I saw this answer of how to create a placeholder for UITextView.
I took the following steps:
Add to the .h class the declaration:
#interface AdjustPhotoViewController : UIViewController<UITextViewDelegate>
Added the method:
- (BOOL) textViewShouldBeginEditing:(UITextView *)textView
{
NSLog(#"%d",[textView tag]);
if ([textView tag]==1){
campaignTitle.text = #"";
}else{
campaignDescription.text = #"";
}
return YES;
}
But I don't see that the method is being invoked!
What am I missing?
textView is already delegated via the storyboard to the view
SOLVED:
The problem was that it wasn't delegated. Although I was using storyboard - it was only an outlet, not a delegate.
Remember that if you are using storyboard, you need to delegate also from the text view to the orange button of the view! not only the other way
What am I missing?
Actually setting the delegate.
textView.delegate = self;
Merely conforming to a protocol won't magically make your object into the delegate of an arbitrary object; that's just a formal thing, and anyways, how on Earth would the UITextField know which particular instance of the class it has to assign its delegate?
Related
In a storyboard when I add a new view (for example a TableView) I can select a class in the "Custom class" field in the identity inspector.
If I understand the rule of this class, I expect this class "answer" to messages sent to my tableview (i.e. this class is my table viewcontroller) and when I run my project it seems to do what I want.
My question is: To do this, I expected my Xcode automatically instantiates an object of my controller class and "link" this object to my GUI in storyboard.
However, I expected that if I override the init method of my controller class with
-(id) init
{
self=[super init];
NSLog(#"object controller created automatically");
return self;
}
I have the string in output when is created my controller object.
Instead, I have no output.
Why is this happenig and what is wrong with the code?
UIView set up by storyboard never called init.
Instead, you should use - (void)awakeFromNib in which your outlet has been ready to use.
- (void)awakeFromNib {
[super awakeFromNib];
NSLog(#"object controller created automatically");
}
From awakeFromNib documentation:
Objects that conform to the NSCoding protocol (including all subclasses of UIView and UIViewController) are initialized using their initWithCoder: method. All objects that do not conform to the NSCoding protocol are initialized using their init method.
If I understand you question you want a message to be printed whenever your viewController is initialised.
Why dont you write the code in the viewDidLoad?
Like:
In your YourControllerClass.m
-(void)viewDidLoad {
[super viewDidLoad];
NSLog(#"Controller created");
}
Now set the class of the controller in the storyboard to YourControllerClassand the message should be printed whenever your controller is created.
Cheers
P.s.: If you still need help or got a question, please write a comment.
I declared a protocol in the header file of a Controller that manages a map view.
#protocol UCMapViewDelegate <NSObject>
#required
- (void)pushMapviewRight;
#end
I'm declaring the implementation of the protocol in another view controller (.h) and implement it in the .m file
// in the UCRootViewController.h
#interface UCRootViewController : UIViewController <UCMapviewDelegate>
// in the UCRootViewController.m
- (void)pushMapviewRight
{
NSLog(#"push mapview right");
}
I'm setting the delegate to a property that points to the rootviewController. This is done in the viewDidLoad() of my MapviewController, with a property #property (weak, nonatomic) id<UCMapViewDelegate> delegate;.
// in UCRootViewController
self.mapviewController.rootviewController = self;
// in UCMapViewController
self.delegate = (id<UCMapviewDelegate>)self.rootviewController;
Calling the delegated method. showMenu() gets executed when a button in the mapviewController gets pressed and it works. but the delegate method does NOT get called.
- (void)showMenu
{
NSLog(#"show menu");
[self.delegate pushMapviewRight];
}
But nothing happens.. what is wrong?! Help is greatly appreciated!
I fixed it. At first I used NSLog to verify that self was not nil (which is pretty obvious
, but still) I'm actually not sure why, but self.mapviewController.rootviewController = self; did not "carry over" to the point where I wanted to reference self.rootViewController, although self was not nil at the point where I set it to be the pointer to rootViewController.
I fixed it by creating another initWithRootViewController:(UCRootViewController*) ctrland passed self as an argument when I created the MapViewController.
Can someone explain why the valid reference to self (=rootViewController), was not available in the MapViewController?
Is the rootViewController property a strong reference or a weak one? It should probably be strong. If there are no weak references to the object, then it will be immediately released, and weak references get nilled out when the objects they point to are released. You need a strong reference somewhere in your application for objects to hang around.
As #CodaFi said, your codes look messy. Why do you set delegate property value in UCMapViewController? The delegate should be set in its parent when popup or prepare for the segue.
Basically, if your UCMapViewController has knowledge about UCRootViewController implementing a delegate method, why not call its method from riitVuewController directly? No need to set delegate at all.
Here is one example of using storyboard and segue, UCMyViewController is going to push segue to UCMapViewController:
- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
...
[segue.destinationViewController setDelegate:self.rootViewController];
...
}
I was wondering how I could access data from another class using Xcode 4.2 and Storyboard?
Say for instance how would I access the text of a text field from another class?
Google hasn't helped and the lesson on MyCodeTeacher.com about this is outdated and doesn't work anymore...
Thanks for bearing with me!
-Shredder2794
Not sure if this is the only or best way, but you can create a property in the destination view's .h file and set it to a value before the segue is performed
in the destination view controller's .h file:
#interface YourDestinationViewController : UIViewController
{
NSString* _stringToDisplay;
//...
}
#property (nonatomic, retain) NSString* stringToDisplay;
//...
and in the presenting view's .m file
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
YourDestinationViewController*viewController = segue.destinationViewController;
viewController.delegate = self;
viewController.stringToDisplay = #"this is the string";
}
Then you can do what you want with the property in whichever of the viewWillAppear/viewDidLoad/viewDidAppear/etc. methods best suits your purpose in the destination view's .m file
And then to check if it works, in the destination view controller's .m file:
-(void)viewWillAppear:(BOOL)animated
{
NSLog(#"self.stringToDisplay = %#", self.stringToDisplay);
...
//and if a label was defined as a property already you could set the
//label.text value here
}
Edit: Added more code, and made it less generic
This isn't specific to Storyboard. There are several ways to do what you are trying to do. You could declare a variable in your AppDelegate (an NSString) and set that in your first class. Then in your second class access the AppDelegate variable and use that to set your label. The code to do this is:
AppDelegate *appDelegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];
label.text = appDelegate.myString;
Another way to do it (probably the easiest) is to declare an NSString in your second class. Then in your first class, before you push the second view set that string variable. Something like this:
MyViewController *vc = [[MyViewController alloc] initWithNibName:#"" bundle:nil];
vc.myString = #"";
The third way to do this is using delegates. This is the most 'complicated' way but is the best. You would create a delegate which gets called when your second view appears. The delegate could then return the value from the first class to you.
You may also be able to use the new completion handler block on the iOS 5 pushViewController: method.
Edit:
Custom init method:
- (void)initWithNibName:(NSString *)nibName bundle:(NSString *)bundle string:(NSString *)myString
And then when you are pushing the view just class this method and set the string through it.
I have a fairly vanilla Source List (dragged out from the Object Library) in my app, with an NSTreeController as its data source. I set the NSTextField inside the DataCell to be editable, but I want to be able to turn that off for some cells. The way I figured you would do this, is with a delegate for the NSTextField, but none of the delegate methods I've tried get called. Is there something I'm missing? I have the delegate set with an outlet in my XIB, and it happens to be the delegate to the owner NSOutlineView, as well, implementing both the NSOutlineViewDelegate and NSTextFieldDelegate protocols.
Also, I can't use the old –outlineView:shouldEditTableColumn:item: NSOutlineViewDelegate method either, since that only works with cell-based Outline Views (I'm assuming this is the case - the Outline View documentation doesn't appear to have been updated for Lion, though the analogous NSTableView documentation has, and those methods don't get called either).
Update
I reproduced this in a brand new test project, so it's definitely not related to any of my custom classes. Follow the steps below to create my sample project, and reproduce this problem.
In Xcode 4.1, create a new project, of type Mac OS X Cocoa Application, with no special options selected
Create two new files, SourceListDataSource.m and SourceListDelegate.m, with the contents specified below
In MainMenu.xib, drag a Source List onto the Window
Drag two Objects onto the dock (left side of the window), specifying the SourceListDataSource class for one, and the SourceListDelegate for the other
Connect the Outline View's dataSource and delegate outlets to those two objects
Select the Static Text NSTextField for the DataCell view inside the outline view's column
Turn on its Value binding, keeping the default settings
Connect its delegate outlet to the Source List Delegate object
Set its Behavior property to Editable
Build and Run, then click twice on either cell in the outline view.
Expected: The field is not editable, and there is a "well, should I?" message in the log
Actual: The field is editable, and no messages are logged
Is this a bug in the framework, or am I supposed to achieve this a different way?
SourceListDataSource.m
#import <Cocoa/Cocoa.h>
#interface SourceListDataSource : NSObject <NSOutlineViewDataSource>
#property (retain) NSArray *items;
#end
#implementation SourceListDataSource
#synthesize items;
- (id)init
{
self = [super init];
if (self) {
items = [[NSArray arrayWithObjects:#"Alo", #"Homora", nil] retain];
}
return self;
}
- (id)outlineView:(NSOutlineView *)outlineView child:(NSInteger)index ofItem:(id)item {
if (!item) {
return [self.items objectAtIndex:index];
}
return nil;
}
- (NSInteger)outlineView:(NSOutlineView *)outlineView numberOfChildrenOfItem:(id)item {
return !item ? self.items.count : 0;
}
- (BOOL)outlineView:(NSOutlineView *)outlineView isItemExpandable:(id)item {
return NO;
}
- (id)outlineView:(NSOutlineView *)outlineView objectValueForTableColumn:(NSTableColumn *)tableColumn byItem:(id)item {
return item;
}
#end
SourceListDelegate.m
#import <Foundation/Foundation.h>
#interface SourceListDelegate : NSObject <NSOutlineViewDelegate, NSTextFieldDelegate> #end
#implementation SourceListDelegate
- (NSTableRowView *)outlineView:(NSOutlineView *)outlineView viewForTableColumn:(NSTableColumn *)tableColumn item:(id)item {
return [outlineView makeViewWithIdentifier:#"DataCell" owner:self];
}
- (BOOL)control:(NSControl *)control textShouldBeginEditing:(NSText *)fieldEditor {
NSLog(#"well, should I?");
return NO;
}
#end
Subclass NSTableCellView, with an outlet for the text field, and set the text field delegate in awakeFromNib. After doing that, control:textShouldBeginEditing: gets called. I'm not sure why, but (edit:) if you set the delegate in the xib, the delegate methods aren't called – I had the same experience as you.
Alternatively, you can forego the delegate and conditionally set Editable using a binding, either to a boolean property of the model, or using a value transformer which acts on a model instance and returns a boolean. Use the Editable binding of the text field.
I've encountered this problem, too. Because I didn't want to lose the bindings, I did the following:
Binding editable of the TextField to the objectValue and set up a custom NSValueTransformer subclass.
The other proposed solutions above are not performant and will not work on modern versions of macOS. NSTableView calls acceptsFirstResponder on EVERY textField in the entire table when one is about to be edited. And first responder methods get called while you just scroll around the table. If you put some logging in those calls, you'll see them in action.
Additionally, assigning the textField's delegate anywhere other than IB is not needed and won't actually work because NSTableView (and therefore NSOutlineView) basically "take over" for the views they contain.
The Correct, Modern Approach:
Subclass NSTableView (or NSOutlineView) and do this:
final class MyTableView: NSTableView
{
override func validateProposedFirstResponder(_ responder: NSResponder, for event: NSEvent?) -> Bool
{
// NSTableView calls -validateProposedResponder on cellViews' textFields A METRIC TON, even while just scrolling around, therefore
// do not interfere unless we're evaluating a CLICK on a textField.
if let textField: NSTextField = responder as? NSTextField,
(event?.type == .leftMouseDown || event?.type == .rightMouseDown)
{
// Don't just automatically clobber what the TableView returns; it'll return false here when delays are needed for double-actions, etc.
let result: Bool = super.validateProposedFirstResponder(responder, for: event)
// IF the tableView thinks this textField should edit, now we can ask the textField's delegate to confirm that.
if result == true
{
print("Validate first responder called: \(responder).")
return textField.delegate?.control?(textField, textShouldBeginEditing: textField.window?.fieldEditor(true, for: nil) ?? NSText()) ?? result
}
return result
}
else
{
return super.validateProposedFirstResponder(responder, for: event)
}
}
}
Notes:
This was written against macOS 11.3.1 and Xcode 12.5 for an application targeting macOS 11.
The isEditable property of the NSTextFields in your NSTableCellViews must be set to true. NSTableView's implementation of -validateFirstResponder will check that property first, so you need not do so in your delegate method.
Working on an experiment on the iPad. Tried some variations on how to do this, but I can't seem to get it to work correctly...
I tap a UIButton on my MainViewController and a TextEntryModule is added to the view. TextEntryModule is its own class (for multiple instantiation) and it contains a UITextView called TextEntry (this all works at the moment).
I tap on the TextEntry UITextView and it brings up the keyboard and another view (located in MainViewController) with a UITextView called TextPreview. (this also works at the moment).
The part I'm having trouble with is synching the two UITextViews. The idea being that when I type into TextEntry, the text in TextPreview will also be updated.
Outlets are linked properly for the text fields, but I think I'm missing something "obvious":
TextEntryModule *tm = (AnnotationModule *)currentModule;
TextPreview.text = tm.TextEntry.text
Thanks in advance!
UITextView: delegate.
- (void)textViewDidChange:(UITextView *)textView
Then assign it the value of the other textview in this method.
Edit
#interface MainViewController <UITextViewDelegate> {
...
}
...
#end
Then you implement this method in the implementation file of MainViewController
#implementation MainViewController
//More code
- (void)textViewDidChange:(UITextView *)textView {
TextEntryModule *tm = (AnnotationModule *)currentModule;
TextPreview.text = tm.TextEntry.text
}
#end
Then you will have to set the TextEntryModule object's delegate to self since the controller now conform to the protocol and can "act" upon this notification.
You need to become a UITextFieldDelegate and monitor when text changes in the one field and then update the other field. Take a look at the documentation on it.