i want my app to be able to track a person when he moves 2 dimensionally upwards. I already have a vertical scroll view, and it works, but when i press a button i want it to track a little stick figure as he walks vertically, how can i control this? i thought of setting the scrollview.contentoffset to a certain position, but it just changes it one time when i want it to change it fluidly. i suppose i could make a timer that updates the contentOffSet every like .001 seconds or something, but i thought there maybe a better way.
Also, while i was searching the UIScrollView's methods, one of them was an isTracking method, which is a boolean, and I'm assuming it returns yes if the scrollview is tracking something, so given that i assume there is a feature in scrollview so that you can track things. Also, if to track things you have to use some other framework thing that would be helpful to know too
THANKYOU FOR ANY HELP!
The property tracking tells if the scroll view is currently tracking the user's movement. So that definitely won't help you out. (See David H's post for a better explanation for what the property indicates.)
However, you could use setContentOffset:animated: and set animated to YES. That results in a smooth transition to the new content offset.
Instead of calculating a reasonable content offset you might find it easier to specify an area that contains the stick figure. If so use scrollRectToVisible:animated:. Obviously animated should be set to YES.
1) don't use contentOffset = x;, use "- (void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated". Experiment how often you need to send this message, but I'm guessing you can do it no more than 10 times a second and get nice results.
2) isTracking means the user has their finger on the scrollView but has not started dragging it. By testing "isTracking" and "isDragging" you can determine if the user is fiddling with your scrollView or not.
Related
I want to create a custom UIView that would be equivalent to a horizontal UIPickerView. The data elements, such as "Mountain View, Sunnyvale, Cupertino, Santa Clara, San Jose" would move left to right. The view would be long and thin. 50px in height, 350x in width sort of thing.
I will need to use protocols to obtain my datasource elements likely, but what I'm more interested in figuring out is the visual aspect of this.
How would I animate things left and right? Should I just make one incredibly long view (off screen), and change the frame left and right. This seems like a bad idea, as likely only 3-5 options need to be visible in the control at one time. If the datasource is 100 elements, there is no point in loading the other 95 off screen in a long view.
So perhaps I should load ~9 or something. The 3-5 on screen, plus an additional ~3 left and right. Each time the control is triggered to move left and right, it will load up another element on the view(?).
Is this a good way to achieve this? A long thin view with ~9 UILabel's. As the control moves to the right, I would shift the further left UILabel to move hidden to the far right, and change the UILabel to be the next in the data source.
I also likely want to change the text size based on its position. If it's currently selected, I either want to bold it and possibly increase the font size. How can I gradually achieve this as the view is moved? It would be weird if the text only changed once it was moved perfectly center inside the view. It should likely gradually grow as it gets closer to the middle.
How can I achieve this?
A collection view would do the trick, obviously there's some coding involved.
I'd suggest you to take a look at the code of, or use, the following library.
I've used it once,does almost exactly what you need and works very well:
AKPickerView
I am making an iOS app for remote controlling the lights in my house. I have a list of groups of bulbs (rooms) that can be turned on and off. My problem is selecting a room, I want it to be like this:
You can either press the arrows left or right to switch the room, or you can put your finger, where it says Living Room and swipe left or right to switch it.
Can someone give me a pointer as how to implement a swipe feature like that? I know there are gesture recognizers. I never used them, but I guess they won't automatically make the text I want to swipe follow my finger.
I guess it would be possible to use the gesture recognizer and manually move the text to get the swipe "feeling". It just seems to me like there should be an easier solution.
I've done something similar several times, and the most elementary way to approach it is to override the touches... methods on NSResponder. This will tell you when a user's finger touches the component, when it moves, and when they let go. From that, it's pretty easy to adjust the position of your UIView, do some custom rendering, or whatever else you need.
Another, higher-level, approach is to use a UIScrollView and implement it's delegate methods. Inside the scroll view are three elements which completely fill the viewport: the one you can see, and those to the left and right. You watch the delegate events for the user adjusting the position of the viewport and as they expose an element to the left or right, you can snap the viewport into place when they let go. Then, you adjust the three inner views to show the appropriate new content and reset the viewport to expose the middle element (which would then be showing the appropriate content).
There are undoubtedly many other approaches, but I've used both of these with good effect.
I solved it in the end by using a pangesturerecgonizer attached to the label. It's pretty straight forward, I just didn't know pan is supposed to mean something like drag and drop, I thought pan would be something completely different.
I am displaying hundreds of thumbnails in my view . I know default way to handle tap on thumbnail is using UICollectionView delegate method "didSelectItemAtIndexPath" but since its many thumbnails i wanted to look into adding gestures to the screen position so when i tap on a particular spot on the screen, it will handle the event accordingly for that particular thumbnail underneath. I would like to know if it is a good/possible approach?
It would be a hell of a lot easier to use a UICollectionView.
If you need a custom layout then you can subclass UICollectionViewLayout and get some really cool dynamic layouts.
You also get the added bonus of dequeued cells meaning that you get better memory management using it.
You may find UIGestureRecognizer useful. A good tutorial to get you started is here.
Anyone have any ideas on how I could go about replicating the scrolling stocks ticker in Notification Center on iOS 5?
What I'm thinking is using a UIScrollView, and use a UIView subclass for the items in the ticker. Would using an NSTimer be the best way to have it scroll automatically? How would I handle manual scrolling acceleration and deceleration like the Apple stocks widget does?
Also, how do I handle infinite scrolling?
Thanks for any suggestions.
Try AutoScrollLabel. It's a relatively old class, but the code design and animation behind it may be useful. If I understand correctly, it's a UIScrollView that holds two labels, each saying the same thing, resulting in "scrolling" as it animates between them. I'm sure you could take that concept and the drawRect: method in the code to create your own subclass of the UIScrollView and animate whatever content you want, complete with infinite scrolling. There may very well be an easier way, but I've used AutoScrollLabel in a few apps and it's easy to use and works without a problem. Let me know if you need more info/a usage example. Hope this helps!
Is there a way to change the orientation of the iPhone using a button?
No. flip the phone, the orientation changes. Leave it at that, or you'll ruin the integrity of the phone.
sometimes we need to show our app in the correct orientation, even if there is not direct way on doing what domness want, you can look at this SO entry and see some responses.
P.S. # domness, try to search for what you need before posting a new question.
What exactly are you trying to reorient? You can change the position of the status bar with UIApplication -setStatusBarOrientation:animated:; rearrange your UI with the proper transformations and you'll pretty much have it.
You can force an orientation change, but only using an unsupported, private API. If this is something you'd like Apple to make public, you should file an enhancement request.
This is my new account btw..
Right, I got this sorted by apply the transformations to what I wanted to show when the button was clicked. It was to show a scrollview with applied animations to objects within the scroll view.