I wish to add a UIToolbar programmatically to a view when a user clicks on a button (in my case when they zoom in on a photo).
It seems to work fine when I create the toolbar in the click method and add to the subview but if I create the toolbar in the viewDidLoad method, assign it to an instance variable,and add that instance variable later to the subview on click, nothing appears. The debugger shows that the instance variable is a UIToolbar and is not null. I didn't want to create and destroy the same toolbar on every click so I thought it was better just to keep it as an instance variable that I add and remove from the view as needed. Is this the right approach?
Why is it visible in the one case and not the other.
Setup
#synthesize toolBar;
- (UIToolbar*)createToolbar
{
UIToolbar* toolbar = [[UIToolbar alloc] init];
toolbar.frame = CGRectMake(0, self.view.frame.size.height - 44, self.view.frame.size.width, 44);
UIBarButtonItem *shareButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAction target:self action:#selector(sharePhoto:)];
NSArray *buttonItems = [NSArray arrayWithObjects:shareButton,nil];
[toolbar setItems:buttonItems];
return toolbar;
}
This works
- (void) clickMyButton {
toolBar = [self createToolbar];
[self.view addSubview:toolBar];
}
This doesn't show anything
- (void)viewDidLoad
{
[super viewDidLoad];
toolBar = [self createToolbar];
}
- (void) clickMyButton {
[self.view addSubview:toolBar];
}
Why doesn't it work in the latter case
The problem is that when viewDidLoad gets called, it is not guaranteed that the frames for your view and subviews are set. Try calling [self createToolbar] from viewWillAppear or viewDidAppear instead.
Related
adding a button to navigation bar on first nib viewController and wanted to view this button to only on main screen not on any other screen
i have worked out on it
i made the button and added to subview of navigation bar
on every button action i have put this
- (IBAction)forth:(id)sender {
forthView *forthview = [[forthView alloc]init];
[self.navigationController pushViewController:forthview animated:YES];
btn.hidden = YES;
}
after this button hides but didnot show up when i got back to main screen
my code for viewdidload is here
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
self.title = #"My First View";
self.navigationController.navigationBar.barStyle = UIBarStyleBlackTranslucent;
btn = [[UIButton alloc] init];
btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
btn.frame = CGRectMake(10, 10, 65, 30);
[btn setTitle:#"Show" forState:UIControlStateNormal];
[self.navigationController.navigationBar addSubview:btn];
btn.hidden = false;
}
Once you hide the button so you need to unhide it again. here is the simple code to unhide the button:
btn.hidden = No
viewDidLoadis only called the first time your view is loaded. Add an NSLog()statement if you want to test when it gets called. Every time your view appers on screen viewWillAppearis called.
So you need to show the button in viewWillAppear
It seems likely that what you really want to be doing is adding a UIBarButtonItem to your main view controller's navigationItem.leftBarButtonItem property. That way the button will have the correct appearance and show and hide as the view controller is displayed.
self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:#"Show"
style:UIBarButtonItemStyleBordered
target:self
action:#selector(onShowButtonPressed:)];
I’m adding a UISegmentedControl right under the NavigationBar in a UITableViewController. This is the code.
- (void)viewDidLoad
{
[super viewDidLoad];
self.navigationBar = self.navigationController.navigationBar;
UIView *segmentView=[[UIView alloc] initWithFrame:CGRectMake(0, self.navigationBar.frame.size.height, self.navigationBar.frame.size.width, 50)];
[segmentView setBackgroundColor:[UIColor whiteColor]];
segmentView.alpha = 0.95;
self.tabSegmentedControl = [[UISegmentedControl alloc] initWithItems:[NSArray arrayWithObjects:#"Favourites", #"All", nil]];
self.tabSegmentedControl.frame = CGRectMake(20, 10, self.navigationBar.frame.size.width - 40, 30);
[self.tabSegmentedControl addTarget:self action:#selector(tabChanged:) forControlEvents:UIControlEventValueChanged];
[segmentView addSubview:self.tabSegmentedControl];
[self.navigationBar addSubview:segmentView];
[self.tabSegmentedControl setSelectedSegmentIndex:1];
}
The view and the SegmentedControl appear on the screen well, but they are not clickable. The selector doesn’t get executed when tapped on the SegmentControl; it doesn’t even switch tabs! In fact, the stuff that is underneath the segmentView (items in the TableView) get clicked when you tap on it. I have tried but failed to understand why this is happening! Any suggestions would be helpful!
You are adding a view below the bounds of its super view. You may see the view however you cannot click it because it is out of bounds. If you set the property of the navigation bar clipsToBounds to YES you should see that the view disappears. What you need to do is add the segment controller to the table view. Here is an example:
- (void)viewDidLoad
{
[super viewDidLoad];
...
[self.view addSubview: self.segmentView]; // need to keep a pointer to segmentView
self.tableView.contentInset = UIEdgeInset(self.segmentView.frame.size.height, 0,0,0);
}
-(void) scrollViewDidScroll:(UIScrollView*) scrollView{
CGRect rect = self.segmentView.frame;
rect.origin = self.tableView.contentOffset;
self.segmentView.frame = rect;
}
I write the codes below in my UIViewController that uses UINavigationController.
- (void)viewDidLoad {
[super viewDidLoad];
self.navigationItem.hidesBackButton = YES;
self.navigationController.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>) self;
}
I build and run my app,
self.navigationItem.hidesBackButton = YES;
above that works correctly, but
self.navigationController.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>) self;
that one DO NOT works.
So, I re-write the code below.
- (void)viewDidLoad {
UIBarButtonItem *backBarButton = [[UIBarButtonItem alloc] initWithCustomView:[[UIView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 44.0f, 44.0f)]];
backBarButton.tintColor = [UIColor clearColor];
self.navigationController.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>)self;
self.navigationItem.leftBarButtonItem = backBarButton;
}
It works correctly.
However, I want to use the first example.
The first one clearly express what I want to do.
Does someone have any idea?
In viewDidLoad, the view controller is not yet contained in a navigation controller, so the navigationController property is nil, which is why that line has no effect.
That said, assigning the delegate of UINavigationController's interactivePopGestureRecognizer is not good practice (I'm pretty sure it expects to be assigned to the navigation controller). Try disabling the gesture recognizer in viewWillAppear: instead:
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
self.navigationController.interactivePopGestureRecognizer.enabled = NO;
}
I have a rootViewController, in it's viewDidLoad method， I initialized another two ViewController2* object and their views as subview of rootViewController.view, then I set first ViewController2* controller.view.hidden = YES.
Then, on v1 has a button handler, when touch it, it present a UINavigationController, after that touch 'dismiss' button call dismissViewControllerAnimated on v1.
The question is: when dismiss complete, the two of ViewController2* fire viewWillAppear. How to make it only fire the viewWillAppear on the visible one, but not on the hidden one?
the rootViewController's implementation:
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.v1 = [[ViewController2 alloc] init];
self.v1.title = #"v1";
[self.view addSubview:self.v1.view];
self.v1.view.hidden = YES;
self.v2 = [[ViewController2 alloc] init];
self.v2.title = #"v2";
[self.view addSubview:self.v2.view];
UIButton * btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[btn setTitle:#"POP" forState:UIControlStateNormal];
[btn sizeToFit];
[btn addTarget:self action:#selector(touchHandler:) forControlEvents:UIControlEventTouchDown];
[self.view addSubview:btn];
}
- (void)touchHandler:(id)sender {
UINavigationController * nc= [[UINavigationController alloc] initWithRootViewController:[[UIViewController alloc] initWithNibName:nil bundle:nil]];
((UIViewController *)[nc.viewControllers objectAtIndex:0]).navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:#"dismiss" style:UIBarButtonItemStyleBordered target:self action:#selector(dismissHandler:)];
[self presentViewController:nc animated:YES completion:nil];
}
- (void) dismissHandler:(id)sender
{
[self dismissViewControllerAnimated:YES completion:nil];
}
#end
ViewController2:
#implementation ViewController2
- (void)viewWillAppear:(BOOL)animated
{
NSLog(#"%#",self.title);
}
#end
viewWillAppear will fire on your UIViewController's, even if the view controllers view is set hidden=YES.
You can surely test if (self.view.hidden == YES) in your viewWillAppear delegate method if you want to prevent some expensive operation from occurring, but beware that if you later make that view un-hidden, that viewWillAppear won't fire then.
Simple, the reason why those methods are called is because the viewController's view is part of the main window's view hierarchy. This means that it has a superview that has a superview that has a superview and so on until that superview is the main window.
Instead of hiding and unhiding the viewController views, you should instead add and remove them from their superview. Also, to make sure that viewWillAppear and viewDidAppear are called correctly at the correct times, take a look at ViewController Containment:
http://www.cocoanetics.com/2012/04/containing-viewcontrollers/
I'm trying to customize my NavigationBar with the help of a toolbar.
I've implemented it programmatically as follows:
UIToolbar* tools = [[UIToolbar alloc] initWithFrame: CGRectMake(0, 0, 100, 44.01)];
and then I added it to my NavigationBar. The problem is that I have this ugly effect on the borders:
I've tried to change the y and the height values, with no results.
Do you have any ideas to avoid this?
Thanks in advance, yassa
I wouldn't do it this way.
You can achieve the same effect by adding a view with 2 buttons to the navigationItem.rightBarButtonItem. it is very simple:
// view that will hold the buttons
UIView* container = [[UIView alloc] init];
// create 1 button and add it to the container
UIButton* button = [[UIButton alloc] init........];
[container addSubview:button];
//create 2 button and add it to the container
button = [[UIButton alloc] init.........];
[container addSubview:button];
// now create a Bar button item
UIBarButtonItem* barButtonItem = [[UIBarButtonItem alloc] initWithCustomView:container];
// set the nav bar's right button item
self.navigationItem.rightBarButtonItem = barButtonItem;
I partially agree with previous answers and comments.
The solution you suggested works fine for custom buttons. But what if I want to implement standard Edit button?
Access to the standard buttons/icons is through the UIBarButtonItem class, not UIButton. And you can't add UIBarButtonItem objects to a UIView.
After many research on the web, I've found the solution that completely cover my requirement. The toolbar must be created in the following way:
UIToolbar *tools = [[UIToolbar alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 95.0f, 44.01f)];
tools.tintColor = self.navigationController.navigationBar.tintColor;
tools.barStyle = -1;
And this is the result:
Hope it helps!
yassa
Or you can do it in this way.
Just create new subclass of UIToolbar like this
#interface MyToolbar : UIToolbar
#end
#implementation MyToolbar
- (id)initWithFrame:(CGRect)frame {
if ((self = [super initWithFrame:frame])) {
self.opaque = NO;
self.backgroundColor = [UIColor clearColor];
self.clearsContextBeforeDrawing = YES;
}
return self;
}
- (void)drawRect:(CGRect)rect {
// do nothing
}
- (void)dealloc {
[super dealloc];
}
#end
And use it as normal UIToolbar. I don't know why but it just works.