Connecting a UIScrollView to a UIView class - ios

I'm currently creating a "slide-show" of pictures that the user can scroll through. Following a guide, I made it so that the UIScrollView I am using shows the edges of the previous and next pictures as the user scrolls along. This comes with a side-effect of the user not being able to scroll if he touches on one of the edges of the pictures, because these edges are technically not within the border of the UIScrollView itself. In order to compensate for this, I am going to create a UIView in which I will embed the UIScrollView. The UIVew will be extend the entire width of the page so that the user can scroll when touching the edges of the pictures. To do this, I need to connect the UIScrollView to the code of the UIView through an IBOutlet. Usually this is simply accomplished by Ctrl-clicking on the UIScrollView and dragging to the code. However, this does not seem to work for me and I am stumped as to why.
Here is a screenshot of the environment I am dealing with when I try to ctrl-click on the UIScrollView and drag to the code to create an IBOutlet (it simply doesn't give the option to create anything).
Here is a screenshot of what running the simulator produces. If i try to click and drag where my mouse currently is, it doesn't scroll, which is the problem I am trying to correct.

It is because you should link your storyboard view to UIView class. You can choose your ScrollViewController class in custom class settings. I added the sample jpg

what you are looking for is not that 'easy' by just connecting the two.
There are two options:
1) In the future you should use a UICollectionView and implement the paging behaviour yourself, that is the cleanest code I think.
NEVER MIND THE SECOND OPTION - I DIDN'T SEE YOU ACTUALLY ALREADY USED THIS
2) To directly answer your question:
You have to subclass the UIView that contains the UIScrollView like this:
header:
#import <UIKit/UIKit.h>
#interface SCTouchForwardView : UIView
#property (nonatomic, weak) IBOutlet UIView* receiver;
#property (nonatomic, assign) BOOL force;
#end
Implementation:
#import "SCTouchForwardView.h"
#implementation SCTouchForwardView
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
UIView* result = [super hitTest:point withEvent:event];
if (![result isKindOfClass:[SCTouchForwardView class]]) {
return result;
}
if (result==self) {
UIView *result = [self.receiver hitTest:[self convertPoint:point toView:self.receiver] withEvent:event];
if (result) {
return result;
}else{
if (self.force) {
return self.receiver;
}
return nil;
}
}
return nil;
}
#end
When you want to use this, you just have to Right-Click-Drag from the container to the UIScrollview and select 'receiver' and what you tried to do will work!

Related

UIView custom xib doesn't show up

I'm having a problem that doesn't seem to have an obvious solution. I've searched around and I've been through all common answers that I could find.
My custom xib views don't show up on the app when I launch. The background is clear, and this xib has 5 image views as you can see below which aren't set to hidden.
The class has about 5 delegates as well which I set from a caller when the delegates have been initialized. The caller of initWithDelegates: is the parent UIViewController that displays this xib.
CustomView.h
#interface CustomView : UIView<SomeProtocol>
// UI Items - THESE AREN'T SHOWING UP
#property (strong, nonatomic) IBOutlet UIImageView *image1;
#property (strong, nonatomic) IBOutlet UIImageView *image2;
#property (strong, nonatomic) IBOutlet UIImageView *image3;
#property (strong, nonatomic) IBOutlet UIImageView *image4;
#property (strong, nonatomic) IBOutlet UILabel *label;
#property (strong, nonatomic) IBOutlet UIStackView *centerStackView;
- (id)initWithDelegates:(UIViewController*)delegate1 withDelegate2:(NSObject<Delegate2>*)delegate2 withDelegate3:(NSObject<Delegate3>*)delegate3 withDelegate4:(UIViewController<Delegate4>*)delegate4
withDelegate5:(NSObject<Delegate5>*)delegate5;
#end
CustomView.m
#implementation CustomView
- (void)awakeFromNib {
[super awakeFromNib];
}
- (id)initWithDelegates:(UIViewController*)delegate1 withDelegate2:(NSObject<Delegate2>*)delegate2 withDelegate3:(NSObject<Delegate3>*)delegate3 withDelegate4:(UIViewController<Delegate4>*)delegate4
withDelegate5:(NSObject<Delegate5>*)delegate5
{
NSArray * arr =[[NSBundle mainBundle] loadNibNamed:#"CustomView" owner:nil options:nil];
self = [arr firstObject];
self.delegate1 = delegate1;
self.delegate2 = delegate2;
self.delegate3 = delegate3;
self.delegate4 = delegate4;
self.delegate5 = delegate5;
[self setLoopImage];
[self layoutIfNeeded];
return self;
}
#end
What else I've verified:
I made sure that the xib file is properly selected under "Custom Class" in the interface builder.
I've walked through the code to make sure there are no crashes or obvious issues.
The xib doesn't appear to have any obvious issues in interface builder such as being set to HIDDEN.
The 5 IBOutlet ImageViews get a memory address and aren't nil.
Any help is appreciated!
UPDATE:
I believe this has something to do with putting the nibs in a nested UIView. In the interface builder, the order is UIViewController -> UIView -> nibs
There doesn't seem to be a method to register nibs from the parent UIViewController as there are in classes like UITableView.
I've also tried:
Setting the background color in the xib to make sure it shows up. It doesn't. However if I set the background color to red in the parent where I added the view in interface builder, it turns red. (See Figure 1), and my xib file is shown in Figure 2
Over-rode initWithFrame to make sure its being called. It is called.
Thinking that the view may be instantiated twice, one via autolayout and one via my custom init method, I tried making the (id)initWithDelegates method not init or register the nib in case that was duplicating the object. I did this by removing 1) return self, 2) the lines that register the nib, and 3) making the method prototype return void - I.E. (void)initWithDelegates - This didn't work either.
I tried these lines within initWithDelegates :
[self addSubview: self.image1];
[self bringSubviewToFront: self.image1];
[self.menuImage setHidden:image1];
-- with no luck.
Figure 1: (Actual result)
Figure 2 (Expected.. with red background)
Check your Autolayout in your custom XIB. Something the contain does not show because of it. For example: only center vertically & center horizontally. Try to do different autolayout constraint in your view in custom class.
I think something is wrong with layout of your CustomView inside ParentView. Could you please:
Check the frame of CustomView when you add it into the ParentView.
Check constraints that has CustomView inside ParentView. If you don't
have them - add it, constraints will iOS the glue how to layout your
CustomView. More information about this you can find here Programmatically Creating Constraints
And also you can try to use "Debug View Hierarchy" in Xcode to
inspect what is going on on your screen, there you can find your
CustomView in the view hierarchy and you will see what is wrong.
nibs cannot be nested within the structure.
Instead of:
UIViewController -> UIView -> nibs..
It should be:
UIViewController -> Container View -> UIView with nibs.

Adding SKScene to a UICollectionViewCell lowers scrolling performance

I am trying to add a SKScene with a simple animation to a UICollectionCell.
I've got my SKView setup in the .xib file of the collection view cell.
If I run it and scroll, it works as expected. But if I change to a different view controller (in a tab bar controller) that also uses those types of cells and start scrolling, it will get stuck.
Here's how I am adding the SKScene:
#interface MAPostCollectionViewCell ()
#property (strong, nonatomic) IBOutlet SKView *viewAnimation;
#property (strong, nonatomic) MAHeartAnimation *heartScene;
#end
#implementation MAPostCollectionViewCell
-(void)layoutSubviews{
[super layoutSubviews];
self.heartScene = [MAHeartAnimation sceneWithSize:self.viewAnimation.bounds.size];
self.heartScene.scaleMode = SKSceneScaleModeAspectFill;
[self.viewAnimation presentScene:self.heartScene];
}
#end
And I only trigger the animation if the user taps a button.
But for the scope of this question, the animation doesn't really matter, as I am not touching that button, just scrolling the UICollectionView.
It turns out you should not use SpriteKit and UIKit this way. Even though they are modular frameworks, they are not performant when using together this way. I ended up using UIKit for the animations that I wanted, by using CALayers.

Initializing Views(button, label, etc) in -init or -loadview

Im curious, where is the best option to allocate/init, set attributes of views (uibutton, uilabel, uitextfield, initializing variables, etc).
This is in regards to developing an app strictly programatically. I see some cases where these views have been allocated/init in the class -init method, but then other times i see other views set in the -loadview method.
Can anyone provide some clarity about this? And maybe some abstract examples of when the best time to do it for either method would be.
Thanks
The -init* family of functions would be a good place to initialize simple properties, e.g. strings, numbers, and the like. The initializer runs just after the memory for the object is allocated, and if you have something that can be initialized there then you should do it there.
For UIViewController instances, you probably have to wait until the nib has been loaded before you can initialize everything else. If you've got images that need to be placed inside subviews, or fonts that need configuring, or whatever, then you need to have the nib loaded first. -viewDidLoad is the best place for that stuff.
For UIView instances (or subclasses like UITableViewCell), you need to wait for the nib to be loaded too. You can use -awakeFromNib in that case.
Here's a quick comment on this:
-SubClass a UIView, smash all your UI elements into that view, well as many as you can at least. Import this subclassed view's header into your view controller's implementation file
-In your view controller, typecast your view controller's view like so:
-(HHYSignUpViewFirstPhase*)contentView
{
return (id)[self view];
}
-Invoke the loadView method
-(void)loadView
{
[self setView:[HHYSignUpViewFirstPhase new]];
}
-In your viewdidLoad, you can now set handlers to buttons and such from your subclassed UIView by calling to "[self contentView]" like so:
-(void)viewDidLoad
{
[super viewDidLoad];
[self setTitles:#"Sign Up"];
[[[self contentView] nameField] setDelegate:self];
[[[self contentView] emailField] setDelegate:self];
[[[self contentView] passwordField] setDelegate:self];
[[[self contentView] signupButton] addTarget:self action:#selector(signupPressed) forControlEvents:UIControlEventTouchUpInside];
}
Now you have it all set up, you just need to add methods to handle events from the button, for example in the view did load from your subview that you subclassed:
-(void)signupPressed
{
///do work
}
UIVIew subclass:
HHYSignUpViewFirstPhase.h
#interface HHYSignUpViewFirstPhase : UIView
#property (nonatomic) UIButton * signupButton;
#property (nonatomic) UITextField * emailField;
#property (nonatomic) UITextField * nameField;
#property (nonatomic) UITextField * passwordField;
#end
HHYSignUpViewFirstPhase.m
#import "HHYSignUpViewFirstPhase.h"
#implementation HHYSignUpViewFirstPhase
-(id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self == nil)
return nil;
//do work, set up buttons, constraints, etc, etc.
return self;
}
#end
Essentially, what I'm saying here is that in the subclassed UIView you can initialize the UIView and set up all its constraints and EVERYTHING, frames included and then in the load view method of your UIViewController, you then call to this view and typcast the view of the UIViewController. So, sometimes you do the set up in the init, sometimes you do it in the load view, it depends on what you are trying to do, but this is how you set this up in a pure programmatic fashion with separation of duties, encapsulation, and all tied together in an MVC framework -- all work is separated into classes, and all controllers control a single class.
http://matthewmorey.com/creating-uiviews-programmatically-with-auto-layout/
and this
https://developer.apple.com/library/ios/featuredarticles/ViewControllerPGforiPhoneOS/ViewLoadingandUnloading/ViewLoadingandUnloading.html#//apple_ref/doc/uid/TP40007457-CH10-SW36

All UITableCells disappear when tapping on UITableView in iOS 7

I am having a problem with my UITableView in iOS7. Initially, the data loads in just fine, and I get output in my console that proves that the cells are speaking to the data source correctly, but as soon as I tap anywhere on the table, the cells disappear and the table goes blank. The height of the cells in the empty UITableView seem to be honoring the height my custom prototype cell (410px), but all the data in the cells vanish, and the empty table view acts like it only has one cell in it (like its default state before it gets hooked up to the delegate).
I am using Storyboards for this app.
To get a little context, this app is similar to the iphone Instagram app, and I am using this application as way to learn iOS 7 development. I have been banging my head up against a wall trying to solve this issue, and I can't find any online resources that can help me solve this, so I wanted to ask all the smart peeps on Stack Overflow.
I have prepared a graphic that helps you see the problem
higher resolution version here
Here is my TableViewController code:
#interface PA_PhotoTableViewController ()
#property (nonatomic, copy) NSArray *photos;
#end
#implementation PA_PhotoTableViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.photos = [[PA_PhotoStore sharedPhotoStore] allPhotos];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [[[PA_PhotoStore sharedPhotoStore] allPhotos] count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
PA_PhotoCell *cell = [tableView dequeueReusableCellWithIdentifier:#"PhotoCell" forIndexPath:indexPath];
PA_Photo *photo = (self.photos)[indexPath.row];
cell.photoTitle.text = photo.title;
cell.photoOwnerName.text = [NSString stringWithFormat:#"%#", photo.owner];
cell.photoLikes.text = #"99";
// Photo Image URL
NSURL *photoImageURL = [NSURL URLWithString:photo.image_full_url];
[cell.photoImage sd_setImageWithURL:photoImageURL placeholderImage:[UIImage imageNamed:#"lightGraySpinningLoader.gif"]];
// Photo Owner Image
[cell.photoOwnerImage sd_setImageWithURL:photoImageURL placeholderImage:[UIImage imageNamed:#"lightGraySpinningLoader.gif"]];
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// This code never gets called when I try to tap on a cell
NSLog(#"A row was selected");
}
- (void)dealloc {
NSLog(#"dealloc called in PA_PhotoTableViewController");
}
and here is the custom cell code PA_PhotoCell (consolidated .h & .m files):
#interface PA_PhotoCell : UITableViewCell
#property (nonatomic, weak) IBOutlet UIImageView *photoImage;
#property (nonatomic, weak) IBOutlet UILabel *photoTitle;
#property (nonatomic, weak) IBOutlet UILabel *photoOwnerName;
#property (nonatomic, weak) IBOutlet UIImageView *photoOwnerImage;
#property (nonatomic, weak) IBOutlet UILabel *photoLikes;
#property (nonatomic, weak) IBOutlet UILabel *photoTimestamp;
#property (nonatomic, weak) IBOutlet UILabel *photoComments;
#end
#implementation PA_PhotoCell
- (void)setSelected:(BOOL)selected animated:(BOOL)animated {
[super setSelected:selected animated:animated];
NSLog(#"in set selected");
}
-(void)setHighlighted:(BOOL)highlighted {
NSLog(#"in set highlighted");
}
You can see a few NSLog() calls to help me see if anything is getting called.
Where am I going wrong? The end goal is to click on one of the TableViewCell instances and launch a UINavigationController, I know how to do that, but I can't move on to that step until I figure out why my UITableView won't scroll, and why it disappears when I click on it!
EDIT: After much testing, debugging and experimentation, I have been able to conclude that the problem is actually not with the UITableView at all, and it is, in fact, a problem with how the UITableView is being loaded into its parent view. I still haven't found a solution to my problem, but I am getting closer to finding the cause. Here is what I have discovered:
First, when any of the UIButtons at the bottom of the screen are tapped (see photo reference), it loads the relevant instance of UIViewController into a UIView called placeholderView. When I run my problematic UITableView OUTSIDE of this UIView (where the UITableViewController is acting on its own, not embedded within another UIView) then the table works perfectly, it scrolls, it revives click events, and so on. So as soon as I load the UITableView into the UIView, the UITableView becomes unresponsive (it doesn't scroll or receive tap events) and any attempt to interact with it, the UITableView goes completely blank. My debugging session concludes that the NSArray *photos never gets reset to nil, or manipulated in anyway, the table just goes blank.
So does anyone have any ideas on what would cause a UITableView to do this when being loaded into a generic UIView? All the other views that get loaded into this generic UIView are responsive, and behave as expected. Its just this UITableView that is giving me problems.
If you review the graphic I attached to this post (above), you will see that I am using what appears to be a UITabBarView, but it is, in fact, just a generic view with UIButtons inside. The reason I decided to craft my own "UITabBarView look-alike" instead of using the ready-made UITAbBarView class was because I wanted to give custom functionality to the "menu" button on the bottom left (I want a nice UIView to slide in from the left, and stop about 60 pixels from the right of the screen when the "menu" button is tapped, and I can't figure out how to customize the behavior of the UITabBarView, so I opted for this approach.
Here is the code that is actually loading the UITableViewController into the subview (via a CustomStoryboardSegway):
// PA_HomeViewCustomStoryboardSegue.m
#import "PA_HomeViewCustomStoryboardSegue.h"
#import "PA_HomeViewController.h"
#implementation PA_HomeViewCustomStoryboardSegue
// to create a custom segue, you have to override the perform method
-(void)perform {
// get the source and destination view controllers
PA_HomeViewController *segueSourceController = (PA_HomeViewController *)[self sourceViewController];
UIViewController *destinationController = (UIViewController *)[self destinationViewController];
for (UIView *view in segueSourceController.placeholderView.subviews){
[view removeFromSuperview];
}
segueSourceController.currentViewController = destinationController;
[segueSourceController.placeholderView addSubview:destinationController.view];
}
#end
and here is the header file for my PA_HomeViewController (the view the contains the "placeholderView" which is the target view that loads the various UIViewControllers after the user has tapped the UIButtons at the bottom of the view (similar to a TabBarView) :
#interface PA_HomeViewController : UIViewController
#property (weak, nonatomic) IBOutlet UIView *placeholderView;
#property (weak, nonatomic) UIViewController *currentViewController;
#end
I am hoping that I am just missing something obvious in the way that I am loading the UITableView into the placeholderView, and something in there is causing the UITableView to go completely blank.
When you display the UITableView in a different view, you must always make sure that the view controller which "hosts" the UITableView has a strong reference to its controller. In your case, the data source for the UITableView seems to be deallocated after adding the UITableView as subview.
Changing the currentViewController property from weak to strong should fix your problem.
In swift you need to declare viewcontroller object globally that would result in Strong, in case if you declare locally it results in keep disappearing the cells.
e.g.
var refineViewController : RefineViewController?
then you can access that controller using below code that would not result in disappearing cells.
func showRefineView(isFindHomeTab isFindHomeTab : Bool){
refineViewController = RefineViewController(nibName: String(BaseGroupedTableVC),bundle : nil)
refineViewController!.refineSearchDelegate = self
refineViewController!.view.frame = CGRectMake(0, -490, self.view.frame.size.width, self.view.frame.size.height)
UIView.animateWithDuration(0.3, delay: 0.0, options: .CurveEaseOut, animations:
{
self.refineViewController!.view.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)
self.refineViewController!.isFindHomeTab = isFindHomeTab
}, completion: nil)
self.view.addSubview(refineViewController!.view)
}
I experienced the exact same problem. The issue was that I was using a custom datasource class (called tableVCDataSource), and was setting the tableView's dataSource incorrectly in the ViewController class. I was doing:
override func viewDidLoad() {
mainTableView.dataSource = TableVCDataSource()
}
when I should have been doing:
fileprivate var tableVCDataSource: TableVCDataSource?
override func viewDidLoad() {
tableVCDataSource = TableVCDataSource()
mainTableView.dataSource = tableVCDataSource
}
This solved my issue.

Handling touches within UIScrollview

I have a view that contains a UIScrollView. The UIScrollView contains an UIImageView (only one for now but there will be more latter). I want to be able to drag the UIImageView out of the UIScrollView and into the superview.
I have reviewed every similar question and example I can find online and still cant get my head around how this works.
At first I couldn't get touches to register all whithin the scrollview. After a lot of searching I have found a way to get touchesbegan to register as follows:
First I created a new view based project and in the auto-created "ViewController.h"
I created an IBOutlet named slider.
Then in the auto-created "ViewController.m" I created the UIScrollview.
In IB I added a UIScrollView to the storyboard then connected it to the "slider" IBOutlet.
Next I added class file to the projects. This new class is a subclass os UIImageView. I named this class "DragableImage" In the
Then in IB I dropped an image into the UIScrollview clicked on it and changed the class to "DragableImage"
In the DragableImage.m I voided touches began and simply told it to become hidden if clicked.
This works and the touch registers and makes the image disappear but how do I now add the new image to the main view and have it follow my finger?
This is what I have in the way of code:
ViewController.h
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController {
IBOutlet UIScrollView *slider;
}
#end
ViewController.m
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad
{
[slider setScrollEnabled:YES];
[slider setContentSize:CGSizeMake(306, 1560)];
[slider setShowsVerticalScrollIndicator:NO];
slider.canCancelContentTouches = NO;
slider.delaysContentTouches = NO;
[super viewDidLoad];
// Do any additional setup after loading the view.
}
- (BOOL)shouldAutorotateToInterfaceOrientation: (UIInterfaceOrientation)interfaceOrientation
{
return YES;
}
#end
DragableImage.h
#import <UIKit/UIKit.h>
#interface DragableImage : UIImageView
#end
DragableImage.m
#implementation DragableImage
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
self.hidden = YES;
}
#end
How to make this work?
There is one obvious problem that can arise here. Namely, how to tell the difference between dragging to scroll and dragging an image. The way I would handle this is to setup a tap and hold gesture recognizer (http://developer.apple.com/library/ios/#documentation/EventHandling/Conceptual/EventHandlingiPhoneOS/GestureRecognizers/GestureRecognizers.html).
Once you detect a hold you could set it up so that further touches/gestures get routed to you drag and drop code. You can find a nice tutorial for that here:
http://www.ancientprogramming.com/2012/04/05/drag-and-drop-between-multiple-uiviews-in-ios/

Resources