I've got a NSSearchField, whose action method does all the searching stuff, by analyzing the sender argument (string).
Now the searching stuff (feeding a large array) is kind of CPU intensive, which lets my search field freeze for some seconds.
In other cases i'd detach another NSThread to prevent my GUI from freezing. But in this case that is not possible, because I would detach another ("search") thread everytime the user enters another letter in the search field.
Is there another way of keeping my NSSearchField from freezing?
BTW: My guess is NO, because even the Developoer Documentation's seach field freezes all the time :)
I use GCD. I use an async queue, and the job periodically checks if the current search pattern has changed from what it was called with, and bails if it has. This seems to work quite well.
Can't you use setSendsWholeSearchString: to stop it searching as letters are typed?
Set an NSTimer every time the user types something.
If there's a timer already set, invalidate or reschedule it.
That way, you only get called upon to refresh the search every N seconds, however fast the user types.
Related
I have a timer that talks to java objects through LS2J. It has only to call some getters of the java objects and to update the GUI with new values. This causes the GUI in iNotes Client to show the "Busy" cursor very shortly when the timer ticks. I is really annoying because it occurs even when another window is open and even in the designer.
I actually have to expect that the functionality in the timer event will get more complicated in the future, so I don't want to solve the problem by making my handler lighter.
Is there a way to tell iNotes client not to show this cursor or even an alternative way to make this regular check without timers?
The NotesTimer class in Notes client (not iNotes) does take over the foreground when it triggers, so there will be a bit of a delay if you do something that takes time to execute. It's possible to set up the Notes client to execute background scheduled agents in local database replicas, so that might be an option. You can to the heavy lifting in background and deposit the results somewhere -- say, in a profile document -- that can be accessed quickly by the UI code.
Alternately, you could try a XPages in the client application. I believe it can do partial refreshes while other stuff is going on.
For the record, I simplified the functionality of the Java call by preparing the data so that the timer only has to read the results. I also made the timer run every 3 seconds instead of 1.
Now I don't see any flicker!
Subject sounds mutually exclusive, and this is probably a terrible hack, but I'll ask anyway.
I have an single-threaded VB.NET application which is setting status bar label to "Loading..." and then synchronously loading data from database which in some cases can take up to 1-2 minutes. Is there any way to show user an AJAX-type animation while data is being loaded? Of course, the correct way is to use separate thread/BackgroundWorker for data access and manage UI separately, but I can't currently change data access model and have been asked for a "temporary fix".
Here are some of my ideas at the moment:
Update label (and only that single label) from another thread, force it's redraw, somehow circumventing windows forms message pump (probably not possible)
Keep another process in background and send "show" message to it from main application. It shows up in front of application, shows animation until "hide" message from main application is received. (problems with user switching away from main application but "animation" form still visible)
I'll probably get down voted for suggesting it (and quite frankly I don't blame people) but this sounds like a job for DoEvents.
I wouldn't normally suggest it, but you are looking for a hack.
Obviously I need to update accurately. However not more often than once every 1 minute I think.
See example use of CLLocationManager and a handler class to do what you are asking. Rather than a timer, it sets up a handler to respond to location events received, checks the accuracy and time passed since previous event, then sends out a notification based on your requirements.
The frequency of your response action is configurable as often as you require.
It works in the background, with battery saving configuration options.
See the code here TTLocationHandler
You may also benefit from some of the discussion in this question thread Invoke get current coordinates every few seconds without NSTimer
Once you have position update you can:
Turn off updating
Start a timer for about 1 minute
Timer turns on updating
Done.
I am writing an app with a synchronization feature. And whenever the app finds a conflict between two objects, i want to display something for the user to choose the correct value.
My first idea was to use UIAlertView but after i create the alert object and show it, the program continues the execution, and may eventually find other conflicts before the user had time to resolve the first one.
My question here is: is there a better approach on this ? Or is there a way to stop the app and wait for the alert's choice ?
Any links, further reading or suggestions are much appreciated. Thanks for your help and time
It depends on how you're setting it up. What you should do is terminate execution of the synchronization when a conflict is found, then start it again from the method called by the alertview.
In an iOS app, I'm writing a class that will be messaged, go do a background request (via performSelectorInBackground:withObject:), and then return the result through a delegate method (that will then be displayed on a map). Everything seems to work right when one request is happening at a time, but I'm trying to figure out how to handle multiple overlapping requests. For example, if a user enters something in a search box that starts a background thread, and then enters something else before the initial background thread completes, how should this be handled?
There are a few options (don't let the second request start while the first is in progress, stop the first as soon as the second is requested, let both run simultaneously and return independent results, etc.), but is there a common/recommended way to deal with this?
I don't think there's universal answer to this. My suggestion is to separate tasks (in form of NSOperations and/or blocks) by their function and relationships between them.
Example: you don't want add image resizing operation to the same queue with fetching some unrelated feed from web, especially if no relationship between them exists. Or maybe you do because both require great amount of memory and because of that can't run in parallel.
But you'd probably want to add web image search operations to same queue while canceling operations of the same type added to this queue before. Each of those image search operations might init image resize operation and place it into some other queue. Now you have an relationship and have to cancel resizing in addition to image search operation. What if image search operation takes longer than associated resize operation? How do you keep a reference to it or know when it's done?
Yeah, it gets complicated easily and sorry if I didn't give you any concrete answers because of uniqueness of each situation but making it run like a Swiss clock in the end is very satisfying :)