UIView and UIViewController - ios

I know this is really basic stuff but i need to understand whether my understanding of this is correct.
So what i want to do is this. I want an view with a label on which when double tapped flips and loads another view. On the second view i want a UIPickerView and above i have a button saying back. Both views will be of same size as an UIPickerView which is 320px x 216px.
What i am thinking of to do is create two UIViewclasses named labelView and pickerView. I would then create a viewController which on loadView loads labelView then when user double taps the labelView i get an event in labelView class which is sent to my viewController that then can unload loadView and load the pickerView.
Does this sound as the best way to do this ? Is there a simpler way ? I am also unsure how i route the event from the labelView class to the viewControllerclass.

I dont exactly know the most efficient way to do it(as i am also now to this language),but it is for sure that i have solved ur problem. I made a simple program for that.Three classes involved here in my eg are BaseViewController (which will show two views),LabelView and PickerView (according to ur requirement).
In LabelView.h
#protocol LabelViewDelegate
-(void)didTapTwiceLabelView;
#end
#interface LabelView : UIView {
id <LabelViewDelegate> delegate;
}
#property(nonatomic,retain)id <LabelViewDelegate> delegate;
-(void)didTouch;
#end
In LabelView.m
#synthesize delegate;
-(id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self)
{
UILabel* labl = [[UILabel alloc] initWithFrame:CGRectMake(10, 5, frame.size.width-20,20)];
labl.text = #"Some Text";
[self addSubview:labl];
[labl release]; labl = nil;
self.backgroundColor = [UIColor grayColor];
UITapGestureRecognizer* ges = [[[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(didTouch)] autorelease];
ges.numberOfTapsRequired = 2;
[self addGestureRecognizer:ges];
}
return self;
}
-(void)didTouch
{
[delegate didTapTwiceLabelView];
}
//=============================================================
In Pickerview.h
#protocol PickerViewDelegate
-(void)didTapBackButton;
#end
#interface PickerView : UIView <UIPickerViewDelegate,UIPickerViewDataSource>{
id <PickerViewDelegate> delegate;
}
#property(nonatomic,retain)id <PickerViewDelegate> delegate;
#end
In Pickerview.m
#implementation PickerView
#synthesize delegate;
-(id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self)
{
UIPickerView* picker = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 30, 320, 216)];
picker.delegate = self;
picker.dataSource = self;
[self addSubview:picker];
[picker release]; picker = nil;
self.frame = CGRectMake(frame.origin.x, frame.origin.y, 320, 250);
UIButton* btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[btn setFrame:CGRectMake(10, 1, 50, 27)];
[btn setTitle:#"Back" forState:UIControlStateNormal];
[btn addTarget:self action:#selector(backButton) forControlEvents:UIControlEventTouchUpInside];
[self addSubview:btn];
}
return self;
}
-(void)backButton
{
[delegate didTapBackButton];
}
//====================================================================
in BaseViewController.h
#import "LabelView.h"
#import "PickerView.h"
#interface VarticalLabel : UIViewController<UITextFieldDelegate,PickerViewDelegate,LabelViewDelegate> {
PickerView* myPickerView;
LabelView* myLabelView;
}
#end
In BaseViewController.m
-(void)viewDidLoad
{
[super viewDidLoad];
myPickerView= [[PickerView alloc] initWithFrame:CGRectMake(0, 50, 320, 250)];
[self.view addSubview:myPickerView];
myPickerView.delegate = self;
myLabelView= [[LabelView alloc] initWithFrame:CGRectMake(0, 50, 320, 250)];
[self.view addSubview:myLabelView];
myLabelView.delegate = self;
myPickerView.hidden = YES;
}
#pragma mark PickerViewDelgate
-(void)didTapBackButton
{
myPickerView.hidden = YES;
myLabelView.hidden = NO;
}
#pragma mark LabelViewDelegate
-(void)didTapTwiceLabelView
{
myPickerView.hidden = NO;
myLabelView.hidden = YES;
}

To get events from a button to the view controller, just hook up the button's event, e.g. touch up inside, to a method in the view controller, using interface builder. (Double tapping is probably more complicated though.)
When you say 'flips', do you mean it actually shows an animation of flipping over a view to show a 'reverse' side? Like in the weather app when you hit the 'i' button? I'm assuming this is what you mean.
Perhaps check TheElements sample example on the iPhone Reference Library, it has an example of flip animation.
Btw, it's not strictly necessary to unload the loadView that is being 'hidden' when you flip -- it saves you having to construct it again when you flip back -- but it may be pertinent if you have memory use concerns, and/or the system warns you about memory being low.
Also, what do you mean by "create a UIView"? Do you mean subclass UIView, or just instantiate a UIVIew and add children view objects to it? The latter is the usual strategy. Don't subclass UIView just because you want to add some things to a UIView.

If you've got one screen of information that gives way to another screen of information, you'd normally make them separate view controllers. So in your case you'd have one view controller with the label and upon receiving the input you want, you'd switch to the view controller composed of the UIPickerView and the button.
Supposing you use Interface Builder, you would probably have a top level XIB (which the normal project templates will have provided) that defines the app delegate and contains a reference to the initial view controller in a separate XIB (also supplied). In the separate XIB you'd probably want to add another view controller by reference (so, put it in, give it the class name but indicate that its description is contained in another file) and in that view controller put in the picker view and the button.
The point of loadView, as separate from the normal class init, is to facilitate naming and linking to an instance in one XIB while having the layout defined in another. View controllers are alloced and inited when something that has a reference to them is alloced and inited. But the view is only loaded when it is going to be presented, and may be unloaded and reloaded while the app is running (though not while it is showing). Generally speaking, views will be loaded when needed and unnecessary views will be unloaded upon a low memory warning. That's all automatic, even if you don't put anything in the XIBs and just create a view programmatically within loadView or as a result of viewDidLoad.
I've made that all sound more complicated than your solution, but it's actually simpler because of the amount you can do in Interface Builder, once you're past the curve of learning it. It may actually be worth jumping straight to the Xcode 4 beta, as it shakes things up quite a lot in this area and sites have reported that a gold master was seeded at one point, so is likely to become the official thing very soon.
With respect to catching the double tap, the easiest thing is a UITapGestureRecognizer (see here). You'd do something like:
// create a tap gesture recogniser, tell it to send events to this instance
// of this class, and to send them via the 'handleGesture:' message, which
// we'll implement below...
UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc]
initWithTarget:self action:#selector(handleGesture:)];
// we want double taps
tapGestureRecognizer.numberOfTapsRequired = 2;
// attach the gesture recogniser to the view we want to catch taps on
[labelView addGestureRecognizer:tapGestureRecognizer];
// we have an owning reference to the recogniser but have now given it to
// the label. We don't intend to talk to it again without being prompted,
// so should relinquish ownership
[tapGestureRecognizer release];
/* ... elsewhere ... */
// the method we've nominated to receive gesture events
- (void)handleGesture:(UIGestureRecognizer *)gestureRecognizer
{
// could check 'gestureRecognizer' against tapGestureRecognizer above if
// we set the same message for multiple recognisers
// just make sure we're getting this because the gesture occurred
if(gestureRecognizer.state == UIGestureRecognizerStateRecognized)
{
// do something to present the other view
}
}
Gesture recognisers are available as of iOS 3.2 (which was for iPad only; so iOS 4.0 on iPhone and iPod Touch).

Related

UIImagePickerController takePicture Dismisses Controller

I have a custom UIImagePickerController that works nicely, only I am facing one issue that I feel should be fairly simple - I just have yet to figure out the solution.
Upon touching my custom added "photo" button, I have it targeted to the build in takePicture method of the UIIPC. Here is my code
#interface CustomCameraController ()
#end
#implementation CustomCameraController {
CGFloat width, height;
}
- (instancetype)init {
if (self = [super init]) {
width = self.view.frame.size.width, height = self.view.frame.size.height;
self.allowsEditing = YES;
self.sourceType = UIImagePickerControllerSourceTypeCamera;
self.showsCameraControls = NO;
self.toolbarHidden = YES;
[self buildCameraOverlay];
}
return self;
}
- (void)buildCameraOverlay {
UIView *customOverlay = [UIView alloc] ...
// ... Custom overlay setup done here
_takePhoto = [[CustomButton alloc] initWithFrame:CGRectMake(0, 0, heightBottomBar*.5, heightBottomBar*.5)];
_takePhoto.center = CGPointMake(bottomBar.frame.size.width/2, bottomBar.frame.size.height/2);
[_takePhoto setImage:[UIImage imageNamed:#"camera button icon"] forState:UIControlStateNormal];
[_takePhoto addTarget:self action:#selector(takePicture) forControlEvents:UIControlEventTouchUpInside];
[bottomBar addSubview:_takePhoto];
// ...
self.cameraOverlayView = customOverlay;
}
This is done in my custom controller CustomCameraController init call.
The problem is, upon taking the picture via takePicture, the camera shutter goes off, everything works just fine, but the controller dismisses itself. I'm trying to figure out how to stop it from closing immediately after taking the picture, so I can A)present the taken picture, and B) give the user the option to choose the image or cancel and retake another one (returning to the camera)
If anyone knows why this happens or something that I am missing / doing incorrectly please let me know. I'm sure it's a simple answer - just can't seem to figure it out. Thanks!
The most common reason for such a weird behaviour is usually lack of delegate methods (for UIImagePickerController in this case) or their wrong implementation.

iOS tap recognizer to catch all taps

I want a pretty simple thing - in my top controller (which is navigation controller) to set up a tap gesture recognizer which will catch all the taps everywhere on the view. Currently when I tap on a button the system is not even thinking to bother my recognizer (except the gestureRecognizer:shouldReceiveTouch: delegate method, where I return YES). Instead, it just executes a button click. So I want to install "the strongest" recognizer on a view hierarchy no matter what.
You might try putting an empty UIView on top of all other views and add the UITapGestureRecognizer to it. We do something similar with help overlays. The biggest issue is figuring out how and when to ignore the touches so the underlying buttons get them when needed.
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
UIButton *b = [UIButton buttonWithType:UIButtonTypeInfoDark];
b.frame = CGRectMake(50,50, b.bounds.size.width, b.bounds.size.height );
[self.view addSubview:b];
UIView *invisibleView = [[UIView alloc] initWithFrame:self.view.bounds];
invisibleView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
[invisibleView addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(tapHit:)]];
[self.view addSubview:invisibleView];
}
-(void)tapHit:(UITapGestureRecognizer*)tap {
NSLog( #"tapHit" );
}
#end

Reusing variables in other method file

I have the following code to generate a UIBUtton from a method file called FirstViewController, since the location of the button will change in different secondviewController or thirdViewController, is it possible to set a variable for the location (CGRect) of the unbutton in the FirstViewController and change the CGRect Value in the second or third viewController?
In FirstViewController.m
-(void)method:(UIView *)_view {
UIButton*Touch1= [UIButton buttonWithType:UIButtonTypeRoundedRect];
[Touch1 addTarget:self action:#selector(TouchButton1:) forControlEvents:UIControlEventTouchUpInside];
[Touch1 setFrame:CGRectMake(50,50, 100, 100)];
**//I want to set a variable for the CGRectMake**
Touch1.translatesAutoresizingMaskIntoConstraints = YES;
[Touch1 setBackgroundImage:[UIImage imageNamed:#"1.png"] forState:UIControlStateNormal];
[Touch1 setExclusiveTouch:YES];
[_view addSubview:Touch1];
NSLog(#"test ");
}
In SecondViewController.m
- (void)viewDidLoad {
[super viewDidLoad];
ViewController * ViewCon = [[ViewController alloc]init];
**//Change variable here by defining the new CGRect here.**
[ViewCon method:self.view];
}
This pattern is incorrect:
ViewController * ViewCon = [[ViewController alloc]init];
[ViewCon method:self.view];
as you are allocating a new view controller just to use one of its the method and then you are throwing the view controller instance away. It's extremely inefficient and inconvenient.
Either move the method to a utility class, as a class method:
[Utils method:self.view rect:rect];
or subclass UIViewController and implement the method in that base class and then derive all similar view controllers from that base class, passing any variables into it.
[self method:rect]; // method implemented in MyBaseViewController
You also asked this question before and accepted an answer that promotes the use of this bad pattern. That will mislead others into using this bad pattern.

Change the view of a UIViewController dynamically in iOS 7

I have 2 Custom View classes(CustomView_A, CustomView_B) derived from UIView. I have UIViewController that should be able to switch between views at run-time..
What so far, I have done is.. in the Storyboard, I am using CustomView_A class as the View class.
#interface MyViewController: UIViewController
#property (nonatomic, weak) CustomView_A *customView_A;
Now I have the second CustomView_B class and I want to change view of MyViewController's view to CustomView_B at run-time.
How can I do that? Thanks in advance..
okay, here is the code as you want -
in your MyViewController.h put -
#property (nonatomic, retain) CustomView_A *customView_A;
#property (nonatomic, retain) CustomView_B *customView_B;
-(void)switchView; // to switch the views.
in your MyViewController.m put -
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.customView_A = [[CustomView_A alloc]initWithFrame:self.view.frame];
self.customView_A.backgroundColor = [UIColor redColor];
UIButton *trigger = [UIButton buttonWithType:UIButtonTypeRoundedRect]; // Just take this button so that your switchView methods will get called on click of this method.
[trigger setFrame:CGRectMake(10, 10, 50, 30)];
[trigger setTitle:#"Click" forState:UIControlStateNormal];
[trigger addTarget:self action:#selector(switchView) forControlEvents:UIControlEventTouchUpInside];
[self.customView_A addSubview:trigger];
[self.view addSubview:self.customView_A];
self.customView_B = [[CustomView_B alloc]initWithFrame:self.view.frame];
self.customView_B.backgroundColor = [UIColor yellowColor];
self.customView_B.hidden = YES;
[self.view addSubview:self.customView_B];
}
- (void)switchView
{
[UIView animateWithDuration:10 delay:10 options:UIViewAnimationOptionCurveEaseInOut animations:^{
self.customView_A.hidden = YES;
self.customView_B.hidden = NO;
} completion:nil];
}
Do opposite when you again want to switch the views.
Don't. What you're describing is an essential misunderstanding of UIViewController. Once a UIViewController instance has a view, that is its view forever.
If you want two different views then either:
Use two view controllers (for example, you can present view controller B and its view on top of view controller A and its view, using a modal segue), or
Make at least one of those views not be owned by a view controller: just place that view in front of the other view and later remove it again, at will.
Try this:
- (IBAction)changeView {
if (self.customView_A.hidden == YES) {
self.customView_A.hidden = NO;
self.customView_B.hidden = YES;
//You should use a UIView animation here to do this.
}
else {
self.customView_A.hidden = YES;
self.customView_B.hidden = NO;
//Same here
)
}
In your viewDidLoad add the view to CGRectZero
- (void)viewDidLoad {
self.customView_A = [[CustomView_A alloc]initWithFrame:CGRectZero];
[self.view addSubview:self.customView_A];
//do the same with the other custom view
}
Sorry if the code is a little faulty, I didn't use Xcode to type this up.

iOS: Dynamic Creation of UISegmentedControl within UIView

I am wanting to create a custom UIView class that will show a dynamic number of UISegmentedControl objects depending on some input. For example, if a client has 5 products in their cart, the UIView should generate 5 UISegmentedControl objects that I will then link with each item.
The problem I am having is getting this to work in a UIView. Here is what I have done so far. I am successfully able to create a UISegmentedControl object and display it programmatically within my main UIViewController. I don't get any display when adding it to my UIView class. Here is the implementation code for the UIView class:
#import "ajdSegmentView.h"
#implementation ajdSegmentView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
NSArray *itemArray = [NSArray arrayWithObjects:#"Yes", #"No", nil];
UISegmentedControl *button = [[UISegmentedControl alloc] initWithItems:itemArray];
button.frame = CGRectMake(35,44, 120,44);
button.segmentedControlStyle = UISegmentedControlStylePlain;
button.selectedSegmentIndex = 1;
[self addSubview:button];
}
return self;
}
#end
I created a new UIView object via Storyboard and placed it inside the UIViewController scene. I made sure to set the class from the generic UIView class to my new custom class. I added and outlet for the UIView in my UIViewController class. Here is the code inside the implementation of UIViewController:
#import "ajdViewController.h"
#interface ajdViewController ()
#end
#implementation ajdViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.segmentView = [[ajdSegmentView alloc] init];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
That's all I have tried. I have been searching through a lot of pages and trying to implement this without asking here, but I seem to be looking in the wrong places.
First you need to check ajdSegmentView is UIVIew or UIViewController. It is fine if it is UIView. If it is type of UIViewController then you need to add this line while adding Segment.
[self.view addSubview:button];
In place of:
[self addSubview:button];
And One more thing You forget to add this View to your main after allocating so You can declare like this:
objajdSegmentView = [[ajdSegmentView alloc] init];
[self.view addSubview:objajdSegmentView.view];
I have just added this thing. i got result like this way.
Hope this will work for you.
You're initializing your custom view using the init method, but your initialization for ajdSegmentView is in your initWithFrame: method (which in your case is not getting called).
So replace:
self.segmentView = [[ajdSegmentView alloc] init];
with:
// Change the frame to what you want
self.segmentView = [[ajdSegmentView alloc] initWithFrame:CGRectMake(0,0,100,40)];
Also don't forget to add your view to the view controller's view also.
[self.view addSubview:self.segmentView];
Unless this view is being created with interface builder, in which case you will need to override initWithCoder: in your ajdSegmentView class.
I'm not familiar with Storyboard though, so maybe I'm missing something, but in a standard scenario what I said above will solve your problem.

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