How to pass data from parent view to child upon opening? - ios

Question

I want to load data (an array of strings) from the parent view into a set of UITextFields in the child view upon presenting the modalView.
I know how to pass from child to parent, and I'm sure it's even easier to go the other way, but I don't know how.
UPDATE: Update removed because I found the problem (double releasing of modal view)

Answer 1

Override the init method for the child view controller.
- (id) initWithStrings:(NSArray *)string {
if (self = [super init]) {
// Do stuff....
}
return self;
}
Then in the parent:
MyChildViewController *vc = [[[MyChildViewController alloc] initWithStrings: strings] autorelease];

Answer 2

Two ways you could do it:
1.Override the init method as Matt suggests
2.Create fields in your child class and pass those values to your text field.
#interface ChildViewController : UIViewController{
NSArray *strings;
UITextfield *textField1;
UITextfield *textField2;
}
...
- (void)viewDidLoad {
[super viewDidLoad];
textField1.text = [strings objectAtIndex:0];
textField2.text = [strings objectAtIndex:1];
}
Then in the parent class:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
ChildViewController *childController = [[ChildViewController alloc] init];
childController.strings = your_array_of_strings;
[self.navigationController pushViewController:childController animated:YES];
[childController release];
}

Answer 3

- (id)initWithDataObject:(YourDataObjectClass *)dataObject {
if (self = [super init]) {
self.dataObject = dataObject;
// now you can do stuff like: self.myString = self.dataObject.someString;
// you could do stuff like that here or if it is related to view-stuff in viewDidLoad
}
return self;
}

Answer 4

If you want to get really fancy, you can make a delegate for your child view.
#protocol MyChildViewDelegate
- (NSArray*)getStringsForMyChildView:(MyChildView*)childView;
#end
#interface MyChildView : UIView
{
id <MyChildViewDelegate> delegate;
...
}
#property (nonatomic, assign) id <MyChildViewDelegate> delegate;
...
#end
Then somewhere in your view you would ask for the strings:
- (void)viewDidLoad
{
...
NSArray* strings = [delegate getStringsForMyChildView:self];
...
}
Then in your controller (or where ever) you can do:
myChildView = [[MyChildView alloc] initWith....];
myChildView.delegate = self;
...
- (NSArray*)getStringsForMyChildView:(MyChildView*)childView
{
return [NSArray arrayWithObjects:#"one", #"two", #"three", nil];
}
It's probably a little overkill in this case, but this is how UITableViews do it too: they have a data source delegate to provide them with their contents.