I'm developing an iphone application with an UIView that have an image as a background and multiple buttons with image as background. The image is an image of a country and the buttons are the regions/states of that country.
The problem is that the screen is too much little to display all this data, so I want to enable pinch-to-zoom of the UIView which allows user to have a better view of the country.
Inside 'viewDiDLoad' of my UIViewController, I added:
UIPinchGestureRecognizer *twoFingerPinch = [[[UIPinchGestureRecognizer alloc]
initWithTarget:self
action:#selector(twoFingerPinch:)]
autorelease];
[[self view] addGestureRecognizer:twoFingerPinch];
and I added twoFingerPinch method:
- (void)twoFingerPinch:(UIPinchGestureRecognizer *)recognizer {
if (recognizer.scale > minValue){
CGAffineTransform transform = CGAffineTransformMakeScale(recognizer.scale, recognizer.scale);
self.view.transform = transform;
}
}
and it work correctly, the problem is that the UIView becomes bigger but user can't navigate inside.
So I switched my UIView to a UIScrollView and inside 'twoFingerPinch' method I added:
if (recognizer.state == UIGestureRecognizerStateEnded){
float scaleForView = mLastScale;
UIScrollView *tempScrollView=(UIScrollView *)self.view;
int newWidth = self.view.frame.size.width * scaleForView;
int newHeight = self.view.frame.size.height * scaleForView;
tempScrollView.contentSize=CGSizeMake(newWidth,newHeight);
mLastScale = 1.0;
}
but it doesn't work well: the UISrollView becomes much bigger but it's not bigger as the image scaled and also is not centered where pinchToZoom started.
How can i solve this problem?
Thank You
Related
I have an app which I'm updating to auto layout and size classes and I'm getting some weird behaviour with the label on a button.
The button should be a circle and have a label in the centre. I'm implementing my own subclass so I can reuse it.
Here's the storyboard:
and the code for the class which extends UIButton:
- (id)initWithCoder:(NSCoder *)aDecoder
{
self = [super initWithCoder:aDecoder];
if (self) {
[self setBackgroundImage:[UIImage imageNamed:#"selected-green"] forState:UIControlStateHighlighted ];
self.layer.borderColor = [UIColor tlbWhiteColor].CGColor;
self.layer.borderWidth = 10;
}
return self;
}
-(void) layoutSubviews {
self.layer.cornerRadius = self.frame.size.width / 2;
}
With this the appears as expected but there is no label. On debugging I see that the frame of the label has 0 height and width. So I extended layoutSubviews:
-(void) layoutSubviews {
self.layer.cornerRadius = self.frame.size.width / 2;
if (self.titleLabel.frame.size.width == 0) {
[self.titleLabel sizeToFit];
[self setNeedsLayout];
[self layoutIfNeeded];
}
}
The label then appears, but it's in the wrong place:
The only extra info I can offer is that in Reveal the button has weird height and width constraints added:
The titleInsets are all at 0.
Help hugely appreciated.
I don't think you need the layoutSubviews override. I think it's a hack and it's hiding your real issue.
What are the constraints on the 'Go' label? How are you centering it in the UIButton? Also what is the height constraint on the label?
My suggestion would be to put both the UIButton and the Go label inside a container view and centre the label inside the container view. The container view should have the same height and width as the UIButton inside it.
Also are you changing the frames of the views programmatically somewhere in the app? Those weird constraints you talk about in reveal point to that.
As per your requirements:
- (void)viewDidLoad {
[super viewDidLoad];
view_1.layer.cornerRadius = 10; //view_1 is white color
view_1.layer.masksToBounds = YES;
view_2.layer.cornerRadius = _view_2.frame.size.width/2;//view_2 is green color
view_2.layer.masksToBounds = YES;
}
output
Ok, this was a real school boy error.
When the docs said 'The implementation of this method is empty before iOS 6' I for some reason took this to mean there's no need to call super on layoutSubviews.
So the fix was:
-(void) layoutSubviews {
[super layoutSubviews]; // <<<<< THIS WAS MISSING
self.layer.cornerRadius = self.frame.size.width / 2;
self.layer.masksToBounds = YES;
}
Im pretty new to coding but I'm starting to get the hang of the basics.
how to make an image stay in its new position after an animation?
Example:
I'm giving an animating object a random position, however, the animation causes the object not to animate at the random position, but instead animate at the position it was given in the view controller. This also happens when I animate a completly different object.
Code I used:
int Random1x;
int Random1y;
IBOutlet UIButton *Start;
IBOutlet UIImageview *Object2;
-(void)ObjectMoving;
-(void)Object2Animate;
-(IBAction)Start:(id)sender{
[self ObjectMoving];
[self Object2Animate];
}
-(void)Object2Animate {
Object2.animationImages = [NSArray arrayWithObjects:
[UIImage imageNamed:#"2.png"],
[UIImage imageNamed: #"3.png"],
[UIImage imageNamed: #"4.png"],
[UIImage imageNamed: #"1.png"], nil];
Object2.animationDuration = .5
[Object2 setanimationRepeatCount: 0]
[Object2 startAnimating];
}
-(void)ObjectMoving {
Random1y = arc4random() % 466;
Random1y = Random1y + 60;
Random1x = arc4random() % 288;
Object2.center = CGPointMake(Random1x, Random1y);
}
I'd greatly appreciate help, thank you!
If you go to your story board file and click on the View Controller and then file inspector you will see a box for Auto Layout
Post back if that worked.
If you do need to use auto layout then you would have to figure out a different way of moving the image.
I have a UIScrollView filled with UIImageView. The UIScrollView are paging enabled to let the users to "flip" those images. Each UIImageView has UIPinchGestureRecognizer for pinch zoom, and UIPanGestureRecognizer for to pan that image when zoomed in.
As probably you have noticed, what I'd like to achieve is just like what iBooks does in its application.
However, I have difficult times to get this work.
In my "BookPageViewController", I have set up UIScrollView, then fill them with images from the folder based on data (page numbers, file names, etc) from sqlite.
_pageScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
NSUInteger pageCount = [pages count];
for (int i = 0; i < pageCount; i++) {
CGFloat x = i * self.view.frame.size.width;
// Page Settings
UIImageView *pageView = [[UIImageView alloc] initWithFrame:CGRectMake(x, 0, self.view.frame.size.width, self.view.frame.size.height)];
pageView.backgroundColor = [UIColor greenColor];
pageView.image = [pages objectAtIndex:i];
pageView.userInteractionEnabled = YES;
pageView.tag = i;
// Gesture Reocgnisers
UIPinchGestureRecognizer *pinchGr = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:#selector(pinchImage:)];
pinchGr.delegate = self;
[pageView addGestureRecognizer:pinchGr];
UIPanGestureRecognizer *panGr = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(panImage:)];
[pageView addGestureRecognizer:panGr];
// Finally add this page to the ScrollView
[_pageScrollView addSubview:pageView];
}
_pageScrollView.contentSize = CGSizeMake(self.view.frame.size.width * pageCount, self.view.frame.size.height);
_pageScrollView.pagingEnabled = YES;
_pageScrollView.delegate = self;
[self.view addSubview:_pageScrollView];
And with the help of another good questions here in Stackoverflow, I have put those:
- (void) pinchImage:(UIPinchGestureRecognizer*)pgr {
[self adjustAnchorPointForGestureRecognizer:pgr];
if ([pgr state] == UIGestureRecognizerStateBegan || [pgr state] == UIGestureRecognizerStateChanged) {
if ([pgr scale]) {
NSLog(#"SCALE: %f", [pgr scale]);
[pgr view].transform = CGAffineTransformScale([[pgr view] transform], [pgr scale], [pgr scale]);
[pgr setScale:1];
} else {
NSLog(#"[PAMPHLET PAGE]: The image cannot be scaled.");
}
}
}
My problem is, when I zoom in the one of the UIImageView with Pinch Gesture, the image exceeds (go over) to the next image and hides it. I believe that there should be the way to "limit" the zoom in/out and the size of UIImageView (not UIImage itself), but I don't know where to go from here. I have also put a code to limit the scale something like:
([pgr scale] > 1.0f && [pgr scale] < 1.014719) || ([pgr scale] < 1.0f && [pgr scale] > 0.98f)
but it didn't work...
I know it's not hard for ios professionals, but I'm quite new to objective-c, and this is my first time to develop real application. If this is not a good practice, I also would like to know any ideas to achieve just how to do this like ibooks do (e.g. put UIImageView in UIScrollView, then put the UIScrollView to another UIScrollView)...
Sorry for another beginner question, but I really need help.
Thanks in advance.
Without trying it out myself, my first guess would be that the transform on the UIImageView also transforms its frame. One way to solve that, would be to put the UIImageView in another UIView, and put that UIView in the UIScrollView. Your gesture recognizers and the transform would still be on the UIImageView. Make sure the UIView's clipsToBounds property is set to YES.
I'm using the Page-Based Application template in Xcode 4 to load pages of a PDF and create a UITextView over hidden text boxes so the user can write notes.
So far I have it all working, but when I add the UITextView, it's in the wrong place in landscape mode (showing 2 pages).
// ModelController.m
- (id)init
{
self = [super init];
if (self) {
NSString *pathToPdfDoc = [[NSBundle mainBundle] pathForResource:#"My PDF File" ofType:#"pdf"];
NSURL *pdfUrl = [NSURL fileURLWithPath:pathToPdfDoc];
self.pageData = CGPDFDocumentCreateWithURL((__bridge CFURLRef)pdfUrl); // pageData holds the PDF file
}
return self;
}
- (DataViewController *)viewControllerAtIndex:(NSUInteger)index storyboard:(UIStoryboard *)storyboard
{
// Return the data view controller for the given index.
if( CGPDFDocumentGetNumberOfPages( self.pageData ) == 0 || (index >= CGPDFDocumentGetNumberOfPages( self.pageData )))
return nil;
// Create a new view controller and pass suitable data.
DataViewController *dataViewController = [storyboard instantiateViewControllerWithIdentifier:#"DataViewController"];
dataViewController.dataObject = CGPDFDocumentGetPage( self.pageData, index + 1 ); // dataObject holds the page of the PDF file
[dataViewController view]; // make sure the view is loaded so that all subviews can be accessed
UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake( 10, 20, 30, 40 )];
textView.layer.borderWidth = 1.0f;
textView.layer.borderColor = [[UIColor grayColor] CGColor];
[dataViewController.dataView addSubview:textView]; // dataView is a subview of dataViewController.view in the storyboard/xib
CGRect viewFrame = dataViewController.dataView.frame; // <- *** THIS IS THE WRONG SIZE IN LANDSCAPE ***
}
This behavior really surprised me, because viewControllerAtIndex isn't called when I rotate the iPad, so I have no way of knowing what the real size of the view frame is. I get the same view frame in both portrait and landscape:
# in Xcode console:
po [dataViewController view]
# result in either orientation:
(id) $4 = 0x0015d160 <UIView: 0x15d160; frame = (0 20; 768 1004); autoresize = RM+BM; layer = <CALayer: 0x15d190>>
#
Does anyone know if there is a transform I'm supposed to use to position the UITextView correctly? I'm concerned that I may have to store the locations of the elements independently and reposition them upon receiving shouldAutorotateToInterfaceOrientation messages.
It seems that Apple may have implemented UIPageViewController improperly, but all I could find was this partial workaround that I'm still trying to figure out:
UIPageViewController and off screen orientation changes
Thanks!
I think the trick here is to override viewDidLayoutSubviews in your DataViewController and manage the size of all your programmatically-inserted non-autosizing views, since you don't really know what the parent is going to do to its subviews until that time.
-(void)viewDidLayoutSubviews
{
[super viewDidLayoutSubviews];
self.textView.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height);
}
I have created a view that contains a CGGradient:
// Bar ContextRef
CGRect bar = CGRectMake(0, screenHeight-staffAlignment, screenWidth, barWidth);
CGContextRef barContext = UIGraphicsGetCurrentContext();
CGContextSaveGState(barContext);
CGContextClipToRect(barContext,bar);
// Bar GradientRef
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGFloat components[16] = { 1.0,1.0,1.0,0.0, 0.0,0.0,0.0,1.0, 0.0,0.0,0.0,1.0, 1.0,1.0,1.0,0.0};
CGFloat locations[4] = {0.95,0.85,0.15,0.05};
size_t count = 4;
CGGradientRef gradientRef = CGGradientCreateWithColorComponents(colorSpace, components, locations, count);
// Draw Bar
CGPoint startPoint = {0.0,0.0};
CGPoint endPoint = {screenWidth,0.0};
CGContextDrawLinearGradient(barContext, gradientRef, startPoint, endPoint, 0);
CGContextRestoreGState(barContext);
This code is called in the drawRect method of the UIView. I then use a UIViewController to access the created view.
- (void)loadView {
MainPageView *mpView = [[MainPageView alloc] initWithFrame:[window bounds]];
[self setView:mpView];
[mpView release];
}
and displayed on the screen through the appDelegate:
mpViewController = [[MainPageViewController alloc] init];
[window addSubview:[mpViewController view]];
[window makeKeyAndVisible];
The UIView contains more objects, such as UIButtons, that are visible. I am assuming because they are added as a subview. But I can't work out how to add the CGGradient as a subview? Does it need to be? Is there another reason CGGradient is not visible?
I also don't get the functionality on the UIButtons. I guess that is because of where I have added the UIButtons to the view. Do the buttons need to be added in the UIViewController or the appDelegate to have functionality. Sorry to ask what would seem like simple questions but I am trying to accomplish the programming without the Interface Builder and material on that is scarce. If anyone could point me in the right direction on both these problems I would really appreciate it.
Thanks!
The functionality on the buttons was lost because the frame was too large but the buttons were still visible because the background was clearColor