Iam doing an ipad app using splitview controller.Iam getting images from webservice by using custom tableview in rootview.But one problem is when loading the images suddenly struck the simulator. so, What i have to do?
My guess is that you aren't fetching the images asynchronously, although it is a bit of a wild guess as the question could do with re-phrasing.
IF that is the issue ...
If you are using the SYNCHRONOUS method NSURLConnection sendSynchronousRequest:returningResponse:error: you need to wrap it in a NSOperation so it doesn't block the main UI thread.
More usually you would use the asynchronous methods of NSURLConnection.
Better still, consider the third party library ASIHTTPRequest which can do all this for you and more.
Related
Lately I have been playing around with the bluetooth framework and grew a strong enough knowledge to start building an application. The only problem is that all the examples I found and all the practice I have made consist in putting the core bluetooth core code inside the same file as the UIView with which the user is interacting.
I would like my future application to have multiple views in which the BLE scan occurs on the background. I initially thought about creating an object with a name similar to bleDeviceFinder and pass this object through each view. However, after thinking about it I realised that if I want something to happen in the current view I need the function didDiscoverPeripheral to have direct access to the UIView objects which it is supposed to affect.
I know it is probably a stupid question, what would be the best way to do so? I was thinking maybe to set and alert and subscribe every view to that alert; is this a good solution?
A quasi singleton BTLEManager that you pass around in the app. It sends NSNotifications for events like discovery, and your ViewControllers observe these notifications. The truth (i.e. list of discovered devices) stays in BTLEManager. Once a viewController has received such a notification it asks the BTLEManager for the list of current devices and then the viewController changes your views accordingly. The Views should never talk to the BTLEManager directly.
That's how I would do it.
I'm testing out in app purchases for my mac app, and I've noticed that the selectors productsRequest:didReceiveResponse: and paymentQueue:updatedTransactions: are getting called on a background thread (not the main/ui thread) when I request products or try to make a purchase.
I haven't seen any documentation warning about this, since that would mean updating UI from within these methods should not be done.
Has anyone else run into this? Should I just be calling performSelectorOnMainThread: within these methods to update the UI?
Ran into the same issue as it appears to behave just like an asynch call using NSURLConnection. I solved my particular issue by using the NSObject method call "performSelectorOnMainThread:withObject:waitUnitlDone:" Probably setting up NSNotification to be caught on the main thread of ViewController or WindowController would work as well.
I'm fairly new to Objective-C and cocoa programming, so I don't really understand the concept of App Delegates.
When we create a cocoa application, do we store our code (Methods, actions, outlets) in the App Delegate files or do we create a new file that will act as a controller and code from there. Right now, I put all of my code in those two files, but from what I read, your goal is to try to make your App Delegate files as slim as possible.
My question is: What's the usage of the app delegate files?
Talking about applicationDidFinishLaunching::
It's just your application entry point. Normally you only create the window and your first ViewController, or your Tabbar - your main starting interface class - here.
All the other delegate methods of the NSApplicationDelegate have other functions of course. Most of them are the point, where you react on the state of the app. Opened / Closed / Backgrounded / Reopened etc.
But you should probably have a look at the programming tutorials in the iPhone documentation. There is a lot of information on how to structure your objc projects. E.g. look here: Start Developing iOS Apps Today
Or if your looking for OSX Apps, look here:
1) Your First Mac App
2) Mac App Programming Guide
There is also a bunch of Sample code.
The App Delegate is a handler location to handle events that occur on the application. Things like open and close. It also hangs around the whole time the application is executing and you can grab the singleton instance at any point by doing [[NSApplication sharedApplication] delegate].
This comes in handy for handing objects between controllers and serving as a router for events. You can also store some data on the delegate if you need to modify/have access to it in different parts of the code.
This all works well for simple applications, but as things become more complex, you need to have some division of responsibilities. The AppDelegate should really only be responsible for actions that occur on the application itself, not on another view or a controller. Putting all/most of your code in the AppDeligate is certainly bad practice and will lead to horrible code as things get more complex and need to be maintained.
Is there disadvantages to using WebKit WebViews compared to using NSViews?
I'm using a webview to create a UI for an application. The application itself does not have much interactivity. I have seen it mentioned, on this website & others, that using a WebView can be convient means of prototyping.
However, with our team this seems like an ideal way to produce the production ready UIs, especially with WebKit. Are we missing something?
Thanks,
Ross
Okay, so you seem to be asking if using an HTML interface (presented via a WebView) for your application has any disadvantages.
The answer to this is "no", at least "not necessarily". This is analogous to building an iPhone specific web application, and there are some excellent examples of those. The caveat would be that a lot of those sites end up recreating the look and feel of a native iPhone app, for consistency and to make the users feel "at home".
Given that you're developing a native app anyway, it seems a shame to throw away, or recreate, the responsiveness and appearance of the native chrome. Of course, for certain types of applications (games are an obvious example) a user has no expectations about the application's UI, so you're free to knock yourself out.
The other factor to consider is the amount of interactivity (although I notice that you say there isn't much in your case). The native controls will make coding a lot simpler than having to capture all user input through the "filter" of a WebView, even though using one might make the initial layout of the screens easier.
I hope that's the sort of answer you were looking for (although it's mostly non technical).
As you might have known if you spend some time in the documentation, you'd have seem that WebView is a subclass of NSView.
The documentation says about WebView:
WebView is the core view class in the WebKit framework that manages interactions between the WebFrame and WebFrameView classes. To embed web content in your application, you just create a WebView object, attach it to a window, and send a loadRequest: message to its main frame.
And about NSView:
NSView is a class that defines the basic drawing, event-handling, and printing architecture of an application. You typically don’t interact with the NSView API directly; rather, your custom view classes inherit from NSView and override many of its methods, which are invoked automatically by the Application Kit. If you’re not creating a custom view class, there are few methods you need to use.
So here's the answer to your question:
Is there disadvantages to using WebKit WebViews compared to using NSViews?
Yes. You can't display any web content with NSView. That's what you need WebView for.
I suggest reading some more documentation though.
I'm writing a Cocoa application where I have an auto generated app delegate:(MyAppDelegate.h/MyAppDelegate.m)
So I am not sure of the best way to structure the class files for this Cocoa application. I understand MVC thoroughly (on the iPhone) but I'm having a block as to try organising the source properly in a Cocoa app.
I need to spawn two separate fullscreen OpenGL views. The problem is that I could simply create classes for "OpenGLView" then instantiate and call all this code into the app delegate, but it seems messy and it's aparently not the place to do it.
How would I best achieve the code structure?
Instantiate your application delegate in the MainMenu.xib file and hook it up. When I've done Cocoa fullscreen stuff, I've instantiated the views in the -applicationDidFinishLaunching method of the application delegate. It *is* messy, because for fullscreen views it doesn't really make sense to use interface builder. This is the same way that other folks do fullscreen apps in Cocoa.