I'm trying to scroll the contents of a UIView using the contentOffset which so far I achieve handling touchesBegan: and touchesMoves: methods of the view, however I get a jumpy effect as I'm changing the bounds of the UIView manually (for example: current position +/- the change of the last position of the finger and the new position)
Is there any easy way to achieve this without manually changing the bounds of the UIView?
IMPORTANT NOTES: I'm not using a UIScrollView because the mentioned UIView has plenty of draggable subviews so if I use a UIScrollView I can't drag because the UIViewScroll scrolling event executes over the subviews events.
Animating the layer of the mentioned UIView causes the contents to move out of control, like if the point of reference had changed somehow.
However I'm always open to suggestions.
I would rather make a UIView container clipping subviews, add the content view which we will drag as a subview and change it's frame. I think it shouldn't have jumpy effect as it must be the same as animating the view frame change.
Related
I have a screen full of different UI objects that I need to scroll if on a 3.5 inch iPhone screen. I've added the ScrollView and setEnabled to YES but it still doesn't work. I'm thinking I should just code all the objects instead of using the IB and then add them to the scrollview. If I use a view with a scrollview on top with a view on top of that, then add them all to the subview, they lose their positioning. As for the constraints on the IB, there are simply too many objects and with hours spent on different constraint use, that will not be an option. Thanks for any suggestions and help.
Try to set the content size to be the size your frame, which is this case your view controller since you mentioned its "a screen full of different UI objects"
self.scrollView.contentSize = self.scrollView.frame.size;
then set scrollView frame to be the size of the view's frame
self.scrollView.frame = self.view.frame;
UIScrollView wont scroll, if the contents inside of the UIScrollview, are small enough to view without scrolling.
So if you have a UIView obj inside of your UIScrollView and that UIView is not Bigger than the UIScrollView, by default the UIScrollview will not scroll.
I am working on creating a color picker for "iOS". I am using this project, since it does what i want: "This"
I want to create a moveable circle (UIView) on top of the palette (UIImageView).
What I want to do is, while users move the circle, take the touch point and call the method getPixelColorAtLocation(); and change the background color of the circle to the color on current point. (Seen on most of the color palette/wheels)
The method getPixelColorAtLocation() is available on a child view. I created a circle with UIView on parent view, the problem is I cant call to getPixelColorAtLocation() from parent view.
My question is, Is there anyway to add a UIView as a subView to UIImageView. If I cant, what choices do I have to achieve what I want?
Yes you can do this.
[myImageView addSubview:sampleView];
An image view is just a subclass of UIView, so you can add subviews to it however you'd like. If there's a reason why you can't do so, then you can always make it a subview of the image view's superview, move it to the front, and then use convertPoint:toView: to convert to the image view's coordinate system, then get the pixel color.
I have a UIScrollView with a UIView as a subview. The UIView has a bunch of data entry fields arranged vertically - essentially just a fixed format data entry Form.
I want to keep the UIView's vertical size and adjust its horizontal size to match the size of the UIScrollView which changes depending on the orientation of the device. Note that this is all placed in the Detail view of a UISplitViewController.
So the user will have to scroll vertically but not horizontally as all the text fields on the UIView should resize themselves to fit horizontally on the screen.
Currently if I resize the UIView by changing the frame width to match the UIScrollView's frame width then the UIView subviews (the text fields) don't resize themselves according to the constraints setup in IB. The UIView just seems to get clipped. There is no horizontal scrolling so this aspect is working correctly.
I have autoresize subviews set on UIView and on UIScrollView.
Any tips on what to do here ? Also where would I put code to resize the UIView if the device orientation changes ?
Additional information.
I created the UIView in IB as a separate view in the same NIB as the DetailViewController containing the UIScrollView. Because it is much taller than the UIScrollView the only way I can find for creating it in IB is if I set it up as a separate view of the desired width and height. I then create an IBOutlet and add this view as a subview to UIScrollView in the viewDidLoad method. This all seems to work find with the views all displaying correctly, with the exception that the UIView subviews are not resized horizontally.
Any suggestions on what I may be doing wrong here?
Since you are using not putting the view inside scrollview directly from the xib, the IB doesn't provide the options to give constraints that has anything to do with superview. You might have to add the constraints programatically.See here.
EDIT:
Also try using the below on the view (haven't tried, should work according to documentation, but not sure with auto-layout):
self.view.autoresizesSubviews = YES;
Or if you don't want to use auto layout at all then the earlier method of setting the view to expand (horizontal/vertical) in the size inspector would do. For this you have to disable auto-layout. Select xib-> File Inspector -> Uncheck auto-layout checkbox
OK after more discovery I think I have found the right way to do what I am trying to do so i thought I should leave a note regarding this. Remember I am trying to create a scrollable form that resizes its width but not its height so the user only has to scroll up and down to access fields.
To create a large fixed size form that requires scrolling on the device make sure you set the ViewController size to Freeform in IB. Then you can create the view to be whatever size you want in IB and at runtime it will resize to the devices size.
Place the UIScrollView (I call it the scrollView) in the main view and pin it left and right and top and bottom (i.e set constraints using IB)
Place a UIView (I call it the contentView) in scrollView and make it the same size as the scrollView and also pin it on all sides to its superview (the scrollView)
Now add all the labels and text fields are required to the contentView and make sure you add vertical constraints from top to bottom and left to right so that autolayout can figure out the width and height in order to calculate the scrollView.contentSize
Set the contentView width constraint as a fixed size to make it look reasonable in IB. Bear in mind we want the width of contentView to always match the scrollView width so the user does not have to scroll sideways, only up and down. We will set the proper width in code at runtime as I have not found any way of doing this in IB only. Perhaps setting priorities on constraints might achieve this but I think UIScrollView won't do this for you.
Now add a property the ViewController.h file and connect this to the contentView width constrain you created in 5) above.
#property (weak, nonatomic) IBOutlet NSLayoutConstraint *contentViewWidth;
Finally create a viewDidLayoutSubviews method in ViewController and add the following code to set the contentView width to be the same as the scrollView width.
- (void)viewDidLayoutSubviews
{
self.contentViewWidth.constant = self.scrollView.frame.size.width;
[self.view layoutSubviews];
}
If things don't resize properly check all your constraints are correctly set. IB seems to do some things that seem strange to me. But finally I have it working with what appears to be minimum coding.
You can also resize vertically in the same way as long as you set the constraint priority on subviews in contentView to be lower than 1,000. Also set a greater than or equal to size with a high priority if you don't want it smaller than a certain size.
If anyone can figure out how to set the contentView such that it resizes its width to match the scrollView using only IB constraints I would love to know how.
THE PROBLEM:
I have an NSScrollView. I'm using it to implement a custom "Table View" with rows of data that are actually NSViews. (Note: this is not an instance of NSTableView.)
As I scroll vertically (there is no horizontal scrolling), I use a boundsChanged notification to add (as subviews of the scrollView's contentView) the NSViews that become visible (the ones with frames that intersect the scrollView's document visible rect) and to remove the ones that are no longer visible (frames outside of the scrollView's visible rect.)
The process works wonderfully except when it comes to inertial scrolling. If I have my cursor over cell X and I flick the trackpad to scroll downwards FAST with inertia, cell X quickly leaves the visible rect and, as such, is removed from the scrollView's contentView. BUT, that kills inertial scrolling. If I do NOT remove cell X as a subView, then inertial scrolling works perfectly.
WHAT I NEED:
A way to keep inertial scrolling while still removing the NSView that the cursor happened to be on top of when the user started the scrolling gesture.
WHAT I'VE TRIED:
I've looked at NSResponder's method:
-scrollWheel:(NSEvent *)theEvent
The default implementation passes scrollWheel to the next responder. So, I subclassed NSScrollView and implemented this method to try to stop it from passing the scrollWheel event to the individual subViews inside the scrollView's contentView. Didn't work.
So then I went into my NSViews (the ones I'm adding to the contentView) and overrode scrollWheel to pass the event back to the scrollView itself. Didn't work.
I still get scrolling in both cases, but not with inertia.
Any ideas? Thanks!
I haven't done this exact thing in Cocoa, but I'd probably be thinking about simply recycling your NSView object, as soon as its off the visible rect, by removing its subviews, then changing its frame to be in place to scroll back onto the visible rect from the top.
You can obviously do this by simply updating its frame, and avoid having to remove and re-add it to the NSScrollView.
I have a custom view subclass similar to NSBox that draws a rounded box background. The problem is that if I place a view like an NSTableView in the box view, it does not clip to the rounded corners. Is there any way to round the corners of NSTableView and its parent scroll view?
I haven't tried this with a table view but have with other controls.
In a subclass of NSTableView (or whatever view/control you want to clip)
Override drawRect:
Create an NSBezierPath with the shape you want (probably appendBezierPathWithRoundedRect:xRadius:yRadius: just remember to use the view's bounds as the size)
Send the path the addClip message to add that shape to the view's clipping path
Call super's drawRect:
If the table view has a header you may need to clip the top corners by subclassing NSTableHeaderView. And if you have scrollbars you may have to do the same thing to them except only clip certain corners. Hopefully you don't have scrollbars because I doubt that would look right. Basically you want to clip the view/control that draws that part, clipping the parent will not cause subviews to be clipped.
If you look at Apple's Welcome to Xcode window they get away with it by drawing a custom header at the top and a text block at the bottom so they don't have to round the table view itself. If you can do something like that I would.