using UIScrollView generating issues - iphone

This may be a simple problem. I have a UIScrollView with 3 views. I need to display 3 dots like Indicator ( to indicate there are more pages to the user). How do i do this?

use a UIPageControl:
pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(...)]; // set in header
[pageControl setNumberOfPages:3];
[pageControl setCurrentPage:0];
[pageControl setBackgroundColor:[UIColor clearColor]];
[self.view addSubview:pageControl];
That is the UI component that shows the dots... the number of pages is the number of dots. The current page is the one that is currently highlighted.
Then you need to use the scroll view delegate method to determine what page you've scrolled to:
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
int newOffset = scrollView.contentOffset.x;
int newPage = (int)(newOffset/(scrollView.frame.size.width));
[pageControl setCurrentPage:newPage];
}

You could create contentView in which you add UIScrollView and UIPageControl, set numberOfPages of pageControl to selected count and when you scroll you change page in your pageControl ( currentPage property ).
Cheers,
Krzysztof Zabłocki

You can use a UIPageControl with 3 dots on it. You'll need screen space (assuming the bottom of the screen) to put the page control so your scrollview won't be able to be full height.

Related

Convert UIViewController to UIScrollViewController

I am new to iPad developer,
I made one Registration form in my application, when i see my application in Portrait mode,
i am able to see whole form with no scrolling, but when i see same form in Landscape mode, i am not able to see part which is at bottom of page, for that a scrolling should be there to see bottom part.
:
In my .h file when i replace
#interface ReminderPage : UIViewController{
...
...
}
:UIViewController with :UIScrollView
and then when i add label in my .m file like this,
UILabel *Lastpaidlbl = [[[UILabel alloc] initWithFrame:CGRectMake(70 ,400, 130, 50)]autorelease];
Lastpaidlbl.backgroundColor = [UIColor greenColor];
Lastpaidlbl.font=[UIFont systemFontOfSize:20];
Lastpaidlbl.text = #"Lastpaid on :";
[self.view addSubview:Lastpaidlbl];
I am getting error on last line Property view not found on object of type classname.
i am unable to add label in my view.
Any help will be appreciated.
The question appears to be really asking how can all the components on the screen be placed inside a UIScrollView, rather than a UIView. Using Xcode 4.6.3, I found I could achieve this by simply:
In Interface Builder, select all the sub-views inside the main UIView.
Choose Xcode menu item "Editor | Embed In | Scroll View".
The end result was a new scroll view embedded in the existing main UIView, will all the former sub-views of the UIView now as sub-views of the UIScrollView, with the same positioning.
If you want to replace your UIViewController with a UIScrollView, you will have to go a bit of refactoring to your code. The error you get is just an example of that:
the syntax:
[self.view addSubview:Lastpaidlbl];
is correct if self is a UIViewController; since you changed it to be UIScrollView, you should now do:
[self addSubview:Lastpaidlbl];
You will have quite a few changes like this one to make to your code and will face some issues.
Another approach would be this:
instantiate a UIScrollView (not derive from it);
add your UIView (such as you have defined it) to the scroll view;
define the contentSize of the scroll view so to include the whole UIView you have.
The scroll view acts as a container for your existing view (you add your controls to the scroll view, then add the scroll view to self.view); this way, you could integrate it within your existing controller:
1. UIScrollView* scrollView = <alloc/init>
2. [self.view addSubview:scrollView]; (in your controller)
3. [scrollView addSubview:<label>]; (for all of your labels and fields).
4. scrollView.contentSize = xxx;
I think the latter approach will be much easier.
Please put all of your UIComponents to the UIScrollview and then it will start scrolling.
please look in to content size. please change it according to the orientation of device.
You're subclassing UIScrollView, so there is no self.view because already self is the view (of the scrollview). You dont need to subclass the scrollview, you can just embed your components in a ivar scrollview and set its contentSize (in your case, you have to enable the scrolling just when the device is in landscape mode). In interface builder you can embed the selected elements in one click, Editor-> Embed in-> scrollview.
First create scrollview
UIScrollView * scr=[[UIScrollView alloc] initWithFrame:CGRectMake(10, 70, 756, 1000)];
scr.backgroundColor=[UIColor clearColor];
[ self.view addSubview:scr];
second
change [self.view addSubview:Lastpaidlbl];
to
[scr addSubview:Lastpaidlbl];
third
set height depends on content
UIView *view = nil;
NSArray *subviews = [scr subviews];
CGFloat curXLoc = 0;
for (view in subviews)
{
CGRect frame = view.frame;
curXLoc += (frame.size.height);
}
// set the content size so it can be scrollable
[scr setContentSize:CGSizeMake(756, curXLoc)];
Finally
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
// Override to allow orientations other than the default portrait orientation.
if (interfaceOrientation==UIInterfaceOrientationLandscapeLeft || interfaceOrientation==UIInterfaceOrientationLandscapeRight) {
self.scr.frame = CGRectMake(0, 0, 703,768);
} else {
self.scr.frame = CGRectMake(0, 0, 768, 1024);
}
return YES;
}

UIScrollView inside UIView

I'm with a project in which I have a UIScrollView inside a UIView. Inside the UIScrollView has to see a list of buttons in 3 columns and X rows. I have the code that displays the buttons, but does not inserted into the UIScrollView, it prints over and does not scroll. Besides this, also cover the TabBar I have in the bottom of the view.
The code of the function that displais the buttons is
for (int y_axis=0; y_axis<=3; y_axis++)
{
for (int x_axis=0; x_axis<=2; x_axis++)
{
UIButton *btn=[[UIButton alloc] initWithFrame:CGRectMake(16+100*x_axis,100.0+115*y_axis,88.0 ,88.0)];
btn.backgroundColor=[UIColor brownColor];
[self.view addSubview:btn];
}
}
How can I do to display this in the UIScrollView? Thanks!!
Assuming you have a UIScrollView scroller, you have to change your last line to this;
[self.scroller addSubview:btn];
If not, you are adding it to the view, and not the scroller. Also, you have to change the scrollers contentsize, which is the X*Y if how much it contains. For it to contain the whole screen and nothing more;
[self.scroller setContentSize:CGSizeMake(320, 480)]
^ ^
Replace that with the width and the height you want to scroll. Each time you add a button below your new buttons, you should update the contentsize.
It's because you are adding buttons on view [self.view addSubview:btn]; not on ScrollView. Try to make a view with all you buttons. and set your view with buttons as contentview of your scrollview .
first you need the UIScrollViewDelegate in your .h file and then also check buttons are subview of yourScrollView or not also you add this button in your scrollview with code like this bellow...
[yourScrollView addSubview:yourbuttonname];
after that in your viewDidLoad method declare contentsize of your scrollview like this...
yourScrollView.contentSize=CGSizeMake(320, anyheight);///here define height which you want to scroll the view...
hope this help you....
:)
Try these steps:
for loop
{
create buttons along with the desired frames;
add those buttons to scrollview;
}
set the content size of the scrollview according to no of rows;
add the scroll view to main view i.e. self.view;

Why does UIScrollView always scrolls to bottom?

I have seen this question being addressed several times here at SO, e.g Problem with UIScrollView Content Offset, but I´m still not able to solve it.
My iphone app is basically a tab bar controller with navigation bar. I have a tableview controller made programmatically and a DetailViewController that slides in when I tap a cell in my tableview controller.
The DetailViewController is made in IB and has the following hierarchy:
top view => UIScrollView => UIView => UIImage and a UITextField.
My goal is to be able to scroll the image and text field and this works well. The problem is that my UIScrollView always gets positioned at the bottom instead at the top.
After recommendations her at SO, I have made my UIScrollView same size as the top view and instead made the UIView with the max height (1500) of my variable contents.
In ViewDidLoad I set the contentSize for the UIScrollView (as this is not accessible from IB):
- (void)viewDidLoad {
[scrollView setContentSize:CGSizeMake(320, 1500)];
[scrollView setContentOffset:CGPointMake(0, 0) animated:YES];
NSLog(#"viewDidLoad: contentOffset y: %f",[scrollView contentOffset].y);
}
Specifically setting the contentOffset, I would expect my scrollView to always end up at the top. Instead it always go to the bottom. It looks to me that there is some autoscrolling beyond my control taking place after this method.
My read back of the contentOffset looks OK. It looks to me that there may be some timing related issues as the scrolling result may vary whether animation is YES or NO.
A ugly workaround I have found is by using this delegate method:
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrView {
NSLog(#"Prog. scrolling ended");
[scrollView setContentOffset:CGPointMake(0, 0) animated:YES];
}
This brings my scrollview to top, but makes it bounce down and up like a yo-yo
Another clue might be that although my instance variables for the IBOutlet are set before I push the view controller, the first time comes up with empty image and textfield:
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if (!detailViewController) {
detailViewController = [[DayDetailViewController alloc] init];
}
// Pass dictionary for the selected event to next controller
NSDictionary *dict = [eventsDay objectAtIndex:[indexPath row]];
// This method sets values for the image and textfield outlets
[detailViewController setEventDictionary:dict];
// Push it onto the top of the navigation controller´s stack.
[[self navigationController] pushViewController:detailViewController animated:NO];
}
If I set animation to YES, and switch the order of the IBOutlet setting and pushViewController, I can avoid the emptiness upon initialization. Why?
Any help with these matters are highly appreciated, as this is really driving me nuts!
Inspired of Ponchotg´s description of a programmatically approach, I decided to skip interface builder. The result was in some way disappointing: The same problem, with the scrollview ending up in unpredictable positions (mostly at bottom), persisted.
However, I noticed that the scroll offset error was much smaller. I think this is related to the now dynamic (and generally smaller) value of ContentOffset. After some blind experimenting I ended up setting
[textView setScrollEnabled:YES];
This was previously set to NO, as the UITextView is placed inside the scrollview, which should take care of the scrolling. (In my initial question, I have erroneously said it was a UITextField, that was wrong)
With this change my problem disappeared, I was simply not able to get into the situation with scrollview appearing at bottom anymore in the simulator! (At my 3G device I have seen a slight offset appear very seldom, but this is easily fixed with scrollViewDidEndScrollingAnimation delegate described previously ).
I consider this as solved now, but would appreciate if anyone understand why this little detail messes up things?
OK! i have a question before i can give a correct answer.
Why are you using a UIView inside the Scrollview?
You can always only put your UIImageView and UITextField inside the UIScrollView without the UIView
and set the contentSize dynamically depending on the size of the text.
to give you an example how i do it:
int contSize = 0;
imageView.frame = CGRectMake(10, 0, 300, 190);
imageView.image = [UIImage imageNamed:#"yourimage"];
contSize = 190 //or add extra space if you dont want your image and your text to be so close
[textField setScrollEnabled:NO];
textField.font = [UIFont systemFontOfSize:15];
textField.textColor = [UIColor grayColor];
textField.text = #"YOUR TEXT";
[textField setEditable:NO];
textField.frame = CGRectMake(5, contSize, 310, 34);
CGRect frameText = textField.frame;
frameText.size.height = textField.contentSize.height;
textField.frame = frameText;
contSize += (textField.contentSize.height);
[scrollView setScrollEnabled:YES];
[scrolView setContentSize:CGSizeMake(320, contSize)];
In the above example I first create an int to keep track of the ysize of my view then Give settings and the image to my UIImageView and add that number to my int then i give settings and text to my UITextField and then i calculate the size of my text depending on how long is my text and the size of my font, then add that to my int and finally assign the contentSize of my ScrollView to match my int.
That way the size of your scrollview will always match your view, and the scrollView will always be at top.
But if you don't want to do all this, you can allways just:
[scrollView setContentOffset:CGPointMake(0, 0) animated:NO];
at the end of the code where you set your image and your text, and the NOto avoid the bouncing.
Hope this helps.

Calculate the contentsize of scrollview

I'm having a scrollview as the detailedview of tableview cell. There are multiple views on the detailedview like labels, buttons etc. which I'm creating through interface builder. What I'm creating through interface builder is static. I'm putting everything on a view of height 480.
A label on my detailedview is having dynamic text which can extend to any length. The problem is that I need to set the scrollview's content size for which I need its height.
How shall I set scrollview's height provided the content is dynamic?
You could try to use the scrollview'ers ContentSize. It worked for me and I had the same problem with the control using dynamic content.
// Calculate scroll view size
float sizeOfContent = 0;
int i;
for (i = 0; i < [myScrollView.subviews count]; i++) {
UIView *view =[myScrollView.subviews objectAtIndex:i];
sizeOfContent += view.frame.size.height;
}
// Set content size for scroll view
myScrollView.contentSize = CGSizeMake(myScrollView.frame.size.width, sizeOfContent);
I do this in the method called viewWillAppear in the controller for the view that holds the scrollview. It is the last thing i do before calling the viewDidLoad on the super.
Hope it will solve your problem.
//hannes
Correct shorter example:
float hgt=0; for (UIView *view in scrollView1.subviews) hgt+=view.frame.size.height;
[scrollView1 setContentSize:CGSizeMake(scrollView1.frame.size.width,hgt)];
Note that this only sums heights, e.g. if there are two subviews side by side their heights with both be added, making the sum greater than it should be. Also, if there are vertical gaps between the subviews, the sum will be less than it should be. Wrong height confuses scrollRectToVisible, giving random scroll positions :)
This loop is working and tested:
float thisy,maxy=0;for (UIView *view in scrollView1.subviews) {
thisy=view.frame.origin.y+view.frame.size.height; maxy=(thisy>maxy) ? thisy : maxy;
}
A somewhat easier way to do this is to nest your layout within a view then put that view within the scrollview. Assuming you use tags, this works as follows:
UIScrollView *scrollview = (UIScrollView *)[self.view viewWithTag:1];
UIView *longView = (UIView *)[self.view viewWithTag:2];
scrollview.contentSize = CGSizeMake(scrollView.frame.size.width, longView.frame.size.height);
That way the longView knows how tall it is, and the scrollview's content is just set to match.
This depends on the type of content you are going to add dynamically. So let's say you have a big text data to show, then use the UITextView and as it is a subclass of the UIScrollView, you can get the setContentSize of TextView when you assign the text content. Based on that you can set the total size of the UIScrollView.
float yPoint = 0.0f;
UIScrollView *myScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0.0f, yPoint, 320.0f, 400.0f)];
UITextView *calculatorTextView = [[UITextView alloc] init]; calculatorTextView.text = #"My looong content text ..... this has a dynamic content"; `
[calculatorTextView sizeToFit];
yPoint = yPoint + calculatorTextView.contentSize.height; // Bingo, we have the new yPoint now to start the next component.
// Now you know the height of your text and where it will end. So you can create a Label or another TextView and display your text there. You can add those components as subview to the scrollview.
UITextView *myDisplayContent = [[UITextView alloc] initWithFrame:CGRectMake(0.0f, yPoint, 300.f, calculatorTextView.contentSize.height)];
myDisplayContent.text = #"My lengthy text ....";
[myScrollView addSubview:myDisplayContent];
// At the end, set the content size of the 'myScrollView' to the total length of the display area.
[myScrollView setContentSize:yPoint + heightOfLastComponent];
This works for me.
I guess there's no auto in case of scrollview, and the contentsize should be calculated for static views on the screen at least and for dynamic once it should be calculated on the go.
scrollView.contentSize = [scrollView sizeThatFits:scrollView.frame.size]
I believe would also work
I had the same situation, but then I wrote a new version in Swift 4 mirroring the better answer in Objective-C by Hannes Larsson:
import UIKit
extension UIScrollView {
func fitSizeOfContent() {
let sumHeight = self.subviews.map({$0.frame.size.height}).reduce(0, {x, y in x + y})
self.contentSize = CGSize(width: self.frame.width, height: sumHeight)
}
}

Learning the basics of UIScrollView

I've been having a very hard time finding good examples of UIScrollView. Even Apple's UIScrollView Suite I find a bit lacking.
I'm looking for a tutorial or example set that shows me how to create something similar to the iPhone Safari tab scrolling, when you zoom out from one browser window and can flick to others.
But I'm having a hard time just getting any old view showing within a scroll view. I have a view set up with an image in it, but when I add it to the scroll view, I only get a black rectangle, no matter what I put in the view I add.
Any links or code snippets would be great!
Here is a scroll view guide from Apple
The basic steps are:
Create a UIScrollView and a content view you want to put inside (in your case a UIImageView).
Make the content view a subview of the scroll view.
Set the content size of the scrollview to the frame size of the content view. This is a very important step that people often omit.
Put the scroll view in a window somewhere.
As for the paging behavior, check out UIScrollView’s pagingEnabled property. If you need to scroll by less than a whole page you’ll need to play tricks with clipsToBounds, sort of the reverse of what is happening in this StackOverflow question.
UIScrollView *scrollview = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
NSInteger viewcount= 4;
for (int i = 0; i <viewcount; i++)
{
CGFloat y = i * self.view.frame.size.height;
UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, y,self.view.frame.size.width, self .view.frame.size.height)];
view.backgroundColor = [UIColor greenColor];
[scrollview addSubview:view];
[view release];
}
scrollview.contentSize = CGSizeMake(self.view.frame.size.width, self.view.frame.size.height *viewcount);
For more information Create UIScrollView programmatically
New 3/26/2013
I stumbled on an easier way to do this without code (contentSize)
https://stackoverflow.com/a/15649607/1705353