I have a uiscrollview dragged onto the storyboard that is 320x570.
In my viewDidLoad, I have added in
self.scrollView.delegate = self;
self.scrollView.userInteractionEnabled = YES;
self.scrollView.contentSize = self.view.frame.size;
Now when I run the app on the iPhone 5 simulator, my view scrolls but not to the very bottom. When I run the app on the iPhone 4 (smaller screen), it does not scroll at all. What determines how far the scroll should go?
self.scrollView.contentSize must be more than self.view.frame.size to scroll.
Small example for you:
(X is extra place that must be scrollable to see in small screens.)
[self.scrollView setContentSize:CGSizeMake(self.view.frame.size.width, self.view.frame.size.height + x)];
In you're case you set height of content same as you're main view so no scroll will be applied.
Related
I have created a tableview in code as follows:
_myTableView = [[UITableView alloc] initWithFrame:
CGRectMake(160, 80, 140, 100) style:UITableViewStylePlain];
_myTableView.delegate = self;
_myTableView.dataSource = self;
_myTableView.scrollEnabled = YES;
[self.view addSubview:_myTableView];
It largely works as it should with the following exception. Because the results in the table vary, I manually adjust the height of the tableview so that it only takes up as much space as the returned rows need as follows:
-(void) changeTVHeight: (float) height {
//height calculated from number of items in array returned.
CGRect newFrame = CGRectMake(120, 80, 180, height);
self.myTableView.frame = newFrame;
}
This works great for shrinking the tableview if there aren't that many results.
However, if there are a lot of results, the tableview expands below the visible part of the screen or the keyboard. In this case, I would like to be able to scroll the Tableview to see the lower rows.
scrollEnabled is set to YES.
But while it does allow one to scroll a bit, the scroll is resisted so with effort you can scroll a little bit but due to rubber band effect you cannot get further than a few rows below the screen and you cannot tap on the lower rows.
I am using autolayout in storyboard for much of the screen. The overall screen scrolls fine but this merely moves the tableview anchored to the screen up and down. There are no constraints on this tableview but it is added as a subview of the view.
My question is how can I make the tableview scrollable so that it scrolls without resistance?
Thanks in advance for any suggestions.
Edit:
I tried adding the tableView to self.scrollView instead of self.view. This anchored the tableView to the scrollview so it is possible to scroll the whole screen down and see the bottom of the tableview. However, this is not ideal because the rest of the screen is empty way down and you can't see the context for the tableview. (It's an autocomplete for a textfield at top of screen.)
In contrast when the tableview is added to self.view, it is in correct place, it semi-scrolls or bounces. It just doesn't scroll down to where I need it to scroll.
You need to set a limit so that the table view cannot be larger than the view itself. Tableviews are built on UIScrollView and will handle scrolling on their own, you don't need to try to size it manually. The reason the table view bounces but doesn't scroll is because it is extending below the bottom of the screen. It wont scroll because it has already scrolled to the bottom, you just can't see it because it's outside of the superview.
-(void) changeTVHeight: (float) height {
CGFloat limitedHeight = MIN(height, self.view.frame.size.height)
CGRect newFrame = CGRectMake(120, 80, 180, limitedHeight);
self.myTableView.frame = newFrame;
}
I have an issue where a scroll view will behave as expected on an iPhone 5 screen (320 points wide) but will have a negative horizontal contentOffset when it's autoresized by its super view to fit an iPhone 6 screen (375 points wide). The reason the offset can be negative is because the view also has a contentInset to the left. But since it was 0 before the automatic resize, I would expect it to still be 0 after.
I am setting up a UIScrollView inside the initWithStyle:reuseIdentifier: method of a UITableViewCell subclass like this:
UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:self.contentView.bounds];
scrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
scrollView.contentSize = self.contentView.bounds.size;
scrollView.contentInset = UIEdgeInsetsMake(0, 100, 0, 0);
[self.contentView addSubview:scrollView];
I can confirm that the contentOffset is (0, 0) at this point (presumably because everything gets autoresized to fit the iPhone 6 screen at a later point in time). I tried probing the value in various methods. In setFrame it's (0, 0) but in the first call to layoutSubviews it's (-55, 0) – presumably because the difference between iPhone 6 and iPhone 5 horizontal display points is 375 - 320 = 55.
Here's a screenshot of what happens on an iPhone 6 screen (in this screenshot I have put additional views inside the scroll view so that it can be seen graphically):
I have a UIScrollView with a 6 textfields in it and a button inside of it. There is not enough content in the scrollView to make it scroll.
But when the keyboard shows, I would like the scrollview to scroll so the user doesn't have to dismiss the keyboard in order to select another textfield that is hidden by the keyboard.
I am using iOS7 and have autolayout enabled.
Any suggestions?
I am using storyboards and the only code I have is the following.
reg.h file
interface registerViewController : UIViewController <UITextFieldDelegate, UIScrollViewDelegate>
In order to make a scrollview scrollable, the content size must be larger than the scrollview's frame so the scrollview has something to scroll to. Use setContentSize to adjust the content size:
[scrollview setContentSize:CGSizeMake(width, height)];
In this case, you should adjust the size to view.frame.width, view.frame.height + keyboard_height, then adjust the content offset once the keyboard appears:
[scrollview setContentOffset:CGPointMake(0, 0 - keyboard_height)];
If for some screwy, autolayout-related reason this still doesn't make the view scrollable, implement this setContentSize function in viewDidLayoutSubviews in order to override the autolayout:
- (void)viewDidLayoutSubviews {
[scrollview setContentSize:CGSizeMake(width, height)];
}
EDIT: To reset the scrollview after dismissing the keyboard, reset the scrollview content size to the scrollview's frame and the offset to zero:
[scrollview setContentSize:CGSizeMake(scrollview.frame.size.width, scrollview.frame.size.height)];
[scrollview setContentOffset:CGPointZero];
P.S. To animate the content offset, use:
[scrollview setContentOffset:offsetSize animated:YES];
There is a contentInset property of UIScrollViews, you can set the contentInset to make additional space at the bottom to allow for scrolling without changing contentSize.
UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, 100, 0.0);
scrollView.contentInset = contentInsets;
above code adds 100 points inset at the bottom.
By the way, there is an official document about this matter. It explains everything you should do. You can find it here. You can find what you are looking for under the section 'Moving Content That Is Located Under the Keyboard'
Try
Create Scroll view
Add View to the scroll view (In my case i added view as mainView).
Set ScrollView autoresizing.
Set MainView autoresizing.
To set the Scroll content Size equal to the view created add below line
Add the below line
-(void)viewDidLayoutSubviews
{
[super viewDidLayoutSubviews];
self.scrollView.contentSize = self.mainView.frame.size;
}
On an iPhone I have a UIViewController with a UIScrollView and I am having problems setting the height.
[_scrollView setScrollEnabled:YES];
//[_scrollView setContentSize:_viewController.frame.size];
_scrollView.contentSize = CGSizeMake(_scrollView.frame.size.width, 700);
NSLog([NSString stringWithFormat:#"%f", _scrollView.frame.size.height]);
NSLog reports 574.000000
I have done this on iPad development and works fine
If you want to make the frame of the scroll view bigger, use
[_scrollView setFrame:newfram];
If you want to set the scrolling area inside the scrollView to be bigger, use
[_scrollView setContentSize:CGSizeMake(_scrollView.frame.size.width, _scrollView.frame.size.height + 300)]; // ) was missing
the previous example adds 300 pixels of extra space to the scroll view. The scroll view will only scroll how you are expecting if the content size is larger than the frame.
The NSLog is correct. The frame.height and contentSize.height properties relate to two different things...
You can think of scrollView.frame.height as the size of the frame in which content appears.
Then consider scrollView.contentSzie.height to be the size of the content displayed within the frame
Hope this helps
I faced a strange problem, the scrollview does not scroll down, only scroll up. I have scrollview in my app, please look at my coding
.....
self.scrollView = [[UIScrollView alloc] initWithFrame: CGRectMake(0, 0, 320,427)];
[self.view addSubViews: self.scrollView];
UIView *blueView = [[UIView alloc] initWithFrame: CGRectMake(0, 47, 320, 320)];
blueView.backgroundColor = [UIColor blueColor];
[self.scrollView addSubViews: blueView];
self.scrollView.contentSize = CGSize(320, 640);
....
My problem is no matter what value I changed contentSize, my ScrollView only scroll up, not scroll down. I want user can move blueView to the top or bottom of iPhone screen from the original position.
do you have this problem?
The Problem
It looks like your issue is with how you're orienting blueView within scrollView. You're setting the frame of blueView to the CGRect (0, 47, 320, 320). When you set the frame like this, one of the things you're implicitly saying is:
The top edge of blueView is 47 points below the top edge of scrollView.
That's a perfectly valid thing to say, but it's what's causing the problem you describe. scrollView won't scroll down because it is designed to start, by default, with the rect (0, 0, 320, 480) in view. The contentSize property only indicates the size of the content within the UIScrollView, not its positioning. When you set it, you're basically telling scrollView:
Starting from your content origin, the content is 320 points wide and 640 points tall.
Thus, scrollView won't scroll up because, as far as it knows, there's no content above the coordinate (0, 0).
The Solution
There are three steps you'll need to take to get the functionality you want.
Set the contentSize to be just big enough to allow blueView to scroll all the way up and down.
Put blueView in the vertical center of scrollView.
Scroll the scrollView so that it is initially centered on blueView.
Set the contentSize to be just big enough to allow blueView to scroll all the way up and down.
We'll want to calculate the correct value of the contentSize property. It is of the type CGSize, so we need two parts: width and height. width is easy – since you don't seem to want horizontal scrolling, just make it the width of the screen, 320. Height is a little more tricky. If you want blueView to just touch the top and bottom of the screen when scrolled up or down, you need to do some math. The correct total height will be double the height of the screen, minus the height of blueView. So:
scrollView.contentSize = CGSizeMake(320, 480 * 2.0 - blueView.frame.size.height);
Put blueView in the vertical center of scrollView.
That's easy; just set the center property of blueView:
blueView.center = CGPointMake(160, scrollView.contentSize.height / 2.0);
Scroll the scrollView so that it is initially centered on blueView.
If you check the Apple UIScrollView documentation, you'll see an instance method - (void)scrollRectToVisible:(CGRect)rect animated:(BOOL)animated. This is exactly what you need to scroll scrollView programmatically. The rect you want is the one centered on blueView, with the size of the iPhone screen. So:
CGRect targetRect = CGRectMake(0, scrollView.contentSize.height / 2.0 - 240,
320, 480);
[scrollView scrollRectToVisible:targetRect animated:NO];
Make sure you do this scrolling in viewWillAppear, so it's ready right when the user sees the view.
That should be it. Let me know if you have any questions!
The content size of the scrollView should be the size of the view it is holding. This is how the code should be, try something like this.
self.scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(X, Y, W, H1)];
UIView * blueView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, W, H2)];
self.scrollView .contentSize = blueView.frame.size;
[self.scrollView addSubview:blueView];
[self.view addSubView: self.scrollView];
Thanks to Riley. Here, the H1 is the height of the UIScrollVIew and H2 is the height of the blueView and (H1 < H2).