Buttons and icons provided by the system

To create a consistent user experience (and make your work easier), iPhone OS provides many standard buttons for the navigation bar and toolbar, as well as icons for the tab bar.

This chapter describes the standard icons and buttons that you can use and how to use them correctly. No matter which type of application you are developingProgram, You should be familiar with the buttons and icons described in this chapter, which helps you:

Correctly Use the elements provided by the system

Avoid designing custom icons that are too similar to the icons provided by the system

Use the buttons and icons provided by the system

In iPhone OS, many Standard toolbar and navigation bar buttons, items in the tab bar, and common buttons common in Built-in applications are available. In Figure 10-1, you can see some Standard toolbar buttons on the toolbar of the mail application.

 

Figure 10-1 standard buttons on the mail application Toolbar

As shown in Figure 10-1, the buttons-"refresh", "Organization", "delete", "reply", and "write" have long been used by many built-in applications, therefore, users are very familiar with their meanings and usage. This means that if your application supports these features, you can use your familiarity with them to make the user interface of the application more concise and efficient. Conversely, this means that if you associate these buttons with other tasks, you may feel confused and uncomfortable, because you think these buttons still have functions they are familiar, but they actually execute other functions.

In addition to making full use of your past experience, using the buttons and icons provided by the system can also bring two benefits:

Shorten development time because you do not need to create custom graphic elements for standard features.

Enhance the stability of the user interface, even if the updated version of the iPhone OS changes the appearance of the standard icon in the future. In other words, you can trust the standard icons. Even if the appearance changes, their meaning remains unchanged.

It is worth noting that in order to take advantage of the user's familiarity, you must use these buttons and icons properly to take advantage of shorter development time and maintain semantic consistency on the user interface. Specifically, this means that you should use the buttons or icons according to their meanings and recommended positions, rather than relying on your hypothetical view of their appearance. See "standard buttons for the toolbar and navigation bar", "Standard icons for the tab bar", and "standard buttons for table rows and other user interface elements, to learn about the meanings and locations of buttons and icons provided by the system.

Interface builder can easily use the buttons provided by the system and apply the icons provided by the system to your control. You can refer to the "iPhone OS user interface objects" section in the interface builder User Guide to learn about the appearance.

If any toolbar buttons, navigation bar buttons, or tab bar project icons provided by the system do not properly reflect a specific function in your application, you should design custom buttons or icons. The "icons in the navigation bar, toolbar, and Tab bar" section provides you with some guidance to help you complete this work.

Standard buttons for the toolbar and navigation bar

The iPhone OS provides standard buttons that are common in the toolbar and navigation bar. The buttons shown in Table 10-1 have two styles for different situations:

Border style-for example, the "add" button in the phone contact application navigation bar. This style applies to the navigation bar and toolbar.

No format style-for example, the "write" button in the mail application toolbar. This style is only applicable to the toolbar. In fact, even if you specify a button in the navigation bar as a non-formatted style, it will be converted to a border style.

Like all buttons provided by the system, do not use the buttons in Table 10-1 for operations other than the intended use. In particular, do not select a button Based on the appearance rather than the document description of the button. Refer to the "use the buttons and icons provided by the system" section, which discusses the significance of correct use of icons. (For the symbol names and availability information of these buttons, see
Uibarbuttonsystemitem
.)

Table 10-1 can be used as a standard button in the toolbar and navigation bar (displayed in an unformatted style)

Button	Description	Name
	Open the action form and allow the user to execute specific actions of the application.	Action
	Open the action form to display the photo selector in Camera mode.	Camera
	Open the edit mode view of the new message	Write
	Show application-specific bookmarks	Bookmarks
	Show search box	Search
	Create a new project	Add
	Delete current item	Recycle Bin
	Move or route an item in an application to a specified destination, such as a folder	Organization
	Send or route one item to another location	Reply
	Stop the current process or task	Stop
	Refresh content (used only when necessary; automatically refreshed in other cases)	Refresh
	Start playing media or slides	Play
	Fast forward to the currently played media or slides	Fast forward
	Pause the currently played media or slides (note that this means that the context is saved)	Pause
	Return to the currently played media or slides	Quick Return

In addition to the buttons shown in Table 10-1, you can also use the "edit" and "cancel" provided by the system in Table 10-2 in your application ", "save" and "finish" buttons to support editing or other types of content operations. (For more information about the symbol names and availability of these buttons, see Introduction.
Uibarbuttonsystemitem
.) These buttons are applicable to the navigation bar and toolbar, but can only be provided to users in a border style. If you use the preceding button, it is converted to a border style even if you specify it as a non-formatted style.

Table 10-2: border-style action buttons in the navigation bar

Button	Description	Name
	Enter edit or content Operation Mode	Edit
	Exit edit or content operation mode without saving changes	Cancel
	Save the changes and exit the edit or content operation mode when appropriate	Save
	Exit the current mode and save the changes (if any)	Complete

Standard icon for label bar

The iPhone OS provides standard icons for the tab bar, as shown in table 10-3. For more information about the symbolic names and availability of these icons, see Introduction.
Uitabbarsystemitem
.

Like all standard buttons and icons, you must use them according to their meanings. In particular, you should use the icon Based on the meaning of the icon, rather than its appearance. In this way, even if the icon's appearance changes, the specific meaning of the icon does not change, so that the user interface of the application looks reasonable, refer to the "use the buttons and icons provided by the system" section to learn more about why these icons are so important.

 

Table 10-3 standard icons used in the label bar

Icon	Description	Name
	Show application-specific bookmarks	Bookmarks
	Show contacts	Contact
	Show download	Download
	Display the favorites of the current user	Favorites
	Show special content of the application	Features
	Show user operation history	History
	Show more tags	More
	Display the last item used	Last use
	Display the items most followed by all users	Follow up most
	Displays the items that have been accessed by the user for a period of time defined by the application.	Recently used
	Enter search mode	Search
	Displays the items with the highest user rating	Highest Level

Standard buttons for table rows and other user interface elements

IPhone OS provides a few buttons for table rows and other elements. The buttons are listed in table 10-4. They should be correctly used according to their meanings, just like all standard buttons and icons. In particular, avoid selecting a button Based on the appearance rather than the document description of the button. Refer to the "use the buttons and icons provided by the system" section, which discusses the significance of correct use of these icons.

Although the details expand button is usually used in table rows, it can also be used elsewhere. For more information about this button, see "Expand details ". IPhone OS also provides a set of controls that can only be used in table rows. For more information about these controls, see Table view elements.

For more information about the symbol names and availability of these buttons, see Introduction.
Uibuttontype
. (For the symbolic names and Availability Information of the table view element "detail expand", see Introduction.
Uitableviewcellaccessorydetaildisclosurebutton
.)

Table 10-4 standard buttons for table rows and user interface elements

Button	Meaning	Name
	Displays the contact selector and adds a contact to a specified item.	Add contact
	Displays a new view that contains the details of the current item.	Details
	Flip to the back of the view (usually in a utility) to display configuration options or other information. Note that the "information" button can also contain a bright Letter "I" in a dark circle ".	Information