I have UIScrollView on which I am using 2 UIButtons. UIScrollView initial frame is (0,0,768,1024). I want when I click on first button the UIScrollView y-cordinate position will be 500, means it will scrolldown 500 positions below to its actual position.
And when I click second Button which Will show on UIScrollView, Position Y-cordinate of UIScrollView y=535, then UIScrollView Move up to Position y= 0 again.
First button click UIScrollView y = 500
Second button click UIScrollView y = 0
Any hints from experts would be very welcome.
Maybe you do not want to change the frame of the scroll view (this would just displace the whole view), but the contentOffset. This can be animated, too.
CGPoint offset = scrollView.contentOffset;
offset.y += 500;
[scrollView setContentOffset:offset animated:YES];
This may solve ur pbm
-(IBAction) clickfirstbutton
{
[scrollview setContentOffset:CGPointMake(0, 500)) animated:TRUE];
}
-(IBAction) clicksecondbutton
{
[scrollview setContentOffset:CGPointMake(0, 0) animated:TRUE];
}
If u don't want animations use
[scrollview setContentOffset:CGPointMake(0, 0) animated:FALSE];
Related
I got an gridview. Each cell within that grid is clickable. If a cell is clicked, another viewcontroller must be presented as a modal viewcontroller. The presentedviewcontroller must slide in fro the right to the left. After that, the modalviewcontroller can be dismissed with a slide. How do i achieve this? I got some images to show it :
Both views are separate viewcontrollers.
[Solution]
The answer from Matthew pointed me in the right direction. What i needed was a UIPanGestureRecognizer. Because UISwipeGestureRecognizer only registers one single swipe and i needed the view to follow the users finger. I did the following to accomplish it :
If i cell is tapped inside my UICollectionView, the extra view needs to pop up. So i implemented the following code first :
/* The next piece of code represents the action called when a touch event occours on
one of the UICollectionviewCells.
*/
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
NSString* release_id = releases[indexPath.row][0];
// Next boolean makes sure that only one new view can be seen. In the past, a user can click multiple cells and it allocs multiple instances of ReleaseViewController.
if(releaseViewDismissed) {
// Alloc UIViewController and initWithReleaseID does a request to a server to initialize some data.
ReleaseViewController *releaseViewController = [[ReleaseViewController alloc] initWithReleaseID: release_id];
// Create a new UIView and assign the height and width of the grid
UIView *releaseViewHolder = [[UIView alloc] initWithFrame:CGRectMake(gridSize.width, 0, gridSize.width, gridSize.height)];
// Add the view of the releaseViewController as a subview of the newly created view.
[releaseViewHolder addSubview:releaseViewController.view];
// Then add the UIView with the view of the releaseViewController to the current UIViewController's view.
[self.view addSubview:releaseViewHolder];
// Place the x coordinate of the new view to the same as width of the screen. Then after that get the x to 0 with an animation.
[UIView animateWithDuration:0.3 animations:^{
releaseViewHolder.frame = CGRectMake(0, 0, releaseViewHolder.frame.size.width, releaseViewHolder.frame.size.height);
// This is important. alloc an UIPanGestureRecognizer and set the method that handles those events to handleSwipes.
_panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(handleSwipes:)];
// Add the UIPanGestureRecognizer to the created view.
[releaseViewHolder addGestureRecognizer:_panGestureRecognizer];
releaseViewDismissed = NO;
}];
}
}
Then my handleSwipes is as follows:
-(void)handleSwipes:(UIPanGestureRecognizer *)sender {
CGPoint translatedPoint = [(UIPanGestureRecognizer*)sender translationInView:self.view];
CGPoint translation = [sender translationInView:sender.view];
CGRect newFrame = [sender view].frame;
[sender setTranslation:CGPointZero inView:sender.view];
if (sender.state == UIGestureRecognizerStateChanged)
{
newFrame.origin.x = newFrame.origin.x + translation.x;
// Makes sure it can't go beyond the left of the screen.
if(newFrame.origin.x > 0) {
[sender view].frame = newFrame;
}
}
if(sender.state == UIGestureRecognizerStateEnded){
CGRect newFrame = [sender view].frame;
CGFloat velocityX = (0.3*[(UIPanGestureRecognizer*)sender velocityInView:self.view].x);
// If the user swipes less then half of the screen, it has to bounce back.
if(newFrame.origin.x < ([sender view].bounds.size.width/2)) {
newFrame.origin.x = 0;
}
// If a user swipes fast, the velocity is added to the new x of the frame.
if(newFrame.origin.x + velocityX > ([sender view].bounds.size.width/2)) {
newFrame.origin.x = [sender view].bounds.size.width + velocityX;
releaseViewDismissed = YES;
}
// Do it all with a animation.
[UIView animateWithDuration:0.25
animations:^{
[sender view].frame = newFrame;
}
completion:^(BOOL finished){
if(releaseViewDismissed) {
// Finally remove the new view from the superView.
[[sender view] removeFromSuperview];
}
}];
}
}
If you want the presented view controller to slide in from the right to the left, it cannot be a modal view. #Juan suggested one way to achieve the right to left and swipe back, but it would result in the grid view being pushed out of the way by the new view. If you would like the new view to cover the grid view when it slides in, you will either need to accept the vertical slide of modal views or write your own code to slide the view in from the right -- the latter would not actually be all that difficult*.
As for the swipe to get back, the easiest way to do that from either a modally presented view or a view you animate in yourself is to use a UISwipeGestureRecognizer. You create the recognizer, tell it what direction of swipe to look for, and you tell it what method to call when the swipe occurs.
*The gist of this approach is to create a UIView, add it as a subview of the grid view, and give it the same frame as your grid view but an x-position equal to the width of the view, and then use the following code to make the view animate in from the right.
[UIView animateWithDuration:0.3 animations:^{
slidingView.frame = CGRectMake(0, 0, slidingView.frame.size.width, slidingView.frame.size.height);
}];
I believe what you need is the following:
Create another controller that is going to handle navigation between these two (ContentViewController for example). This controller should have a ScrollView with paging enabled.
Here is a simple tutorial if you don´t already know how to do this: click here
Once the cell is clicked you have to:
Create the new ViewController to be shown.
Enable paging and add this ViewController to the ContentViewController
Force paging to this newly created ViewController
Additionally you have to add some logic so that when the user swipes to change back to the first page, paging is disabled until a new cell is clicked to repeat the process.
I searched here a lot but I am not able to do it.
Basically, I want to scroll below i.e in downward direction to check whether a coupon image which I am using is available or not. This is initiated by a button click.
This is how I create the scroll view:
UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 20, 320, 440)];
scrollView.contentSize = CGSizeMake(320,500);
[self.view addSubView:scrollView];
-(void)movedown
{
[scrollView setContentOffset:CGPointMake(0,500) animated:YES];
}
it can be used to move down as upto 500 in y direction as u desired for 500 from scrollView.contentSize = CGSizeMake(320,500);
- (IBAction) yourBtnInScrollViewPressed : (id) sender
{
[yourScrollView scrollRectToVisible:CGRectMake(x, y, yourScrollView.frame.size.width, yourScrollView.frame.size.height) animated:YES];
}
You can change the UIScrollView position as required on button pressed.
- (IBAction) yourBtnInScrollViewPressed : (id) sender
{
[yourScrollView setContentOffset:CGSizeMake(x,y)];
//set Your x and Y coordinates as you required.
}
You can change the currently codinates of your UIScrollView.
I made a pretty decent post about automagically scrolling UIScrollViews. Maybe it can help you out a bit.
UITableView scroll smooth with certain speed?
Good luck ;)
-(IBAction)scrolldown
{
[scrollView setContentOffset:CGSizeMake(100,30)]; //change 30 if you want to see below images.
}
I need in my project to make the scroll an image continuously, ie from the bottom of the image once scrolled by continuing to scroll to the top should start from the base and so on, in a sort of loop, how can I do to do this?
Thanks
In this example i am taking total 5 images
- (void)viewDidLoad {
[super viewDidLoad];
// add the last image (image4) into the first position
[self addImageWithName:#"image4.jpg" atPosition:0];
// add all of the images to the scroll view
for (int i = 1; i < 5; i++) {
[self addImageWithName:[NSString stringWithFormat:#"image%i.jpg",i] atPosition:i];
}
// add the first image (image1) into the last position
[self addImageWithName:#"image1.jpg" atPosition:5];
scrollView.contentSize = CGSizeMake(320, 2496);
[scrollView scrollRectToVisible:CGRectMake(0,416,320,416) animated:NO];
}
- (void)addImageWithName:(NSString*)imageString atPosition:(int)position {
// add image to scroll view
UIImage *image = [UIImage imageNamed:imageString];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
imageView.frame = CGRectMake(0,position*416,320, 416);
[scrollView addSubview:imageView];
[imageView release];
}
implement delegate method
- (void)scrollViewDidEndDecelerating:(UIScrollView *)sender {
NSLog(#"%f",scrollView.contentOffset.y);
// The key is repositioning without animation
if (scrollView.contentOffset.y == 0) {
// user is scrolling to the left from image 1 to image 4
// reposition offset to show image 4 that is on the right in the scroll view
[scrollView scrollRectToVisible:CGRectMake(0,1664,320,416) animated:NO];
}
else if (scrollView.contentOffset.y == 2080) {
// user is scrolling to the right from image 4 to image 1
// reposition offset to show image 1 that is on the left in the scroll view
[scrollView scrollRectToVisible:CGRectMake(0,416,320,416) animated:NO];
}
}
I gives the two reference link for the automatically scroll the scroll view where the you can grap the source code also and implement into your project it's amazing funcationality
1) Automatically scroll the scroll view
2) As par your requirement created post of like wise gallery.
May this post is useful for you.
Happy codeing
Thanks and Regards,
#Samuel
I have a UIScrollView that I can swipe through to display new views. I have a button that I want to programmatically scroll through the views. So if I click it once, it will scroll to the next view. How can I implement this?
Here is the scrollview code
- (void)scrollViewDidEndDecelerating:(UIScrollView *)aScrollView
{
NSUInteger offset = aScrollView.contentOffset.x;
NSUInteger width = aScrollView.contentSize.width;
int anIndex = (offset == 0) ? 0 : (int)(width/(width - offset));
selectedDeal = [deals objectAtIndex:(anIndex > [deals count]- 1 ? [deals count]- 1 : anIndex)];
}
[myScrollView scrollRectToVisible:myView.frame animated:TRUE];
This will scroll so that myView becomes visible, assuming myView is added to the scroll view and it is not already visible. You need to keep track of current visible view and in the button handler you need to pass next view's frame as parameter to the above method.
[myScrollView setContentOffset:CGPointMake(self.view.frame.size.width, 0)animated:YES];
[myScrollView scrollRectToVisible:self.view.frame animated:YES];
I'm using an UIScrollView and I have an image that indicates to the user that there is more content that they can scroll through vertically. I would like this image to be hidden when the scrollview is all the way at the bottom. Is there a way to do this? Would I have to subclass UIScrollView and make my own?
your scroll view's delegate should repsond to scrollViewDidEndScrollingAnimation: and use that to check where you are
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView {
// Get some details about the view
CGSize size = [scrollView frame].size;
CGPoint offset = [scrollView contentOffset];
CGSize contentSize = [scrollView contentSize];
// Are we at the bottom?
if (-offset.y + size.height <= contentSize.height)
NSLog(#"bottom");
else
NSLog(#"not bottom");
}
NB The if statement was done in my head so it might be the wrong way round ;)