There is a strang flicker when I use AVPlay：
I create a demo to show this bug： Demo 。
I am referring to the flicker from the beginning, that one happens because I have a transition between the image and the movie. but I need
the image showing before the video appear.
because I have to keep image showing,before the video is downloaded completely.
Can anyone fix this bug？
You can make this transition smoother by using an animation when hiding the image view:
if (!self.imageView.hidden) {
NSTimeInterval fadeDuration = .5;
static CGFloat invisibleAlpha = .0;
[UIView animateWithDuration:fadeDuration animations:^{
self.imageView.alpha = invisibleAlpha;
} completion:^(BOOL finished) {
[self.player play];
}];
}
Note that you can set the .5 value to another value.
Related
Whilst playing around with UIView animation, I came across a situation where I think some refactoring is needed:
The following views whose opacity are initially set to 0.0f.
Ex:
[UIView animateWithDuration:1.0f
animations:^
{
firstView.layer.opacity = 1.0f;
}
completion:^(BOOL finished)
{
[UIView animateWithDuration:1.0f
animations:^
{
secondView.layer.opacity = 1.0f;
firstView.layer.opacity = 0.0f;
}
completion:^(BOOL finished)
{
[UIView animateWithDuration:1.0f
animations:^
{
thirdView.layer.opacity = 1.0f;
secondView.layer.opacity = 0.0f;
}
completion:^(BOOL finished)
{
thirdView.layer.opacity = 0.0f;
}];
}];
}];
All 3 views are just subclass of UIView's, which are added as subviews of the main view.
This simply animates the opacity of the first view to 1.0f and then that of the second view, and then that of the third view.
Simple. Nothing special here.
My Question is:
What if I had more views, let say 100, that I wanted to perform the same action (same sequence of animation), this block of code would expand and expand.
So for the sake of refactoring and being adhered to good practice of writing code, I thought may be this could be done with less code via the use of a method and perhaps a loop.
Could you enlighten me on this in regards to refactoring; in addition, would dispatch_apply be useful here along with the refactoring process if a loop is needed?
If you wanted to animate 100 images, you would probably want to use 2 views and load alternating images into each one. I recently created a sample app on github that does exactly that:
Animating UIImages with cross-fade opacity changing
I've been reading about UIView animateWithDuration which I'm trying to use so when a button is pressed a graphic appears then slowly fades out (i.e. alpha is set to 0).
I'm using the code below in my viewdidload just for test purposes however its not working:
[UIView animateWithDuration:10 animations:^{
self.completeImage.alpha = 1.0;
self.completeImage.alpha = 0.5;
self.completeImage.alpha = 0.0;
}];
Any ideas?
Thanks.
That is not working because automatically it sets the alpha to 0.0;
The 3 lines of code are executed at the same time (one after the other).
The proper way to use the UView animation block it is like this:
self.completeImage.alpha = 0.0;
[UIView animateWithDuration:2.0
animations:^{
// do first animation
self.completeImage.alpha = 1.0;
}
completion:^(BOOL finished){
[UIView animateWithDuration:2.0
animations:^{
// do second animation
self.completeImage.alpha = 0.0;
}
completion:^(BOOL finished){
;
}];
}];
Hope this achieve what you are looking for.
In addition:
" I'm trying to use so when a button is pressed a graphic appears
then slowly fades out (i.e. alpha is set to 0)."
As per your above information in the question, addition of the code in viewDidLoad will not prove fruitful. You need to add this code in the action target method of your button in order to play the animation on click of a button. Generally if you're using the nib, then the action method will be like below:
-(IBAction)on_pressing_my_button:(id)sender
{
///your animation code goes here..
}
I'm running into an issue: I'm successfully transitioning from one view to the next one - from view containing a static image to one containing a video (mov or mp4, etc using avPlayer), vice versa or whatever else type of sequence.
However when I'm transitioning from a view containing a video to a one containing an image I'm still hearing the sound of the video after the image is loaded. Strange. The funniest is that it does not happen when I transitioning from video to video... Any idea guys?
Please check the code I'm using to transition the view (with a dissolve effect):
- (void) replaceView: (UIView *) theCurrentView withView: (UIView *) theReplacementView
{
theReplacementView.alpha = 0.0;
[self.view addSubview: theReplacementView];
[UIView animateWithDuration: 1.5
animations:^{
theCurrentView.alpha = 0.0;
theReplacementView.alpha = 1.0;
}
completion:^(BOOL finished) {
[theCurrentView removeFromSuperview];
}];
self.currentView = theReplacementView;
[self.view addSubview:theReplacementView];
}
Try explicitly stop video playback in viewWillDisappear method.
I have to give a delete thumbnail animation in my ipad application just like iphone/ipad applications delete effect.
Any body help me please sample photo is attached
If you need more details then kindly mention it in comments
I have done this using CGAffineTransformMakeRotation. Don't know there is some other better method. But What I have done is my logic you can copy that as it is and you just need to add a delete button on the left top of that view. In the following code I am just animating the thumbnail or any view just like iPad does on its home screen. One thing, You need to declare int direction globally. and every time when you will call this method you will set direction = 1;
-(void)shakeToDelete:(UIView *)shakeMe
{
[UIView animateWithDuration:0.1 animations:^
{
shakeMe.transform = CGAffineTransformMakeRotation(0.05 * direction);
}
completion:^(BOOL finished)
{
direction = direction * -1;
[self shakeToDelete:shakeMe];
}];
}
/// edit
I tried this way and got it working in my sample screen as attached in photo
You better should use an autoreverse and looped animation, cause creating animations over and over will fulfill the phone memory.
With this code, only one animation is retained.
view.transform = CGAffineTransformMakeRotation(-kDeleteAnimationAmplitude);
[UIView animateWithDuration:0.1 delay:0 options:UIViewAnimationOptionRepeat|UIViewAnimationOptionAutoreverse animations:^{
view.transform = CGAffineTransformMakeRotation(kDeleteAnimationAmplitude);
} completion:nil];
Then if you want to stop your animation, just call:
[view.layer removeAllAnimations];
I have a requirement to animate images . I have a large number of images and this needs to be played as an video. In between playing sometimes i need to change some images as they will be updated at server. so playing should automatically update this new images .
I have tried using UIImageView. There we cannot control the animation.
I then tried CAKeyframeAnimation supplying image array to values property. I could play and pause the animation. But here also i cannot dynamically change the image while playing.
Can anyone help me in solving this problem.
Thanks
mia
The animation system on UIImageView is very limited. I would suggest that you make your own implementation with say 2 image view.
You would than change the image in one imageview and the fade in and out using UIView animateWithDuration
I have written a method for you. Please note: I have not tested it.
It assumes you have your frames in a array called 'frames' and have two UIIMageView placed on top of each other called 'imgv1' and 'imgv2'
-(void)performAnimationOfFrameAtIndex:(NSNumber*)indexNum
{
int index = [indexNum intValue];
if(index >= frames.count)
{
return;
}
UIImage *img = [frames objectAtIndex:index];
UIImageView *imgIn;
UIImageView *imgOut;
if(index % 2 == 0)
{
imgIn = imgv1;
imgOut = imgv2;
}
else {
imgIn = imgv2;
imgOut = imgv1;
}
imgIn.image = img;
[self.view sendSubviewToBack:imgIn];
[UIView animateWithDuration:0.1 animations:^{
imgIn.alpha = 1;
imgOut.alpha = 0;
} completion:^(BOOL finished) {
[self performSelectorOnMainThread:#selector(performAnimationOfFrameAtIndex:) withObject:[NSNumber numberWithInt:index+1] waitUntilDone:NO];
}];
}
Use two UIImageViews and swap them.
If you have a weak reference on the "animation" UIView, be sure to check if animation has finished in the completion block. Otherwise you may experience performance issues when you navigate to another view, recursive calls to animation method will continue!
- (void)animateImagesAtIndex:(NSNumber *)imageIdx {
// Do something here
[UIView animateWithDuration:1 animations:^{
// Do swap
}
completion:^(BOOL finished) {
if (finished) {
[self animateImagesAtIndex:imageIdx];
}
}];
}
UIImageView supports animations for a series of images. You only have to set the properties animationImages with an array of the images, and call the methods startAnimating and stopAnimating.