I have created a scrollview programmatically in ios.
I am displaying 2-3 images on that scrollview and adding images vertically one below other.
When I touch on the image and scroll vertically it works. But if I touch the empty space between the images and try to scroll it does not work. Scrollview does not respond to that.
Here is the relevant code :
UIImageView* imageView = [[UIImageView alloc] initWithFrame:imageRect];
[imageView setImage:[UIImage imageNamed:#"background.png"]];
[scrollView addSubview:imageView];
[self didAddSubview:imageView];
.....
......
[scrollView setScrollEnabled:YES];
[[self view] addSubview:scrollView];
Any inputs will be helpful.
Thanks.
You can set the content size of scrollView use this code hope it will help you :-
- (void) viewDidLoad
{
[super viewDidLoad];
UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 568)];
[scrollView setScrollEnabled:YES];
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(20, 20, 250, 200)];
[imageView setImage:[UIImage imageNamed:#"background.png"]];
[scrollView addSubview:imageView];
[self.view addSubview:scrollView];
scrollView.contentSize = CGSizeMake(320, 600);
}
Set,
[scrollView setFrame:size];
[scrollView setContentSize:contentsize];
If it will not scroll vertically or horizontally then you have to change content size it should be greater then current size.
This question is old but I was having the exact same issue with my scrollview, and this was the only page I found about this all over the internet.
I was using a content view inside scroll view, and I just set a background color on my contentView and it worked.
Content size was being set automatically throw auto layout, so no need to set it manually.
Related
I am a newbie to IOS app development. I am trying to implement a scrollview. I am not able to scroll at all.
Below is my view implementation.
I created a scroll view and added small blocks with different colors in it.
I added one block out of current screen bounds so that I can scroll down the UIScrollView and view it.
#implementation CustomView
- (instancetype)init
{
self = [super init];
if (self) {
CGRect screenRect = CGRectMake(70, 100, 250, 800);
UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:screenRect];
scrollView.scrollEnabled = YES;
[scrollView setBackgroundColor:[UIColor yellowColor]];
[scrollView setAlpha:0.2];
[self addSubview:scrollView];
CGRect temp = CGRectMake(100, 150, 10, 10);
UIView *firstView = [[UIView alloc] initWithFrame:temp];
[firstView setBackgroundColor:[UIColor redColor]];
[scrollView addSubview:firstView];
temp = CGRectMake(150, 200, 10, 10);
UIView *secondView = [[UIView alloc] initWithFrame:temp];
[secondView setBackgroundColor:[UIColor greenColor]];
[scrollView addSubview:secondView];
temp = CGRectMake(200, 750, 10, 10);
UIView *thirdView = [[UIView alloc] initWithFrame:temp];
[thirdView setBackgroundColor:[UIColor orangeColor]];
[scrollView addSubview:thirdView];
scrollView.contentSize = screenRect.size;
}
return self;
}
#end
I am using the view I created before in my view controller. I am adding it to my view controller's view.
#interface ViewController ()
#property (nonatomic, readonly) CustomView *currentView;
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
_currentView = [[CustomView alloc] init];
[self.view addSubview:_currentView];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
I am not able to scroll at all with this implementation. am i missing something ?
Can someone please explain what is wrong with my code.
Thank you
When you add a scrollview to the screen it should be the size which you want to display on the screen. It will be displayed on the screen simply as an UIView only when you look at it.
UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame: CGRectMake(20, 20, 250, 250)];
The above initialisation will give you a scroll view of the size 250X250 placed at the position (20,20).
For scrolling you need to define the content size of the scroll view.
This content size should be bigger than your scrollview size otherwise you will not be able to differentiate it. The size of the contentsize should be decided based on the content you are going to put inside it.
For example if the three views you are adding inside the scrollview occupy a total width of 500 and a height of 300 then your content size should be equal to that only.
[scrollView setContentSize:CGSizeMake(500, 300)];
This will allow you to scroll inside the scrollview.
Also the content you are adding to you scrollview should be added considering the top left corner of the scrollView as the (0,0) location.
So if you want to display something on the top left corner of your scrollView then the frame dimensions of that particular view should be like this
CGRectMake(0,0,30,30);
This will add a view of the size 30X30 on the top left corner of the scrollView.
Hope it helps.
Your scroll view doesn't scroll because its frame is as large as its content size. Add this line in the view controller after before adding the scrollview as subview:
_currentView.frame = self.view.bounds ;
The contentSize property should not be the size of the screen, it needs to be larger if you want scrolling to work. You should calculate the size of the content within the scrollView, for example the combined height of all the subviews and the spaces between them or maybe the MaxY of the bottom view.
Also, try using a UITableView (or a UIStackView in iOS 9) to accomplish the same behavior without doing any math
First of all, what you are trying to do should be done using UITableView. I am not sure why are you trying to do it this way.
Anyhow, did you try to set also the contentSize property of UIScrollView?
https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIScrollView_Class/#//apple_ref/occ/instp/UIScrollView/contentSize
My UIScrollView isn't scrolling. (I'm trying to get it to scroll horizontally) I'm setting the contentSize to be (960, 300). I have set the framesize of the UIScrollView to be width:320 height:300 in the storyboard.
I have a container view inside the scroll view that has a width of 960 points.
At 320 points, I have a subview that has a background color of brown. When I scroll, I can see the brown subview, but it bounces back when I let go of the drag.
This is my viewDidLoad method:
- (void)viewDidLoad
[super viewDidLoad];
self.scrollView.scrollEnabled = YES;
[self.scrollView setFrame:CGRectMake(0,0,320,300)];
self.scrollView.contentSize = CGSizeMake(960, 300);
UIView *subview1 = [[UIView alloc] initWithFrame:CGRectMake(320, 0, 320, 300)];
[subview1 setBackgroundColor:[UIColor brownColor]];
UIView *containerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 960, 300)];
[containerView addSubview:subview1];
[self.scrollView addSubview:containerView];
}
Here is a sample code for create a scroll view programmatically:
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
UIScrollView* scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 300)];
scrollView.backgroundColor = [UIColor redColor];
scrollView.scrollEnabled = YES;
scrollView.contentSize = CGSizeMake(960, 300);
[self.view addSubview:scrollView];
UIView *subview1 = [[UIView alloc] initWithFrame:CGRectMake(320, 0, 320, 300)];
[subview1 setBackgroundColor:[UIColor brownColor]];
UIView *containerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 960, 300)];
containerView.backgroundColor = [UIColor greenColor];
[containerView addSubview:subview1];
[scrollView addSubview:containerView];
So, there is no issue in your code, but something wrong with your storyboard configure.
I have a few thoughts about what you are trying to accomplish. I don't know how old is your code, but today we have many better ways to work with scrollview and they don't include setting up the intrinsic size or fame.
Well, despite my doubt about the objective of the code, I tried to run it here, using storyboard, a single view, a default configured scrollView and the experiment went well, your code actually works, I think maybe you have some problem with your scrollView. I know this will sound weird but did you checked if the scrollView has the property "Scrolling Enabled" checked?
If you can give me more information about this issue, I can help you.
I have a button at the 1000 height pixel mark and I need a uiscrollview in order to access that button. I implemented the scrollview code below and it shows the scroll view ,but doesn't allow me to scroll down. I might be missing a key function. Any tips or advice is appreciated.
UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 680)];
scrollView.contentSize = CGSizeMake(320, 1000);
scrollView.clipsToBounds = YES;
super.view.backgroundColor = [UIColor whiteColor];
[scrollView setUserInteractionEnabled:YES];
[[self view] addSubview:scrollView];
The problem is that your button's y coordinate is 1000 pixels, as you have stated. And the y-coordinate of scrollview's contentZize is maximum upto 1000 pixels as well. So the scrollview can jus scroll up to exactly where the button starts.
UIButton *btn =[UIButton buttonWithType:UIButtonTypeCustom];
btn.frame = CGRectMake(50, 1000, 100,45);
[scrollView addSubview:btn];
set the content size of scrollview like this
scrollView.contentSize = CGSizeMake(320, 1100);
This will surely solve it.
Within my UIView, I have a UIScrollView which fills the first view, so than when the content is bigger than the iPhone screen size, the user can scroll the page down. It works well, but when the user finishes the scroll movement - i.e. removes his fingers, the page snaps back into it's original position. Obviously that is not what I want, how can it be avoided?
Here is the relevant code in the UIView class which declares and uses the UIScrollView class.
#implementation TestView
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
// Initialization code.
}
CGRect scrollViewFrame = CGRectMake(0, 0, 320, 460);
UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:scrollViewFrame];
scrollView.canCancelContentTouches=NO;
[self addSubview:scrollView];
CGSize scrollViewContentSize = CGSizeMake(320, 500);
[scrollView setContentSize:scrollViewContentSize];
CGRect rectForBigRedSquare = CGRectMake(50, 50, 200, 200);
UILabel *redSquare = [[UILabel alloc] initWithFrame:rectForBigRedSquare];
[redSquare setBackgroundColor:[UIColor redColor]];
[scrollView addSubview:redSquare];
return self;
}
An additional question is this: how is it possible to make it such that the user can only scroll down, that is to see content at the bottom which was out of view, but not to scroll up so that there is space before the start of the content. In
Basically you just have to set contentSize of your scrollview according to the contents.
CGSize scrollViewSize = CGSizeMake(newWidth, newHeight);
[self.myScrollView setContentSize:scrollViewSize];
Okay, the easiest way to get this scrollview working as you desire is to ensure that content size of the scrollview is identical to the frame size of the content you wish to scroll.
You can achieve this by having a content view into which you add all the views you wish to be visible and then add that content view to the scrollview while ensuring that the content size of the scrollview is set to the content view's frame size.
UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 460)];
UIView* contentView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 1280, 460)];
UIView* redView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 460)];
[redView setBackgroundColor:[UIColor redColor]];
[contentView addSubview:redView];
[redView release];
UIView* blueView = [[UIView alloc] initWithFrame:CGRectMake(960, 0, 320, 460)];
[redView setBackgroundColor:[UIColor blueColor]];
[contentView addSubview:blueView];
[blueView release];
CGSize contentViewSize = contentView.frame.size;
[scrollView addSubview:contentView];
[scrollView setContentSize:contentViewSize];
[contentView release];
[self addSubview:scrollView];
The app I was working on had similar symptoms. The user could scroll down but on release the view would snap back to the initial position. The page was set up as follow:
[VIEW]
[SAFE AREA]
[SCROLL VIEW]
[CONTENT VIEW]
I strongly suspect that a combination of Auto-Layout and manual constraints caused by several adjustment iterations was causing the issue. To resolve this all constraints where removed from the View.
The Scroll View was assigned the following constraints:
Scroll View.leading = Safe Area.leading
Scroll View.top = Safe Area.top
Scroll View.trailing= Safe Area.trailing
Scroll View.bottom = Safe Area.bottom
The Content View was then assign the following constraints
ContentView.Leading = Scroll View.Leading
ContentView.top = Scroll View.top
ContentView.centerX = ScrollView.centerX
The Content View was also given the following self constraint
height = 1000
I have 4 labels on UIViewController. Now I want to know how can i make my current view to scrollable view using UIScrollView ?
You have to create and add these labels there. Something like this (Warning: untested)
UIScrollView * content = [[UIScrollView alloc] initWithFrame:self.view.bounds];
[content setContentSize:CGSizeMake(width, height)];
//Here you can add those labels to content view
[self.view addSubView:content];
To get scrolling to work you must specify size of the content (setContentSize:) larger than main view size. And don't forget to release the scroll view.
Simplest method:
-(void)scrollview
{
UIScrollView *scrollview=[[UIScrollView alloc]initWithFrame:CGRectMake(10, 10, 250, 150)];
scrollview.showsVerticalScrollIndicator=YES;
scrollview.scrollEnabled=YES;
scrollview.userInteractionEnabled=YES;
scrollview.backgroundColor = [UIColor greenColor];
[mainScrollView addSubview:scrollview];
scrollview.contentSize = CGSizeMake(250,150);
}