NSPanel Class Reference

Inherits from
Conforms to
Framework
/System/Library/Frameworks/AppKit.framework
Availability
Available in OS X v10.0 and later.
Companion guide
Declared in
NSPanel.h
Related sample code

Overview

The NSPanel class implements a special kind of window (known as a panel), typically performing an auxiliary function.

For details about how panels work (especially to find out how their behavior differs from window behavior), see “How Panels Work”.

Tasks

Configuring Panels

Instance Methods

becomesKeyOnlyIfNeeded

Indicates whether the receiver becomes the key window only when needed.

- (BOOL)becomesKeyOnlyIfNeeded
Return Value

YES when the panel becomes the key window only when needed, NO otherwise.

Discussion

By default, this attribute is set to NO, indicating that the panel becomes key as other windows do.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSPanel.h

isFloatingPanel

Indicates whether the receiver is a floating panel.

- (BOOL)isFloatingPanel
Return Value

YES when the receiver is a floating panel, NO otherwise.

Availability
  • Available in OS X v10.0 and later.
See Also
Declared In
NSPanel.h

setBecomesKeyOnlyIfNeeded:

Specifies whether the receiver becomes the key window only when needed.

- (void)setBecomesKeyOnlyIfNeeded:(BOOL)becomesKeyOnlyIfNeeded
Parameters
becomesKeyOnlyIfNeeded

YES makes the panel become the key window only when keyboard input is required. NO makes the panel become key when it’s clicked.

Discussion

This behavior is not set by default. You should consider setting it only if most user interface elements in the panel aren’t text fields, and if the choices that can be made by entering text can also be made in another way (such as by clicking an item in a list).

If the receiver is a non-activating panel, then it becomes key only if the hit view returns YES from needsPanelToBecomeKey. This way, a non-activating panel can control whether it takes keyboard focus.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSPanel.h

setFloatingPanel:

Controls whether the receiver floats above normal windows.

- (void)setFloatingPanel:(BOOL)floatingPanel
Parameters
floatingPanel

YES to make the receiver a floating panel (NSFloatingWindowLevel). NO to make the receiver behave like a normal window (NSNormalWindowLevel).

Discussion

By default, panels do not float above other windows. It’s appropriate for an panel to float above other windows only if all of the following conditions are true:

  • It’s small enough not to obscure whatever is behind it.

  • It’s oriented more to the mouse than to the keyboard—that is, if it doesn’t become the key window or becomes so only when needed.

  • It needs to remain visible while the user works in the application’s normal windows—for example, if the user must frequently move the cursor back and forth between a normal window and the panel (such as a tool palette), or if the panel gives information relevant to the user’s actions in a normal window.

  • It hides when the application is deactivated (the default behavior for panels).

Availability
  • Available in OS X v10.0 and later.
See Also
Declared In
NSPanel.h

setWorksWhenModal:

Specifies whether the receiver receives keyboard and mouse events even when some other window is being run modally.

- (void)setWorksWhenModal:(BOOL)worksWhenModal
Parameters
worksWhenModal

YES to make the panel receive events even during a modal loop or session. NO to prevent the panel from receiving events while a modal loop or session is running.

Discussion

See “How Modal Windows Work” for more information on modal windows and panels.

Availability
  • Available in OS X v10.0 and later.
See Also
Declared In
NSPanel.h

worksWhenModal

Indicates whether the receiver receives keyboard and mouse events even when some other window is being run modally.

- (BOOL)worksWhenModal
Return Value

YES when the receiver receives keyboard and mouse events even when some other window is being run modally, NO otherwise.

Discussion

By default, this attribute is set to NO, indicating a panel’s ineligibility for events during a modal loop or session. See “How Modal Windows Work” for more information on modal windows and panels.

Availability
  • Available in OS X v10.0 and later.
See Also
Declared In
NSPanel.h

Constants

Alert Panel Return Values

These constants define values returned by the NSRunAlertPanel function and by the NSApplication method runModalSession: when the modal session is run with an NSPanel provided by the NSGetAlertPanel function. (Deprecated. NSRunAlertPanel and NSGetAlertPanel are deprecated; use NSAlert APIs instead.)

enum {
   NSAlertDefaultReturn = 1,
   NSAlertAlternateReturn = 0,
   NSAlertOtherReturn = -1,
   NSAlertErrorReturn = -2
};
Constants
NSAlertDefaultReturn

The user pressed the default button.

Available in OS X v10.0 and later.

Declared in NSPanel.h.

NSAlertAlternateReturn

The user pressed the alternate button.

Available in OS X v10.0 and later.

Declared in NSPanel.h.

NSAlertOtherReturn

The user pressed a second alternate button.

Available in OS X v10.0 and later.

Declared in NSPanel.h.

NSAlertErrorReturn

The alert cannot identify the reason it was closed; it may have been closed by an external source or by a button other than those listed above.

Available in OS X v10.0 and later.

Declared in NSPanel.h.

Declared In
NSPanel.h

Modal Panel Return Values

These constants define the possible return values for such methods as the runModal... methods of the NSOpenPanel class, which tell which button (OK or Cancel) the user has clicked on an open panel. (Deprecated. In an NSWindow object, use the NSModalResponse constants instead.)

enum {
   NSOKButton = 1,
   NSCancelButton = 0
};
Constants
NSCancelButton

The Cancel button

Available in OS X v10.0 and later.

Declared in NSPanel.h.

NSOKButton

The OK button

Available in OS X v10.0 and later.

Declared in NSPanel.h.

Declared In
NSPanel.h

Style Masks

The NSPanel class defines the following constants for panel styles:

enum {
   NSUtilityWindowMask = 1 << 4,
   NSDocModalWindowMask = 1 << 6,
   NSNonactivatingPanelMask = 1 << 7
   NSHUDWindowMask = 1 << 13
};
Constants
NSDocModalWindowMask

The panel is created as a modal sheet.

Available in OS X v10.0 and later.

Declared in NSPanel.h.

NSUtilityWindowMask

The panel is created as a floating window.

Available in OS X v10.0 and later.

Declared in NSPanel.h.

NSNonactivatingPanelMask

The panel can receive keyboard input without activating the owning application.

Valid only for an instance of NSPanel or its subclasses; not valid for a window.

Available in OS X v10.2 and later.

Declared in NSPanel.h.

NSHUDWindowMask

The panel is created as a transparent panel (sometimes called a “heads-up display”).

Valid only for an instance of NSPanel or its subclasses; not valid for a window.

Using the C bitwise OR operator, NSHUDWindowMask can be combined with other style masks (some of which are documented in Window Style Masks) with the following results:

NSBorderlessWindowMask

Borderless window with transparent panel transparency and window level.

A panel that uses NSBorderlessWindowMask can’t become key unless you implement canBecomeKeyWindow to return YES. Note that you can also set a panel’s style mask to NSBorderlessWindowMask in Interface Builder by deselecting Title Bar in the Appearance section of the Attributes inspector.

NSTitledWindowMask | NSUtilityWindowMask

Titled window with transparent panel transparency and window level. This combination can be additionally combined with any of the following:

NSClosableWindowMask

Titled window with transparent panel close box, transparency, and window level.

NSResizableWindowMask

Titled window with transparent panel resize corner, transparency, and window level.

NSNonactivatingPanelMask

No effect on appearance, but owning application is not necessarily active when this window is the key window.

The following constants cannot be combined with NSHUDWindowMask: NSMiniaturizableWindowMask, NSTexturedBackgroundWindowMask, NSDocModalWindowMask, and NSUnifiedTitleAndToolbarWindowMask.

Available in OS X v10.5 and later.

Declared in NSPanel.h.

Declared In
NSPanel.h