I have this app I'm working on, which on a second view asks (textfield) the name for a button to be created on first view. After specifying the name and pressing OK button, the first view pops up (as demanded) but there's no new button, although created indeed. Can I use the following code in a second view method, to "refresh" the first view before presenting itself. What's wrong with this code? Any other approach? Thank you.
-(void)initWithView:(View1Controller *)aSuperview
{
theSuperview = aSuperview;
}
- (IBAction)itemNameButton
{
...
CGRect rectang;
rectang = CGRectMake(0, 0, 320, 460);// just in case
[theSuperview.view setNeedsDisplayInRect:rectang];
...
}
You should adhere to the Model-View-Controller paradigm. Views creating buttons in other views is a bad thing in general. Instead, there should be a controller (probably a UIViewController subclass) that handles receiving the input from view 2 when the user clicks OK (via an action and a outlet to the textfield) and then tells view 1 (a custom view subclass) what to do using a defined set of methods (something like -addButtonWithTitle:(NSString *)buttonTitle). The process of adding the button itself should be fairly straight forward, something like:
- (void)addButtonWithTitle:(NSString *)buttonTitle {
UIButton *newButton = [UIButton buttonWithType:UIButtonTypeRoundedRect]; // whatever type you want
newButton.titleLabel.text = buttonTitle;
[self addSubview:newButton];
newButton.center = self.center; // set your position here
}
A view controller's responsibility is to control a given view. Its responsibility is not to communicate with other controllers in order to ask them to change their views, so doing this sort of thing is usually an indication of bad design.
You should have a method in your superview's controller which adds the button to its view, and then use delegation in order to be notified by your subview when it's necessary to add the button.
For a nice and simple introduction to delegates and protocols, I found this blog post to be one of the best out there.
Related
I have a view controller that I need to refresh it self so, I basically reload it with the following code.
-(void)check{
GameController*myNewVC = [[GameController alloc] init];
[self presentModalViewController:myNewVC animated:NO];
}
I can call the method above in gamecontroller and it works fine, but in a button sub class I use the method below and it doesn't work because nothing happens.
.h
#interface CellButton : UIButton {
}
.m
GameController*myNewVC = [[GameController alloc] init];
[myNewVC check];
What can I do to get this working?
I have a view controller that I need to refresh it self so, I basically reload it
Don't do that. Your view controller isn't refreshing itself, it's replacing itself, and it's hard to think of a reason that it should need to do that.
Put the code the loads the data in a separate method, and call that method on the existing view controller instead of creating a whole new view controller. For example, many view controllers that manage a UITableView will call the table's -reloadData method to tell the table to discard any cells that are currently visible and request new ones. No matter what kind of view(s) your view controller manages, you can do something similar.
I can call the method above in gamecontroller and it works fine, but
in a button sub class I use the method below and it doesn't work
because nothing happens.
That's most likely because you say you're using the code in a UIButton subclass, and the code says:
[self presentModalViewController:myNewVC animated:NO];
So, the button is telling itself to present the view controller. However, UIButton doesn't have a presentModalViewController:animated: method. I'm surprised that "nothing happens" -- I'd expect an exception due to the unimplemented method. It should work fine if you replace self above with a pointer to your view controller. Or, much better, put the code in an IBAction method in the view controller, set the buttons action to that method, and its target to the view controller.
(from your comment...)
There is a function in the button class that will dictate weather or
not the view controller will refresh it self.
That sounds like a poor plan -- in a well designed MVC application, logic that controls whether the view controller will refresh belongs in the view controller. Have the view controller enable/disable or show/hide the button based on whatever conditions control the refreshing behavior.
I'm very new to xCode and objective-C so I wanted to make a simple textRPG.
I'm currently making a character creation process consisting of 4 xib-files. The only way I got switching views to work was to look at the utility-template. Problem is, now I have the first screen being the delegate for the second screen, being the delegate for the third screen etc. So by the end of the character creation process I can't dismiss the views because that just "steps back" through the views.
When I've searched around for a solution I've found a addSubview-method but it seems like that makes a new view, like, empty to arrange programmatically.
All I need is a simple way to switch from one loaded xib to another xib. Have I misunderstood addSubview or do I need something completely different?
(If it helps: I've worked with VB for several years, in case you notice that I missed some kind of concept concerning views and such)
Thanks in advance! :)
Use this code. It is really simple and works well.
View *view = [[View alloc] initWithNibName:#"xibNameGoesHere" bundle:nil];
view.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentViewController:view animated:YES completion:nil];
This will switch to another xib file and the two views won't own one another. I am using it in my own game right now.
#Joakim Ok, this is the way I do it. I have a class called RootViewController : UIViewContoller, whose view I add directly to the window. Then I make a subclass of UIView i.e. MyView. All of my views then subclass MyView. I also make an enum for all my views. In RootViewController you should have a switchView:(int)view method that looks something like this:
-(void) switchView:(myView) view
{
[_currentView removeFromSuperview];
switch(view)
{
case titleView:
_currentView = [[TitleView alloc] initWithRoot:self];
break;
case homeView:
_currentView = [[HomeView alloc] initWithRoot:self];
break;
default: break;
}
[self.view addSubview:_currentView];
[_currentView release];
}
in #interface RootViewContoller define MyView *_currentView;
TitleView and HomeView both subclass MyView and have a common method -(id)initWithRoot:(RootViewController*) rvc.
To switch between views use [_rvc switchView:homeView];
Hope this helps :)
It is called UINavigationController. Idea is
1) You push corresponding 'next' controller into navigation controller each time user submits current screen. Bonus - you'll get 'back' button for free on each step of character creation.
2) After character is created you pop all character creation controllers from stack.
Please read View Controller Programming Guide for iOS before trying to 'switch views' and such. You'll save tons of time and nerves.
another idea is not to use interface builder at all. i have been working with iphone apps for two years now and found that interface builder really prolongs the time to actually make something. make your own root controller and think about the logic you need to navigate through the views.
I have a button called Reset in my iPhone application. It is for resetting purposes. I called viewDidLoad() method for this. Is it right?
How to reset a page in iPhone?
how to write code for this? Any help would be appreciated.
You should not call -viewDidLoad in your own code. It gets called on view controllers (VCs) when their view has just finished loading.
To return a VC to its original state depends largely on the specifics of the situation, but you could probably either set its properties and whatnot back to their original values or you could alloc and init a new VC, remove the old VC's view from the view hierarchy and add the new VC's view.
Alternately, you could just implement a -resetToOriginalState method on your VC.
resetToOriginalState is not a inbuilt method, you have to write this method on your own and instead of calling viewDidLoad call this method 'resetToOriginalState:' when the respective button is clicked. If you are creating button programmatically you can set the target/action of that button like this:
resetBtn is the instance of the UIButton:
UIButton *resetBtn = [[UIButton alloc] initWithFrame:CGRectMake(x,y,w,h)];
[resetBtn addTarget:self action:#selector(resetToOriginalState:) forControlEvents:UIControlEventTouchUpInside];
- (void)resetToOriginalState:(id)sender {
//Do your stuff here
}
If your using Interface Builder connect the action method (resetToOriginalState) to the button.
Basically i have a WebView on SecondViewController and I wish for the WebView to be visible on every view like a tab bar and fully controllable on each view.
Please note the WebView will be on a webpage with a online slideshow so I cannot simply reload on each view
Also in the SecondViewController I have
- (void)webViewDidFinishLoad:(UIWebView *)YouTubePlayer {
I would suggest adding the webView on you window after the you add the tabbarcontroller.view just like:
[window addSubview:tabbarController.view];
[window addSubview:webview];
[window makeKeyAndVisible];
and initially make don't make it visible. You should handle all the webview related methods in the app delegate. Now whenever you don't need it you can hide it by calling the methods your wrote in app delegate from your view controllers.
Hope this helps.
I'd just set up a singleton UIWebView and add it to each view-controller-view when that view controller is about to become visible. Here's one way to do it:
//.h
#interface SharedWebView : UIWebView
{
}
+ (SharedWebView*) shared;
#end
//.m
SharedWebView* g_sharedWebView;
#implementation SharedWebView
+ (SharedWebView*) shared
{
if ( g_sharedWebView == nil )
{
g_sharedWebView = [[SharedWebView alloc] init];
// ... any other intialization you want to do
}
return g_sharedWebView;
}
#end
// in your view controller(s)
#property (readonly) UIWebView* webView
- (UIWebView*) webView
{
return [SharedWebView shared];
}
- (void) viewWillAppear: (BOOL) animated
{
[super viewWillAppear: animated];
[self.view addSubview: self.webView ];
self.webView.frame = CGRectMake(10, 10, 300, 300);
// want to re-set the delegate?
// self.webView.delegate = self;
}
The simplest approach is to just make all of your view controllers aware of this extra view (make the view available through a singleton PinnedViewController or whatever). During each view controller's -viewWillAppear, just do this:
[self addSubview:[[PinnedViewController sharedController] view]];
This will move the view to whoever is currently active (making a view your subview automatically removes you from your old hierarchy).
If that is cumbersome or otherwise unworkable, there are two other options. First, you can subclass UITabViewController (I assume that's what you're using here from your question), and inject your extra view (resizing the content view to make room). This is undocumented and unsupported, so take heed. But it's not incredibly difficult if you don't do too many other fancy tricks.
The other tricky solution is to create a second UIWindow that you float over the main UIWindow (or resize the main UIWindow to make room for it). This is only semi-documented and is also not really supported. But this approach can work if you're trying to put the extra view below the tabbar for instance.
But if your system is simple enough, I recommend just letting your view controllers all manage the pinned view manually. You'll save a lot of code spelunking that way, and you won't have to rely on any undocumented internal view hierarchies.
Sounds like you try to put views on top of this view but not modal. There was this blog entry I once saw that described how you would do something like this. I think it should apply also for your case: semi-modal-transparent-dialogs-on-the-iphone
In iOS UIViewControllers are expected to manage an entire "screen" worth of content so it's not normal to try to share a single view across many view controllers. Trying to have UIViewControllers whose views only manage part of their window is problematic and will result in unexpected behavior as UIKit will not send messages like -viewWillAppear to all view controllers with visible views. Instead you would normally create a single UIViewController whose view includes that web view and whatever other views compose your tab like interface.
Alternately you could have a hierarchy of many view controllers and add a single web view as a subview of all of them. You would then pull your web view delegate behavior out into some non-UIViewController controller class to manage the behavior of the web view.
You can have all your views take up a portion of the screen and have your UIWebView take up the rest. The logic for switching between the other views should remain the same.
For example, in your viewDidLoad method for your UIViewControllers, you could have something like:
self.view.frame = CGRectMake(0, 100, 320, 380);
And in your (say) AppDelegate, you would have your normal call to show the main UIViewController (in your case, it sounds like a UITabBarController?) and also have a call to add the UIWebView. Say, something like:
myWebView.view.frame = CGRectMake(0, 0, 320, 100);
The view controllers and UIWebView would be independent of each other.
You see this pattern, I believe, with apps that have iAds. I've done something just like this with one of my free apps.
Hope this helps!
I got the same effect by simply adding it to the navigationController itself(if you don't have one then just add it).
works great for me in one of my apps.
Could you not use two webviews on your application and simply change the uppermost webview with your more dynamic content?
This is a very simple iPhone / Cocoa question. I have a button that transitions between two views. I set most of this up using interface builder. When I click the button and the second view is displayed, how do I programmatically change the text of the button (to say 'back', for instance)?
In your class declaration, declare a button object, and make sure it is specified as an IBOutlet:
IBOutlet UIButton* myButton;
Once you save this change, if you go back to Interface Builder, you should see this outlet when you right click on your File's Owner (assuming you have specified the File's Owner properly). Associate this outlet with the onscreen UIButton by right-click dragging.
Now the on screen object is associated with your in-code name.
Whereever you want to change the text on the UIButton, just say:
[myButton setTitle:#"Back - or whatever else you want it to say"
forState: UIControlStateNormal ];
// you can set different title text for each state
// of the button (selected, active, or normal)
Alternately, you can assign a unique tag to the control and use -[UIView viewWithTag:] to get a UIView pointer to the control. In most cases, outlets are the preferred mechanism, but tags are useful in things like table cells.
You'll need to set up an outlet for IB:
#interface MyViewController : UIViewController {
IBOutlet UIButton *myButton;
}
Save, bring up IB, set the file's owner to MyViewController, then create referencing outlets from both your UIView and UIButton to the appropriate points in the file's owner in the Connections Inspector.
Then in the implementation, you could do:
[myButton setTitle:#"Back" forState:UIControlStateNormal];
If you get lost with the connections, I'd recommend having a look at the lecture notes and video lectures at http://www.stanford.edu/class/cs193p/cgi-bin/index.php , which go into some detail about iPhone basics.
Hope that helps.
Most of the posts so far have focused on creating the button, and are very correct. The following answers the rest of the question:
When I click the button and the second view is displayed, how do I programmatically change the text of the button (to say 'back', for instance)?
The easiest way, if I understand your circumstance correctly, is to use the plug-n-play UINavigationBarController. First you want to push your second view controller onto the view stack:
// In firstViewController.m
self.navigationController = [[UIViewController alloc]initWithNibName:#"secondView" bundle:nil];
[self pushViewController:secondViewController animated:TRUE];
When your second view controller is shown, you should automatically get a back button on the left side of the nav-bar. If there is a need to change the text of that back button, you can simply refer to it like so:
// In secondViewController.m
-(void)ViewWillAppear
{
[self.navigationItem.backBarButtonItem setText:#"GoBack"];
}
There are also the left and rightBarButtonItem(s) which are handy for more complex navigation. Here is a less plug-n-play scenario:
// In secondViewController.h
-(IBAction)goBack; (this should appear as an action in your associated nib file)
// In secondViewController.m
-(void)viewDidLoad
{
self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:#"GoBack" style:UIBarButtonItemStylePlain target:self action:#selector(goBack)];
}
-(IBAction)goBack
{
// logic to be done before going back
[self popViewControllerAnimated:secondViewController animated:TRUE];
}
You need to define and connect an "outlet". Take a look at the documentation, making note of the section on "Connections and Bindings".