I need to use MTD with Json to dinamycally create forms, but also i need to check the user input:
Some fields may only accept numbers, and some other have a fixed length etc.
This can be done with an action that checks every EntryElement value against the specified conditions, and then using some messaging to tell the user about the necessary corrections.
If we have a low number of fields this is Ok, but when one has more than 50 fields then this turn out to be very awkward in terms of usability. The ideal solution would be to notify the user about corrections, in the moment the user ends typing in the EntryElement
Now MTD provides some sort of mechanism to do this:
JsonElement jsonElement;
jsonElement = JsonObject.Load("file.json");
((EntryElement) jsonElement["field_1"]).EntryEnded = delegate { doSomething();};
Provided that "field_1" is an EntryElement marked with the id attribute with "field_1" value
The above code works as expected, ie: When i change the focus to another part, the EntryEnded event activates. Now for the million dollar question:
How do i know to which EntryElement does the Event correspond? or in other words. How do i get the ID of the EntryElement when calling the Event?
If none of the above is possible which would be suitable solution?
Thanks in advance for any leads,
Found a way to do it:
((EntryElement)jsonElement ["field_1"]).EntryEnded += (object sender, EventArgs e ) =>
{
NSIndexPath pt = ((EntryElement)sender).IndexPath;
Console.WriteLine("section: "+pt.Section+" row: "+pt.Row);
};
This little thing will print the Section and the Row of the EntryElement that received
the EntryEnded event. This is not exactly as getting the id, but at least now i have information about its location, and from this i can get a lot more info (specially if i took care to save it somewhere else)
This is probably a basic trick, but i didn`t found it anywhere else!
Related
I´m kind of new to the reactive pattern and now I have my first bigger question.
I have done a few asychronous requests in the reactive way. But what I wan´t to do now is a "Eventlistener".
I have a Session object, at the moment I have an SessionEventListener protocol. The Session has a list of listeners and informs all of them about a successfull login and an logout. This Listeners can subscribe and unsubscribe. This thing I want to create reactive now.
How would you do that?
My Idea is to define a BehaviourSubject:
public let loginEventBehaviourSubject = BehaviorSubject(value: true)
now I can send onNext true if the session logged in, and false if it was logged out:
loginEventBehaviourSubject.onNext(true) // on login
loginEventBehaviourSubject.onNext(false) // on logout
And my "listeners" can subscribe to it.
But I would prefere to have subjects for every event:
public let loginEventBehaviourSubject = BehaviorSubject(value: )
public let logoutEventBehaviourSubject = BehaviorSubject(value: )
But then I wouldn´t need the bool. Can I make a kind of "empty" Subject, that only fire "events" without submitting really data.
And then my last question:
Why do I have to add an instance to the initializer of the Subject. Why can´t I create it like: BehaviourSubject<Bool>()?
You need to give an initial value to behavior subject because of it's API. Indeed, it defines BehaviorSubject<T>.value() method, which returns a T. And it would not make sense to call value without a proper initial value. In the presented case, I think PublishSubject is a better representation of the task at hand. You can find more documentation on the available kinds of subjects on the reactivex website.
If you are only interested in the .next event of your subjects, you can do let loginSubject = PublishSubject<Void>() (using behavior subject, you could have written BehaviorSubject<Void>(value: ())) and will the be able to call loginSubject.onNext().
Note though that using any subject is often an anti-pattern. Indeed, subject are most of the time intended to bridge from the imperative to the reactive world and you can very often create things like loginEventObservable as a combination of other observables. For more information on this, I recommend reading To Use Subject Or Not To Use Subject?. It is written using the .Net implementation of Rx, but the theory stays the same.
I have successfully implemented the tutorial:
http://developer.android.com/reference/android/support/v4/view/ViewPager.html, as a Tab'ed viewpager activity with fragments on each tab. Each Fragment maintains various UI TextFields etc and everything is working fine with the exception of getActivity(), which returns null when called from any of the fragments.
UPDATE: Read this, then please see my own answer below that broadens the scope regarding the cause of this error. Continued:
BUT, the null status appears after a while. Initially, in fragment.onStart(), the getActivity() is working so that the default UI setup may be performed. But the first time the user has made changes, getActivity() already returns null.
Strange to say, in the same moment, it is still possible to make any change to the fragment UI fields from the Activity, which means that as the context=activity is passed to the fragment in a setSomeText(this, ...), this will enable the fragment to make the corresponding changes. Of course, the design should be such that the Fragment takes care of it's own detailed task.
It does not help to save the context in the onStart(), because that reference will point to a null after a while.
It is explicitely stated in the tutorial that the feature is in early development, but as this "null" problem has become quite a timethief here, and as I see that "getActivity returns null" is a very common problem, I wanted to muse aloud whether there could be a bug in the getActivity() when combined with ViewPager and/or Tab?
What took me so long to detect the problem was that it is hard to guess that a fragment would EVER loose knowledge of its activity. Anyway, I am on the next hurdle and just wanted to share this finding: Don't trust getActivity(), but pass on context from Activity to its Fragments as a parameter in the set/get methods or other api.
This is not an answer, but I needed the space to explain and I am circeling in the problem:
It seems there is more general problem than just getActivity(). Because variable declarations of the fragments are also "vanishing" to null. A new instance of the fragment has "taken over". This happens when current tab is shifted more than one tab to either side.
EXAMPLE: I define 5 tabs. I have a tab 2 that can be manipulated from UI. After a change of 2 content, I move between tabs, either with tab click or fingersweep. Either way.
RESULTS? As long as I visit the next tab on left or right side, and then move back, the changed data are still there on tab 2. As soon as I move two or more tabs away from tab 2 and then return, the fragment instance of tab 2 is always reset. Does not matter how many tabs are present. Whether I hit last or first tab during this process is not significant. The code? it is the same as in the referenced tutorial, and in addition:
//add tabs (notice the once only saving of the fragment into profileViewer)
mTabsAdapter.addTab(actionBar.newTab()
//.setText(R.string.action_favorite)
.setIcon(R.drawable.ic_action_favorite),
TabFragmentDemo.class, null);
mTabsAdapter.addTab(actionBar.newTab()
//.setText(R.string.new_profile)
.setIcon(R.drawable.ic_action_add_person),
ProfileViewer.class, null);
profileViewer = (ProfileViewer) mTabsAdapter.getItem(NEW_PROFILE);
mTabsAdapter.addTab(actionBar.newTab()
//.setText(R.string.action_select)
.setIcon(R.drawable.ic_action_view_as_list),
TabFragmentDemo.class, null);
mTabsAdapter.addTab(actionBar.newTab()
//.setText(R.string.action_select)
.setIcon(R.drawable.ic_action_view_as_list),
TabFragmentDemo.class, null);
mTabsAdapter.addTab(actionBar.newTab()
//.setText(R.string.action_select)
.setIcon(R.drawable.ic_action_view_as_list),
TabFragmentDemo.class, null);
Then a simple dialogFragment selecting a date and then this date is set (Does not help to omit the datepicker and just set a date directly)
public void showDatePickerDialog(View v) {
dateOfBirthPicker = new DateOfBirthPicker();
dateOfBirthPicker.show(fragmentManager, datePickerTag);
}
//the callback from datepicker:
#Override
public void onDateSet(DatePicker view, int year, int month, int day) {
//update the fragment
profileViewer.setCardFromDate (this, day, month, year);
Notice that "this" is passed on as forced context to the fragment. The big question here is why the tab looses its original fragment as long as there is nothing in my code requesting that ?
Just started coding with Appwarps and I'm running into an issue. I have a lobby built that shows live rooms, but I really do not want to show the rooms for matches that have already started. I figured I would use
void Client::setCustomRoomData(std::string roomId, std::string customData)
But I have some doubts on how to use it. Once the game starts, I plan on sending
SetCustomRoomData(roomId, "Closed");
to notify the server that open seating is now closed. However, when I check the room properties on another device when it calls
void CCAppwarpDelegate::onGetLiveRoomInfoDone(AppWarp::liveroom revent)
{
CCLog("CustomData=%s",revent.customData.c_str());
...
it returns blank. What am I missing here? Besides the code not working, what really makes me question myself is that I don't understand the mechanics of the properties. How do you have multiple custom properties since you aren't assigning it any kind of index...or do room only have a single custom property at any given time?
You don't need to use customData and instead use only room properties. Room properties is a set of key/value pairs that you can associate with a room.
I recommend you read the following link
http://appwarp.shephertz.com/game-development-center/matchmaking-basic-concept/
So the flow is as follows -
you first create the room using the createRoom API and pass a
properties dictionary containing <"closed", "false">.
Then once the game is active, you use updateRoomProperties API
on the room and pass <"closed", "true"> to the API.
Then when you want to show the list you should use
getRoomWithProperties and pass <"closed", "false">. This will get
you a list of rooms that are not yet "closed".
I have three dropdown boxes on a Main_Form. I will add the chosen content into three fields on the form, Form_Applications.
These three lines are added :
Form_Applications.Classification = Form_Main_Form.Combo43.Value
Form_Applications.Countryname_Cluster = Form_Main_Form.Combo56.Value
Form_Applications.Application = Form_Main_Form.Combo64.Value
The first two work perfectly but the last one gives error code 438!
I can enter in the immediate window :
Form_Applications.Classification = "what ever"
Form_Applications.Countryname_Cluster = "what ever"
but not for the third line. Then, after enter, the Object doesn't support this property or method error appears.
I didn't expect this error as I do exactly the same as in the first two lines.
Can you please help or do you need more info ?
In VBA Application is a special word and should not be used to address fields.
FormName.Application will return an object that points to the application instance that is running that form as opposed to an object within that form.
From the Application object you can do all sorts of other things such as executing external programs and other application level stuff like saving files/
Rename your Application field to something else, perhaps ApplicationCombo and change your line of code to match the new name. After doing this the code should execute as you expect.
Form_Applications.Application is referring to the application itself. It is not a field, so therefore it is not assignable (at least with a string).
You really haven't provided enough code to draw any real conclusions though. But looking at what you have posted, you definitely need to rethink your approach.
It's to say definitely but you are not doing the same. It looks like you are reading a ComboBox value the same (I will assume Combo64 is the same as 43 and 56) but my guess is that what you are assigning that value to is the problem:
Form_Applications.Application =
Application is not assignable. Is there another field you meant to use there?
I'll take a real example I have to implement in a program I'm coding:
I have a database that has the score of every game bowled in the past three years in a bowling center. With a GUI, you can choose to either search for the best score on each lane, search for the best score between two dates, for the best score for each week, etc.
I'm wondering what the best way to implement this is. Should I code something like this:
public Vector<Scores> grabMaxScores(sortType, param1, param2)
{
if(sortType.equals("By lane"))
...
else if(sortType.equals("Between given dates")
...
}
Or is it more appropriate to code different methods for each type and call the correct one in the listener?
public Vector<Scores> grabMaxScoresBetweenDates(startDate, endDate)
{
...
}
public Vector<Scores> grabMaxScoresByLane(minLane, maxLane)
{
...
}
I'm not necessarily asking for this particular problem, it's just a question I find asking myself often when I'm coding multiple methods that are alike where the principle is the same, but the parameters are different.
I can see there are good reasons to use each of them, but I want to know if there is a "more correct" or standard way of coding this.
In my personal opinion, I would prefer your second option over the first. This is because you have the opportunity to be precise about things like the types of the parameters. For example, minLane and maxLane may just be integers, but startDate and endDate could very well be Date objects. It's often nicer if you can actually specify what you expect, as it reduces the need for such things as casting and range checks, etc. Also, I would find it more readable, as the function names just say what you are trying to do.
However, I may have an alternative idea, which is kind of a variation on your first example (I actually got this inspiration from Java's Comparator, in case you're familiar with that). Rather than pass a string as the first argument, pass some sort of Selector object. Selector would be the name of a class or a interface, which would look something like so (in Java):
interface Selector {
public void select(Score next);
public Score getBest( );
}
If the select method "likes" the value of next which is given to it, it can store the value for later. If it doesn't like it, it can simply discard it, and keep whatever value it already has. After all the data is processed, the best value will be left over, and can be requested by calling getBest. Of course, you can alter the interface to suit your particular needs (e.g. it seems like you might be expecting more than one value to be retrieved. Also, generics might help a lot as well).
The reason I like this idea is that now your function is very general purpose. In order to add new functionality, you don't need to add functions, and you don't need to modify any functions you already have. Instead, the user of your code can simply define their own implementation of Selector as they see fit. This allows your code to be far more compositional, which makes it easier to use. The only inconvenience is the need to define implementations of Selector, though, you could also provide several default ones.
The approach you have used would also work. But if you want to add some new functionality like "get lowest scores on Friday evening", you will need to add one more function, which kinda not so good thing to do.
As you have already have the data in a database you can generate database queries which would fetch the required results and display. So you need not modify your code every time.