vertical scrollable CCLayerColor issue - iphone

i'm trying to do a scrollable layer with cocos2d
what i want is for the layer to start scrolling from the top to bottom but no matter what i do when it enters the scene the layer is positioned at (0,0) aka..bottom
i've tried a couple of things but nothing seems to work
-(id) init
{
if( (self=[super init] )) {
self.isTouchEnabled = YES;
isDragging = NO;
yvel = 0.0f;
contentHeight = 1000.0f;
scrollLayer = [CCLayerColor layerWithColor:ccc4(200, 200, 200, 240)];
scrollLayer.contentSize = CGSizeMake(320,contentHeight);
scrollLayer.anchorPoint = ccp(0,1);
scrollLayer.position = ccp(0, 480);
[self addChild: scrollLayer];
CCLabelTTF *label = [CCLabelTTF labelWithString:[NSString stringWithFormat:#"test label"]
fontName:#"Marker Felt"
fontSize:24];
label.position=ccp(100, 100);
[scrollLayer addChild:label];
[self scheduleUpdate];
}
return self;
}
the other methods are update and touches handlers so the problem couldn't be there
with this code...shouldn't it initialize with the content at the top left of the screen?

after a painful few hours i finally solved the problem...but i still dont know why it works
instead of scrollLayer.position = ccp(0, 480); i replaced with scrollLayer.position =ccp(0,-contentHeight); and deleted scrollLayer.anchorPoint = ccp(0,1); cuz it wasnt doing anything
and i have absolutely no idea why it works
can someone explain this?

Related

UIScrollView - Prevent UIImageView as subview of UIScrollView from being dragged off screen

I have a UIImageView element as a subview of my main UIScrollView element.
I want the Image to fill out the whole screen at all times, but I can drag the edges a bit too far, so that the yellow "background" becomes visible.
If I lift my finger, the Image "bounces" back and fills out the screen correctly.
I want to prevent this dragging of the image off screen.
I do however want the image to bounce back once I drag it out of the "safety area".
This is my ScrollView initialization:
- (id)initWithFrame:(CGRect)frame{
self = [super initWithFrame:CGRectMake(0, 0, frame.size.height, frame.size.width)];
if (self) {
[self initImageValues];
self.showsVerticalScrollIndicator = NO;
self.showsHorizontalScrollIndicator = NO;
self.bouncesZoom = YES;
self.decelerationRate = UIScrollViewDecelerationRateFast;
self.delegate = self;
self.backgroundColor = [UIColor yellowColor];
self.minimumZoomScale = 1.0;
self.maximumZoomScale = 2.0;
[self setCanCancelContentTouches:YES];
self.clipsToBounds = YES;
// Load Image
imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:imageName]];
[self addSubview:imageView];
[self setContentSize: CGSizeMake(imageView.frame.size.width, imageView.frame.size.height)];
// Set bigger "bounce" zone (safety area)
self.contentInset=UIEdgeInsetsMake(-SAFETY_ZONE,-SAFETY_ZONE,-SAFETY_ZONE,-SAFETY_ZONE);
self.scrollEnabled = YES;
}
return self;}
Use these delegate methods:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
Then read the offset and return if it's out of the "safety area".
Could be that you need another delegate method from the UIScrollView though, but a workaround like this should fix your problem :)
try setting bounces on the scrollview:
self.bounces = NO;
TRY this:
**
self.scrollView.maximumZoomScale = 1.0;
self.scrollView.minimumZoomScale = 1.0;
**
Try setting its bounces property to NO.

How to zoom in and zoom out mutiple images on scroll view

i have a scroll view with multiple images and i am using this code. i have the images with dimensions (2121 x 2892) in Portrait and (2112 x 1500) in landscape mode
scrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
scrollView.pagingEnabled = YES;
scrollView.delegate = self;
scrollView.showsVerticalScrollIndicator = NO;
scrollView.showsHorizontalScrollIndicator = NO;
scrollView.maximumZoomScale = 3.0f;
scrollView.minimumZoomScale = 1.0;
NSInteger numberOfViews = [arrayImages count];
for (int i = 0; i < numberOfViews; i++)
{
CGFloat yOrigin = i * scrollView.frame.size.width;
imageView = [[UIImageView alloc]initWithFrame:CGRectMake(yOrigin +30, 0, self.view.frame.size.width-60 , self.view.frame.size.height)];
imageView.userInteractionEnabled = YES;
imageView.image = [UIImage imageNamed:[arrayImages objectAtIndex:i]];
[scrollView addSubview:imageView];
imageView.userInteractionEnabled = YES;
}
[self.view addSubview:scrollView];
i want to implement the zoomin and zoom out functionality on double tab and moving with two fingers. I saw many sample application but i am not be able to do the same. if anybody have its own code please share with me.
I want to implement the zoomin and zoom out functionality on double tab and moving with two fingers.
For the zoom in on double tap, check out the gesture recogniser part of this tutorial.
As for moving around with 2 fingers, you could use a UIPanGestureRecogniser for 2 touches and change the contentOffset of the scroll view accordingly when a pan is recognised.
simple add a subview to scrollview and add all imageViews in it. and in scrollview's delegate method and do like this
-(UIView *) viewForZoomingInScrollView:(UIScrollView *)inScroll {
return view;
}

iOS - UIScrollView is not working (it doesn't scroll at all - the image stays fixed)

I would like to display an image (width: 320 pixels, height: 1250 pixels) in an image view.
When I compile the application I get no scrolling at all. The view stays fixed.
What I did:
Added an UIScrollView via Interface Builder to my view.
Added an UIImageView via Interface Builder to my view.
Verified that UIImageView is below UIScrollView in Interface Builder.
Set the size of the UIScrollView with ViewDidLoad.
How do I do this?
Code:
- (void)viewDidLoad
{
[super viewDidLoad];
scrollView.contentSize = CGSizeMake(320, 1250);
}
Screenshots:
ImageView:
ScrollView:
I just have done the same task..
Try this one.....
scrollView.delegate = self;
scrollView.scrollEnabled = YES;
int scrollWidth = 120;
scrollView.contentSize = CGSizeMake(scrollWidth,80);
int xOffset = 0;
imageView.image = [UIImage imageNamed:[imagesName objectAtIndex:0]];
for(int index=0; index < [imagesName count]; index++)
{
UIImageView *img = [[UIImageView alloc] init];
img.bounds = CGRectMake(10, 10, 50, 50);
img.frame = CGRectMake(5+xOffset, 0, 50, 50);
NSLog(#"image: %#",[imagesName objectAtIndex:index]);
img.image = [UIImage imageNamed:[imagesName objectAtIndex:index]];
[images insertObject:img atIndex:index];
scrollView.contentSize = CGSizeMake(scrollWidth+xOffset,110);
[scrollView addSubview:[images objectAtIndex:index]];
xOffset += 70;
}
Also set this one....
imagesName = [[NSArray alloc]initWithObjects:#"image1.jpg",#"image2.jpg",#"image3.jpg",#"image4.jpg",#"image5.jpg",#"image6.png",#"image7.png",#"image9.png",nil];
images = [[NSMutableArray alloc]init];
So for me the problem was that setting the content size didn't work in viewDidLoad(). I tried everything and I didn't understand why it wouldn't want to work, and then I tried the same stuff in viewDidAppear() and it magically worked...
From you last screenshot and from your comments it looks like your scrollView is way to big.
The scrollview must be visible on screen completely. For example a full screen UIScrollView on iPhone would have a size of 320 x 460.
If the scrollview is the same size as its content you can't scroll.
The greenish rectangle shows the size of your scrollview, the pinkish the size of your content (your image):
Xcode 11+, Swift 5
You can find the complete solution here.
I came across this same issue on iOS6 and the solution was to programmatically adjust the ContentSize.
So I will just quote from Raja (above) to show this:
CGSize scrollViewContentSize = CGSizeMake(320, 400);
[self.scrollView setContentSize:scrollViewContentSize];
NOTE: I was not having this issue on iOS5.. seems like iOS6 decided to do alot of prank just like the rotation/orientation saga
Since Xcode 5 it does not work like before. Also scrolling to the end of a scrollable text field makes problems. There are also differences between doing it on iPhone or iPad. On iPhone it worked without delayed timer.
This worked for me:
- (void)viewDidLoad
{
[super viewDidLoad];
NSTimer *timerforScrollView;
timerforScrollView =[NSTimer scheduledTimerWithTimeInterval:0.1
target:self selector:#selector(forScrollView)userInfo:nil repeats:NO];
}
- (void) forScrollView {
[scrollviewPad setScrollEnabled:YES];
[scrollviewPad setContentSize:CGSizeMake(768, 1015)]; // must be greater then the size in Storyboard
}
I found I had a similar problem but none of the above code worked. The issue was due to autolayout. I found that if I turned off autolayout by going to the storyboard clicking on Utilities -> File Inspector and unchecked Use Autolayout the scrolling did work (I also set scroll.contentSize = ...).
Sometimes autoLayout checkbox is ticked in the xib. That also creates this issue in xcode 5. Which makes the UIScrollView scrolling off.
Don't forget to add the category protocol to the interface, like this
#interface MyViewController : <UIScrollViewDelegate>
If you don't, you will not be able to set the scroll view delegate to self
(i.e. [MyScrollView setDelegate:self];)
If you do this, it should work.
My code is:
-(void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
[contentScrollView setDelegate:self];
[contentScrollView setScrollEnabled:YES];
contentScrollView.contentSize = CGSizeMake(310, 500);
contentScrollView.frame = CGRectMake(5, 188, 310, 193);
}
Did you assign the scroll's view delegate? Always remember these:
[self.scrollView setDelegate:self];
[self.scrollView setScrollEnabled:YES];
The image view has to be a subview (so inside AND below) of the scrollview. From your description it seems they are paralell
You forgot one line. Add this to your view load function:
[scrollView setScrollEnabled:YES];
You could try disabling AutoLayout. In XCode 5 I tested all the above answers and I could only scroll it by disabling autolayout and activating all autosizing masks under the Size Inspector. The following code was used too:
self.scrollView.contentSize = CGSizeMake(320, 900);
self.scrollView.delegate = self;
self.scrollView.scrollEnabled = YES;
self.scrollView.frame = self.view.frame;
CGRect scrollViewFrame = CGRectMake(0, 0, 320, 400);
self.scrollView = [[UIScrollView alloc] initWithFrame:scrollViewFrame];
[self.view addSubview:self.scrollView];
CGSize scrollViewContentSize = CGSizeMake(320, 400);
[self.scrollView setContentSize:scrollViewContentSize];
scrollView.delegate = self;
[self.scrollView setBackgroundColor:[UIColor blackColor]];
[scrollView setCanCancelContentTouches:NO];
scrollView.indicatorStyle = UIScrollViewIndicatorStyleWhite;
scrollView.clipsToBounds = YES;
scrollView.scrollEnabled = YES;
scrollView.pagingEnabled = YES;
NSUInteger nimages = 0;
CGFloat cx = 0;
for (; ; nimages++) {
NSString *imageName = [NSString stringWithFormat:#"image%d.jpg", (nimages + 1)];
UIImage *image = [UIImage imageNamed:imageName];
if (image == nil) {
break;
}
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
CGRect rect = imageView.frame;
rect.size.height = image.size.height;
rect.size.width = image.size.width;
rect.origin.x = ((scrollView.frame.size.width - image.size.width) / 2) + cx;
rect.origin.y = ((scrollView.frame.size.height - image.size.height) / 2);
imageView.frame = rect;
[scrollView addSubview:imageView];
[imageView release];
cx += scrollView.frame.size.width;
}
[scrollView setContentSize:CGSizeMake(cx, [scrollView bounds].size.height)];
Assuming that scrollView is a subview of view and fills it entirely you can use the following in viewDidLoad:
[scrollView setContentSize: CGSizeMake(self.view.frame.size.width, self.view.frame.size.height)];
I had a UIScrollView that was not scrolling and this allowed it to scroll.
Just add code
scrollView.contentSize = CGSizeMake(WIDTH,HEIGHT);
to method -(void)viewDidLayoutSubviews.
For more information checkout Stanford CS193p Lecture No 8 to understand View Controller Life cycle.
I had the same issue and was looking for the answer in this thread. I tried all the stuff, but nothing works. Then I found this:
.
You just need to deselect "Use Auto Layout" in File Inspector of your ViewController. Ta-Da, it works immediately for me. Enjoy.

How to add a moving text in iPhone

I want to add some text which is a long text lets say a story and I want it to be presented in a moving up fashion. That is it will be displayed in a box and the text will be moved line by line to show the whole story. So one line gets out of the box from top and other comes from the bottom. Like a HTML marquee behavior.
You should look into whether or not UIScrollView's contentOffset property is animatable using UIView animation blocks.
If it's not, then you could try using an NSTimer and in its function, either set the contentOffset or call [scrollView scrollRectToVisible:desiredContentFrame animated:YES]; where desiredContentFrame.origin.y is just a little bit lower than what you previously had it at (depending on the scroll speed you want). Then play around with the firing frequency of your timer and the desiredContentFrame.origin.y's delta to see what looks best and has the best performance.
Here's a quick hack showing both ways:
- (void)startAnimTimer
{
currentRect = CGRectMake(0, 0, 1, 1);
[NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:#selector(doScroll) userInfo:nil repeats:YES];
}
- (void)startAnimUIView
{
[UIView beginAnimations:#"scrollUIViewAnim" context:nil];
[UIView setAnimationDuration:20.0];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
CGPoint newContentOffset = CGPointMake(0, scrollView.contentSize.height);
scrollView.contentOffset = newContentOffset;
[UIView commitAnimations];
}
- (void)loadView {
[super loadView];
self.scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(5, 5, 200, 200)];
scrollView.contentSize = CGSizeMake(200, 1000);
scrollView.backgroundColor = [UIColor magentaColor];
CGFloat y = 10;
CGFloat yDelta = 21;
for(int i = 0; i < 47; i++)
{
// Add some UILabels to the scrollview just so we can see it animating
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(10, y, 180, 20)];
label.text = [NSString stringWithFormat:#"Cheezburger %d", i];
[scrollView addSubview:label];
[label release];
y += yDelta;
}
[self.view addSubview:scrollView];
// Comment out one of these
//[self startAnimTimer];
[self startAnimUIView];
}
- (void)doScroll
{
CGFloat scrollDelta = 1.0f;
CGRect newRect = CGRectMake(0, currentRect.origin.y + scrollDelta, currentRect.size.width, currentRect.size.height);
// Scroll the scrollview to the next position
[scrollView scrollRectToVisible:newRect animated:YES];
currentRect = newRect;
}
This method may help (or not):
- (void)scrollRectToVisible:(CGRect)rect animated:(BOOL)animated
If not, just make a big UILabel and animate its frame using a CABasicAnimation.
I think you want to look at the Scroll View (UIScrollView) in the iPhone SDK.
http://developer.apple.com/IPhone/library/documentation/UIKit/Reference/UIScrollView_Class/Reference/UIScrollView.html
Depending on your implementation, you may not be able to use it "out of the box" but it should provide the functionality you seem to be describing. I'm not sure it will do the auto-scroll thing but that should be pretty easy to implement... maybe.... But, I'm still confident it could be done.

UIPickerView not appearing until touch occurs

I'm programatically adding two custom UIPickerViews to another view (MainView). They work just fine but they are not visible until a touch event occurs in any part of the MainView. I've checked the class references for UIPickerView and UIView but haven't found anything that manages to "refresh" the view, unless I'm missing something obvious?
Here's my drawRect method in MainView.m. I've tried doing the same thing in viewDidLoad but with no success. Could the custom rotations/transforms etc have something to do with it?
- (void)drawRect:(CGRect)rect {
CGRect pickerFrame = CGRectMake(50, -32, 30, 180);
m_picker1 = [[UIPickerView alloc] initWithFrame:pickerFrame];
m_picker1.delegate = self;
m_picker1.tag = k_ptag1;
m_picker1.showsSelectionIndicator =YES;
m_picker1.backgroundColor = [UIColor clearColor];
CGAffineTransform rotate = CGAffineTransformMakeRotation(3.14/2);
rotate = CGAffineTransformScale(rotate, 0.075, 0.85);
[m_picker1 setTransform:rotate];
[self addSubview:m_picker1];
pickerFrame = CGRectMake(50, 67, 30, 180);
m_picker2 = [[UIPickerView alloc] initWithFrame:pickerFrame];
m_picker2.delegate = self;
m_picker2.tag = k_ptag2;
m_picker2.showsSelectionIndicator =YES;
m_picker2.backgroundColor = [UIColor clearColor];
rotate = CGAffineTransformMakeRotation(3.14/2);
rotate = CGAffineTransformScale(rotate, 0.075, 0.85);
[m_picker2 setTransform:rotate];
[self addSubview:m_picker2];
}
You add subviews in a view's controller, not the view itself. I would suggest familiarising yourself with the MVC design pattern.
drawRect is only supposed to be used for the actual drawing of the view itself, not subviews.