Cannot scroll when adding UIScrollView to UIView - ios

I'm trying to add a scrollview to my UIView, and put a label, textview, image on it but the scroll bar doesn't show up and I can't scroll.
//faux view
UIView* fauxView = [[[UIView alloc] initWithFrame: CGRectMake(10, 10, 200, 200)]autorelease] ;
[self.bgView addSubview: fauxView];
//the new panel
self.bigPanelView = [[[UIView alloc] initWithFrame:CGRectMake(0, 0, self.bgView.frame.size.width, self.bgView.frame.size.height)]autorelease];
self.bigPanelView.center = CGPointMake( self.bgView.frame.size.width/2, self.bgView.frame.size.height/2);
self.bigPanelView.backgroundColor = self.initialBackgroundColor;
UIScrollView * scroll = [[UIScrollView alloc] initWithFrame:self.bigPanelView.bounds];
[scroll setContentSize:CGSizeMake(200, 200)];
[self.bigPanelView addSubview:scroll];
scroll.showsVerticalScrollIndicator = YES;
// add label
UILabel *lblTitle = [[[UILabel alloc] initWithFrame:CGRectMake(0, 25, self.bgView.frame.size.width, 46)]autorelease];
// If I change the 25 to 235 the label will come under the screen but still I cannot scroll.
lblTitle.textAlignment = NSTextAlignmentCenter; // Align the label text in the center
lblTitle.backgroundColor = [UIColor clearColor];
lblTitle.text = self.initialTitle;
lblTitle.textColor = self.initialTitleColor;
lblTitle.font = [UIFont systemFontOfSize:31];
[scroll addSubview: lblTitle];

You have to make the scrollview's contentSize larger than the view:
[scroll setContentSize:CGSizeMake(200, 200)];
needs to be something like:
[scroll setContentSize:CGSizeMake(400, 400)];
Of course, make that the size of the content of whatever you're going to put the scroll view, and that way, it only scrolls if needs to.

For Scrolling - The scrollView contentSize should be larger then the scrollView frame.

Related

UIImageView size changes

I have navigation bar with custom view on it. UIImageView and UILabel are subviews of titleView. And I add UITapGestureRecognizer to titleView to make it show another UIViewController when the user taps on it. When you tap on titleView other UIViewController opens. But when you click on back button in my titleView size of UIImageView changes. Here is the code
UIView *titleView = [[UIView alloc] initWithFrame: CGRectMake(0, 0, self.view.frame.size.width, 30)];
UILabel *title = [[UILabel alloc] initWithFrame: CGRectMake(0, 0, self.view.frame.size.width/2, 30)];
title.text = _groupName;
[title setTextColor:[self colorFromHexString:#"#474747"]];
[title setFont:[UIFont fontWithName:#"Roboto-Bold" size:16]];
[title setTextAlignment:NSTextAlignmentCenter];
[title setBackgroundColor:[UIColor clearColor]];
_imageView.frame = CGRectMake(0, 0, 30, 30);
_imageView.layer.cornerRadius = 15.0;
_imageView.layer.masksToBounds = YES;
_imageView.layer.borderColor = [UIColor lightGrayColor].CGColor;
_imageView.layer.borderWidth = 0.1;
_imageView.contentMode = UIViewContentModeScaleAspectFit;
title.frame = CGRectMake(title.frame.origin.x+20, title.frame.origin.y, self.view.frame.size.width/2, 30);
UITapGestureRecognizer *recognizer;
recognizer = [[UITapGestureRecognizer alloc]initWithTarget:self action:#selector(titleTapped:)];
titleView.userInteractionEnabled = YES;
[titleView addGestureRecognizer:recognizer];
[titleView addSubview:title];
[titleView setBackgroundColor:[UIColor clearColor]];
[titleView addSubview:_imageView];
self.navigationItem.titleView = titleView;
Here are the images where you can see the changes
I check your code Add clips to bounds and do not need to title frame two times.
_imageView.frame = CGRectMake(0, 0, 30, 30);
_imageView.layer.cornerRadius = 15.0;
_imageView.layer.masksToBounds = YES;
_imageView.clipsToBounds = true;
Rather than setting the frame of the views directly, you might try using Auto Layout; I suspect what's happening is that your custom view is getting re-layed-out after the back button, and it's reverting to the image view's instrinsicSize.
What you could do instead is turn off translatesAutoresizingMaskIntoConstraints on the subviews, and then add constraints to position them, and finally add width and height constraints to the image view.
Using Auto Layout is also recommended if you ever intend to internationalize your app -- if you set up your constraints correctly, then the translated title will fit and you won't have to ever play around with hardcoded values.

How can I get the text to center in my scrollable UILabel?

The scrollable label works fine, but for some reason I cant get the text in the UILabel to center in the UIScrollView, it always stays left aligned. Here is an image of what I am talking about, and my code. (P.S. the UILabel is a subview of the UIScrollView, and the UIScrollView is a subview of the UITableViewCell.
scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(cell.frame.size.width/21.5, 25, cell.frame.size.width - 40 , 20)];
scrollView.showsHorizontalScrollIndicator = NO;
[cell addSubview:scrollView];
scrollLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, scrollView.frame.size.width, 20)];
scrollLabel.text = secondaryLabel.text;
scrollLabel.font = secondaryLabel.font;
scrollLabel.backgroundColor = [UIColor clearColor];
scrollLabel.textColor = [UIColor whiteColor];
scrollLabel.numberOfLines = 1;
scrollLabel.textAlignment = NSTextAlignmentCenter;
[scrollLabel sizeToFit];
[scrollView addSubview:scrollLabel];
scrollView.contentSize = CGSizeMake(scrollLabel.frame.size.width, 20);
I think the code you written for UILabel is pretty much right and the center TextAlignment is there but the problem is you need to pass the right X & Y for UILabel Frame's. For now they are getting set to 0-0 and are adding on the Scrollview's starting frame. This might can solve your problem.

CGRectMake( ) - y reference looks totally wrong

I am facing a really strange issue:
I am instantiating multiple UIImageView inside a for loop with the method CGRectMake, the y origin I am giving seems to be totally wrong on the screen:
Here is my code:
- (void)makeTheView
{
self.view.backgroundColor = [UIColor whiteColor];
UIScrollView *header = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 64, self.view.frame.size.width, 100)];
header.backgroundColor = [UIColor colorWithRed:254/255.0f green:255/255.0f blue:213/255.0f alpha:1.0f];
[self.view addSubview:header];
for (int i = 0; i < 10; i++) {
UIImageView *avatar = [[UIImageView alloc] initWithFrame:CGRectMake(5 + i * 75, 5, 70, 70)];
avatar.image = [UIImage imageNamed:#"bo_pic_baby5.jpg"];
[avatar.layer setCornerRadius:8.0];
avatar.layer.masksToBounds = YES;
NSLog(#"%f", avatar.frame.origin.y);
UILabel *title = [[UILabel alloc] initWithFrame:CGRectMake(0, 50, avatar.frame.size.width, 20)];
title.backgroundColor = [UIColor colorWithRed:148/255.0f green:148/255.0f blue:148/255.0f alpha:0.5f];
title.font = [UIFont fontWithName:#"Arial" size:15];
title.text = #"崔健";
title.textAlignment = NSTextAlignmentCenter;
title.textColor = [UIColor whiteColor];
[avatar addSubview:title];
[header addSubview:avatar];
}
}
According to this code avatar is within header at 5px from the top of header.
But the following is what I obtain visually:
note: when the white area begin, the header view stopped
This is not a real issue since I can reevaluate my frames like this :
CGRectMake(5 + i * 75, - 20, 70, 70)
but it looks really weird, and I am quite sure I am missing something totally trivial here...
I think this will be fixed by:
self.automaticallyAdjustsScrollViewInsets = NO;
Since iOS 7, view controllers automatically adjust scroll view insets so that the scroll view content is not hidden behind the navigation bar because it expects scroll views to start at the top of the screen.
However, the usual solution is to just set the scrollview frame.origin.y to 0.
Your Code is Absolutely Correct , As you are Adding the scrollview on (0,64) Position , So 64 will be count from Bottom of the Navigation Bar, If you want it on top (Just Below the Navigation bar), Change this declaration to as below :
UIScrollView *header = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 100)];

How to create UIScrollview inside UIScrollview programmatically

Please tell me how to set scrollview inside a scrollview like nested process.
The following code works partially.
int x=10;
int y=10;
for(int i=0; i<5; i++)
{
UIScrollView *scrollview=[[UIScrollView alloc]initWithFrame:CGRectMake(x, y, 50, 50)];
scrollview.showsVerticalScrollIndicator=YES;
scrollview.scrollEnabled=YES;
scrollview.userInteractionEnabled=YES;
scrollview.backgroundColor = [UIColor greenColor];
[self.view addSubview:scrollview];
scrollview.contentSize = CGSizeMake(50,50);
y=y+95;
}
Now all I can see are 3 scrollviews and the others are hidden. How can I create main scroll to view so that the child scrollViews are not hidden?
You need to have an initial scrollView that you then put these scrollViews in.
UIScrollView * mainScrollView = [[UIScrollView alloc] initWithFrame:self.view.frame];
mainScrollView.contentSize = CGSizeMake(50, (y + 95) * 5);
// further configure
[self.view addSubview: mainScrollView];
Then change
[self.view addSubview:scrollview];
To
[mainScrollView addSubview: scrollView];
//I have created Two Scroll view programmatically this way
UIScrollView *scrollViewOuter = [[UIScrollView alloc] initWithFrame:CGRectMake(100.0f, 100.0f, 600.0f, 600.0f)];
scrollViewOuter.backgroundColor = [UIColor scrollViewTexturedBackgroundColor];
scrollViewOuter.contentSize = CGSizeMake(2000.0f, 2000.0f);
UIScrollView *scrollViewInner = [[UIScrollView alloc] initWithFrame:CGRectMake(10.0f, 10.0f, 200.0f, 200.0f)];
scrollViewInner.backgroundColor = [UIColor whiteColor];
scrollViewInner.contentSize = CGSizeMake(2000.0f, 2000.0f);
[scrollViewOuter addSubview:scrollViewInner];
[self.window addSubview:scrollViewOuter];
//You can change frame and use in your own way
Just create a parent scrollview that is big enough to hold the 5 smaller ones, then change this line:
[self.view addSubview:scrollview];
to
[parentScrollView addSubview:scrollview];

UIScrollView won't stay in place after user finishes scrolling

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

Resources