Imitating screenshot flash animation on iOS - ios

Question

Im looking for a way to copy the "blink" animation, that is played when pressing home+lock.
Does anyone know if this animation is available somehow?

Answer 1

On an iOS device you take a screenshot when you press home + lock and the screen flashes white. Do you mean this effect? If so, try this:
Add a UIView with a white background color to your view hierarchy such that it covers the whole screen. Then, start an animation that fades the opacity of this view to zero. On completion, remove the view from its superview:
[UIView animateWithDuration: 0.5
animations: ^{
whiteView.alpha = 0.0;
}
completion: ^(BOOL finished) {
[whiteView removeFromSuperview];
}
];

Answer 2

Try:
[UIView animateWithDuration:1 animations:^{
self.view.backgroundColor = [UIColor blackColor];
for (UIView *view2 in self.view.subviews) {
view2.backgroundColor = [UIColor blackColor];
}
}];
[UIView animateWithDuration:1 animations:^{
self.view.backgroundColor = [UIColor whiteColor];
for (UIView *view2 in self.view.subviews) {
view2.backgroundColor = [UIColor whiteColor];
}
}];

Answer 3

I have found very easy way to imitate exactly the Screenshot Flash Apple uses. I wish everyone try it at least once.
UIView * flashView = [[UIView alloc] initWithFrame:self.view.frame];
flashView.backgroundColor = [UIColor whiteColor];
[self.view addSubview:flashView];
[UIView animateWithDuration:1 delay:0.3 options:0 animations:^{
flashView.alpha = 0;
} completion:^(BOOL finished)
{
[flashView removeFromSuperview];
}];
}

Answer 4

These examples gave me inspiration, but did not give me the desired effect. This is my attempt, looks pretty close to the real deal.
func mimicScreenShotFlash() {
let aView = UIView(frame: self.view.frame)
aView.backgroundColor = UIColor.whiteColor()
self.view.addSubview(aView)
UIView.animateWithDuration(1.3, delay: 0, options: UIViewAnimationOptions.CurveEaseInOut, animations: { () -> Void in
aView.alpha = 0.0
}, completion: { (done) -> Void in
aView.removeFromSuperview()
})
}

Answer 5

Two problems with the current solutions:
putting views over other views can (in my experience with UICollectionView and other crap) trigger autolayout. Autolayout is bad. Autolayout makes the machine do a burst of work and can have side effects other than just calculating for no reason other than to burn CPU and battery. So, you don't want to give it reasons to autolayout, for instance, adding a subview to a view that really, really cares about keeping itself laid out nicely.
your view doesn't cover the whole screen necessarily, so if you want to flash the whole screen, you're better off using a UIWindow ... this should insulate from any view controllers that are touchy about having subviews added
This is my implementation, a category on UIView. I've included methods to take a screenshot before flashing the window, and saving it to the camera roll afterwards. Note that UIWindow seems to want to do its own animations when being added, it will normally fade in over maybe a third of a second. There may be a better way of telling it not to do this.
// stupid blocks
typedef void (^QCompletion)(BOOL complete);
#interface UIView (QViewAnimation)
+ (UIImage *)screenshot; // whole screen
+ (void)flashScreen:(QCompletion)complete;
- (UIImage *)snapshot; // this view only
- (void)takeScreenshotAndFlashScreen;
#end
#implementation UIView (QViewAnimation)
+ (UIImage *)screenshot;
{
NSArray *windows = [[UIApplication sharedApplication] windows];
UIWindow *window = nil;
if (windows.count) {
window = windows[0];
return [window snapshot];
} else {
NSLog(#"Screenshot failed.");
return nil;
}
}
- (UIImage *)snapshot;
{
UIGraphicsBeginImageContextWithOptions(self.bounds.size, YES, 0);
[self drawViewHierarchyInRect:self.bounds afterScreenUpdates:YES];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
+ (void)flashScreen:(QCompletion)complete;
{
UIScreen *screen = [UIScreen mainScreen];
CGRect bounds = screen.bounds;
UIWindow * flash = [[UIWindow alloc] initWithFrame:bounds];
flash.alpha = 1;
flash.backgroundColor = [UIColor whiteColor];
[UIView setAnimationsEnabled:NO];
[flash makeKeyAndVisible];
[UIView setAnimationsEnabled:YES];
[UIView animateWithDuration:0.3
delay:0
options:UIViewAnimationCurveEaseOut
animations:^{
flash.alpha = 0;
}
completion: ^(BOOL finished)
{
flash.hidden = YES;
[flash autorelease];
if (complete) {
complete(YES);
}
}];
}
- (void)takeScreenshotAndFlashScreen;
{
UIImage *image = [UIView screenshot];
[UIView flashScreen:^(BOOL complete){
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND,0),
^{
UIImageWriteToSavedPhotosAlbum(image,self,#selector(imageDidFinishSaving:withError:context:),nil);
});
}];
}
- (void)imageDidFinishSaving:(UIImage *)image
withError:(NSError *)error
context:(void *)context;
{
dispatch_async(dispatch_get_main_queue(),^{
// send an alert that the image saved
});
}
#end