "It works like your OS, when you delete >something it just gets tossed in the trash/recycle bin. That's all."
better safe than sorry though
if you are trying to "delete" stuff because you messed up while developing >something, follow this three step process: 1) localStorage.clear() in every >browser tab you have up, 2) Crash the server and rm data.json, 3) restart >everything. You should then have a clean slate. Often times while I'm >devleoping something I put localStorage.clear() at the top of my code so I only >have to worry about clearing the server.
Welcome to the gun community! Thanks for asking questions.
Yes, deleting data is most simply done with gun.put(null). Take:
var gun = Gun();
var users = gun.get('users');
users.put({alice: {name: 'alice'}, bob: {name: 'bob'}});
// now let's delete bob
users.path('bob').put(null);
If (as you mentioned in the question) however, you mean "delete data" as in wanting to clear out mistakes while developing your app. You'll want to do what you mentioned: localStorage.clear() in all browsers, crash the all servers and rm data.json.
For other developers, it might be useful to know that gun uses a type of tombstone method. You can't actually delete nodes themselves, they just get de-referenced, kinda like how your OS just moves files into a trash/recycle-bin. This tombstone method is very important in a distributed environment, such that the "delete" operation is replicated to every peer.
Thanks for answering your own question though! As always, if you get lost or need help hop on the https://gitter.im/amark/gun .
I'm trying to find the best solution (performance & accurate) to have a static list of objects in a web service.
Some web methods will be making amendments to these objects and returning the state of the object after the amendments and others will be requesting the current state.
This needs to be accurate at every operation as it's money related. This web service will be bombarded with requests from different areas of our large scale project.
I've been looking at ConcurrentDictionary, and while reading some other SO questions I came across the following answer: https://stackoverflow.com/a/1966462/151625
The following paragraph is something that I do not want:
Now consider this. In the store with one clerk, what if you get all the way to the front of the line, and ask the clerk "Do you have any toilet paper", and he says "Yes", and then you go "Ok, I'll get back to you when I know how much I need", then by the time you're back at the front of the line, the store can of course be sold out. This scenario is not prevented by a threadsafe collection.
So essentially I'm asking, should I lock values within a ConcurrentDictionary, or does it defeat the whole purpose of it? If I should/could, what is the best way to do it, if not, what alternative do I have?
I was wondering if someone could point me in the right direction.
Here is my problem: I have a large form/checklist that I would like to make digital for ease of use.
Thoughts: I would like to use existing tools that would be easy to integrate. My first option is Access 2010.
My question: I would like to enter the questions into a database and then use those entries to auto generate a form that can be used to allow the user to input the actual data into the database. An example would be I have 11 Sections of questions and under each section I have sub-sections that can contain anywhere from 1-... how many every questions we need.
Is it possible to use data stored in an Access database to generate a form with Checkboxes that can be used to input data?
Please point me in the right direction. Obviously there is the option of just creating multiple forms or one big form, but I would like this form to easily be changed etc... Less work more automation.
Thanks,
Alex
Depending on the requirements of your project, this may be quite possible. If you want to use Access as both the back-end and front-end, then you'll need to work within a few limitations:
Because Access combines the user interface and design interface into the same screen, it requires a certain amount of trust that the user can't or won't try to get too creative with changing the data, seeing everyone else's data, changing the design of your form because they are bored, etc. There are ways around these problems, but they can get complicated.
Will all your users be using Window's machines with Access 2010 installed and with the original default settings? If so, good. If not, there may be ways that this could still work.
(There's more, but that's all I can think of right now)
To get started, here's a broad outline:
Make a table for your questions. This table would just have the questions.
Make a form using that question table as the source. Leave the checkboxes and other answer fields unbounded. Include a 'submit' button at the bottom.
The submit button will create a sql query to insert the user's answers into a 2nd table.
If you have any specific questions, we here at SO will be glad to answer them.
In order to dynamically and easily change the number of questions in the sections, what I would do is:
In the main Questions table, add a field called Section to allocate the questions into diffferent ones, and another one Yes/No field to select those that are included (you may also exclude them by leaving the section field empty, as you wish). This will solve the problem of changing the design easily. you probaly will need an admin form in order to do this changes, to avoid touching the tables directly, but this is your decision.
Secondly, in order to allow the users to efectively answer the generated form, you have to ask yourself if you want to accumulate the answer sets, and if you are going to control who answers
I'm new to Silverlight, but being dumped right into the fray - good way to learn I suppose :o)
Anyway, the webapp I'm working on has a relatively complex database structure that represents various object types that are linked to each other, and I was wondering 2 things:
1- What is the recommended approach when it comes to dataclasses? Have just one big dataclass, or try and separate it into several smaller dataclasses, keeping in mind they will need to reference each other?
2- If the recommended approach is to have several dataclasses, how do you define the inter-dataclasses references?
I'm asking because I did a small test. In my DB (simplified here, real model is more complex but that's not important), I have a table "Orders" and a table "Parameters". "Orders" has a foreign key on "Parameters". What I did is create 2 dataclasses.
The first one, ParamClass, were I dropped the "Parameters" table only, so I can have a nice "parameter" class. I then created a simple service to add basic SELECT and INSERT functionality.
The second one, OrdersClass, where I dropped both tables, so that the relation between the tables would automatically create a "EntityRef<parameter>" variable inside the "order" class. I then removed the "parameters" class that was automatically created in the OrdersClass dataclass, since the class has already been declared in the ParamClass dataclass. Again I created a small service to test it.
So far so good, it builds happily. The problem is that when I try to handle things on the application code, I added service references for both dataclasses, but it is not happy doing something like:
OrdersServiceReference.order myOrder = new OrdersServiceReference.order();
myOrder.parameter = new ParamServiceReference.parameter(); //<-PROBLEM IS HERE
It comlpains that it cannot implicitly convert from type 'MytestDC.ParamServiceReference.parameter' to 'MytestDC.OrdersServiceReference.parameter'
Do I somehow need to declare some sort of reference to ParamClass from OrdersClass, or how do I "convert" one to the other?
Is this even a recommended and efficient way of doing this?
Since it's a team-project, I initially wanted to separate the dataclasses so that they (and their services) can be easily checked out by one member without checking out the whole entire dataclass.
Any help appreciated!
PS: using Silverlight 4, in case that's important
Based on the widely accepted Single Responsability Principle (SRP), a class should always be responsible for one task, and one task only.
That pretty much invalidates your "one big dataclass" approach.
I would always recommend smaller, more manageable bits that can be combined, instead of one humonguous class that does everything (except brew coffee for you).
Resources for the SRP:
Wikipedia on SRP
OODesign: Single Responsibility Principle
ObjectMentor: list of articles on good app design - which has a few links to PDF documents, like this one on SRP written by Robert C. Martin - the "guru" on proper OO design
OK, some more research let me to this: it is not simple to separate classes from a relational model using LINQtoSQL. I ended up switching to an Entity Framework approach, which itself doesn't deal with it gracefully (see here and there, for example), but at least it solved another major problem I had with LINQtoSQL.
There are other ORMs out there that are apparently much more capable at this (NHibernate comes up often in recommendations), unfortunately, I don't have time to investigate them now, being under such a tight deadline.
As for the referencing, it was quite simple, change the line to:
myOrder.parameter = new OrderServiceReference.parameter();
even though I removed the declaration from that dataclass.
Hope this helps someone!