I am creating a few buttons programmatically, similar to:
for( int i = 0; i < 5; i++ ) {
UIButton* aButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[aButton setTag:i];
[aButton addTarget:self action:#selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
[aView addSubview:aButton];
}
And that I can implement the function of the button this way so that I know witch one was tapped:
- (void)buttonClicked:(UIButton*)button
{
NSLog(#"Button %ld clicked.", (long int)[button tag]);
}
But my question is a little bit trickier than that, I don't want just to access the button inside it's button method but also outside of it so that I can change the UIButton frame using an animation.
I was thinking that I should somehow be able to recreate the pointer to any of the buttons previously created by using the tags that I assign initially.
Can anyone point me in the right direction?
The correct way to do this is by using the next line of code:
UIButton *aButtonReconstruct = (UIButton *)[self.view viewWithTag:aTag];
where aTag is an int and is greater than 0, because all the views have the tag 0 by default, so in the for loop used in the first place, the count should start at minimum 1. In our case aTag having values from 1 to 6 after we change the for loop.
Also there shouldn't be more view with the same tag.
I am creating an iOS app with a seating plan layout.
Trying to use an object-oriented approach, I created a class for TableLayoutObjects as they have different properties.
And to lay these TableLayoutObjects out on the screen I am representing them as UIButtons that are created as I loop through the array of TableLayoutObjects.
- (void) loadTables
{
for (TableLayoutObjects *layoutObjs in arrTableLayoutObjects)
{
if ([layoutObjs.shape isEqualToString:#"r"]) {
// rectangle
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
......
if(layoutObjs.isInteractable) {
[button addTarget:self action:#selector(tableTouchedDown:) forControlEvents:UIControlEventTouchDown];
[button addTarget:self action:#selector(tableTouchedUpInside:) forControlEvents:UIControlEventTouchUpInside];
}
} else {
// text only. use label
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(layoutObjs.posX, layoutObjs.posY, layoutObjs.width, layoutObjs.height)];
......
}
}
}
My event handlers look like the below for now.
// reverts back to original color and perform other instructions
- (void) tableTouchedUpInside:(UIButton *) button
{
button.layer.backgroundColor = [UIColor colorWithWhite:0.2f alpha:.5f].CGColor;
}
My question is: how do I identify the UIButtons to their TableLayoutObjects? In the event handler after I change the colour of the button, I will also want to get or set some properties of the selected TableLayoutObjects. How can I do that?
I think your example is a perfect fit for implementing a UICollectionView. Solution with the buttons is less clean and more complex.
You can set the tag of the button to the index into the arrTableLayoutObjects array of the associated item.
Alternatively, create a custom class which takes the table as a parameter and is the target of the button. This object now has direct access to the button and the table item.
I'm trying to change the title of an UIButton I've created programmatically, when the user clicks in it. So, this is my code to create the UIButton:
myButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, parentView.frame.size.width, parentView.frame.size.height)];
[myButton setBackgroundColor:[UIColor blackColor]];
[myButton setAlpha:0.7];
[myButton setTitle:#"Hello" forState:UIControlStateNormal];
[myButton addTarget:self action:#selector(userClicked:) forControlEvents:UIControlEventTouchUpInside];
[parentView addSubview:myButton];
And, in my userClicked: method, I do:
-(void) userClicked:(UIButton*)button
{
NSLog(#"USER CLICKED!!!");
if ([NSThread isMainThread])
{
NSLog(#"is main thread");
}
[button setTitle:#"Bye" forState:UIControlStateHighlighted];
[button setTitle:#"Bye" forState:UIControlStateNormal];
[button setTitle:#"Bye" forState:UIControlStateSelected];
[self someLengthyComputation];
}
The weird thing is that I can see the log messages printed:
USER CLICKED!!!
isMainThread
But, the title of the button does not change! What am I doing wrong?
EDIT: Setting the title for several states doesn't work either.
EDIT2: If I print the description of button in the debugger window of Xcode, it shows the right title!
Printing description of button->_titleView:
<UIButtonLabel: 0xa4c9310; frame = (95 216; 130 22); text = 'Bye'; clipsToBounds = YES; opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0xa44f080>>
This worked for me to update the title text (iOS 7.1, Xcode 5.1):
button.enabled = FALSE;
[button setTitle:#"Test" forState:UIControlStateNormal];
button.enabled = TRUE;
I was having the same problem, and I noticed that everywhere else I was setting the attributedTitle. So any updates to the title were not affecting the attributed title.
My solution:
[button setAttributedTitle:#"" forState:UIControlStateNormal];
instead of
[button setTitle:#"" forState:UIControlStateNormal];
At the moment, the shortest work around I came with is calling:
[button setNeedsLayout];
After updating the title.
This seems to happen in iOS 7.1.
All my buttons, which were behaving correctly in previous iOS versions (or maybe just compiled with previous SDKs) suddenly stopped doing that when compiled in Xcode 5.1.1 SDK 7.1.
Looks like Apple's bug.
I had a similar problem using storyboards. Using the answers above I had to use
[mybutton setTitle:#"SomeText" forState:UIControlStateNormal];
[button setNeedsLayout];
[button layoutIfNeeded];
AND I had to make sure that the button type was 'Custom' not 'System' in the attributes inspector.
Please see if this might help you...when the button is clicked check for condition if buttonToggled...like below when you have a function like changeButtonText
-(IBAction)changeButtonText:(id)sender {
if (!buttonToggled) {
[sender setTitle:#"Initial Text" forState:UIControlStateNormal];
buttonToggled = YES;
} else {
[sender setTitle:#"Alternative Text" forState:UIControlStateNormal];
buttonToggled = NO;
}
}
There are several issues in your code:
You are assigning callback to the button:
#selector(userClicked:)
but your code is in another method:
-(void)userTapOnTapToRefreshView:(UIButton*)button
To fix that you need to implement something like this:
-(void)userClicked:(id)sender
{
[(UIButton*)sender setTitle:#"Bye" forState:UIControlStateNormal];
}
Also this part of code does not make sense for me:
[parentView myButton];
Try to change it to:
[parentView addSubview:myButton];
Hope it will help :)
For Swift 3 to 5 just use the following:
button.setTitle("My title", for: .normal)
or for a attributed text use this:
button.setAttributedTitle(<AttributedString>, for: .normal)
This is kinda late and somewhat relates to Walter Schurter's response:
I had a similar issue where my button text was being set correctly until I updated to 7.1. Then I found that since my button was disabled, I had to set the title color and title text for the disabled state to get the text to show up. Then everything worked like a charm!
In iOS 7, UIButton's title is not updated when it is disabled. It seems like a bug on iOS 7.
As a workaround, update both normal and disabled title. It works!
[button setTitle:title forState:UIControlStateNormal];
[button setTitle:title forState:UIControlStateDisabled];
Try this:
[button setTitle:#"Bye" forState:UIControlStateHighlighted];
or:
[button setTitle:#"Bye" forState:UIControlStateSelected];
You could also modify your void function:
-(void) userClicked
{
NSLog(#"USER CLICKED!!!");
if ([NSThread isMainThread])
{
NSLog(#"is main thread");
}
[myButton setTitle:#"Bye" forState:UIControlStateNormal];
}
In my case I tried everything but nothing was working.
Then I just changed button type from system to custom from storyboard. BOOM! everything started behaving normally.
Change the button type to 'Custom', instead of 'System' and it will work as expected :)
Well, is all about the enabled state of a UIButton, Apple has changed something in 7.1 that does not allow you to change the title if you have the UIButton on a disabled state, thats all.
Thanks Apple, i have lost 10 min. debuging an app that was working fine.
Just found out this morning, got updated XCode yesterday to the 5.1.1 and iOS to 7.1
It could be the button layout refresh issue.....
Try using...
[button setNeedsLayout];
[button layoutIfNeeded];
It will force button to update the layout.
Finally, I've figured it out. There were two problems:
1) button was not in state UIControlStateNormal.
2) I was calling a method performing a long computation just after setting the title, [self someLengthyComputation].
I've solved the problem by:
1) Setting the title for all states of the button.
2) Performing that big computation in another thread, not the main thread.
My working code now is:
-(void) userClicked:(UIButton*)button
{
NSLog(#"USER CLICKED!!!");
if ([NSThread isMainThread])
{
NSLog(#"is main thread");
}
[button setTitle:#"Bye" forState:UIControlStateHighlighted];
[button setTitle:#"Bye" forState:UIControlStateNormal];
[button setTitle:#"Bye" forState:UIControlStateSelected];
dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
[self someLengthyComputation];
});
}
Thank you very much to everybody who has answered/commented!
This may be trivial, but if you set some button image (instead of background image) which fills the whole button frame, this will shift the title right and thus make it invisible.
If so, try changing button image to background image.
Per Apple developer guide, you should not set either the button title label text or color directly as a property (for example, do not do this: myButton.titleLabel.text=#"SomeText" or myButton.titleLabel.textColor=[UIColor blackColor]).
Rather, you set them using the UIButton setter functionality, like this:
[myButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
...or like this:
[myButton setTitle:#"SomeText" forState:UIControlStateNormal];.
See the Apple guide.
Conclusion after trying many solutions is to use setAttributedTitle instead of setTitle.
To make the title string for AttributedString:
NSMutableAttributedString *attString = [[NSMutableAttributedString alloc] initWithString:#" new Test "];
[button setAttributedTitle:attString forState:UIControlStateNormal];
By the way, this problem is not occasionally happen in normal but it suddenly happen mainly for the following reasons:
If you change the enabled state of a UIButton and try to change the title.
If you use an attributed value and then want to change it using setTitle, the attributed value is superior to the title in that case.
If you navigate to another view controller and then return back to update the button title.
There is no requirement to use:
[button setNeedsLayout];
[button layoutIfNeeded];
Instead, first set type as DEFAULT to CUSTOM
If you applied setAttributedTitle then use:
[button setAttributedTitle:[NSAttributedString new] forState:UIControlStateNormal];
Otherwise there is no need to change anything.
If the color of the text has not changed then apply same thing and set title color with:
[button setTitleColor:[any_color] forState:UIControlStateNormal];
None of the above worked for my case (I was having a button on top of a view presented with UIPopoverController), and I had to removeFromSuperview before setTitle, then addSubview back - hope this helps someone with similar issues
I doubt if 'button' passed in as a parameter is myButton.Anyway,if myButton is a member var,you can just [myButton setTitle:#"Bye" forState:UIControlStateNormal];
Try to declare you button as a property, either in the interface or in the implementation part of you view / view controller
#property(nonatomic,strong) UIButton* myButton;
then create it
self.myButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, parentView.frame.size.width, parentView.frame.size.height)];
[_myButton setBackgroundColor:[UIColor blackColor]];
...
It should work. Don't ask me why really - I just think it's all about ARC / Modern memory management..
EDIT:
It should also work if you keep a reference on the button in your implementation..
#implementation myViewController
{
UIButton* myButton;
}
-(void)createButton
{
myButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, parentView.frame.size.width, parentView.frame.size.height)];
[myButton setBackgroundColor:[UIColor blackColor]];
...
}
...
instead of
yourButton.titleLabel?.text = "T"
use this
yourButton.setTitle("TITLE", for: .normal)
Always do addSubview before setting the text on UIButton.
In my app, I need to parse some data from the network, and add some customized buttons.
Later, when user click on it, I would provide more details.
An image view is the background for the app
The position of these buttons(xPos, yPos) are parsed from the server(dynamic data)
no prints when I click on these buttons that I add programmatically
The code I have for adding it is like this
...
[businessButton setImage:businessImage forState:UIControlStateNormal];
[businessButton setFrame:CGRectMake([xPos floatValue], [yPos floatValue], [businessImage size].width/2, [businessImage size].width/2)];
[businessButton addTarget:self.imageView action:#selector(serviceProviderSelected:) forControlEvents:UIControlEventTouchUpInside];
...
- (void)serviceProviderSelected:(id)sender
{
NSLog(#"sp tapped\n");
}
I created another dummy app to do (what I think is the same thing), and the button works out fine...
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
UIButton *customizedButton = [UIButton buttonWithType:UIButtonTypeCustom];
UIImage *image = [UIImage imageNamed:#"business-icon.png"];
[customizedButton setImage:image forState:UIControlStateNormal];
[customizedButton setFrame:CGRectMake(100, 100, 20, 20)];
[customizedButton addTarget:self action:#selector(customButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:customizedButton];
}
- (IBAction)buttonPressed:(id)sender {
NSLog(#"yes, pressed\n");
}
I've been suspecting that the buttons I create in code are already released, and printed out the array that I use for storing these Buttons, they are valid addresses though...
Thanks!
William
I just found out why.
Instead of [self.imageView addSubview:businessButton];, [self.view addSubview:businessButton]; works now.
I think I didn't really understand how the view relationship was after adding an imageView in storyboard.
UIImageView has user interactions disabled by default. you have to set this property to YES in order to get an UIButton or anything else working as it's subview
You need to do:
[businessButton addTarget:self action:#selector(serviceProviderSelected:) forControlEvents:UIControlEventTouchUpInside];
The target needs to be the class that defines the selector.
I have a UIPickerView which works correctly, now I want to add a button above it so that I can dismiss it.
and here is my code where I initiate a UIPickerView as well as its dismiss button:
- (UIPickerView *)creatPickerView {
UIPickerView *tempPickerView = [[[UIPickerView alloc]
initWithFrame:CGRectMake(kPickerViewX, kPickerViewY, kPickerViewWidth, kPickerViewHeight)] autorelease];
tempPickerView.showsSelectionIndicator = YES;
tempPickerView.delegate = self;
tempPickerView.dataSource = self;
UIButton *pickerButton = [[UIButton alloc] initWithFrame:CGRectMake(270, -32, 50, 32)];
[pickerButton setBackgroundImage:[UIImage imageNamed:#"hidePicker.png"]
forState:UIControlStateNormal];
[pickerButton addTarget:self action:#selector(hidePicker)
forControlEvents:UIControlEventTouchUpInside];
[tempPickerView addSubview:pickerButton];
[pickerButton release];
[self.view addSubview:tempPickerView];
return tempPickerView;
}
and it works well on my iPhone 4.3 Simulator, like this:
apparently there is a button on the upper right of the pickerView,
problem is, when I run the app in my device - a 5.0.1 iPhone4 and a 4.2.1 iTouch, the button is missed like it has never been added to the pickerView.
Can anyone help me with this?
Thanks a lot and a lot!
I found the reason, it seems the png has some problem,
after I change another png, it comes up in the screen!
but the real problem is that I place the button outside of the pickerView which results in the button's untouchableness.
But anyway the pickure is only a small problem.