CODEWITHSUNDEEP
iosiphoneobjective-cuiviewuiscrollview
Preston Cheung
Preston Cheung

Reputation: 175

UIScrollView does not scroll

I got a problem about UIScrollView. I am making a custom view which inherits UIView. The view has a UIScrollView on which there are lots of buttons which should scroll left and right. The UIScrollView and buttons can show normally. But I cannot scroll the buttons. Could someone give me some suggestions? Thanks a lot!

MZMPhotoCalenderSwitcher.h

#import <UIKit/UIKit.h>

@interface MZMPhotoCalenderSwitcher : UIView <UIScrollViewDelegate>

@property (strong, nonatomic) UIScrollView *topSwitcher;

@end

MZMPhotoCalenderSwitcher.m

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.topSwitcher = [[UIScrollView alloc] initWithFrame:CGRectMake(0, LABEL_HEIGHT + VIEW_Y, self.view.bounds.size.width, TOP_SWITCHER_HEIGHT)];
    self.topSwitcher.backgroundColor = [UIColor greenColor];
    self.topSwitcher.pagingEnabled = YES;
    self.topSwitcher.showsHorizontalScrollIndicator = NO;
    self.topSwitcher.showsVerticalScrollIndicator = NO;

    [self add:3 ButtonsOnView:self.topSwitcher withButtonWidth:44.8f andHeight:20.0f];
}

- (void)add:(int)num ButtonsOnView:(UIScrollView *)view withButtonWidth:(CGFloat)width andHeight:(CGFloat)height
{
    CGFloat totalTopSwitcherWidth = num * width;
    [view setContentSize:CGSizeMake(totalTopSwitcherWidth, view.bounds.size.height)];
    CGFloat xOffset = 0.0f;

    for (int i=1; i<=num; i++)
    {
        UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
        [button setFrame:CGRectMake(xOffset, 0, width, height)];
        xOffset += width;
        [button setTitle:[NSString stringWithFormat:@"%d", i] forState:UIControlStateNormal];

        button.titleLabel.font = [UIFont systemFontOfSize:10];
        [button setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];
        [button setTitleColor:[UIColor blackColor] forState:UIControlStateSelected];
        [button setTag:i];
        [button addTarget:self action:@selector(buttonEvent) forControlEvents:UIControlEventTouchUpInside];

        if (i % 2 == 0)
            [button setBackgroundColor:[UIColor yellowColor]];
        else
            [button setBackgroundColor:[UIColor redColor]];

        [view addSubview:button];
    }
}

Upvotes: 3

Views: 8569

Answers (10)

Guy
Guy

Reputation: 361

Combining all of this advise into one simple answer:

// In viewDidLoad 

// set the size of the scrollview (in this case I made it the size of its container
self.scrollView.frame = self.view.frame;
// now set the size of the content to be scrolled within the scrollview
// the content to be displayed must be bigger than the scrollView
// in this case I added 100 to make the content size, so that it is taller than the height of the scrollView
// now it scrolls
    self.scrollView.contentSize = CGSizeMake(self.scrollView.frame.size.width, self.scrollView.frame.size.height + 100);

Upvotes: 1

dulan
dulan

Reputation: 1604

I'm using Xcode 6/iOS 8+ now with auto-layout turned on, and I had the same problem in the first place, removing auto-layout doesn't work at all, so in order to make scroll view scrollable vertically, I made sure the following:

  1. The scroll view content size height MUST be bigger than the screen height, this almost goes without saying...

  2. The top/bottom/left/right constraint of the scroll view HAS TO BE pinned, I did this using storyboard so no code showing up here

If you want to make the scroll view scrollable horizontally, then make sure its content size width is bigger than the screen width, the other rule applies the same.

This worked for me, hope it can help someone.

Upvotes: 1

AJ112
AJ112

Reputation: 5301

Just disable "Auto Layout" in your project and it will start working!

Upvotes: 1

Preston Cheung
Preston Cheung

Reputation: 175

It's amazing.

I just move the codes which was in viewDidLoad to initWithFrame:, then it works. I do not know why it is?

Upvotes: 0

Shaik Riyaz
Shaik Riyaz

Reputation: 11462

try this . . . . 

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.topSwitcher = [[UIScrollView alloc] initWithFrame:CGRectMake(0, LABEL_HEIGHT + VIEW_Y, self.view.bounds.size.width, TOP_SWITCHER_HEIGHT)];
    self.topSwitcher.backgroundColor = [UIColor greenColor];
    self.topSwitcher.pagingEnabled = YES;
    self.topSwitcher.showsHorizontalScrollIndicator = NO;
    self.topSwitcher.showsVerticalScrollIndicator = NO;
    [topSwitcher setContentSize:CGPointMake(self.view.bounds.size.width,TOP_SWITCHER_HEIGHT+400)];

    [self add:3 ButtonsOnView:self.topSwitcher withButtonWidth:44.8f andHeight:20.0f];
}

Upvotes: 0

Bimawa
Bimawa

Reputation: 3720

Where are you add ScrollView on SuperVIew? And where are you recalculate Content size property of scrollView? 

[view setContentSize:CGSizeMake(<summYourViews.width>,<summYourViews.height>)];

Upvotes: 0

Pravin
Pravin

Reputation: 44

You have to set scrollview frame size and content size.

Upvotes: 0

Akshay Nalawade
Akshay Nalawade

Reputation: 1447

Below following line

[view addSubview:button];

add

view.contentSize = CGSizeMake(view.contentSize.width, button.frame.origin.y + button.frame.size.height);

This will set content size of scroll view to the bottom of your button.

Upvotes: 5

Alex
Alex

Reputation: 1051

Your problem is that you haven't set your contentSize, therefore, the contentSize is the same than the frame view.

You need to do this in your viewDidLoad

- (void)viewDidLoad {
    ........
    self.scrollView.contentSize = CGSizeMake(/*yourWidth*/, /*yourHeight/*);
    ........
}

Try do adjust your contentSize to the last position of your object plus its size plus a padding.

Upvotes: 0

Vishwa Patel
Vishwa Patel

Reputation: 484

It should be issue of content size, also check that scrollEnabled property of UIScrollView object is set to TRUE,

Check solution of UIScrollView won't scroll!

Upvotes: 1

Related Questions