uibutton interview questions
Top uibutton frequently asked interview questions
I create a button programmatically
button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[button addTarget:self
action:@selector(aMethod:)
forControlEvents:UIControlEventTouchDown];
[button setTitle:@"Show View" forState:UIControlStateNormal];
button.frame = CGRectMake(80.0, 210.0, 160.0, 40.0);
[view addSubview:button];
how can I change title color?
Source: (StackOverflow)
How can I add 2 buttons into the UINavigationBar without XIB?
The 2 buttons should be aligned on the right side of the UINavigationBar.
I know how I can add one button, but how about two?
Source: (StackOverflow)
I have added multiple target-action-forControlEvents: to a UIButton. I'd like to remove all of these in one go without deallocating anything. I will then set new targets.
Is this possible and how do I go about it?
Source: (StackOverflow)
How can I create a basic UIButton programmatically? For example in my view controller, when executing the viewDidLoad method, three UIButtons will be created dynamically and its layout or properties are set.
Source: (StackOverflow)
I need to display the email address from left side of a UIButton, but it is being positioned in the centre.
Is there any way to set the alignment to the left side of a UIButton?
This is my current code:
UIButton* emailBtn = [[UIButton alloc] initWithFrame:CGRectMake(5,30,250,height+15)];
emailBtn.backgroundColor = [UIColor clearColor];
[emailBtn setTitle:obj2.customerEmail forState:UIControlStateNormal];
emailBtn.titleLabel.font = [UIFont systemFontOfSize:12.5];
[emailBtn setTitleColor:[[[UIColor alloc]initWithRed:0.121 green:0.472 blue:0.823 alpha:1]autorelease] forState:UIControlStateNormal];
[emailBtn addTarget:self action:@selector(emailAction:) forControlEvents:UIControlEventTouchUpInside];
[elementView addSubview:emailBtn];
[emailBtn release];
Source: (StackOverflow)
I'm writing some unit tests and, because of the nature of this particular app, it's important that I get as high up the UI chain as possible. So, what I'd like to do is programmatically trigger a button-press, as if the user had pressed the button in the GUI.
(Yes, yes -- I could just call the IBAction selector but, again, the nature of this particular app makes it important that I fake the actual button press, such that the IBAction be called from the button, itself.)
What's the preferred method of doing this?
Source: (StackOverflow)
I have the following code...
UILabel *buttonLabel = [[UILabel alloc] initWithFrame:targetButton.bounds];
buttonLabel.text = @"Long text string";
[targetButton addSubview:buttonLabel];
[targetButton bringSubviewToFront:buttonLabel];
...the idea being that I can have multi-line text for the button, but the text is always obscured by the backgroundImage of the UIButton. A logging call to show the subviews of the button shows that the UILabel has been added, but the text itself cannot be seen. Is this a bug in UIButton or am I doing something wrong?
Source: (StackOverflow)
I'm setting text color for UIButton
headingButton.titleLabel.textColor = [UIColor colorWithRed:36/255.0
green:71/255.0
blue:113/255.0
alpha:1.0];
It's not changing color same code I'm using in another code it's working.
Source: (StackOverflow)
I would like to place an icon left of the two lines of text such that there's about 2-3 pixels of space between the image and the start of text. The control itself is Center aligned horizontally (set through Interface Builder)
The button would resemble something like this:
| |
|[Image] Add To |
| Favorites |
I'm trying to configure this with contentEdgeInset, imageEdgeInsets and titleEdgeInsets to no avail. I understand that a negative value expands the edge while a positive value shrinks it to move it closer to the center.
I tried:
[button setTitleEdgeInsets:UIEdgeInsetsMake(0, -image.size.width, 0, 0)];
[button setImageEdgeInsets:UIEdgeInsetsMake(0, button.titleLabel.bounds.size.width, 0, 0)];
but this doesn't display it correctly. I've been tweaking the values but going from say -5 to -10 on the left inset value doesn't appear to move it in expected manner. -10 will scoot the text all the way to the left so I expected -5 to scoot it half way from the left side but it doesn't.
What's the logic behind insets? I'm not familiar with image placements and related terminology.
I used this SO question as a reference but something about my values isn't right.
UIButton: how to center an image and a text using imageEdgeInsets and titleEdgeInsets?
Source: (StackOverflow)
At some point in my app I have a highlighted UIButton (for example when a user has his finger on the button) and I need to change the background color while the button is highlighted (so while the finger of the user is still on the button).
I tried the following:
_button.backgroundColor = [UIColor redColor];
But it is not working. The color remains the same. I tried the same piece of code when the button is not highlighted and it works fine. I also tried calling -setNeedsDisplay after changing the color, it didn't have any effect.
How to force the button to change the background color?
Source: (StackOverflow)
I set an images for button's states Normal,Highlighted and Selected, but when the button in selected state and I press/highlight it I didn't see my highlighted image but just grayed picture.
Is it possible to set an image for highlighted state when the button selected?
my code:
[button setImage:[UIImage imageNamed:@"normal.png"] forState:UIControlStateNormal];
[button setImage:[UIImage imageNamed:@"pressed.png"] forState:UIControlStateHighlighted];
[button setImage:[UIImage imageNamed:@"checked.png"] forState:UIControlStateSelected];
when I do:
[button setSelected:YES];
and press the button, the "pressed.png" image doesn't select.
Source: (StackOverflow)
In interface builder, holding Command + = will resize a button to fit its text. I was wondering if this was possible to do programmatically before the button was added to the view.
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button.titleLabel setFont:[UIFont fontWithName:@"Arial-BoldMT" size:12]];
[button addTarget:self action:@selector(buttonTapped:) forControlEvents:UIControlEventTouchUpInside];
// I need to know the width needed to accomodate NSStringVariable
[button setTitle:NSStringVariable forState:UIControlStateNormal];
// So that I can set the width property of the button before addSubview
[button setFrame:CGRectMake(10, 0, width, fixedHeight)];
[subNavigation addSubview:button];
Source: (StackOverflow)
After my user clicks a button, I'd like that button to stay pushed during the time that I perform a network operation. When the network operation is complete, I want the button to return to its default state.
I've tried calling -[UIButton setSelected:YES] right after the button push (with a corresponding call to -[UIButton setSelected:NO] after my network op finishes) but it doesn't seem to do anything. Same thing if I call setHighlighted:.
I suppose I could try swapping out the background image to denote a selected state for the duration of the network op, but that seems like a hack. Any better suggestions?
Here's what my code looks like:
- (IBAction)checkInButtonPushed
{
self.checkInButton.enabled = NO;
self.checkInButton.selected = YES;
self.checkInButton.highlighted = YES;
[self.checkInActivityIndicatorView startAnimating];
[CheckInOperation startWithPlace:self.place delegate:self];
}
- (void)checkInCompletedWithNewFeedItem:(FeedItem*)newFeedItem wasNewPlace:(BOOL)newPlace possibleError:(NSError*)error;
{
[self.checkInActivityIndicatorView stopAnimating];
self.checkInButton.enabled = YES;
self.checkInButton.selected = NO;
self.checkInButton.highlighted = NO;
}
Source: (StackOverflow)
I have a UIButton, that when pressed, brings up a new view where the user can change some settings. When the view is dismissed, I'd like to update the title/text of the UIButton to reflect the new state. I'm calling:
[myButton setTitle: @"myTitle" forState: UIControlStateNormal];
[myButton setTitle: @"myTitle" forState: UIControlStateApplication];
[myButton setTitle: @"myTitle" forState: UIControlStateHighlighted];
[myButton setTitle: @"myTitle" forState: UIControlStateReserved];
[myButton setTitle: @"myTitle" forState: UIControlStateSelected];
[myButton setTitle: @"myTitle" forState: UIControlStateDisabled];
But it never seems to change from the original text/title as specified in IB.
Source: (StackOverflow)