My app has a set of horizonal bars (obstacles) that move up from the bottom of the screen. When they hit an invisible horizontal bar at the bottom 1/3rd of the screen, I want to spawn another set of obstacles.
I have set the spawning bar to be a gray rectangular sprite for now, just for debugging. When the obstacles move upwards, they simply pass under the spawning bar and no contact is detected. However, when I set the physicsBody.dynamic property of the spawning bar to "YES" the contact is detected. I can't use this, though, because it would push the bar offscreen.
Is there a problem with detecting contact between 2 non-dynamic bodies? How can I fix this?
Whoops, I upon further research, Sprite Kit doesn't check for contact between 2 static bodies. I had to set one of them to dynamic.
Related
Using Auto Layout constraints, I am trying to set up a subview with a vertical position that never changes, even when the in-call status bar (or some other non-standard status bar) is showing. I don't want to position the view relative to the Bottom Layout Guide because I want its y-coordinate to be the same for 3.5" and 4" devices.
Here's an illustration of what I want to have happen:
Initially, I set up the subview with a "Top Space to: Top Layout Guide" constraint for its y-position. With this configuration, the In-Call Status Bar pushed the subview 20px downward:
Next, I tried replacing that constraint with "Top Space to: Superview," where Superview was the root view of the controller. No change. Is there some other way to maintain a constant y-position for a view with Auto Layout constraints? I know I could resort to handling this manually by subscribing to UIApplicationDidChangeStatusBarFrameNotification, but I'd like to keep things simple if I can.
Your label is positioned to have a margin on top, between the start of the view and the start of the label. When the status bar grows, your view is shrunk. If you wish the label to remain in the same place, you can listen to UIApplicationWillChangeStatusBarFrameNotification notifications and adjust your view's size and origin to offset the additional space of the status bar. If you only want your label to shift up, you can also listen to the notification above, and adjust the top space constraint accordingly.
No you cannot.
The frame looses 20 px height in Portrait :( and the layoutguides don't care about it.
So either you do what Leo Natan said and use the notifications UIApplicationWillChangeStatusBarFrameNotification
Or either you will have to use the bottomConstraint as you dont want to do.
I'm making a Shooter game like "1943" and "Jamestown". I was wondering how I would make the scrolling background to simulate moving forward and How would I make this efficient? I was thinking about using a animated GIF or to make a looping BitMap. Please could someone help me out.
Thanks!
Take a look at the XNA framework for game development to develop a game that will use the computer's resources efficiently for smooth gameplay and frame rates. There are a number of books and online tutorials available.
If you're wanting a quick and dirty vertical background scroll in a windows form, you could always place a panel control inside another panel, set the outer panel to not display scrollbars, and make the inner panel twice as tall (or more), and set the background texture of the inner panel to be the background image you want to display. You can then animate the inner panel to move from top to bottom and reset back to the top when it reaches the bottom. Also be sure to design your background image so that the view at the top and the view at the bottom are the same for a smooth transition when the panel gets reset. You'll also want to call panel.Refresh() when you move the panel.
All that said, the XNA framework is really the way to go for game development.
I'm trying to make an animation effect similar to the one on Safari(iPhone) when you add an element to the reading list. It's similar to the one that appears when starting to download an item from App Store application: the application item drops to the dock to start downloading.
First it bounces up and then goes to the dock. It's a very nice effect that Apple uses on their OS.
I have an image view on screen that I want to drop with this kind of animation to my toolbar in my application.
If there is someone who did it or know what's the name of the effect, could please tell me how to do it.
Thank you.
"Add to reading list" shows no animation on my phone but of your description it sounds like the "Open in background"-animation in Safari (iPhone). My answer describes that animation.
I wrote a thing like that a few months ago and much of it is doable while some of it is not. Your questions showed me that more people are to know how it is done so I wrote a blog post about it. I will describe the high level approach and challenges here but you can read more about it in that post.
Getting to content to animate
If you choose to animate the view that is on screen down to the (in your case) tool bar then you will only have to access its layer. If you want the original view to remain and animate a visual copy (like the "open in background"-Safari animation) down to the bar item then you should create a new layer and draw the content of your layer into an image and set that image as the content of the layer that you are animating
Calculating the end position
The start position of the animation is simply the frame of the view. The end position is very tricky since bar items (both tool bar items and tab bar items) are not UIView subclasses and doesn't have a public view property. This causes problems when you want to shake the bar item later on.
I decided to make a visual approximation of the end position using some simple heuristics. If you know before hand that you will only animate to a single bar item then the end position can be hard coded to a suitable frame.
Animating along a path
There is nothing special to moving, scaling and rotating the layer from the start to the end position. If you want to read more about how I did it you can look at the post I wrote.
Shaking the bar item
This cannot be done without a lot of custom code or using private API at the moment. Since bar items doesn't have a view or a layer there is no accessible layer for you to animate. I guess that you could have a custom animating image that does the shake and set that during the animation and set the new image afterwards. The approach of drawing into an image and animating that doesn't work that well either since there is no accessible layer who can draw its content into the image (you want this for the special effect of the tool bar item and tab bar item).
...put all this together and tweak it to your special needs and you will have an animation that resembles the animation you are looking for.
How do you host the PitchShift Audio Unit plugin correctly in its own window?
I am developing a Mac app that hosts Apple's system supplied Audio Unit plugins. With the new OSX 10.7 Lion, some of the plugins have updated views. PitchShift is one of these.
PitchShift and a few others have new knobs to change there parameters. When a knob is being turned with the mouse, a horizontal bar showing the knob's parameter value is displayed below the knob.
This bar stays on screen after the knob is released and even after the window is closed. If I click one of the knobs, thus creating a rogue value bar, and move the window the PitchShift view is in, the bar stays where the window used to be. And if I click the knob again at this point, a new bar appears, but both bars are actively updated with the changing knob parameter value information. This happens every time I repeat this process with more bars staying on screen.
After a few times with this happening, my app exits with bad access at NSApplicaionMain() call in the main.m file.
I checked in Logic 9, and this does not happen there. The bar seems to be tied directly to the knob, and thus disappears immediately after you let the knob go with the mouse.
I set the PitchSHift view to be the contentView of a dedicated NSWindow.
How is Logic keeping this from happening, or just how can I?
I've tried seeing if the parameter value bars where subviews of the PitchShift view, but they don't seem to be.
Any help would be greatly appreciated.
EDIT: When the a value bar first appears, I get the following output in the console from my program: Circle and line do not intersect
So I've found that it is using core-animations CALayers. The problem now is that the value bar layers aren't a part of the PitchShiftView's layer hierarchy. In other words, I can find all the other layers that build up the pitchShiftView, but not the layers for the value bars. Which seems like it might be the whole problem to begin with.
I finally figured it out. The parameter value bars are child windows of the window that owns the audio unit view.
To solve the problem, I catch the mouse up events for the window in my subclass of NSApplication, and I then close the child window (aka the value bar) so that they don't stay on screen.
This did not stop the exit bad access. I now think that is a separate issue that only appeared to be related to these lingering child windows.
How do I add some extra drag to the UIScrollView physics. It scrolls just a little too fast for what I am doing. (I don't want to disable altogether, I still like the rubber band effect when you get to the end or beginning of the view.) Is there any way to slow it down?
Actually, after reading the Documentation I discovered the property for UIScrollView that slows down the scrolling, so Apple does make this readily available for anyone else looking for this:
scrollView.decelerationRate = UIScrollViewDecelerationRateFast;
Even though it says fast, it is speeding up deceleration which in effect slows the scrolling down. This was exactly what I needed. And no worry of patents. :)
Actually you can make block animation with ScrollToRowAtIndexPath:... with animated set to NO. This way block animation will animate underlaying variables manually using selected time.
As UICollectionView is subclass of UIScrollView You can use scroll view delegate method.
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset {
targetContentOffset->x = (targetContentOffset->x - scrollView.contentOffset.x) / 6 + scrollView.contentOffset.x;
targetContentOffset->y = (targetContentOffset->y - scrollView.contentOffset.y) / 6 + scrollView.contentOffset.y;
}
This is simply not possible right now. Maybe Apple will one day extend the API to allow it, but until that day, you're stuck with the default speed.
The only other option would be your own scrolling implementation. This isn't trivial if you want all the nice polish such as the rubber band effect and the way the scrolling will lock horizontally or vertically. Not to mention flicking to scroll.
Also, Apple has a patent for some of those scrolling behaviours, so writing your own might even be dangerous. Source: "Apple's touch-screen patent".
A computing device, comprising: a touch screen display; one or more processors; memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including: instructions for detecting one or more finger contacts with the touch screen display; instructions for applying one or more heuristics to the one or more finger contacts to determine a command for the device; and instructions for processing the command; wherein the one or more heuristics comprise: a vertical screen scrolling heuristic for determining that the one or more finger contacts correspond to a one-dimensional vertical screen scrolling command rather than a two-dimensional screen translation command based on an angle of initial movement of a finger contact with respect to the touch screen display; a two-dimensional screen translation heuristic for determining that the one or more finger contacts correspond to the two-dimensional screen translation command rather than the one-dimensional vertical screen scrolling command based on the angle of initial movement of the finger contact with respect to the touch screen display; and a next item heuristic for determining that the one or more finger contacts correspond to a command to transition from displaying a respective item in a set of items to displaying a next item in the set of items.
But of course, I am not a lawyer.