Hi I am new i want to develop a application that we zoom in and zoom out image but i am not understand how to do this. any one help me with code and other
For iPhone OS 3.2 or higher, use the bundled gesture recogniser UIPinchGestureRecognizer.
In my opinion the easiest way would be to add an UIScrollView to your viewcontroller which will be the scrollviews delegate.
Then you'll implement the viewForZoomingInScrollView UIScrollViewDelegate method where you'll return the UIImageview that has to be zoomed/pinched.
You would also need to set the maximumZoomScale and minimumZoomScale properties of the UIScrollView.
UIScrollView documentation
UIScrollViewDelegate documentation
A scroll view also handles zooming and panning of content. As the user makes a pinch-in or pinch-out gesture, the scroll view adjusts the offset and the scale of the content. When the gesture ends, the object managing the content view should should update subviews of the content as necessary. (Note that the gesture can end and a finger could still be down.) While the gesture is in progress, the scroll view does not send any tracking calls to the subview.
The UIScrollView class can have a delegate that must adopt the UIScrollViewDelegate protocol. For zooming and panning to work, the delegate must implement both viewForZoomingInScrollView: and scrollViewDidEndZooming:withView:atScale:; in addition, the maximum (maximumZoomScale) and minimum ( minimumZoomScale) zoom scale must be different.
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I have an atypical iOS interface. Perhaps it's not practical but I'm giving it a go. Hope someone can help!
I have a menu in the form of a UIVIew. It contains 5 small UIImageViews. A UIPinchGestureRecognizer is attached to the UIVIew. When pinched inward, the 5 UIImageViews animate from off screen to form a circle in the middle of the window. When pinched outward, they animate back offscreen. Everything works great there.
I'd like to be able to, at any point in the application, pinch the screen to reveal the menu, select one of the 'buttons' (UIImageView), and load the associated subview.
The real problem is, if the current visible view is a UIScrollView or UITableView, my app is having trouble figuring out whether the menu or other subview should handle the touch event. If I really focus and make sure two finger touch the screen at the EXACT same time, the pinch will work and pull the menu inward. But otherwise, it attempts to scroll the current visible view.
I would like all events except the pinch gesture, (and a tap gesture when the menu is visible), to pass through the menu view to the rest of the subviews.
I understand I can override the hitTest:withEvent method to determine the correct view to handle the event, but I'm unclear at this point how exactly to use it. Neither the Apple docs nor any answers I've read on stack overflow have made this method clear to me.
Any help is much appreciated.
As UITableView is a subclass of UIScrollView, it inherits all of UIScrollView's properties including its gesture recognisers.
UIScrollView declares a UIPinchGestureRecognizer and UIPanGestureRecognizer. I'm not sure of the implementation details but I imagine the UITableView disables the pinch gesture recogniser as you are not supposed to be able to zoom a tableview!
In any case, you can attach your own UIPinchGestureRecognizer to the table view:
UIPinchGestureRecognizer *yPGR = [[UIPinchGestureRecognizer alloc]
initWithTarget:probablySelf action:yourMenuShowSelectorHere];
UITableView *tv = ...
// ...
[tv addGestureRecognizer:yPGR];
Then, you can make sure that the UITableView scoll does NOT scroll until your pinch has failed:
[tv.panGestureRecognizer requireGestureRecognizerToFail:yPGR];
This way, the UITableView will not scroll until it is sure that it has not detected a pinch.
EDIT: UIScrollView only uses (or at least declares public access to) UIGestureRecognizers in iOS 5 and up.
I want to implement a scroll view which looks like the stock ticker. It can respond slide or tap gesture.
How can I implement this? Please advise me. Thank you!
Use a NSTimer to reposition the contentOffset of your Scrollview.
Use the UIScrollViewDelegate to stop your animation while the user is dragging the scrollview.
Conceptually I'd setup an container UIScrollView with the contents of the scrolling area as subviews. To simulate a circular scroll I'd keep an array of the subviews. I'd add a view just off screen at the starting edge, and take away a view just off screen at ending edge.
UIScrollViewDelegate methods will be called when a person starts or stops dragging the view, which you can use to start and stop the animated scrolling. Other methods in this protocol can be used to reset the contents of the scrollview when the edge is reached, so more views can be added as needed.
I'd probably use a CADisplayLink to manually manage the animations. The method given to the CADisplayLink would update the scroll and manage adding and subtracting views to the edges. It would also stop scrolling based on a flag set by the UIScrollViewDelegate methods when the person is dragging the scroll.
Unless you jailbreak, you can't put custom views in Notification Centre.
I have a scrollview with an imageview on it. I am able to zoom the image view placed inside the scrollview. On top of it I have some uibuttons, which do not reposition after zoom.
How do I reposition UIButtons after zoom?
Please help
Thanks
One way would be to implement the scrollViewDidZoom: delegate method of your scroll view delegate, determine the currently visible rectangle using contentOffset and contentSize properties of your UIScrollView, compute the new location of your buttons relative to the visible rectangle of the scroll view, and reposition your buttons into that rectangle by setting their frame property as desired.
As Fisk mentioned, the UIScrollViewDelegate should help. One of the delegate methods is:
-(void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale
If you implement the UIScrollview delegate this method should get called when your scrollview is done zooming. So in this method you can reposition your button after the zoom:
[yourButton1 setCenter:CGPointMake(newX,newY)];
Good luck.
Your question is a bit vague. However, whatever it is that you are doing, I believe UIScrollViewDelegate can help you.
This is a delegate for the scroll view that lets you know when it is scrolling. I never got where the buttons are supposed to be, but with this delegate I guess you can simply place them wherever they need to be.
I have a UIScrollView and an UIImageView as its subview. I want to draw on the imageview in response to the single touches. And I want to zoom and pan the image view in the scroll view on pinch and pan gestures respectively. I found many solutions. But its not perfect. Please give me a straight forward solution.
use after subclassing UIScrollview.See the link.If you are doing application for iphone4 OS,try to use UIGestureRecogniser.see the sample code for it in Apple site.
If you are only using the scrollview for panning and zooming, I would suggest subclassing UIImageView to provide that functionality yourself along with the drawing. This will allow you to have finer control over it and quicker code. A scrollview is not very good at allowing complex gestures within it. (other than taps)
I placed a few uiimageview objects into a scrollview. How can the imageview know the scrollview is being scrolled? Since the imageview is a subview of the scrollview i can't set the scrollview delegate to the imageview.
I want to create something similar to the apps view on the iphone. Where you can hold down an app and then drag it, but if you hold and move your finger too far to the left or right the action is stopped and scrolling takes over.
"Since the imageview is a subview of the scrollview i can't set the scrollview delegate to the imageview."
And why not?
You have viewcontroller which shows the particular scrollview correct? this viewcontroller should be the delegate of the scrollview, and viewcontroller should also hold pointers (either explicitly in an array or through tag of some sort) to the uiimageviews.
Then, whenever scrollview notifies viewcontroller (through scrollviewdidscroll type of delegate method), implement your logic to update uiimageview.
To implement the exact touch sequence, you can subclass UIGestureRecognizer or write your own touch handler.. take a look at Apple's documentation on Event Handling Guide :
http://developer.apple.com/library/ios/#documentation/EventHandling/Conceptual/EventHandlingiPhoneOS/Introduction/Introduction.html#//apple_ref/doc/uid/TP40009541
It doesn't, it just draws and draws. The scrollView makes sure you only see the part you really want to see
You might want to look at three20, they have a class that is very similar to the springboard. -- Used in facebook.app
Thanks Everyone, but I found out that UIScrollView sends the touchesCancelled message to the subview when scrolling starts.