how to dynamic fill the text field in ios app - ios

Question

I have a one page application with a couple of text fields. One field is a Drop-down menu, with which the user can choose the item to fill in this text field (text1). After this text field (text1) is filled, how can I automatically update other text fields (text2, text3, etc).
For example: I have three text fields, text1, text2, text3. On the backend, I have a matching array list between them, so the value from text1 will able to find the proper value for text2 and text3. But, how can I dynamically update text2 and text3 after the user changes the value of text1.
Another more basic question: how can I display the text string in text field in viewdidload?
For example: I have retrieved value from database, how to display this value in text field upon load of the view.

Answer 1

ok, I'll try to address the questions one by one:
first the displaying of a text field on load.
create a outlet to a label to hold your text.
example - start in .h file
#property (weak, nonatomic) IBOutlet UILabel *textbox1;
Now in Interface Builder, drag out a label and then connect the label you just dragged with the property you setup.
Now you have an outlet to store you value.
now to put something in it go to .m file in -(void)viewDidLoad add something like this:
self.textbox1.text = #"some text to display";
That should get something on the screen.
Now, if you want to dynamically update other on-screen labels either during or after the user is typing, you need to implement a text field delegate. Its a little complicated to try and explain the whole thing, but basically in your .h file your implementation line should look like this:
#interface YourViewControllerNameHere : UIViewController <UITextFieldDelegate>
then in your .m file you have a few changes to make
first in viewDidLoad add this line
self.textbox1.delegate = self; //this tells the UILabel to send changes to your program
then in some open space you can implement these callback methods:
then run your program and the logging will tell you when and where things are happening.
basically, you call your code from the correct method depending on what you want to do.
- (void)textDidChange:(id<UITextInput>)textInput {
NSLog(#"text did change");
}
- (void)textFieldDidBeginEditing:(UITextField *)textField {
NSLog(#"text field did begin editing");
}
-(void)textFieldDidEndEditing:(UITextField *)textField {
NSLog(#"text field did end editing");
}
-(void)textWillChange:(id<UITextInput>)textInput {
NSLog(#"text will change");
}
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSLog(#"text field should change characters in range");
//if this is disabled no character will appear
//use to filter out bad characters
return YES;
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
NSLog(#"text field should return");
return YES;
}