问题
My iPad app is currently built as such: xml data is pulled from my website and parsed in a View Controller "FishIDView". This view controller has a UIScrollView "scrollView" that has a subview "XMLView" which is a UIView. scrollView is setup so that it scrolls and pages through the XMLViews based on the number of items contained in the XML. For example 12 items = 12 pages, or instances of XMLView. These pages contain photos of individual fish. Each of these pages contain a button that creates a subview of the UIView "XMLView" called "flipView", and displays the subview via the flip from left animated transition. This subview contains information about the pictured fish. flipView has a button that returns the user (flips back) to the fish picture.
My problem is that when I'm looking at the flipView (which is a subview of XMLView which is a subview of scrollView), scrolling is still enabled. If I scroll left or right while on flipView, I see the XMLView of the next fish. I want scrolling to be disabled while looking at flipView.
Any suggestions on what I can do to send something like a setScrollEnabled:NO command to scrollView (on FishIDView) from the subview?
EDIT:
So I assume I need to use a protocol and delegate. I thought I could figure it out, but I'm getting caught up on the implementation.
In my XMLView.h (leaving out extraneous code):
@protocol XMLViewDelegate <NSObject>
- (void) stopScrolling;
@end
@interface XMLView : UIView
{
...
id secondDelegate;
}
...
@property (nonatomic, retain) id <XMLViewDelegate> secondDelegate;
...
@end
Then in my XMLView.m (with the IBAction hooked to a UIButton which works correctly):
...
@synthesize secondDelegate;
...
-(IBAction)goToInfo
{
//[self newPage];
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:1.0];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:self cache:YES];
[self.secondDelegate stopScrolling];
[self addSubview:flipView];
...
NSLog(@"button pressed");
}
In FishIDView.h:
@interface FishIDView : UIViewController <XMLViewDelegate>
FishIDView.m:
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[scrollView setScrollEnabled:YES];
XMLView *subsubView = [[XMLView alloc] init];
subsubView.secondDelegate = self;
...
}
-(void) stopScrolling
{
[scrollView setScrollEnabled:NO];
NSLog(@"NO more scrolling!!!");
}
When I click on my button in XMLView that triggers "goToInfo", the rest of the action happens, but the log "No more scrolling!!" never displays.
Did I go about this the wrong way? I'm still trying to figure out delegates, so I may be completely wrong with this methodology.
EDIT 2:
I've now tried getting rid of the delegate and going what sounds like a more simplistic route, but it's still not working correctly.
In XMLView.m:
-(IBAction)goToInfo
{
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:1.0];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:self cache:YES];
//The next 2 lines are what I added
ViewController *mainView = [[ViewController alloc] init];
[mainView stopScrolling];
[self addSubview:flipView];
[infoButton setEnabled:FALSE];
[infoButton setHidden:YES];
[title setHidden:YES];
[UIView commitAnimations];
NSLog(@"button pressed");
}
Then in FishIDView.h
-(void) stopScrolling;
FishIDView.m
-(void) stopScrolling
{
[scrollView setScrollEnabled:NO];
NSLog(@"NO more scrolling!!!");
}
The "No more scrolling!!!" prints, but scrollView is still scroll enabled! Why would it run the NSLog portion of stopScrolling but not setScrollEnabled:NO? Can anyone help me?
回答1:
Solved! I incorporated Notifications instead of trying to directly call a method from a subview.
Quick overview of my setup. UIViewController FishIDView contains a UIScrollView called scrollView. scrollView has a subview XMLView. XMLView has a button that shows its subview, flipView. I wanted scrolling to be disabled on scrollView when flipView was visible.
In XMLView.h (with irrelevant code omitted):
#import <UIKit/UIKit.h>
#import <QuartzCore/QuartzCore.h>
#define kApplicationDidStopScrollingNotification @"StopScroll"
#define kApplicationDidResumeScrollingNotification @"ResumeScroll"
#import "FishIDView.h"
@interface XMLView : UIView
{
IBOutlet UIButton *infoButton;
IBOutlet UIButton *closeButton;
IBOutlet UIView *flipView;
}
@property (nonatomic, retain) IBOutlet UIButton *infoButton;
@property (nonatomic, retain) IBOutlet UIButton *closeButton;
- (IBAction)goToInfo;
- (IBAction)closeSubView;
@end
In XMLView.m:
#import "XMLView.h"
@implementation XMLView
@synthesize infoButton, closeButton;
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
return self;
}
//Allows button to be pressed while contained in subview of scrollview
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
CGPoint hitPoint = [infoButton convertPoint:point fromView:self];
CGPoint closePoint = [closeButton convertPoint:point fromView:flipView];
if ([infoButton pointInside:hitPoint withEvent:event]) return infoButton;
if ([closeButton pointInside:closePoint withEvent:event]) return closeButton;
return [super hitTest:point withEvent:event];
}
-(IBAction)goToInfo
{
//post notification for FishIDView to listen to to trigger method that disables scrolling
[[NSNotificationCenter defaultCenter] postNotificationName:kApplicationDidStopScrollingNotification object:nil];
[self addSubview:flipView];
//custom transition between views. A cross-fade effect
flipView.alpha = 0.0f;
[UIView beginAnimations:@"fadeInSecondView" context:NULL];
[UIView setAnimationDuration:0.5];
flipView.alpha = 1.0f;
[infoButton setEnabled:FALSE];
[UIView commitAnimations];
}
- (IBAction)closeSubView
{
//post notification to resume scrolling
[[NSNotificationCenter defaultCenter] postNotificationName:kApplicationDidResumeScrollingNotification object:nil];
flipView.alpha = 1.0f;
[UIView beginAnimations:@"fadeInSecondView" context:NULL];
[UIView setAnimationDuration:0.5];
flipView.alpha = 0.0f;
[infoButton setEnabled:TRUE];
[UIView commitAnimations];
[flipView performSelector:@selector(removeFromSuperview) withObject:nil afterDelay:1.2];
}
@end
Make sure to put #import "XMLView.h" into your FishIDView.h file at the top and create the -(void) methods at the bottom.
#import <UIKit/UIKit.h>
#import "XMLView.h"
@class AppDelegate;
@interface FishIDView : UIViewController <UIScrollViewDelegate>
{
...
}
@property ...
//These are the 2 methods that turn scrolling on and off
-(void) stopScrolling;
-(void) resumeScrolling;
@end
Then in FishIDView.m
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[scrollView setScrollEnabled:YES];
//Listen for the notification to stop scrolling
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(stopScrolling) name:kApplicationDidStopScrollingNotification object:nil];
//Listen for the notification to resume scrolling
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(resumeScrolling) name:kApplicationDidResumeScrollingNotification object:nil];
[self layoutSubview];
}
-(void) stopScrolling
{
[scrollView setScrollEnabled:NO];
NSLog(@"NO more scrolling!!!");
}
-(void) resumeScrolling
{
[scrollView setScrollEnabled:YES];
NSLog(@"begin scrolling again!!");
}
If anyone has questions or is having trouble implementing this, I'll be happy to share more of my code. I just omitted most of it because it doesn't really pertain to this subject.
来源：https://stackoverflow.com/questions/7971466/disable-scrolling-via-ibaction-contained-in-subview