I'm using the arc4random command to change between three randomly selected views. In those three views, I have four labels displaying random texts when clicking on a button. So the labels are empty when you go to a random view until the button is clicked. But I need the four different labels to already be loaded with the random texts when going to the new view. How do I do that?
In your interface of randomly selected file put the following code.
In view1.h
#interface view1
{
NSString *strValue;
UILabel *lblText;
}
#property (nonatomic, retain) NSString *strValue;
In view1.m
#synthesize strValue;
- (void)viewDidLoad
{
lblText.text = strValue;
}
In your main view, from where you are calling the random view set following code...
- (void)btnClicked:(id)sender
{
view1 *objView1 = [[view1 alloc] initWithNibName:#"view1" bundle:nil];
objView1.strValue = #"Random Text";
[self.navigationController pushViewController:objView1 animated:TRUE];
}
Related
Im using a custom ModalViewController called MZFormSheetController to display a Detail View for UICollectionView. Currently I have created properties in the modal view controller such as these :
#property (strong,nonatomic) NSString *user;
#property (strong,nonatomic) NSString *caption;
#property (weak, nonatomic) IBOutlet UILabel *username;
#property (weak, nonatomic) IBOutlet UILabel *captiontext;
And I attempt to set the display of the detail view controller when the user taps on the UICollectionViewCell like this:
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
NSDictionary *entry = [self entries][indexPath.row];
NSDictionary *text = [self entries][indexPath.row];
ModalViewController *m = [self.storyboard instantiateViewControllerWithIdentifier:#"modalView"];
m.entry = [self entries][indexPath.row];
m.text = [self entries][indexPath.row];
m.user = entry[#"user"][#"full_name"];
m.caption = text[#"caption"][#"text"];
MZFormSheetController *formSheet = [[MZFormSheetController alloc] initWithViewController:m];
formSheet.transitionStyle = MZFormSheetTransitionStyleDropDown;
formSheet.shouldDismissOnBackgroundViewTap = YES;
[formSheet presentAnimated:YES completionHandler:^(UIViewController *presentedFSViewController) {
}];
formSheet.didTapOnBackgroundViewCompletionHandler = ^(CGPoint location)
{
};
}
I have created two labels in storyboard for the modalviewcontroller and I attempt to make them equal the caption and user values from the MainViewController like this
[self.username.text isEqualToString:self.user];
[self.captiontext.text isEqualToString:self.caption];
However after all this the labels of the modal view controller still say label like this..
Your labels are not being updated to the correct values because the -isEqualToString: method is used to test whether two NSStrings are equal, and it doesn't actually set the value of any NSString. If you want to assign a value to a string variable, you do it the same as you would assign any other variable. Therefore, in order to set the labels properly, you just need to assign the text property of the UILabels, like this:
self.username.text = self.user;
self.captiontext.text = self.caption;
Did you set username and captiontext inside your ModalViewController in viewDidLoad method ? After init from storyboard, all IBOutlets are nil, you need to setup then inside viewDidLoad.
- (void)viewDidLoad
{
[super viewDidLoad];
self.username.text = self.user;
self.captiontext.text = self.caption;
}
I have a view controller that has navigation bar with a done button, and two text fields. When the done button is pressed, the method postInfo is called. Here is the implementation:
- (void)postInfo{
ListingViewController* lvc = [[ListingViewController alloc] init];
NSString* listingName = listingNameField.text;
NSString* listingPrice = listingPriceField.text;
NSLog(#"%#", listingName);
NSLog(#"%#", listingPrice);
[lvc.titleLabel setText:listingName];
[lvc.priceLabel setText:listingPrice];
[self.navigationController pushViewController:lvc animated:YES];
}
Here ListingViewController.h:
#import <UIKit/UIKit.h>
#interface ListingViewController : UIViewController
#property (weak, nonatomic) IBOutlet UILabel *priceLabel;
#property (weak, nonatomic) IBOutlet UILabel *titleLabel;
#end
The UILabel's are set through a xib file and are empty. Will post whatever other code is needed upon request.
At the time you do that push, the next controller's view hasn't been loaded yet, so you can't access its views. You need to create NSString properties in ListingViewController and pass a string to those in your postnfo method. Then in ListingViewController's viewDidLoad method, use those properties to populate the labels (which will have been loaded by the time viewDidLoad runs).
Change your code to this.
- (void)postInfo
{
ListingViewController* lvc = [[ListingViewController alloc] init];
[lvc view]; // loads the view
NSString* listingName = listingNameField.text;
NSString* listingPrice = listingPriceField.text;
NSLog(#"%#", listingName);
NSLog(#"%#", listingPrice);
[lvc.titleLabel setText:listingName];
[lvc.priceLabel setText:listingPrice];
[self.navigationController pushViewController:lvc animated:YES];
}
This happens because until the view property of the view controller is accessed, the view will not be loaded and all of the subviews are nil. They can be configured after viewDidLoad is called on the view controller being pushed. Calling [lvc view] loads the view immediately.
I usually get this too (in the example of when using segues). I get around it by setting an NSString property instead of an IBOutlet during prepareForSegue of the destinationController. Then during viewDidLoad of the next View Controller, I take the value of the property and assign it to the UILabel.
You may find the explanation in this answer useful: https://stackoverflow.com/a/8094146/2358334
If you set a breakpoint just after the line you call
testViewController *viewController = segue.destinationViewController;
when you build and run the project, you will find that the UITextField
property in the destinationViewController is not allocated and
initiated (memory is 0x0) at the breakpoint. Meanwhile the NSString
property is already allocated and initialised (so you can set its
value).
Try to do this
first you need to load the view (push viewcontroller) and then you can access the properties (because you have created views by IBOutlet
- (void)postInfo{
ListingViewController* lvc = [[ListingViewController alloc] init];
NSString* listingName = listingNameField.text;
NSString* listingPrice = listingPriceField.text;
NSLog(#"%#", listingName);
NSLog(#"%#", listingPrice);
[self.navigationController pushViewController:lvc animated:YES];
[lvc.titleLabel setText:listingName];
[lvc.priceLabel setText:listingPrice];
}
I have a view with a view controller and when I show this view on screen, I want to be able to pass variables to it from the calling class, so that I can set the values of labels etc.
First, I just tried creating a property for one of the labels, and calling that from the calling class. For example:
SetTeamsViewController *vc = [[SetTeamsViewController alloc] init];
vc.myLabel.text = self.teamCount;
[self presentModalViewController:vc animated:YES];
[vc release];
However, this didn't work. So I tried creating a convenience initializer.
SetTeamsViewController *vc = [[SetTeamsViewController alloc] initWithTeamCount:self.teamCount];
And then in the SetTeamsViewController I had
- (id)initWithTeamCount:(int)teamCount {
self = [super initWithNibName:nil bundle:nil];
if (self) {
// Custom initialization
self.teamCountLabel.text = [NSString stringWithFormat:#"%d",teamCount];
}
return self;
}
However, this didn't work either. It's just loading whatever value I've given the label in the nib file. I've littered the code with NSLog()s and it is passing the correct variable values around, it's just not setting the label.
Any help would be greatly appreciated.
EDIT: I've just tried setting an instance variable in my designated initializer, and then setting the label in viewDidLoad and that works! Is this the best way to do this?
Also, when dismissing this modal view controller, I update the text of a button in the view of the calling ViewController too. However, if I press this button again (to show the modal view again) whilst the other view is animating on screen, the button temporarily has it's original value again (from the nib). Does anyone know why this is?
When a view controller is being initialized, inside the initWithNibName method, the views that reside in the view controller aren't yet initialized and you can't set their properties yet. Do whatever you need that is view based in the "viewDidLoad" method.
I am not a pro but this may help you.
In the header view1.h, declare the desired property:
// view1.h
#interface view1 : UIViewController {
NSString *passingVariable;
}
#property (nonatomic, strong) NSString *passingVariable;
#end
and then in the implementation of view1, synthesize the variable:
// view1.m
#implementation view1
#synthesize passingVariable;
// the rest of the implementation
#end
and, finally in the implementation of the other view controller, view2:
// view2.m
#import "view1.h"
#implementation view2
-(IBAction)changeview
{
view1 *myview = [[view1 alloc] init];
myview.passingVariable = #"Hello Variable";
[self.navigationController pushViewController:myview animated:YES];
}
#end
here i am trying to move from view2 to view 1 and also initializing the passingVariable ivar of view1. hope this will help you.
Here i'm passing the ViewController's label text to SecondViewController's Label Text
ViewController.h
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController
{
// please make your control on XIB set these IBOutlet's
//I'm not showing how to connect these with XIB
IBOutlet UILabel *lblView;
IBOutlet UIButton *buttonGo;
}
//this is method which will push the view
-(IBAction)buttonGoClickAction:(id)sender;
ViewController.m
-(IBAction)buttonGoClickAction:(id)sender
{
SecondViewController *secondViewObject = [[SecondViewController alloc]initWithNibName:#"SecondViewController" bundle:nil];
//before pushing give the text
secondViewObject.string = lblView.text;
[self.navigationController pushViewController:secondViewObject animated:YES];
}
SecondViewController.h
#import <UIKit/UIKit.h>
#interface SecondViewController : UIViewController
{
IBOutlet UILabel *labelView;
NSString *string;
}
//set the string property
#property(nonatomic, retain) NSString *string;
#end
SecondViewController.m
#import "SecondViewController.h"
#implementation SecondViewController
//synthesize string here
#synthesize string;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
//Here you will get the string
labelView.text = string;
}
Firstly you check that have you attach this label IBOutlet in xib or not if you made it via Interface Builder....
use it like this....
SetTeamsViewController *vc = [[SetTeamsViewController alloc] initWithTeamCount:teamCount];
Take a string variable in .h file and set that string here .. NSSting *str in .h
- (id)initWithTeamCount:(int)teamCount {
self = [super init];
if (self) {
// Custom initialization
str = [NSString stringWithFormat:#"%d",teamCount];
}
return self;
}
and set your label in viewDidLoad: or in viewWillApear:
self.teamCountLabel.text = str;
May this will help you
As said by stavash, control in the xib are created in the view did load. To be more precise, they are created with that line :
[super viewDidLoad];
So, mylabel doesn't exist before that time (it is nil).
The easiest way is to do that :
SetTeamsViewController *vc = [[SetTeamsViewController alloc] init];
[self presentModalViewController:vc animated:YES];
vc.myLabel.text = self.teamCount;
[vc release];
The longer but more correct path is to have a member NSString* in SetTeamsViewController class, to set it to teamCount before showing the window, and in the view did load to put that membre value in your label.
Cdt
It depends on your need. You can use Singleton class for sharing of your variables between different classes. Define all variable which you wants share in your DataClass.
in .h file (where RootViewController is my DataClass, replace name with your new class)
+(RootViewController*)sharedFirstViewController;
in .m file
//make the class singleton:-
+(RootViewController*)sharedFirstViewController
{
#synchronized([RootViewController class])
{
if (!_sharedFirstViewController)
[[self alloc] init];
return _sharedFirstViewController;
}
return nil;
}
+(id)alloc
{
#synchronized([RootViewController class])
{
NSAssert(_sharedFirstViewController == nil,
#"Attempted to allocate a second instance of a singleton.");
_sharedFirstViewController = [super alloc];
return _sharedFirstViewController;
}
return nil;
}
-(id)init {
self = [super init];
if (self != nil) {
// initialize stuff here
}
return self;
}
after that you can use your variable in any other class like this
[RootViewController sharedFirstViewController].variable
Hope it's help you:)
With Storyboards the the right way is to pass the indexPath as sender argument in performSegueWithIdentifier
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[self performSegueWithIdentifier:#"segueIdentifier" sender:indexPath];
}
and to set a property in the destination controller:
- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([[segue identifier] isEqualToString: #"segueIdentifier"]) {
NSIndexPath *indexPath = sender;
DetailViewController *dest = [segue destinationViewController];
dest.usersArray = [self.usersArray objectAtIndex:indexPath.row];
}
}
What I have done whenever I needed another class to have the variables from the previous class I either set up a global class that will store the values incase I need them in more locations or in the interface you can set #public variables. These variables can be set using the controller that you created for the next view as such.
controller->pub_var1 = val1;
controller->pub_var2 = val2;
This will be done before you pass the view to the root controller or just before you call the next view. You will need to #import "class.h" so that you can access those public variables.
I can show code if this is not clear
I want to assign two UIButtons to UITextView so that when one of the buttons is pressed the textview content should change from what it had when the previous button was pressed.
MyViewController.h:
#interface MyViewController : UIViewController
{
NSString* savedText;
}
#property(nonatomic, retain) IBOutlet UITextView* textView;
- (IBAction)buttonOnePressed:(id)sender;
- (IBAction)buttonTwoPressed:(id)sender;
#end
Connect the view controller's textView outlet to the text view in the xib file. Connect the buttons to the corresponding actions. (See Apple's Xcode tutorial if you don't know how to do this.)
MyViewController.m:
- (void)buttonOnePressed:(id)sender
{
[savedText release];
savedText = [textView.text copy];
}
- (void)buttonTwoPressed:(id)sender
{
textView.text = savedText;
}
(These aren't the complete files, of course, just the bits to make it do what you're asking.)
when i select a cell in my modified picker view, a blue background colour appears.
all other treads i have seen do not give me a good answer.
anyone has a solution?
pickerView.showsSelectionIndicator = NO;
Just set the UITableViewCell selectionStyle property to UITableViewCellEditingStyleNone
cell.selectionStyle = UITableViewCellEditingStyleNone;
I have add toolbar at the top of picker view and add cutom button as a sub view of toolbar and both picker view and toolbar are add as a subview of Main view so you can handle this.
I've met this one. Let's get a look at it in details. To create your custom picker view, you create your custom UIView class, e.g. :
#interface TimeAroundView : UIView
{
NSString *title;
UIImage *image;
}
#property (nonatomic, retain) NSString *title;
#property (nonatomic, retain) UIImage *image;
#end
Then in your custom picker view controller you create some container, e.g. NSArray, which will get all TimeAroundView objects you want to represent in your picker view. So, for every object you must do
timeAroundViewObject.userInteractionEnabled = NO;
I think -(id)init is the best place for filling that container in, so you get something like this:
- (id)init
{
self = [super init];
if (self) {
// create the data source for this custom picker
NSMutableArray *viewArray = [[NSMutableArray alloc] init];
TimeAroundView *earlyMorningView = [[TimeAroundView alloc] initWithFrame:CGRectZero];
earlyMorningView.title = #"Early Morning";
earlyMorningView.image = [UIImage imageNamed:#"12-6AM.png"];
earlyMorningView.userInteractionEnabled = NO;
[viewArray addObject:earlyMorningView];
[earlyMorningView release];
TimeAroundView *lateMorningView = [[TimeAroundView alloc] initWithFrame:CGRectZero];
lateMorningView.title = #"Late Morning";
lateMorningView.image = [UIImage imageNamed:#"6-12AM.png"];
lateMorningView.userInteractionEnabled = NO;
[viewArray addObject:lateMorningView];
[lateMorningView release];
// .... (more of objects)
self.customPickerArray = viewArray;
[viewArray release];
}
return self;
}
And in your pickerView:viewForRow:forComponent:reusingView: you just return proper element from array.
That works for me.