I have a project with two view controllers. When I press a button, the other view is loaded. The first time I do this, the program pauses for a second as the second view controller loads. I have very little in the viewDidLoad method. After I navigate to the second view after the first time, the views are swapped in and out quickly. How can I remedy this/what am I missing?
Also, there is no slow down if I do not create the array in the viewDidLoad method.
Here's my viewDidLoad:
- (void)viewDidLoad
{
NSArray *array = [[NSArray alloc] initWithObjects:#"sound1", #"sound2", nil];
self.listData = array;
[super viewDidLoad];
}
And my button to load the second view:
- (IBAction)soundListButton:(id)sender {
NSLog(#"Pressed!");
BBRViewController * controller = [[BBRViewController alloc]
initWithNibName:#"BBRViewController" bundle:nil];
controller.modalTransitionStyle=UIModalTransitionStyleCoverVertical;
[self presentViewController:controller animated:YES completion:nil];
}
Related
I have 2 views, in the second one I initialize a NSMutableArray and I want to pass it back to the first View. In the second view I have a button connected with the following action:
-(IBAction)back:(id)sender {
[self dismissViewControllerAnimated:YES completion:nil]
}
With this action I go back from my second ViewController to the first ViewController, is there a way to pass the NSMutableArray from that action?
If you are not using prepareForSegue then you can user NSUserDefaults:
-(IBAction)back:(id)sender {
NSMutableArray *mutableArray = [[NSMutableArray alloc]init];
[[NSUserDefaults standardUserDefaults]setObject:mutableArray forKey:#"array"];
[self dismissViewControllerAnimated:YES completion:nil];
//I'm guessing you are going to load the viewController that's up next?
}
You can retrieve it in the viewDidLoad like so:
// to retrieve in maybe viewDidLoad?
NSArray * array = [[NSUserDefaults standardUserDefaults]arrayForKey:#"array"];
NSMutableArray *mutableArray = [array mutableCopy];
I've created a small test project to play with NSOutlineView before using it in one of my projects. I'm successful in displaying a list of items with children using a NSTreeController who's content is bound to an Array.
Now while I created this object it took me ages to realize that my array contents would only show up if i created them in my init method:
- (id)init
{
self = [super init];
if (self) {
results = [NSMutableArray new];
NSMutableArray *collection = [[NSMutableArray alloc] init];
// Insert code here to initialize your application
NSMutableDictionary *aDict = [[NSMutableDictionary alloc] init];
[aDict setValue:#"Activities" forKey:#"name"];
NSMutableArray *anArray = [NSMutableArray new];
for (int i; i<=3 ; i++) {
NSMutableDictionary *dict = [NSMutableDictionary new];
[dict setValue:[NSString stringWithFormat:#"Activity %d", i] forKeyPath:#"name"];
[anArray addObject:dict];
}
results = collection;
}
return self;
}
If I put the same code in applicationDidFinishLaunching it wouldn't show the items.
I'm facing the same issue now when trying to add items to the view. My understanding of using the NSTreeController is that it handles the content similar to what NSArrayController does for a NSTableView (OutlineView being a subclass and all). However, whenever I use a KV compliant method to add items to the array the items do not show up in my view.
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
NSMutableDictionary *cDict = [[NSMutableDictionary alloc] init];
[cDict setValue:#"Calls" forKey:#"name"];
[results addObject:cDict];
[outlineView reloadData];
}
I've also tried calling reloadData on the outlineview after adding an object, but that doesn't seem to be called. What am I missing?
Here's a link to my project: https://dl.dropboxusercontent.com/u/5057512/Outline.zip
After finding this answer:
Correct way to get rearrangeObjects sent to an NSTreeController after changes to nodes in the tree?
It turns out that NSTreeController reacts to performSelector:#selector(rearrangeObjects) withObject:afterDelay:
and calling this after adding the objects lets the new objects appear.
I have the following code to load a UIImagePickerController which works fine.
UIImagePickerController *mediaUI = [[UIImagePickerController alloc] init];
mediaUI.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
mediaUI.mediaTypes = [[NSArray alloc] initWithObjects: (NSString *) kUTTypeMovie, nil];
mediaUI.delegate = self;
[controller presentModalViewController: mediaUI animated: YES];
return YES;
I would like to load a modal view with some help information on how to use the UIImagePickerController:
UIStoryboard *storyboard = self.storyboard;
HelpViewController *svc = [storyboard instantiateViewControllerWithIdentifier:#"HelpViewController"];
[self presentViewController:svc animated:YES completion:nil];
How can I display the UIImagePickerController after the user dismisses the HelpViewController view?
Don't be tempted to move directly from HelpViewController to UIImagePickerController, you need to get there via your mainViewController.
Let's put your code into a method...
- (void) presentImagePicker {
UIImagePickerController *mediaUI = [[UIImagePickerController alloc] init];
mediaUI.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
mediaUI.mediaTypes = [[NSArray alloc] initWithObjects: (NSString *) kUTTypeMovie, nil];
mediaUI.delegate = self;
[controller presentModalViewController: mediaUI animated: YES];
return YES;
}
(Note that presentModalViewController:animated is depracated since ~iOS5, and you should really replace it with
[controller presentViewController:mediaUI animated:YES completion:nil];)
Let's call your viewControllers mainVC, helpVC and imageVC. There are two ways you can implement this.
method 1 - performSelector
The quick-and-slightly-dirty solution is to do this in your helpVC's dismiss button method:
- (IBAction)dismissHelpAndPresentImagePicker:(id)sender
{
UIViewController* mainVC = self.presentingViewController;
[mainVC dismissViewControllerAnimated:NO completion:
^{
if ([mainVC respondsToSelector:#selector(presentImagePicker)])
[mainVC performSelector:#selector(presentImagePicker)];
}];
}
It's slightly dirty because you need to ensure that presentImagePicker is implemented in mainVC - the compiler will give you no warnings if it is not. Also you are running a completion block after it's object has been dismissed, so there's no certainty it's going to work (in practice, it does, but still...)
Note that you have to assign the pointer self.presentingViewController's to a local variable (mainVC). That's because when helpVC is dismissed, it's presentingViewController property is reset to nil, so by the time you get to run the completion block you cannot use it. But the local variable mainVC is still valid.
method 2 - protocol/delegate
The clean way to do this is to use a protocol in helpVC to declare a delegate method, and make mainVC the delegate. This way the compiler will keep track of everything and warn you if it is not correctly implemented.
Here are the steps to do that:
In helpVC.h add this protocol above the #interface section:
#protocol helpVCDelegate
- (void) dismissHelpAndPresentImagePicker;
#end
In helpVC.h interface section declare a property for its delegate:
#property (nonatomic, weak) id <helpVCDelegate> delegate;
(the <helpVCDelegate> tells the compiler that the delegate is expected to conform to the protocol, so it will have to implement dismissHelpAndPresentImagePicker)
In helpVC.m your method can now look like this:
- (IBAction)dismissHelpAndPresentImagePicker:(id)sender
{
[self.delegate dismissHelpAndPresentImagePicker];
}
In MainVC, when you create HelpVC (=svc in your code), set MainVC as it's delegate:
HelpViewController *svc = [storyboard instantiateViewControllerWithIdentifier:#"HelpViewController"];
svc.delegate = self;
[self presentViewController:svc animated:YES completion:nil];
And be sure to implement the delegate method dismissHelpAndPresentImagePicker
- (void) dismissHelpAndPresentImagePicker
{
[self dismissViewControllerAnimated:NO completion:^{
[self presentImagePicker];
}];
}
Personally I would always use method 2. But I offered up a that solution earlier today to a similar question, and the questioner seemed to think protocol/delegate was overcomplicated. Maybe my answer just made it seem so, I have tried to simplify it here.
I have a problem, I have created a project window based application in xcode, then I create a UITabBarController that manages two views all programmatically, the second view is a tableView and I want to see in the top a UINavigationController, I have tried a lot but I don't know how to have a UINavigationController in the second view. this is the code:
ProjectAppDelegate.m
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
//Creo una tabBarController
UITabBarController *tabBarController = [[UITabBarController alloc] init];
//Create the two view controllers
UIViewController *vc1 = [[Visuale1ViewController alloc] init];
UIViewController *vc2 = [[Visuale2ViewController alloc] init];
//Make an array containing the two view controllers
NSArray *viewControllers = [NSArray arrayWithObjects:vc1, vc2, nil];
//The viewControllers array retains vc1 and vc2, we can release
//our ownership of them in this method
[vc1 release];
[vc2 release];
//Attach them to the tab bar controller
[tabBarController setViewControllers:viewControllers];
//Setto la tabBarController come rootViewController di window
[window setRootViewController:tabBarController];
//The window retain tabBarController, possiamo lasciare il nostro riferimento
[tabBarController release];
[self.window makeKeyAndVisible];
return YES;
}
Visuale1ViewController.h
#implementation Visuale1ViewController
- (id)init{
[super initWithNibName:#"Visuale1ViewController" bundle:nil];
//Get the tab bar item
UITabBarItem *tbi = [self tabBarItem];
//Give it a label
[tbi setTitle:#"Visuale 1"];
return self;
}
// The designated initializer. Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
- (id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)bundle {
return [self init];
}
Visuale2ViewController.h
#implementation AnswerViewController
- (id)init{
//Call the superclass's designated initializer
/*[super initWithNibName:nil
bundle:nil];*/
[super initWithStyle:UITableViewStyleGrouped];
answers = [[NSMutableArray alloc] init];
for (int i = 0; i<10 ; i++) {
[answers addObject:[Answer DefaultAnswer]];
}
//Get the tab bar item
UITabBarItem *tbi = [self tabBarItem];
//Give it a laber
[tbi setTitle:#"Visuale 2"];
return self;
}
- (id)initWithStyle:(UITableViewStyle)style{
return [self init];
}
//All below are all methods to work the table view, and all go well, the only problem it's the UINavigationController, to manage then the detail of the table...
Now I want to know how I can put a UINavigationController in the second view. I try do this, in ProjectAppDelegate.m:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
//Creo una tabBarController
UITabBarController *tabBarController = [[UITabBarController alloc] init];
//Create the two view controllers
UIViewController *vc1 = [[Visuale1ViewController alloc] init];
UIViewController *vc2 = [[Visuale2ViewController alloc] init];
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:vc2];
//Make an array containing the two view controllers
NSArray *viewControllers = [NSArray arrayWithObjects:vc1, navController, nil];
//The viewControllers array retains vc1 and vc2, we can release
//our ownership of them in this method
[vc1 release];
[vc2 release];
//Attach them to the tab bar controller
[tabBarController setViewControllers:viewControllers];
//Setto la tabBarController come rootViewController di window
[window setRootViewController:tabBarController];
}
In this way I can visualize the NavigationBar, but I lost the name of the SecondTabBar. Sorry for my english, how I can do this?
Yes in the second view you have to set title as
[self.navigationItem setTitle:#"Visuale2"];
For TabBar title-
UITabBar *tabBar = [self.tabBarController tabBar];
NSArray *tabBarItems = [tabBar items];
UITabBarItem *secondTabBarItem = [tabBarItems objectAtIndex:1];
[secondTabBarItem setTitle:#"Visuale2"];
I left the code as it was and I added in init Visale2ViewController this:
UIImage *i = [UIImage imageNamed:#"Hypno.png"];
[tbi setImage:i];
and now in can see the text Visuale2 in tabBar and the image...i don't know why...
You need to set the tabBarItem property for your UINavigationController. Something like this.
UITabBarItem *tabItem = [[UITabBarItem alloc] initWithTitle:#"Visuale 2" image:nil tag:1];
UIViewController *vc2 = [[Visuale2ViewController alloc] init];
navController = [[UINavigationController alloc] initWithRootViewController:vc2];
navController.tabBarItem = tabItem;
After looking at it,the scenario seems to be same like me.What I faced for the first time when doing Tab+Navigation.
I am sure that there is some problem with your Tab+Navigation based application. Although it shows the Tab as well as navigation are not able to navigate the basic flow.And it is very difficult to solve your problem with such less code.
Instead of this, I had an alternate solution for the same:
Once you have a tab bar in a XIB, the easiest way to approach this is to drag a UINavigationController object over from the Library window (looks like a left nav bar button on a gold background) into the Tree View for your tab bar (the text only view, not the GUI). Place it under the tab bar, then drag your existing view controller under the tab bar controller instead of under the tab bar.
When you go to view that tab you should then see a navigation bar on the top of it... if you are loading the navigation controller from another xib, you'll modify the nav bar in the tab bar xib.
else you can below you can follow the best url for the same:
http://books.google.co.in/books?id=2yYlm_2ktFYC&pg=PA179&lpg=PA179&dq=navigation+with+the+tab+based+application+iphoneSDK&source=bl&ots=nf2YYjX5Am&sig=COpHj9wOtsDChQBglpsljSTsElw&hl=en&ei=3ZoFTeGSOI_tsgbc_Iz6CQ&sa=X&oi=book_result&ct=result&resnum=6&ved=0CDAQ6AEwBQ#v=onepage&q&f=false
http://www.youtube.com/watch?v=LBnPfAtswgw
Hope this will surely solve your problem.
I want to implement this
1) when user start typing in a textfield a popOver flashes and shows the list of items in a table view in the popover as per the string entered in textfield.
2) Moreover this data should be refreshed with every new letter entered.
kind of predictive search.
Please help me with this and suggest possible ways to implement this.
UISearchDisplayController does most of the heavy lifting for you.
Place a UISearchBar (not a UITextField) in your view, and wire up a UISearchDisplayController to it.
// ProductViewController.h
#property IBOutlet UISearchBar *searchBar;
#property ProductSearchController *searchController;
// ProductViewController.m
- (void) viewDidLoad
{
[super viewDidLoad];
searchBar.placeholder = #"Search products";
searchBar.showsCancelButton = YES;
self.searchController = [[[ProductSearchController alloc]
initWithSearchBar:searchBar
contentsController:self] autorelease];
}
I usually subclass UISearchDisplayController and have it be it's own delegate, searchResultsDataSource and searchResultsDelegate. The latter two manage the result table in the normal manner.
// ProductSearchController.h
#interface ProductSearchController : UISearchDisplayController
<UISearchDisplayDelegate, UITableViewDelegate, UITableViewDataSource>
// ProductSearchController.m
- (id)initWithSearchBar:(UISearchBar *)searchBar
contentsController:(UIViewController *)viewController
{
self = [super initWithSearchBar:searchBar contentsController:viewController];
self.contents = [[NSMutableArray new] autorelease];
self.delegate = self;
self.searchResultsDataSource = self;
self.searchResultsDelegate = self;
return self;
}
Each keypress in the searchbar calls searchDisplayController:shouldReloadTableForSearchString:. A quick search can be implemented directly here.
- (BOOL) searchDisplayController:(UISearchDisplayController*)controller
shouldReloadTableForSearchString:(NSString*)searchString
{
// perform search and update self.contents (on main thread)
return YES;
}
If your search might take some time, do it in the background with NSOperationQueue. In my example, ProductSearchOperation will call showSearchResult: when and if it completes.
// ProductSearchController.h
#property INSOperationQueue *searchQueue;
// ProductSearchController.m
- (BOOL) searchDisplayController:(UISearchDisplayController*)controller
shouldReloadTableForSearchString:(NSString*)searchString
{
if (!searchQueue) {
self.searchQueue = [[NSOperationQueue new] autorelease];
searchQueue.maxConcurrentOperationCount = 1;
}
[searchQueue cancelAllOperations];
NSInvocationOperation *op = [[[ProductSearchOperation alloc]
initWithController:self
searchTerm:searchString] autorelease];
[searchQueue addOperation:op];
return NO;
}
- (void) showSearchResult:(NSMutableArray*)result
{
self.contents = result;
[self.searchResultsTableView
performSelectorOnMainThread:#selector(reloadData)
withObject:nil waitUntilDone:NO];
}
It sounds like you have a pretty good idea of an implementation already. My suggestion would be to present a UITableView in a popover with the search bar at the top, then simply drive the table view's data source using the search term and call reloadData on the table view every time the user types into the box.