How to detect coordinate of UISLDER? - iphone

I am using uislider in my application.Now i want to get position of center button when i am moving slider.How it possible?

UISlider *slider = mySlider;
CGRect bounds = slider.bounds;
CGRect trackRect = [slider trackRectForBounds:bounds];
CGRect thumbPosition = [slider thumbRectForBounds:bounds trackRect:trackRect
value:slider.value];
See the documentation here.

It's one of the subviews. However, accessing it like this is prone to breakage in future OS versions. You can probably make a reasonable guess of the coordinates with a little math though.

Related

gesture issue in iOS 7

I am facing gesture issue which is occurred only in iOS 7. I am adding UIPinchGestureRecognizer on UITextView like this :
pinchGestRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:#selector(scaleTextViews:)];
pinchGestRecognizer.delegate = self;
[multipleTextView addGestureRecognizer:pinchGestRecognizer];
And in scaleTextViews: method I have written this code:
- (void)scaleTextViews:(UIPinchGestureRecognizer *)pinchGestRecognizer1
{
multipleTextView.transform = CGAffineTransformScale([multipleTextView transform], [pinchGestRecognizer1 scale], [pinchGestRecognizer1 scale]);
[pinchGestRecognizer1 setScale:1];
}
When I zoom in the textview in iOS 7 and give a color to the text then my textView getting cutoff and changed its position.
Please suggest me what to do.
Thanks in advance...
If I understood your problem correctly, you want to change the way a view (in your case a label) is scaled when pinched. You can achieve different scaling types by changing the view layers anchor point.
For your example:
multipleTextView.layer.anchorPoint = CGPointMake(1, 1);
You can play around with anchorPoint, to find the effect that you would like to get.

caricature - Image animation in iOS

How to Implement this kind of animation in iOS objective c.
Currently I have implemented "CABasicAnimation" for this but still not able to achieve this very smoothly .
any suggestion ??
Thank you
You'll need to use Core Image with a combination of different distortion filters.
You can then animate the intensity of the filters over time.
I don't think that with CABasic animation you can obtain that. Probably is a little "movie" made by combination of CIFilterd images (check CIFilter class in the doc). Another way around (but I'm writing as I'm thinking) is mask the image somehow with a CAShapeLayer and use CAAnimation on it.
As Leena pointed out this is a simple loop of images.
Create your frames outside Xcode and then animate them this way:
NSArray *frames = [NSArray arrayWithObjects:[UIImage imageNamed:#"firstFrame.png"],
[UIImage imageNamed:#"secondFrame.png"],
// add other frames
, nil];
UIImageView *animatedImage = [[UIImageView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 100.0f, 100.0f)];
animatedImage.animationImages = frames;
animatedImage.animationDuration = 3.0f; // seconds
animatedImage.animationRepeatCount = 0; // 0 = loops forever
[animatedImage startAnimating];
[self.view addSubview:animatedImage];
[animatedImage release];

Resizing UITableViewCell content width automatically

I have some code that creates a table cell with a slider. It's pretty straightforward and it sizes well on the iPhone. I've anonymized it a bit here:
UITableViewCell* cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"Foo"] autorelease];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
CGRect contentViewFrame = cell.contentView.frame;
CGRect sliderFrame = CGRectMake(10, 0, 280, contentViewFrame.size.height);
UISlider* slider = [[UISlider alloc] initWithFrame:sliderFrame];
UIImage* minimumImage = [UIImage imageNamed:#"min.png"];
UIImage* maximumImage = [UIImage imageNamed:#"max.png"];
slider.minimumValueImage = minimumImage;
slider.maximumValueImage = maximumImage;
slider.value = 0.5f;
[slider addTarget:self action:#selector(sliderAction:) forControlEvents:UIControlEventValueChanged];
[cell.contentView addSubview:slider];
[slider release];
Of course, this is incorrectly sized for the iPad. So my first thought was to set the autoresizingMask property to UIViewAutoresizingFlexibleWidth. Problem solved, right? Nope. Now on the iPhone, the width of the slider-plus-images content is less than 280 and so it doesn't go right to the end -- it ends up about 20 pixels short.
On the iPad, the same thing -- the width of the UISlider automatically resizes to about 20 pixels short of the end of the cell.
Perhaps the auto resize flag is paying attention to the non-existent accessoryView of the cell? I tried setting it to nil explicitly, but I think it's nil by default, so nothing changed.
I'd like this cell's content to resize automatically to be the "full" width of the cell, regardless of device and orientation. Is there an easy way to do this?
It works exactly how you described. I am inclined to think it's iOS bug. On iPAD when you create new UITableViewCell its width set for 320. hardcoded(!) both view and contentView. It does not resize properly if set to UIViewAutoresizingFlexibleWidth. I had it set to view.frame.size.width/2 with funny results: on iPhone it's 160, on iPad it's 608!!!
I ended up manually resizing my cells and their content.
Bit late but i found the solution of the same question today, but you need to create a custom UITableViewCell.
Then you can overwrite the function
- (void) layoutSubviews
{
[dateLabel setFrame:CGRectMake(10.f, 16.f, 80.f, 12.f)];
[textLabel setFrame:CGRectMake(106.f, 16.f, contentView.frame.size.width-105.f + 1.f, 12.f)];
}
In that function the self.frame.size.width is the actual one.
And it works with rotation of the device, too.
You should be able to tell the resizing system to "stick" the object a fixed distance from the right edge (where it's not resizing far enough). If you experiment with IB you can create a view that resizes in width and is fixed to the right side.
Do you have UIViewAutoresizingFlexibleRightMargin set as well?
Set your cell's contentMode to UIViewContentModeRedraw.

Why Is my UISlider Thumb Image Being Shown Multiple Times and Not Disappearing As They Should?

This slider is possessed:
Slider http://gorgando.com/possessedSlider.jpg
Whenever I enter "editing mode" for the tableview or leave "editing mode" a duplicate thumb image will appear where the thumb is. It is now behaving consistently in this way. If I switch back and forth from editing mode I'll get lots of thumb images like the screenshot shows.
This is the code that I use to create the slider (in the cellForRowAtIndexPath method):
CGRect frame = CGRectMake(20, 42.0, 280.0, 22);
self.slider = [[UISlider alloc] initWithFrame:frame];
[self.slider addTarget:self action:#selector(sliderAction:) forControlEvents:UIControlEventValueChanged];
self.slider.continuous = YES;
self.slider.minimumValue = 0.0;
self.slider.maximumValue = 5.0;
self.slider.value = 0.0;
[[interestCell contentView] addSubview:self.slider];
Appreciate any thoughts you might have!
[I just edited/updated this to reflect the questions/suggestions I received but it's still having problems].
Try adding it to the cell's contentView and not the cell itself.
Finally figured it out!
I had to move my code to the viewDidLoad method except for setting the slider to the contentView, which happens in the cellForRowAtIndexPath method still. What a strange problem that was. Thanks to those who helped and commented!

Photos app-like gap between pages in UIScrollView with pagingEnabled

UIScrollView in paging mode assumes the pages are located right next to each other, with no gap. However if you open a photo in the Photos app and swipe through photos, you can see that it has some gap between pages. I want these gaps too.
I'm looking for existing solutions if any, or for some more bizarre ideas about implementing the page gaps besides the one I have explained below. Or maybe there's some obvious easy way I am missing?
To be clear: I want the gap to only be visible while scrolling, so I cannot simply inset the page content.
My plan is to try moving the page content from inside scrollViewDidScroll callback, so that (assuming you're scrolling to the right) initially the target page is slightly offset to the right of its page boundaries, and by the time you arrive at the target page it's back at its proper location, and the source page is slightly offset to the left of its boundaries. (Or maybe instead of moving things continuously, I'll be better off shifting the offsets, say, exactly halfway between pages.)
I'm the author of the ScrollingMadness article+example that I've been referring some people to here. I've implemented progammatic zooming, and got in-photo zooming+scrolling working together with inter-photo paging. So I know how to play with UIScrollView, and am looking for the advanced stuff.
Please don't point me at TTScrollView. I've already pointed many people to it myself, but I consider it's feel too far from the native UIScrollView behaviour, and do not want to use it in my projects.
Note that this answer is quite old. The basic concept still works but
you should not be hard coding view sizes in iOS7 and 8. Even if you ignore
that advice, you should not use 480 or 330.
Have you tried making the frame of the UIScrollView slightly larger than the screen (assuming that you want to display your images fullscreen and then arranging your subviews on the same slightly-larger-than-the-screen boundaries.
#define kViewFrameWidth 330; // i.e. more than 320
CGRect scrollFrame;
scrollFrame.origin.x = 0;
scrollFrame.origin.y = 0;
scrollFrame.size.width = kViewFrameWidth;
scrollFrame.size.height = 480;
UIScrollView* myScrollView = [[UIScrollView alloc] initWithFrame:scrollFrame];
myScrollView.bounces = YES;
myScrollView.pagingEnabled = YES;
myScrollView.backgroundColor = [UIColor redColor];
UIImage* leftImage = [UIImage imageNamed:#"ScrollTestImageL.png"];
UIImageView* leftView = [[UIImageView alloc] initWithImage:leftImage];
leftView.backgroundColor = [UIColor whiteColor];
leftView.frame = CGRectMake(0,0,320,480);
UIImage* rightImage = [UIImage imageNamed:#"ScrollTestImageR.png"];
UIImageView* rightView = [[UIImageView alloc] initWithImage:rightImage];
rightView.backgroundColor = [UIColor blackColor];
rightView.frame = CGRectMake(kViewFrameWidth * 2,0,320,480);
UIImage* centerImage = [UIImage imageNamed:#"ScrollTestImageC.png"];
UIImageView* centerView = [[UIImageView alloc] initWithImage:centerImage];
centerView.backgroundColor = [UIColor grayColor];
centerView.frame = CGRectMake(kViewFrameWidth,0,320,480);
[myScrollView addSubview:leftView];
[myScrollView addSubview:rightView];
[myScrollView addSubview:centerView];
[myScrollView setContentSize:CGSizeMake(kViewFrameWidth * 3, 480)];
[myScrollView setContentOffset:CGPointMake(kViewFrameWidth, 0)];
[leftView release];
[rightView release];
[centerView release];
Apologies if this doesn't compile, I tested it in a landscape app and hand edited it back to portrait. I'm sure you get the idea though. It relies on the superview clipping which for a full screen view will always be the case.
So I don't have enough "rep" to post a comment on the answer above. That answer is correct, but there is a BIG issue to be aware of:
If you're using a UIScrollView in a viewController that's part of a UINavigationController, the navigation controller WILL resize the frame of your scrollView.
That is, you have an app that uses a UINavigationController to switch between different views. You push a viewController that has a scrollView and you create this scrollView in the viewController's -init method. You assign it a frame of (0, 0, 340, 480).
Now, go to your viewController's -viewDidAppear method, get the frame of the scrollView you created. You'll find that the width has been reduced to 320 pixels. As such, paging won't work correctly. You'll expect the scrollView to move 340 pixels but it will, instead, move 320.
UINavigationController is a bit notorious for messing with subviews. It moves them and resizes them to accommodate the navigation bar. In short, it's not a team player -- especially in this case. Other places on the web suggest that you not use UINavigationController if you need precise control over your views' size and locations. They suggest that, instead, you create your own navigationController class based on UINavigationBar.
Well that's a ton of work. Fortunately, there's an easier solution: set the frame of the scrollView in your viewController's -viewDidAppear method. At this point, UINavigationController is done messing with the frame, so you can reset it to what it should be and the scrollView will behave properly.
This is relevant for OS 3.0. I have not tested 3.1 or 2.2.1. I've also filed a bug report with Apple suggesting that they modify UINavigationController with a BOOL such as "-shouldAutoarrangeSubviews" so that we can make that class keep its grubby hands off subviews.
Until that comes along, the fix above will give you gaps in a paginated UIScrollView within a UINavigationController.
Apple has released the 2010 WWDC session videos to all members of the iphone developer program. One of the topics discussed is how they created the photos app!!! They build a very similar app step by step and have made all the code available for free.
It does not use private api either. Here is a link to the sample code download. You will probably need to login to gain access.
http://connect.apple.com/cgi-bin/WebObjects/MemberSite.woa/wa/getSoftware?code=y&source=x&bundleID=20645
And, here is a link to the iTunes WWDC page:
http://insideapple.apple.com/redir/cbx-cgi.do?v=2&la=en&lc=&a=kGSol9sgPHP%2BtlWtLp%2BEP%2FnxnZarjWJglPBZRHd3oDbACudP51JNGS8KlsFgxZto9X%2BTsnqSbeUSWX0doe%2Fzv%2FN5XV55%2FomsyfRgFBysOnIVggO%2Fn2p%2BiweDK%2F%2FmsIXj
The way to do this is like you said, a combination of a few things.
If you want a gap of 20px between your images, you need to:
First, expand your scroll view's total width by 20px and move it left by 10px.
Second, when you lay out the xLoc of your images, add 20px for each image so they're spaced 20px apart.
Third, set the initial xLoc of your images to 10px instead of 0px.
Fourth, make sure you set the content size of your scroll view to add 20px for each image. So if you have kNumImages images and each is kScrollObjWidth, then you go like this:
[scrollView setContentSize:CGSizeMake((kNumImages * (kScrollObjWidth+20)), kScrollObjHeight)];
It should work after that!
This is just a hunch, so apologies if completely wrong, but is it possible that the contentSize is just set to slightly wider than the screen width.
The correct information is then rendered within the view to the screen width and UIScrollView takes care of the rest ?
Maybe you want to try UIScrollView's contentInset property?
myScrollView.contentInset = UIEdgeInsetsMake(0, 0, 0, 10.0);
I just thought I'd add here for posterity the solution I ended up going with. For a long time I've been using Bryan's solution of adjusting the frame in -viewDidAppear, and this has worked brilliantly. However since iOS introduced multitasking I've been running into a problem where the scroll view frame gets changed when the app resumes from the background. In this case, -viewDidAppear was not being called and I couldn't find a delegate method that would be called at the right time to reverse the change. So I decided to make my scroll view a subview of my View Controller's view, and this seemed to fix the problem. This also has the advantage of not needing to use -viewDidAppear to change the frame - you can do it right after you create the scroll view. My question here has the details, but I'll post them here as well:
CGRect frame = CGRectMake(0, 0, 320, 460);
scrollView = [[UIScrollView alloc] initWithFrame:frame];
// I do some things with frame here
CGRect f = scrollView.frame;
f.size.width += PADDING; // PADDING is defined as 20 elsewhere
scrollView.frame = f;
[self.view addSubview:scrollView];
To avoid messing with UIScrollView's frame, you could subclass UIScrollView and override layoutSubviews to apply an offset to each page.
The idea is based on the following observations:
When zoomScale !=1, the offset is zero when it is at the left / right edge
When zoomScale ==1, the offset is zero when it is at the visible rect centre
Then the following code is derived:
- (void) layoutSubviews
{
[super layoutSubviews];
// Find a reference point to calculate the offset:
CGRect bounds = self.bounds;
CGFloat pageGap = 8.f;
CGSize pageSize = bounds.size;
CGFloat pageWidth = pageSize.width;
CGFloat halfPageWidth = pageWidth / 2.f;
CGFloat scale = self.zoomScale;
CGRect visibleRect = CGRectMake(bounds.origin.x / scale, bounds.origin.y / scale, bounds.size.width / scale, bounds.size.height / scale);
CGFloat totalWidth = [self contentSize].width / scale;
CGFloat scrollWidth = totalWidth - visibleRect.size.width;
CGFloat scrollX = CGRectGetMidX(visibleRect) - visibleRect.size.width / 2.f;
CGFloat scrollPercentage = scrollX / scrollWidth;
CGFloat referencePoint = (totalWidth - pageWidth) * scrollPercentage + halfPageWidth;
// (use your own way to get all visible pages, each page is assumed to be inside a common container)
NSArray * visiblePages = [self visiblePages];
// Layout each visible page:
for (UIView * view in visiblePages)
{
NSInteger pageIndex = [self pageIndexForView:view]; // (use your own way to get the page index)
// make a gap between pages
CGFloat actualPageCenter = pageWidth * pageIndex + halfPageWidth;
CGFloat distanceFromRefPoint = actualPageCenter - referencePoint;
CGFloat numOfPageFromRefPoint = distanceFromRefPoint / pageWidth;
CGFloat offset = numOfPageFromRefPoint * pageGap;
CGFloat pageLeft = actualPageCenter - halfPageWidth + offset;
view.frame = CGRectMake(pageLeft, 0.f, pageSize.width, pageSize.height);
}
}