Hey I just had a question regarding XCode's behavior with multiple views implementing the same UIView class of my own creation. I am working with a tabbed application and controller, and I have multiple views on the storyboard, all of which implement a class that I created. On one of the views, I have a text field and a button, and on another, I have a text view with a startup text reading "Waiting...". As you can probably guess, I want to enter text into the text field on the first view, press the button, then display the proper output text in the textview on the other view.
My question is: is there a problem with implementing the same class between multiple views?
I have researched numerous discussions on the TextView method of setting text inside of it, but all of the suggestions between the forums say something different, and none of the methods seem to work appropriately.
[textView setText string] doesn't want to work when I switch to the other tab,
textView.text = #"Message here" doesn't work either
I'd appreciate your help, and I've attached my code for reference.
#import "MasterController.h"
#interface MasterController ()
#end
#implementation MasterController
#synthesize input;
#synthesize output;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
}
- (void)viewDidUnload
{
[self setInput:nil];
[self setOutput:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
- (IBAction)generate:(id)sender
{
[output setText:input.text];
}
- (IBAction)textFieldReturn:(id)sender
{
[sender resignFirstResponder];
}
- (void)dealloc
{
[input release];
[output release];
[super dealloc];
}
#end
//MasterController.h
#import <UIKit/UIKit.h>
#interface MasterController : UIViewController
- (IBAction)generate:(id)sender;
- (IBAction)textFieldReturn:(id)sender;
#property (retain, nonatomic) IBOutlet UITextField *input;
#property (retain, nonatomic) IBOutlet UITextView *output;
#end
If you have several views that are controlled by the same view controller, they will not communicate with each other in the way that you are trying to make them. When you call [output setText:input.text] , you are saying: set the text for the output text field for the view that you are currently on.
One somewhat hacky way of getting around this is to create a second view controller and have it inherit from your "Master." Variables are set as protected as default and will retain their information when subclassed.
If you want to communicate between the different view controllers properly, however, you should look into state injection in this question: What's the best way to communicate between view controllers? Or use a communication system such as NSNotification center. Or you could use NSCoding, all of which are fairly easy to implement.
Related
I followed the advice here on how to setup a MainWindowController: NSWindowController for my project's single window. I used a Cocoa class to create the .h/.m files, and I checked the option Also create .xib for User Interface. As a result, Xcode automatically hooked up a window, which I renamed MainWindow.xib, to my MainWidowController.
Next, I deleted the window in the default MainMenu.xib file (in Interface Builder I selected the window icon, then I hit the delete key). After that, I was able to Build my project successfully, and my controller's window in MainWindow.xib displayed correctly with a few buttons on it.
Then I tried adding an NSTableView to my MainWindowController's window. In Xcode, I dragged the requisite delegate and datasource outlets for the NSTableView onto File's Owner, which is my MainWindowController, and I implemented the methods in MainWindowController.m that I thought would make the NSTableView display my data:
- tableView:viewForTableColumn:row:
- numberOfRowsInTableView:
Now, when I Build my project, I don't get any errors, but the data doesn't appear in the NSTableView.
My code is below. Any tips are welcome!
//
// AppDelegate.h
// TableViews1
//
#import <Cocoa/Cocoa.h>
#interface AppDelegate : NSObject <NSApplicationDelegate>
#end
...
//
// AppDelegate.m
// TableViews1
//
#interface AppDelegate ()
#property (weak) IBOutlet NSWindow *window;
#property (strong) MainWindowController* mainWindowCtrl;
#end
#implementation AppDelegate
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
// Insert code here to initialize your application
[self setMainWindowCtrl:[[MainWindowController alloc] init] ];
[[self mainWindowCtrl] showWindow:nil];
}
- (void)applicationWillTerminate:(NSNotification *)aNotification {
// Insert code here to tear down your application
}
#end
...
//
// MainWindowController.h
// TableViews1
//
#import <Cocoa/Cocoa.h>
#interface MainWindowController : NSWindowController
#end
...
//
// MainWindowController.m
// TableViews1
//
#import "MainWindowController.h"
#import "Employee.h"
#interface MainWindowController () <NSTableViewDataSource, NSTableViewDelegate>
#property (strong) NSMutableArray* employees;
#property (weak) IBOutlet NSTableView* tableView;
#end
#implementation MainWindowController
- (NSView*)tableView:(NSTableView *)tableView
viewForTableColumn:(NSTableColumn *)tableColumn
row:(NSInteger)row {
Employee* empl = [[self employees] objectAtIndex:row];
NSString* columnIdentifier = [tableColumn identifier];
//The column identifiers are "firstName" and "lastName", which match my property names.
//You set a column's identifier by repeatedly clicking on the TableView until only
//one of the columns is highlighted, then select the Identity Inspector and change the column's 'Identifier' field.
NSString* emplInfo = [empl valueForKey:columnIdentifier]; //Taking advantage of Key-Value coding
NSTableCellView *cellView =
[tableView makeViewWithIdentifier:columnIdentifier
owner:self];
NSLog(#"The Table view is asking for employee: %#", [empl firstName]);
[[cellView textField] setStringValue:emplInfo];
return cellView;
}
- (NSInteger)numberOfRowsInTableView:(NSTableView *)tableView {
return [[self employees] count];
}
- (void)windowDidLoad {
[super windowDidLoad];
// Implement this method to handle any initialization after your window controller's window has been loaded from its nib file.
Employee* e1 = [[Employee alloc] initWithFirstName:#"Joe" lastName:#"Blow"];
Employee* e2 = [[Employee alloc] initWithFirstName:#"Jane" lastName:#"Doe"];
[self setEmployees:[NSMutableArray arrayWithObjects:e1, e2, nil]];
//Test to see if the employees array was populated correctly:
Employee* e = [[self employees] objectAtIndex:0];
NSLog(#"Here is the first employee: %#", [e firstName]);
//I see the output: "Here is the first employee: Joe"
}
- (id)init {
return [super initWithWindowNibName:#"MainWindow"];
}
- (id)initWithWindowNibName:(NSString *)windowNibName {
NSLog(#"Clients cannot call -[%# initWithWindowNibName] directly!",
[self class]
);
[self doesNotRecognizeSelector:_cmd];
return nil;
}
#end
...
//
// Employees.h
// TableViews1
#import <Foundation/Foundation.h>
#interface Employee : NSObject
#property NSString* firstName;
#property NSString* lastName;
- initWithFirstName:(NSString*)first lastName:(NSString*)last;
#end
...
//
// Employees.m
// TableViews1
//
#import "Employee.h"
#implementation Employee
- (id)initWithFirstName:(NSString *)first lastName:(NSString *)last {
if (self = [super init]) {
_firstName = first; //I read that you shouldn't use the accessors in init methods.
_lastName = last;
}
return self;
}
#end
File's Owner(=MainWindowController) connections:
NSTableView connections:
Response to comments:
Here is why calling [self tableView] reloadData] at the end of -windowDidLoad, as suggested in the comments, didn't work:
My _tableView instance variable--created by my #property declaration in MainWindowController.m--doesn't point to anything; therefore calling:
[[self tableView] reloadData]
I think is equivalent to calling:
[nil reloadData]
which doesn't do anything.
I never assigned anything to the _tableView instance variable in the -init method, nor did I assign it a value by dragging an outlet somewhere in Interface Builder. To fix that problem, I selected MainWindow.xib (the controller's window) in the Project Navigator(left pane), and then in the middle pane(Interface Builder), I selected the cube representing the File's Owner(selecting the Identity Inspector in the right pane reveals that the File's Owner is the MainWindowController). Then in the right pane, I selected the Connections Inspector, and it revealed an outlet called tableView, which is the IBOutlet variable I declared in MainWindowController.m.
Next, I dragged from the tableView outlet onto the TableView in the middle pane:
Doing that assigns the NSTableView object to the _tableView instance variable that was created by my #property declaration in MyWindowControler.m:
#property (weak) IBOutlet NSTableView* tableView;
As an experiment, I disconnected the outlet, then commented out the #property declaration for tableview, and the tableView outlet no longer appeared in the Connections Inspector. Also, if I change the declaration from:
#property (weak) IBOutlet NSTableView* tableView;
to:
#property (weak) NSTableView* tableView;
...then the tableView outlet doesn't appear in the Connections Inspector. That experiment answered a couple of questions I had about whether I should declare a property as an IBOutlet or not: if you need to assign one of the objects in Interface Builder to one of your variables, then declare the variable as an IBOutlet.
Thereafter, calling [self tableView] reloadData] at the end of -windowDidLoad succeeds in populating the TableView. However, I have not seen any tutorials that call reloadData, and even Apple's guide does not do that.
So, I am still puzzled about whether calling -reloadData is a hack or it's the correct way to do things.
Without it, your table view sits there blissfully clueless about your
expectation that it should even bother asking its datasource for data.
I assumed that an NSTableView automatically queries its datasource when it is ready to display itself, and that my code needed to be able to provide the data at that time.
I don't see you sending -reloadData to your table view anywhere. Tacking it onto the end of -windowDidLoad would be a good place. Without it, your table view sits there blissfully clueless about your expectation that it should even bother asking its datasource for data.
For all it knows, the data is simply not ready / available, so why would it try? More importantly, when should it try? It'd be rather rude of it to try whenever it pleases, considering the UI may not have finished loading / connecting to outlets, or its datasource may be in a vulnerable state (like teardown during/after dealloc) and sending datasource requests may result in a crash, etc.
Two things:
1st, set some breakpoints on when you set your employees array in windowDidLoad vs. when the table first attempts to populate itself and your numberOfRowsInTableView implementation gets called. If the latter happens before the former, then you'll need to add a reloadData after you create your array.
2nd, I personally always use NSCell instead of NSViews for my tables, so I always implement objectValueForTableColumn in my table's datasource. So I'm not sure if there's something different you need to do when you use NSView objects and implement viewForTableColumn. Is there a reason you're not using NSCell?
I see there are lots of posts on this topic but none seem to solve my problem.
I have to a view controller with has just a textfield, a navigation bar button (called save) and a number/punctuation keyboard.
The other view controller has a static table view with 2 rows.
Workflow: When a user taps on the 1st row in the table, the second view controller appears (this already works).
The user then enters a number and when they tap save, the number typed should be used to set the detail label of the 1st row in the table view.
I have set up my protocols and delegates but something is wrong as the 2nd view controller does not disappear and also detail label never gets updated to reflect this typed number.
I am very stumped. Been through lots of code samples and tried so many things but still no solution. Any help is greatly appreciated.
Below is my code for both classes.
1st View (The table view)
.h file (The hourlyRateDetialLabel is the detail label from the table view):
#import UIKit/UIKit.h
#import "priceCalculatorHrRateSettingsViewController.h"
#interface priceCalculatorSettingsViewController : UITableViewController<SettingsViewControllerDelegate>
#property (strong, nonatomic) IBOutlet UILabel *hourlyRateDetialLabel;
#end
.m file
#import "priceCalculatorSettingsViewController.h"
#import "priceCalculatorHrRateSettingsViewController.h"
#interface priceCalculatorSettingsViewController ()
#end
#implementation priceCalculatorSettingsViewController
#synthesize hourlyRateDetialLabel;
- (void)viewDidLoad
{
[super viewDidLoad];
}
#pragma mark - Table view delegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
priceCalculatorHrRateSettingsViewController *vc = [[priceCalculatorHrRateSettingsViewController alloc] init];
vc.settingsViewDelegate = self;
}
- (void) HourlyRateDidSave:(priceCalculatorHrRateSettingsViewController *)controller didSetHourlyRate:(NSString *)rateValue{
self.hourlyRateDetialLabel.text = rateValue;
[self dismissViewControllerAnimated:YES completion:nil];
}
#end
The 2nd Class (The View with the textfield and save button)
.h file
#import UIKit/UIKit.h
#class priceCalculatorHrRateSettingsViewController;
#protocol SettingsViewControllerDelegate <NSObject>
- (void)HourlyRateDidSave:
(priceCalculatorHrRateSettingsViewController *)controller didSetHourlyRate:(NSString *)rateValue;
#end
#interface priceCalculatorHrRateSettingsViewController : UIViewController<UITextFieldDelegate>
#property (strong, nonatomic) IBOutlet UITextField *setHourlyRate;
#property (weak, nonatomic) id<SettingsViewControllerDelegate> settingsViewDelegate;
- (IBAction)saveHourlyRateValue:(id)sender;
#end
.m file
#import "priceCalculatorHrRateSettingsViewController.h"
#interface priceCalculatorHrRateSettingsViewController ()
#end
#implementation priceCalculatorHrRateSettingsViewController{
}
#synthesize setHourlyRate = _setHourlyRate;
#synthesize settingsViewDelegate;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
//Automatically show the keybaord
[_setHourlyRate becomeFirstResponder];
}
- (void)viewDidUnload
{
[self setSetHourlyRate:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (IBAction)saveHourlyRateValue:(id)sender {
[self.settingsViewDelegate HourlyRateDidSave:self didSetHourlyRate:_setHourlyRate.text];
}
#end
The provided code includes:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
priceCalculatorHrRateSettingsViewController *vc = [[priceCalculatorHrRateSettingsViewController alloc] init];
vc.settingsViewDelegate = self;
}
This creates a controller when a cell is selected but never presents it and yet the unexpected behavior is described as:
...2nd view controller does not disappear...
These seems to be at odds with each other. Without an accurate description of 1. the expected behavior 2. the observed behavior and 3. the actual implementation producing the observed behavior, it is almost impossible for anyone to solve this problem. Please do not ask us all to guess how to help.
So I've got an NSViewController (MyVC) set up like so:
//MyVC.h
...
#property (nonatomic, retain) IBOutlet NSTextField *input;
...
//MyVC.m
...
#synthesize input;
- (id)init
{
self = [super initWithNibName: #"MyVC" bundle: [NSBundle mainBundle]];
NSLog(#"%#", input); //prints (null) always
return self;
}
- (void)loadView
{
[super loadView];
NSLog(#"%#", input); //still (null)
}
...
//MyVC.xib
Custom View [Referencing Outlet: File's Owner.view]
Text Field [Referencing Outlet: File's Owner.input]
Now, when I load this NSViewController (by way of MyVC *vc = [[MyVC alloc] init];) and load it into a window, I see the Text Field appropriately. However, as the above paste (and several BAD_ACCESSes) would suggest, vc.input is never properly pointing to the Text Field.
Notes:
This project is running ARC.
This is not a simplification or generalization. I've run this exact code to no avail.
All IBOutlets are definitely set up appropriately.
The error was a combination of things.
One of my revisions was missing the IBOutlet tag, and none of them were retaining references to the ViewController at runtime.
I'm working on a game for the iPad, and I have it start up with a menu screen. For a while, the menu screen would come up just fine in the simulator. I'm using the main view controller that xcode provides when starting up a view-based application. But, unfortunately, I accidentally cut off the connection between the UIView and the view controller in interface builder, and after reconnecting it, the screen comes up as blank now. It works fine when I simulate the screen in interface builder, but not when running in xcode. Here's the code for the view controller:
//
// FunctionMachineViewController.h
// FunctionMachine
//
// Created by Kameron Schadt on 5/24/11.
// Copyright 2011 Willamette University. All rights reserved.
//
#import <UIKit/UIKit.h>
#interface FunctionMachineViewController : UIViewController {
IBOutlet UITextField* equation;
IBOutlet UISlider* startLevel;
IBOutlet UITextView* startLevelNumber;
}
- (IBAction) startOnePlayer:(id)sender;
- (IBAction) startTwoPlayer:(id)sender startingEquation:(NSString*)equationUsed;
- (IBAction) sliderValueChanged:(UISlider*)sender;
#property(nonatomic, retain) IBOutlet UISlider* startLevel;
#property(nonatomic, retain) IBOutlet UITextField* equation;
#property(nonatomic, retain) IBOutlet UITextView* startLevelNumber;
#end
//
// FunctionMachineViewController.m
// FunctionMachine
//
// Created by Kameron Schadt on 5/24/11.
// Copyright 2011 Willamette University. All rights reserved.
//
#import "FunctionMachineViewController.h"
#import "GameViewController.h"
#implementation FunctionMachineViewController
#synthesize equation, startLevel, startLevelNumber;
- (IBAction)sliderValueChanged:(UISlider*)sender {
[startLevelNumber setText:[NSString stringWithFormat:#" %.1f", [sender value]]];
}
-(IBAction)startOnePlayer:(id)sender
{
GameViewController* GameView = [[GameViewController alloc] initWithNibName:nil bundle:nil];
[GameView isOnePlayer:YES];
[self presentModalViewController:GameView animated:YES];
}
-(IBAction)startTwoPlayer:(id)sender startingEquation:(NSString*)equationUsed
{
GameViewController* GameView = [[GameViewController alloc] initWithNibName:nil bundle:nil];
[GameView isOnePlayer:NO];
[self presentModalViewController:GameView animated:YES];
}
- (void)viewDidLoad {
[super viewDidLoad];
}
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation: (UIInterfaceOrientation)interfaceOrientation {
return YES;
}
- (void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
- (void)viewDidUnload {
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)dealloc {
[super dealloc];
}
#end
I didn't really see any problem here, so I'm assuming it has something to do with me reconnecting the view controller to the view. I don't have an actual view file that I'm using, just the viewcontroller. Can anybody help?
Check the setting of "Main nib file base name" in [YourApp]-info.plist, in the "Supporting Files" folder – if you've changed the name of your root view controller, you may need to change the name here as well.
For some odd reason my Referencing outlet for the App Delegate was disconnected.
Try creating a referencing outlet from delegate to File's Owner using the connections inspector (farthest right menu) for your App Delegate.
I've asked about this earlier but the question itself and all the information in it might have been a little confusing, plus the result i want to get is a little more complicated. So i started a new clean test project to handle just the part that im interested to understand for the moment.
So what i want, is basically this: i have a view container (inherits NSView). Inside, i want to place some images, but not just simple NSImage or NSImageView, but some custom view (inherits NSView also), which itself contains a textfield and an NSImageView. This 'image holder' as i called it, is in a separate nib file (im using this approach since i am guiding myself after an Apple SAmple Application, COCOA SLIDES).
The results i got so far, is something but not what i am expecting. Im thinking i must be doing something wrong in the Interface Builder (not connecting the proper thingies), but i hope someone with more expertise will be able to enlighten me.
Below i'll try to put all the code that i have so far:
//ImagesContainer.h
#import <Cocoa/Cocoa.h>
#interface ImagesContainer : NSView {
}
#end
//ImagesContainer.m
#import "ImagesContainer.h"
#import "ImageHolderView.h"
#import "ImageHolderNode.h"
#class ImageHolderView;
#class ImageHolderNode;
#implementation ImagesContainer
- (id)initWithFrame:(NSRect)frame {
self = [super initWithFrame:frame];
if (self) {
// Initialization code here.
//create some subviews
for(int i=0;i<3;i++){
ImageHolderNode *node = [[ImageHolderNode alloc] init];
[self addSubview:[node rootView]];
}
}
NSRunAlertPanel(#"subviews", [NSString stringWithFormat:#"%d",[[self subviews] count]], #"OK", NULL, NULL);
return self;
}
- (void)drawRect:(NSRect)dirtyRect {
// Drawing code here.
[[NSColor blackColor] set];
NSRectFill(NSMakeRect(0,0,dirtyRect.size.width,dirtyRect.size.height));
int i=1;
for(NSView *subview in [self subviews]){
[subview setFrameOrigin:NSMakePoint(10*i, 10)];
i++;
}
}
#end
//ImageHolderView.h
#import <Cocoa/Cocoa.h>
#interface ImageHolderView : NSView {
IBOutlet NSImageView *imageView;
}
#end
//ImageHolderVIew.m
#import "ImageHolderView.h"
#implementation ImageHolderView
- (id)initWithFrame:(NSRect)frame {
self = [super initWithFrame:frame];
if (self) {
}
return self;
}
- (void)drawRect:(NSRect)dirtyRect {
// Drawing code here.
[[NSColor blueColor]set];
NSRectFill(NSMakeRect(10,10, 100, 100));
//[super drawRect:dirtyRect];
}
#end
//ImageHolderNode.h
#import <Cocoa/Cocoa.h>
#class ImageHolderView;
#interface ImageHolderNode : NSObject {
IBOutlet ImageHolderView *rootView;
IBOutlet NSImageView *imageView;
}
-(NSView *)rootView;
-(void)loadUIFromNib;
#end
//ImageHolderNode.m
#import "ImageHolderNode.h"
#implementation ImageHolderNode
-(void)loadUIFromNib {
[NSBundle loadNibNamed:#"ImageHolder" owner: self];
}
-(NSView *)rootView {
if( rootView == nil) {
NSRunAlertPanel(#"Loading nib", #"...", #"OK", NULL, NULL);
[ self loadUIFromNib];
}
return rootView;
}
#end
My nib files are:
MainMenu.xib
ImageHolder.xib
MainMenu is the xib that is generated when i started the new project.
ImageHolder looks something like this:
image link
I'll try to mention the connections so far in the xib ImageHolder :
File's Owner - has class of ImageHolderNode
The main view of the ImageHolder.xib , has the class ImageHolderView
So to resume, the results im getting are 3 blue rectangles in the view container, but i cant seem to make it display the view loaded from the ImageHolder.xib
If anyone wants to have a look at the CocoaSlides sample application , its on apple developer page ( im not allowed unfortunately to post more than 1 links :) )
Not an answer, exactly, as it is unclear what you are asking..
You make a view (class 'ImagesContainer'). Lets call it imagesContainerView.
ImagesContainerView makes 3 Objects (class 'ImageHolderNode'). ImagesContainerView asks each imageHolderNode for it's -rootView (maybe 'ImageHolderView') and adds the return value to it's view-heirarchy.
ImagesContainerView throws away (but leaks) each imageHolderNode.
So the view heirachy looks like:-
+ imagesContainerView
+ imageHolderView1 or maybe nil
+ imageHolderView2 or maybe nil
+ imageHolderView3 or maybe nil
Is this what you are expecting?
So where do you call -(void)loadUIFromNib and wait for the nib to load?
In some code you are not showing?
In general, progress a step at a time, get each step working.
NSAssert is your friend. Try it instead of mis-using alert panels and logging for debugging purposes. ie.
ImageHolderNode *node = [[[ImageHolderNode alloc] init] autorelease];
NSAssert([node rootView], #"Eek! RootView is nil.");
[self addSubview:[node rootView]];
A view of course, should draw something. TextViews draw text and ImageViews draw images. You should subclass NSView if you need to draw something other than text, images, tables, etc. that Cocoa provides.
You should arrange your views as your app requires in the nib or using a viewController or a windowController if you need to assemble views from multiple nibs. Thats what they are for.
EDIT
Interface Builder Connections
If RootView isn't nil then it seems like you have hooked up your connections correctly, but you say you are unclear so..
Make sure the IB window is set to List view so you can see the contents of you nib clearly.
'File's Owner' represents the object that is going to load the nib, right? In your case ImageHolderNode.
Control Click on File's owner and amongst other things you can see it's outlets. Control drag (in the list view) from an outlet to the object you want to be set as the instance var when the nib is loaded by ImageHolderNode. I know you know this already, but there is nothing else to it.
Doh
What exactly are you expecting to see ? An empty imageView? Well, that will look like nothing. An empty textfield? That too, will look like nothing. Hook up an outlet to your textfield and imageView and set some content on them.