Set alpha transparency on accessoryView - iphone

I am trying to add a UIView as an accessoryView to a UITextField, but the alpha property doesnt seem to be respected.
Here is my current code.
self.keyboardAccView = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 480.0)];
[self.keyboardAccView setBackgroundColor:[UIColor lightGrayColor]];
[self.keyboardAccView setOpaque:NO];
[self.keyboardAccView setAlpha:0.0];
UITapGestureRecognizer *hideKeyboardTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(hideKeyboard:)];
[self.keyboardAccView addGestureRecognizer:hideKeyboardTap];
[hideKeyboardTap release], hideKeyboardTap=nil;
The alpha value doesnt seem to matter. No matter what I set it to, the accessoryView is always set to no transparency.
What I'm trying to accomplish is show a transparent view above the keyboard that will dismiss the keyboard anytime the user taps away from the keyboard. If there is a better/proper way to do this that I am completely missing, I'm all ears as well.
EDIT *
I know I could just use [UIColor clearColor] as the backgroundColor but I more want to know why the alpha setting isnt honored, in case I truly did want to have a semi-transparent accessoryView

yes - there is a better way to do it! :)
I personally do it like this - I change my ViewController.xib class (UIView to UIControl) and then I create a simple IBAction which resigns first responder whenever is the UIControl tapped.
The method should look like this:
- (IBAction)hideKeyboard {
[textField resignFirstResponder];
}
That's it :)

Related

Set UIImageView background color upon user intervention

I am developing an application in which I have a horizontal scroller.
The scroller area comprise of different colors [which are nothing but UIImageView of colors].
Above the scroller area is a canvas [which is also a UIImageView].
Now, what I want is that when I select any color in the scroller area, it should set on the canvas.
It is pretty much like a color picker but I am already providing solid color options to be selected by the user.
How should I go about it ? Any sample Code to get me started or my mind kicking would be awesome ?
Thanx a ton
To implement it easily.
Use UIView not UIImageView
Set UIView backgroundColor and place it on the scroll
Set UITapGestureRecognizer on views,Refer here
when a purticular view is touched you have its instance of view which
is touched
get the background color of the view and set it in the scroller
Can you take UIButtons instead of UIImageViews inside your scrollView to show colours to be picked.
This will make the implementation easier. User will select any colour button and you will receive a callback in buttons action selector method. Then based on button tag or any property you can set the colour to your canvas.
In current implementation it will be tricky as you need to know the exact content offset where the tap is done to make out which UIImageView was pressed.
coding steps:
In your scroll view add UIButtons instead of UIImageView like:
UIButton* button = [[UIButton alloc] initWithFrame:someRect];
//put some tag to button
button.tag = someInt;
//add selector to each button to get callback
[view addTarget:self action:#selector(btnSelected:) forControlEvents:UIControlEventTouchUpInside];
[scrollView addSubview:button];
In the btnSelected method put this code:
-(IBAction)btnSelected:(id)sender;
{
UIButton* button = (UIButton*) sender;
if (button.tag == someInt) {
//do something like
canvas.backgroundColor = button.backgroundColor;
}
}
Instead of using UIImageViews or UIViews as suggested, I would put custom UIButtons for picking colors.
UIButton * colorButton;
//You will probably do these inside a for loop
colorButton = [UIButton buttonWithType:UIButtonTypeCustom];
[colorButton setFrame:CGRectMake(X, Y, buttonSize, buttonSize)];
[colorButton setTitle:#"" forState:UIControlStateNormal];
[colorButton setBackgroundColor:SOME_COLOR];
//Border visualization would be good if you are putting buttons side-by-side
[colorButton.layer setBorderWidth:1.0];
[colorButton.layer setBorderColor:[[UIColor darkGrayColor] CGColor]];
//You can use this tag to identify different buttons later
[colorButton setTag:INDEX+SOME_OFFSET]; //use loop index with some offset
[colorButton addTarget:self action:#selector(colorButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
-(void) colorButtonPressed:(UIButton *) sender
{
UIColor *selectedColor = sender.backgroundColor; //Or identify with sender.tag
[yourCanvas doSmtOnCanvas:selectedColor];
}
Initialize UIImageView then add gesture recognizer to all imageViews by calling this method.
- (void) setupImageView : (UIImageView *) imageView{
[imageView setUserInteractionEnabled:YES];
UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(changeUIImageViewBackgroundColor:)];
tapGestureRecognizer.numberOfTapsRequired = 1;
[imageView addGestureRecognizer:tapGestureRecognizer];
}
Now change color of canvasView within the selector by following way:
- (void) changeUIImageViewBackgroundColor : (UITapGestureRecognizer *) recognizer{
UIImageView *imageView = (UIImageView *)[recognizer view];
[canvasView setBackgroundColor:[imageView backgroundColor]];
}
You can put a tap gesture in your scrollview and whenever a tap is made in the scroll check whether the tap is on the imageview. (You will get whether the tap point in on imageview or not) and according you can change the image.
Second alternative is to take a custom button and handle on its click.
Hope it helps

Using UILongPressGestureRecognizer For Subviews of UIScrollview

For the past four hours, I have tried many Stack Overlow solutions but none have helped solve my problem.
Here it is,
I have a UIScrollView
Within that ScrollView there is one custom UILabel and 8 custom UIImageViews
I want to detect a long press
Something like this works
UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(longPressDidFire:)];
longPress.minimumPressDuration = 0.5;
[scroll addGestureRecognizer:longPress]; //scroll defined elsewhere
However, if I replace the scroll with any subviews of scroll, the long press event never fires.
How do I detect a long press of a subview of a scroll view?
This is quite a messy hack, however, since I can detect long presses of a scroll view, is there any way where I can detect the
position of the press so that I can see which specific subview is
being pressed.
Also, (insert subview here).userInteractionEnabled = YES, I set this property for all my subviews of the scroll view, so this should not be a problem.
I have also tried using touchesBegan and touchesEnded method as suggested elsewhere in Stack Overflow.
Also, for the image views, I do set a new UILongPressGestureRecognizer for every custom image view, using a for loop, as I am aware of the 1 view per gesture recognizer rule.
From A First Time iOS Developer,
Graham
P.S. I'd really prefer if I could find a solution for 1. rather than the messy 2.
More Code As Requested:
In the Init of the view Controller
UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(longPressDidFire:)];
longPress.minimumPressDuration = 0.5;
[self.titleLabel addGestureRecognizer:longPress]; //titleLabel property initialized elsewhere
[mainView addSubview:self.titleLabel];
In a "load images" method
for (NSData * dataImg in results) {
//Does some work turning data into an image, into an image view called img
img.delegate = self;
img.userInteractionEnabled = YES;
UILongPressGestureRecognizer *aLongPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(longPressDidFire:)];
aLongPress.minimumPressDuration = 0.5;
[img addGestureRecognizer:aLongPress];
[imgContainer addSubview:img];
}
Even More Code + Notes
self.view (UIView)
->scroll (UIScrollView)
->->mainView (UIView)
->->->titleLabel (UILabel)
->->->imgContainer (UIView)
->->->->images (UIImageViews)
[self.view addSubview:scroll];
[scroll addSubview:mainView];
[mainView addSubview:self.titleLabel];
[mainView addSubview:imgContainer];
[imgContainer addSubview:img]; //done 8x via for loop
Thanks to #RegularExpression's answer, I now am aware that the mainView is getting pressed, but not its subviews, so I need to find a way to display the mainView's subviews above it. :)
Another update, titleLabel works. ImageViews still don't work though. :(
I know this is a bit late and an answer has been chosen, but in case someone else wants a nice simple solution if you've got iOS7.
Inside your delegate of the UILongPressGestureRecognizer implement the gestureRecognizer:shouldRequireFailureOfGestureRecognizer:otherGestureRecognizer selector
Check if otherGestureRecognizer is a UIPanGestureRecognizer and return YES, otherwise return NO
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRequireFailureOfGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
if ([otherGestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]]) {
return YES;
}
return NO;
}
The scroll view will actually produce a UIScrollViewPanGestureRecognizer, which is part of the private API, but it's a subclass of UIPanGestureRecognizer so the above works fine.
To support iOS6 or below, then you'll need to loop through the gestureRecognizers of the UIScrollView, detect which one is a UIPanGestureRecognizer and perform the requireGestureRecognizerToFail selector on your UILongPressGestureRecogizer with that.
your code seems to be fine,it should work i think.i used below code and its working fine for me.
UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(handleLongPress:)];
longPress.delegate = (id)self;
longPress.minimumPressDuration=0.05;
imageView.userInteractionEnabled = YES;
[imageView addGestureRecognizer:longPress];
and its method,
- (IBAction)handleLongPress:(UILongPressGestureRecognizer *)sender {
NSLog(#"detected");
if (sender.state == UIGestureRecognizerStateEnded){
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:#"Alert" message:#"YES" delegate:nil cancelButtonTitle:#"OK" otherButtonTitles: nil];
[alert show];
}
}
Here i took imageView as subview of scrollview as u said
Since your UIScrollView is the common parent, that's probably where your gesture recognizer needs to be. You can determine which subview is being pressed by looking at the location of the point supplied in your action. So, the individual subviews do not need gesture recognizers.
So, you would do something like this:
- (void)longPressDidFire:(UILongPressGestureRecognizer *)sender
{
if (sender.state == UIGestureRecognizerStateEnded)
CGPoint point = [sender locationInView:scroll];
UIView *tappedView = [scroll hitTest:point withEvent:nil];
So, then you have the view that was long-pressed.
Other things that could cause the action not to fire would be a delegate problem or if the scroll is contained by another view that is intercepting the touch.
HTH
Instead of
[scroll addGestureRecognizer:longPress];
Add the gesture on your subviews, right after you declare them and before you add them to scrollview
[subview addGestureRecognizer:longPress];
Woohoo it works!
The problem was:
imgContainer was a UIView with an empty frame with several UIImageViews as subviews
I was under the impression that as I added a subview to imgContainer, imgContainer would expand.
This is not true.
I had to set imgContainer's frame to the same content frame as the scroll view and then everything became ok.
I hope this answer helps any other future iOS firs timers like me.

UIView.setalpha is not working?

I have created a bar to appear over the keyboard for next/previous/done like the safari browser. However, the setalpha property of the UIview of the bar doesn't seem to be working. No matter what value I set it to, nothing changes. Here is the code...
here is where the create view is called..
-(void)textFieldDidBeginEditing:(UITextField *)textField{
// Call the createInputAccessoryView method we created earlier.
// By doing that we will prepare the inputAccView.
[self createInputAccessoryView];
// Now add the view as an input accessory view to the selected textfield.
[textField setInputAccessoryView:inputAccView];
// Set the active field. We' ll need that if we want to move properly
// between our textfields.
txtActiveField = textField;
}
here is where i actually create and set its values...
-(void)createInputAccessoryView{
// Create the view that will play the part of the input accessory view.
// Note that the frame width (third value in the CGRectMake method)
// should change accordingly in landscape orientation. But we don’t care
// about that now.
inputAccView = [[UIView alloc] initWithFrame:CGRectMake(10.0, 0.0, 310.0, 40.0)];
// Set the view’s background color. We’ ll set it here to gray. Use any color you want.
[inputAccView setBackgroundColor:[UIColor darkGrayColor]];
// We can play a little with transparency as well using the Alpha property. Normally
// you can leave it unchanged.
[inputAccView setAlpha: 0.1f];
... code for adding buttons and their properties
}
so basically this is all there is to it. but the setAlpha property does nothing, regardless of what I set it to. However, background color works fine. Any ideas?
Thanks
If you want it to look like the prev/next/done bar in Safari etc, create a UIToolbar with the style set to translucent black. This also has the advantage of laying out your buttons nicely, with the correct style, and auto adjusting between landscape and portrait.
Not a direct answer to your question but probably a better way of acheiving what you actually want.
out of utter curiosity try using:
UIView *overlay = [[UIView alloc] initWithFrame:CGRectMake(10.0, 0.0, 310.0, 40.0)];
overlay.backgroundColor = [UIColor blackColor];
overlay.alpha = 0.5f;
[self.view addSubview:overlay];
it's hard to tell what the issue is without being able to see how many views you have and how you've stacked them. check you've defined your "addSubview" and what the hierarchy looks like

disable elements on UIView behind modal UIView

i have a UIView that is smaller than the superview so i can represent this view as a modal view when a button is clicked.
I have managed to do the following:
* add a subview to the superview.
* centered this modal view
I am now trying to make the elements behind the UIView unclickable. And also add a grey shadow te the ourside of my modal view so that the user understands that the modal view is the view in focus.
I would like to know how to achieve this.
I do not wish to use the presentation modal transition. I know and have already implemented this in other projects.
Any help is appreciated.
The simplest thing would be to lay a fullscreen UIView with a translucent gray background behind your "modal" view. Then it will intercept all of the touches. It might look something like this:
UIView *dimBackgroundView = [[UIView alloc] initWithFrame:theSuperview.bounds];
dimBackgroundView.backgroundColor = [[UIColor grayColor] colorWithAlphaComponent:.5f];
[theSuperview addSubview:dimBackgroundView];
[theSuperview addSubview:modalView];
For future reference, you can set myView.userInteractionEnabled = NO to disable touch events on a view.
There are several ways to do it.
If you have a custom view which has custom location, you can modify it like that:
Create an instance var:
UIView* backgroundView;
And whenever you need it, put it behind your custom view:
if (backgroundView == nil)
backgroundView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.height, [UIScreen mainScreen].bounds.size.width)];
backgroundView.backgroundColor = [[UIColor grayColor] colorWithAlphaComponent:.5f];
[self.view addSubview:backgroundView];
[backgroundView animateBump:customView.view];
[backgroundView addSubview:customView.view];
When you do not need it anymore
[backgroundView removeFromSuperview];

How to add Activity Indicator as subview to UIButton?

Can we add activity indicator as subview to UIButton?
If yes then plz tell me how to do that?
I used [button addSubview:activityIndicator];
Not working...
I found that adding a UIActivityIndicatorView to a UIButton was a really useful method to allow users to know something is happening without having to use the MBProgressHUD (I think the HUD is really good but should not be used in all situations.
For this reason I created two functions:
I have already allocated my UIButton so it is a class variable called _confirmChangesButton
I then create my activity indicator, set its frame (taking into account the button size) and then adding the indicator is easy.
- (void)addActivityIndicatorToConfirmButton {
// Indicator needs to be in the middle of the button. So half the screen less half the buttons left inset less half the activity indicator size
CGRect rect = CGRectMake([UIScreen mainScreen].bounds.size.width/2 - 10 - 15, 5, 30, 30);
UIActivityIndicatorView * activity = [[UIActivityIndicatorView alloc] initWithFrame:rect];
activity.hidesWhenStopped = YES;
[_confirmChangesButton setTitle:#"" forState:UIControlStateNormal];
[_confirmChangesButton addSubview:activity];
[activity startAnimating];
}
Having a removal function is also useful if you are using blocks. It might be that the completion task comes back with a failure and so we want to remove the indicator and change the title back. In this function we need to make sure to remove the indicator and not the button label which is the other subview on this button.
- (void)removeActivityIndicatorFromConfirmButton {
UIActivityIndicatorView * activity = _confirmChangesButton.subviews.lastObject;;
[activity removeFromSuperview];
[_confirmChangesButton setTitle:#"Confirm Change" forState:UIControlStateNormal];
}
I found that using these two you can create a much better user experience letting the user know what is going on when they press buttons.
Hope this helps
Use the below code below to add acitivity indicator a button or any uiview object
UIActivityIndicatorView *aView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
aView.frame = CGRectMake(0, 0, {yourButton}.frame.size.width, {yourButton}.frame.size.height);
aView.backgroundColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:0.7];
[{yourButton} addSubview:aView];
[aView startAnimating];
Hope this will help..
I don't think it's possible to add a view to a button. UIButton have this method because it's inherited from UIVIew.
The real question is : why do you want to add an activity indicator on a button and not elsewhere ?
did you do [activityIndicator startAnimating]; ALso as u are using it in a tableview just check if the tags are set properly