Publishers of technology books, eBooks, and videos for creative people

Home > Articles > Apple > iPhone

  • Print
  • + Share This
This chapter is from the book

Text

For entering text into your applications, the iPhone SDK provides two classes, UITextField and UITextView. Both allow the user to enter and edit text using an onscreen keyboard and support features such as cut/copy and paste, spell check, and more, but the two classes function differently.

To create a text field:

  1. You can use the UITextField class to enter small amounts of text, such as user names, passwords, or search terms. This field is limited to a single line of text.
  2. As with most other views, you use the initWithFrame: method to create them:

    CGRect textRect = CGRectMake (10,10,300,20);
    UITextField *myTextField = [[UITextField alloc] initWithFrame:textRect];
    myTextField.backgroundColor = [UIColor whiteColor];
    

    This also sets the background color of the text field; otherwise, it's transparent by default.Text fields also don't have a border by default.

  3. Use the borderStyle property to choose from four different styles (Figure 4.30).

    The UITextBorderStyleRoundedRect style has a white background and will ignore the backgroundColor property. If you set a custom UIImage as the background, the borderStyle property will be ignored.

    Figure 4.30

    Figure 4.30 Border styles available for text fields.

  4. You can set the text font, color, and alignment to apply to the entire text field.

    Text fields do not support the styling of individual text elements.

  5. You can set your text field to automatically resize the font to accommodate larger text:

    myTextField.font = [UIFont systemFontOfSize:22.0];
    myTextField.adjustsFontSizeToFitWidth = YES;
    myTextField.minimumFontSize = 2.0;
    

    This example sets the initial font size as 22 and then tells the text field to automatically shrink the font to a minimum size of 2 if the text is wider than the text field's bounds.

  6. Setting the clearsOnBeginEditing property to YES will clear any existing text when you first touch the control:

    myTextField.clearsOnBeginEditing = YES;
    myTextField.clearButtonMode = UITextFieldViewModeWhileEditing;
    

    The clearButtonMode property adds a small button to the end of the text field, letting you clear the text at any time (Figure 4.31). You can determine when this button is shown, such as only when editing the text.

    Figure 4.31

    Figure 4.31 Press the clear button to remove any text in the text field.

To use keyboards:

  1. Tap in the text field to open a keyboard from the bottom of the screen.
  2. You can choose from a number of keyboard styles (Figure 4.32), each designed for particular situations such as entering numbers or using a web browser.
    Figure 4.32

    Figure 4.32 Two of the keyboards available by setting the keyboardType property of a text field.

  3. Set the style with the keyboardType property.

    By default, the keyboard will automatically suggest words as you type.

  4. To disable this function, set the autocorrectionType property to UITextAutocorrectTypeNo.
  5. Set the autocaptializationType property to determine whether the keyboard capitalizes your typing by word, sentence, or even all characters.
  6. You can change the text on the Return key via the returnKeyType property.
  7. Use the enablesReturnKeyAutomatically property to determine whether the Return key is enabled even if you haven't entered any text into the text field.

    In Code Listing 4.23, the secureTextEntry property is set to YES, which is useful for text fields that contain passwords or other sensitive information. As you enter text, you will see only the last letter typed.

    figure_04_41.jpg

    Code Listing 4.23 Creating a secure text field.

  8. You may have noticed that the keyboard doesn't disappear when you press the Return key. To hide the text field, you must implement the textFieldShouldReturn: delegate and tell the text field to resign its first responder status:
    [textField resignFirstResponder];
    return YES;
    
  9. Similarly, you can make the keyboard appear automatically when the view is loaded by setting the first responder status in the viewDidLoad: method:
    [myTextField becomeFirstResponder];
    
  10. To prevent the keyboard from showing at all, which is useful if you are implementing your own custom keyboard, return NO from the textFieldShouldBeginEditing: delegate method.

Restricting content

You can also use the delegate methods to control the text being entered into the text field. The textField:shouldChangeCharactersInRange:replacementString: delegate is called whenever the text is changed. You could, for example, use this method to restrict the number of characters entered. Code Listing 4.24 shows a text field that allows a maximum of ten characters.

figure_04_42.jpg

Code Listing 4.24 Limiting the contents of a text field to ten characters.

You should check the length of the replacement rather than just looking at the length of the text in the text field, since the text field's contents can be altered via copy and paste as well as by using the keyboard.

For the same reason, simply changing the keyboard type to numeric does not guarantee that a user will enter only numeric values (since a user could paste non-numeric values into the field). Code Listing 4.25 shows the same delegate method, this time restricting the text field to allow numeric values only.

figure_04_43.jpg

Code Listing 4.25 Restricting the contents of a text field to numeric values.

Text views

The UITextView class allows for multiline editable text. Although similar to text fields, text views feature a number of important differences.

Text views don't have any support for automatically reducing the font size like text fields have. Also, they don't have any support for clearing the text other than through programmatically setting the text property. There is also no support for secure text entry.

As with text fields, text views also apply the same text style to the entire text. Apple recommends using a UIWebView (see the "Web Views" section) if you require multiple styles in your text.

Data detectors

Text views can analyze their contents and convert any links or phone numbers into tappable links by using a capability known as data detectors. Tapping the link will either launch the browser or call the phone number.

Two data detector types are available: UIDataDetectorTypePhoneNumber for phone numbers and UIDataDetectorTypeLink for Web http: links. To enable both, set the dataDetectorTypes property:

myTextView.dataDetectorTypes = UIDataDetectorTypeAll;

There's one caveat with data detectors: The default behavior of text views is to show the keyboard when tapped, so you can't tap the link of a data detector. For data detectors to work, you must set the editable property of the text view to NO. In Figure 4.33, the URL is underlined just as it would be in a web browser. Tapping it will launch the Safari application.

Figure 4.33

Figure 4.33 A text view with an active data detector.

Hiding the keyboard

A text view's keyboard behaves the same as a text field, with one important difference: Since a text view supports multiline editing, pressing the Return button on the keyboard will insert a carriage return instead of calling a delegate method. Just as with the text field, resign the text view's first responder status to hide the keyboard when you have finished editing the text. This is often done as an action within another control.

Scrolling the interface

You may have noticed that since the iPhone's keyboards are very large, they take up a lot of the screen and can overlap other controls when shown. It would be handy if your interface moved up when the keyboard appeared and then moved back down once it disappeared.

You can make that happen by placing the controls inside a UIScrollView. When the keyboard appears, you simply scroll everything up, scrolling back down when the keyboard hides.

To scroll the interface in response to the keyboard:

  1. Create and add a scroll view, making it the full size of the main view:
    CGRect viewRect = [self.view bounds];
    myScrollView = [[UIScrollView alloc] initWithFrame:viewRect];
    myScrollView.contentSize = viewRect.size;
    [self.view addSubview:myScrollView];
    
  2. Add the controls to the scroll view instead of the main view (since you want them to scroll).
  3. Implement the textViewDidBeginEditing: delegate method, which is called when the keyboard is shown.

    Here you need to calculate both the bottom of the text view and the top of the keyboard and then tell the scroll view to scroll the difference. You must also look at the orientation property of the iPhone because the keyboard will have a different height in portrait mode than in landscape mode.

  4. Implement the textViewDidEndEditing: delegate so that when the keyboard is hidden, you scroll the text view to its original position. Code Listing 4.26 shows the completed code.
    figure_04_45.jpg

    Code Listing 4.26 Scrolling an interface in response to a keyboard.

  • + Share This
  • 🔖 Save To Your Account

Peachpit Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from Peachpit and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Peachpit products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email ask@peachpit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by Adobe Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.peachpit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020