Well I have an image and I I want that when I touch it and then I move my finger it follows it.but I want that it follows it only vertically like a vertical scrollview(but I don't wanna use a scrollview).How can I do this please. sorry for my english I'm french :/
Why wouldn't you subclass UIScrollView for your view that displays the image? If you do it's pretty simple: define its size so that the horizontal length doesn't exceed the screen length. You'd have to also remember to change this if you allow rotation of the device/view to landscape. Suppose the width of your UIScrollView is 320, you would do this:
CGSize scrollableSize = CGSizeMake(320, myScrollableHeight);
[myScrollView setContentSize:scrollableSize];
Where myScrollableHeight is the full height of the image.
I've never used it but if that doesn't work there is apparently a method you can provide for your UIScrollView class that is called whenever the user attempts to scroll and you can just not adjust the X-coordinate there:
float oldX; // make this ivar in your .h file
- (void)scrollViewDidScroll:(UIScrollView *)aScrollView
{
[aScrollView setContentOffset: CGPointMake(aScrollView.contentOffset.y, oldX)];
}
Take a look at Apple's MoveMe sample. This should give you an idea. If you only want it to move vertically, only change the y value while dragging.
Just adding a panning gesture to the image parent view and moving the image.center (only the y in your case) should be enough. Look at apple documentation for more details
Related
I have a UIScrollView of size 320*460 and with content size 1024*1024.
I can place 25 images of 256*256 in it with the 13th picture shown at the centre of the
screen when it loades with bits of surrounding pictures around it.
When i swipe to any side I want it to appear just like the mapView. With new images
appearing and showing.
How can I do it?
It's very easy & somewhat tricky...
You don't need to define the specific size for the ScrollView.....
Generally we use to define ....as per the Examples of Apple
//#define SCROLLVIEW_CONTENT_HEIGHT 460
//#define SCROLLVIEW_CONTENT_WIDTH 320
which is of no use...if you need the infinite height..
just set the height of the ScrollView dynamically as per the Objects added to the ScrollView....
No need to set the predefined height for this...take the dynamic height....
scrollview.contentSize = CGSizeMake(320, txtView.contentSize.height+450);
CGPoint topOffset = CGPointMake(0,0);
[scrollview setContentOffset:topOffset animated:YES];
Hope this will surely work for you..
Good Luck :)
Checkout the sample code called 'Tiling'. It might be what you're looking for.
When scrolling stops, couldn't you just adjust the bounds so that you are now "re-centered" with your new offset?
Presumably you can't scroll more than so many pixels before your finger hits the edge of the screen, so you only need bounds that a few hundred pixels outside the original center.
Once you have a new center, adjust your bounds accordingly, retiling as necessary.
I'm now trying to create my own Text panel (with code highlighting and so on).
In fact everything is ready except one thing - scrolling
What I've done:
created UIScrollView and inserted my own view as a subview using Interface builder.
in ViewController viewDidLoad method I've pointed initial textfield size to be the UIScrollView content size.
And when user writes too much into my text field. I call delegate (which is ViewController) to change size.
To do that I simply write
[scrollView setContentSize:newSize];
And what I get is increasing of the scroll view but not my text field - just blank lines appears. I think I need to set my view's size too but I can't figure out how...
And a second part of my question:
Every time I call [textField setNeedsDisplay] it calls drawRect: method with rectangle which is equal to the whole size of my view (which is much bigger than it's visible part). What will it look like if I try to use my view to modify file which size is more than 3 mb? How can I force it to redraw only visible part?
Thanks for your attention.
Part 1:
The scroll view's content size is not actually related to the size or position of the views it contains. If you want to change the size of the content view as well as the scroll view's content, you need to call two different methods.
CGSize newSize;
UIScrollView *scrollView;
// assume self is the content view
CGRect newFrame = (CGRect){CGPointZero,newSize}; // Assuming you want to start at the top-left corner of the scroll view. Change CGPointZero as appropriate
[scrollView setContentSize:newSize]; // Change scroll view's content size
[self setFrame:newFrame]; // Change views actual size
Part 2:
setNeedsDisplay marks the entire view as needing display. To cause it to display only the visible part, you need to use setNeedsDisplayInRect:visibleRect.
Assuming the view is at the top-left corner (its frame's origin is 0) and the scroll view does not allow zooming, the visible rect can be found using the scroll view's content offset and bounds size.
CGRect visibleRect;
visibleRect.origin = [scrollView contentOffset];
visibleRect.size = [scrollView bounds].size;
[self setNeedsDisplayInRect:visibleRect];
You could also choose to draw a part of the visible rect if only part changes.
It's simpler than you think, for example you have an UITextView called "textDesc" inside your UIScrollView, and you want to know the size of content, so next step will looks like that:
int contentHeight = textDesc.frame.size.height + textDesc.frame.origin.y;
After calculating the size of textDesc, just set it:
[scrollView setContentSize:(CGSizeMake(320, contentHeight))];
That's all, now your scrollView know the size of your text inside him, and will resize automatically, hope this helps, good luck.
Set your text field autoresizingMask property to flexible height and width:
[textField setAutoResizingMask:UIViewAutoResizingFlexibleHeight | UIViewAutoResizingFlexibleWidth];
This should expand the view automatically when you change it's parent's size (the scrollView's contentSize)
Otherwise try:
[textField setFrame:CGRectMake(0, 0, scrollView.contentSize.width, scrollView.contentSize.height)];
just after you change the scroll view's contentsize.
I'm trying to make a timeline view that shows events as UIButtons that can be pressed for more info.
Ideally I want to lay out the buttons on a UIScrollView, and allow them to stretch/shrink horizontally, but not vertically.
What I'm trying to accomplish would basically be equivalent to using pinch gestures to resize the content view, and using a scroll view to move side to side - could you point me in the right direction, or suggest how you might accomplish something like this?
My first thought is a UIScrollView to scale a UIView subview, and have the UIView subview contain another subview that does not resize vertically, but only does horizontally when bounds change, and disable vertical scrolling. Maybe I could skip one of these UIView subviews and have only one do everything. It just feels like I'm trying to hack this together like an HTML page or something with all these containers.
Not sure if I've explained any of this well enough to hope for an answer, any help is appreciated though.
I've implemented horizontal-only scaling by creating a subclass of UIView that simply overrides setTransform and sets the Y scale to 1 whenever the UIScrollView changes the scale:
#interface DiagramStripView : UIView { }
#end
#implementation DiagramStripView
- (void)setTransform:(CGAffineTransform)newValue;
{
newValue.d = 1.0;
[super setTransform:newValue];
}
#end
As the class name suggests, my view holds a series of diagrams that are each one screen wide. When the user lets go, the view controller resets the view's scale to 1 and redraws everything to the new scale:
- (void) scrollViewDidEndZooming:(UIScrollView *)scrollView
withView:(UIView *)view atScale:(float)scale
{
diagramStripView.transform = CGAffineTransformIdentity;
[self redrawDiagrams:scale];
}
Haven't tried this, but you could try placing everything in a UIScrollView, and whenever you detect a zoom level change, adjust all of the child view transforms to CGAffineTransformMakeScale(1.0, 1.0/zoomLevel). This way, the scrollview is zooming everything up, but each subview is scaling themselves vertically downward, canceling out the zoom.
Assuming you don't actually want to stretch/shrink the button text, the easiest way is to resize all the buttons. I know, it's a pain.
I am trying to create an app with horizontal scrolling, so that one would be able to scroll horizontally through a series of images. I watched the WWDC Session 104 video on this, and while they made an interesting app, they flew through the basics of it very quickly.
I understand using the UIScrollView, and that I have to enable paging. After that they say that I should add more views as subviews of the scrollview, but I am not clear on how to do that. I am also not clear on how I add my images to those views.
As you can probably tell I am pretty new at this so any help would be appreciated.
You want to look into UIImageView. It's a view specifically for holding images.
When you add your images, you want to set their rects (probably using initWithFrame: for each UIImageView) so that:
the first image is at 0,0
the second image is at 320,0
third is at 640,0 (etc)
I.e. each image is 320 pixels right of the previous.
The final step is to set the contentSize for your UIScrollView -- this is a CGSize which describes the total size of the scroll view.
If you have 3 images, you would then set it to (320*3) * 480 using e.g.
myScrollView.contentSize = CGSizeMake(320*3, 480);
A lot of people, when they initialize the scroll view, have a for loop or similar which steps through the images they want to display. These for loops tend to look something like this:
CGFloat scrollWidth = 0.f;
for (UIImage *someImage in someNSArrayWithImages) {
UIImageView *theView = [[UIImageView alloc] initWithFrame:
CGRectMake(scrollWidth, 0, 320.f, 480.f)];
theView.image = someImage;
[myScrollView addSubview:theView];
[theView release];
scrollWidth += 320.f;
}
myScrollView.contentSize = CGSizeMake(scrollWidth, 480.f);
This way you'll get things lined up and you'll get the content size for you at the same time.
If you want to make it so that the scroll view "intelligently" scrolls to each image and stops when people slide left/right, you can do myScrollView.pagingEnabled = YES.
Hope that helps get you going.
Assuming you have "infinite" images, putting them all there at or before launch time in a huge UIScrollView will not be an option. (there is a limit to the size of a UIView)
The way I solved it: Make a UIScrollView covering the whole screen. It's content should be a UIView of 3*320 width and 480 height, extending 320px left and 320px right.
Put 3 UIImageView's in it, left, middle and right. Set paging=YES, so the uiscrollview clips to the 3 "pages" you've created.
Make sure your class is the delegate of the uiscrollview, and listen for
-(void)scrollViewDidEndDragging:(UIScrollView*)sv willDecelerate:(BOOL)notFinished
-(void)scrollViewDidEndDecelerating:(UIScrollView*)sv
-(void)scrollViewDidEndScrollingAnimation:(UIScrollView*)sv
and make the appropriate transitions on hitting paging boundaries; shift images and set ContentOffset so you're looking at the center image again.
I suggest you make this first, and only then read on...
Then you will hit on a bug, documented here UIScrollView - (bounces = NO) seems to override (pagingEnabled = YES) and here http://www.iphonedevsdk.com/forum/iphone-sdk-development/935-paging-uiscrollview.html, which makes that you cannot disable bouncing and have paging enabled at the same time. So enable bouncing, and subclass UIScrollView, overruling setContentOffset in there to prevent bouncing. (having bouncing really enabled will make for a rather unusual user experience)
Have a look at Apple's PageControl sample code. It's fairly short and easy to follow so you'll get the gist of setting up a project where multiple view controllers are loaded as you swipe horizontally.
Once you have this setup then it's the view controller's responsibility to load its own content (in your case, an image). You should make sure you understand how to load images first (using threads, etc) before you tackle paging, etc.
Think of it as two independent tasks. The view control is responsible for loading and displaying an image. The scroll view with paging just tells the appropriate view controller when to load itself (it doesn't care what the view controller does once its loaded)
Good luck!
I have a UIScrollView of size 320*460 and with content size 1024*1024.
I can place 25 images of 256*256 in it with the 13th picture shown at the centre of the
screen when it loades with bits of surrounding pictures around it.
When i swipe to any side I want it to appear just like the mapView. With new images
appearing and showing.
How can I do it?
It's very easy & somewhat tricky...
You don't need to define the specific size for the ScrollView.....
Generally we use to define ....as per the Examples of Apple
//#define SCROLLVIEW_CONTENT_HEIGHT 460
//#define SCROLLVIEW_CONTENT_WIDTH 320
which is of no use...if you need the infinite height..
just set the height of the ScrollView dynamically as per the Objects added to the ScrollView....
No need to set the predefined height for this...take the dynamic height....
scrollview.contentSize = CGSizeMake(320, txtView.contentSize.height+450);
CGPoint topOffset = CGPointMake(0,0);
[scrollview setContentOffset:topOffset animated:YES];
Hope this will surely work for you..
Good Luck :)
Checkout the sample code called 'Tiling'. It might be what you're looking for.
When scrolling stops, couldn't you just adjust the bounds so that you are now "re-centered" with your new offset?
Presumably you can't scroll more than so many pixels before your finger hits the edge of the screen, so you only need bounds that a few hundred pixels outside the original center.
Once you have a new center, adjust your bounds accordingly, retiling as necessary.