UITextField is a type of view which can display a value just like the UILabel and also lets the user change it on the screen using the keyboard.
- Programmatically create UITextField and add them to the current view
- Set the border style
- Overlay custom views such as currency symbol, search icon, etc inside the view
- Vertical and Horizontal alignment of the Text
- Associate various keyboard types with the input text view
- Display Hint to the user when the text field is empty
- Display clear button on the text field
- Listen for events using the UITextField Delegate
- Restrict data entry to only certain types such as numeric only
- Restrict the number of maximun number of characters that are allowed in the text field
Interface file for the view controller – UITextFieldViewController.h
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#import <UIKit/UIKit.h> @interface UITextFieldViewController : UIViewController @property (nonatomic, strong) UITextField *myTextField; @property (nonatomic, strong) UILabel *myLabel; @end |
Implementation file for the view controller – UITextFieldViewController.m
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#import "UITextFieldViewController.h" @interface UITextFieldViewController () @end @implementation UITextFieldViewController @synthesize myTextField, myLabel; - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. self.view.backgroundColor = [UIColor whiteColor]; //create a label with the local currency symbol UILabel *dollarSign = [[UILabel alloc] initWithFrame:CGRectZero]; dollarSign.text = [[[NSNumberFormatter alloc] init] currencySymbol]; [dollarSign sizeToFit]; //create a label to display current user interaction with our editable text views CGRect myFrame = CGRectMake(10.0f, 10.0f, 250.0f, 40.0f); self.myLabel = [[UILabel alloc] initWithFrame:myFrame]; self.myLabel.text = @“Mycodetips…”; self.myLabel.font = [UIFont boldSystemFontOfSize:16.0f]; self.myLabel.textAlignment = NSTextAlignmentLeft; [self.view addSubview:self.myLabel]; //lets create 3 UITextViews on the screen for (NSInteger i=1; i<4; i++) { //set the origin of the frame reference myFrame.origin.y += myFrame.size.height + 10.0f; //create the text field self.myTextField = [[UITextField alloc] initWithFrame:myFrame]; //set the border style for the text view self.myTextField.borderStyle = UITextBorderStyleRoundedRect; switch (i) { case 1: //the vertical alignment of text within the frame, set this to center self.myTextField.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter; //the horizontal alignment of the text self.myTextField.textAlignment = NSTextAlignmentLeft; //set the type of the keyboard to display self.myTextField.keyboardType = UIKeyboardTypeDecimalPad; //display the currency symbol in the left of the text field view self.myTextField.leftView = dollarSign; self.myTextField.leftViewMode = UITextFieldViewModeAlways; break; case 2: self.myTextField.contentVerticalAlignment = UIControlContentVerticalAlignmentTop; self.myTextField.textAlignment = NSTextAlignmentCenter; break; case 3: self.myTextField.contentVerticalAlignment = UIControlContentVerticalAlignmentBottom; self.myTextField.textAlignment = NSTextAlignmentRight; self.myTextField.keyboardType = UIKeyboardTypeEmailAddress; break; default: self.myTextField.contentVerticalAlignment = UIControlContentVerticalAlignmentBottom; self.myTextField.textAlignment = NSTextAlignmentCenter; break; } //display hint for the user data entry when the field is empty self.myTextField.placeholder = [NSString stringWithFormat:@"Enter data in field %i", i]; //add tag to identify your text views self.myTextField.tag = i; //display the clear button on the text field self.myTextField.clearButtonMode = UITextFieldViewModeAlways; //change the return key text to "Done" self.myTextField.returnKeyType = UIReturnKeyDone; //set the delegate for the text field to the view controller so that it can listen for events self.myTextField.delegate = self; //add the text field to the current view [self.view addSubview:self.myTextField]; } } //Asks the delegate if editing should begin in the specified text field. - (BOOL)textFieldShouldBeginEditing:(UITextField *)textField{ return YES; } //Tells the delegate that editing began for the specified text field. - (void)textFieldDidBeginEditing:(UITextField *)textField{ NSInteger i = textField.tag; self.myLabel.text = [NSString stringWithFormat:@"Begin editing Text field %i", i]; } //Asks the delegate if editing should stop in the specified text field. - (BOOL)textFieldShouldEndEditing:(UITextField *)textField{ return YES; } //Tells the delegate that editing stopped for the specified text field. - (void)textFieldDidEndEditing:(UITextField *)textField{ NSInteger i = textField.tag; self.myLabel.text = [NSString stringWithFormat:@"Editing done for Text field %i", i]; } //Asks the delegate if the specified text should be changed. - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{ //get the current data strsing inside the text field NSString *myTextData = [textField.text stringByReplacingCharactersInRange:range withString:string]; NSLog(@"Current data in text field is %@", myTextData); NSCharacterSet * set = [[NSCharacterSet characterSetWithCharactersInString:@"0123456789."] invertedSet]; NSInteger i = textField.tag; switch (i) { case 1: //first field should only have numeric data otherwise don't allow change if ([string rangeOfCharacterFromSet:set].location != NSNotFound) { return NO; } break; default: //don't allow more than 15 characters if ([myTextData length] > 15) { return NO; } break; } //set the display label value with the current data in the text field self.myLabel.text = [NSString stringWithFormat:@"Data: %@", myTextData]; return YES; } //Asks the delegate if the text field’s current contents should be removed. - (BOOL)textFieldShouldClear:(UITextField *)textField{ NSInteger i = textField.tag; NSLog(@"Text field %i just got cleared", i); return YES; } //Asks the delegate if the text field should process the pressing of the return button. - (BOOL)textFieldShouldReturn:(UITextField *)textField{ //Notifies the receiver that it has been asked to relinquish //its status as first responder in its window. [textField resignFirstResponder]; return YES; } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } @end |