FMX.TabControl.TPreviousTabAction

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Delphi

TPreviousTabAction = class(TTabControlAction)

C++

class PASCALIMPLEMENTATION TPreviousTabAction : public TTabControlAction

Properties

Type	Visibility	Source	Unit	Parent
class	public	FMX.TabControl.pas FMX.TabControl.hpp	FMX.TabControl	FMX.TabControl

Description

TCustomAction is the base class for FireMonkey actions intended to be used with menu items and controls.

FMX.TabControl.TPreviousTabAction inherits from FMX.ActnList.TCustomAction. All content below this line refers to FMX.ActnList.TCustomAction.

TCustomAction is the base class for FireMonkey actions intended to be used with menu items and controls.

TCustomAction introduces support for the properties, events, and methods of menu items and controls that are clients of action objects.

Most properties and events introduced in TCustomAction are public; therefore, use TCustomAction as a base class when deriving your own actions that publish specific subset of properties of associated controls.

Action objects centralize the response to user commands (actions) and represent user interface elements in applications that use actions. They provide an easy way to synchronize, for example, the enabled state and caption of a speed button and a menu item, and handle the response when users click these components. Each such component, called the client, has its properties dynamically updated by the action and forwards user actions to the action for a response.

At design time, you can work in the Action List editor with actions contained in an action list. The action list is a container for actions, which it organizes into categories.

Component and control public properties and events that are supported in TCustomAction, either directly or through an ancestor, are:

• Properties--Caption, Checked, Enabled, HelpType, HelpContext, HelpKeyword, Hint, ImageIndex, ShortCut, Visible.
• Events--OnHint, OnUpdate, OnExecute.

Because the OnHint, OnUpdate, and OnExecute events are public, they do not appear in the Object Inspector. That is, the Object Inspector does not support generating custom event handlers for these events.

You can derive from TCustomAction if you want to retain the public scope of supported properties and events or modify the public scope to the published scope.

FMX.StdActns Unit

TCustomAction can also act as the base class for predefined action classes. For predefined actions that augment the behavior of TCustomAction, see the action classes in the FMX.StdActns unit.

TSysCommonAction Descendants

TSysCommonAction is the base class for standard actions providing system functionality.

TSysCommonAction extends the TCustomAction class redeclaring properties and events, used in system actions, with the published visibility: CustomText, Enabled, HelpContext, HelpKeyword, HelpType, Hint, SecondaryShortCuts, ShortCut, Visible, UnsupportedArchitectures, OnCanActionExec, OnUpdate.

The published scope of properties and events provides the possibility to use the assistant of the Object Inspector for editing values of these properties and defining event handlers at design time.

Standard actions descending from TSysCommonAction are TFileExit, TWindowClose, TFileHideApp, and TFileHideAppOthers:

• TFileExit is the standard action for shutting down an application. Add TFileExit to an action list to let users shut down the application using a menu, control, tool bar button, or shortcut. Clients (controls, menu commands, toolbar buttons) linked to this action cause the application to shut down. TFileExit is not immediate, it calls the method like Terminate that closes the main form. TFileExit has the default ShortCut CMD+Q.

• TWindowClose is the standard action for closing the active modeless form. TWindowClose is not immediate, it calls the method like Close that closes the active modeless form. TWindowClose has the default ShortCut CMD+W.

• TFileHideApp is the standard action for hiding and showing (if hidden) a running Mac OS X application. TFileHideApp hides all the windows of the receiver application, and the next application in line is activated. If the windows of the receiver application are hidden, then TFileHideApp restores the hidden windows to the screen and makes the receiver active. TFileHideApp has the default ShortCut CMD+H.

In the current version, TFileHideApp is implemented only for Mac OS X.

• TFileHideAppOthers is the standard action for hiding all Mac OS X applications, except the receiver. TFileHideApp has the default ShortCut ALT+CMD+H.

In the current version, TFileHideAppOthers is implemented only for Mac OS X.

TObjectViewAction Descendants

• TCustomViewAction is the base class for actions that show a specified component when executed.

TCustomViewAction descendants are associated with a component that is made visible when the action executes.

• TObjectViewAction extends the TCustomViewAction class defining that a component should be an TFmxObject type object. TObjectViewAction descendants are associated with an TFmxObject type component that is made visible when the action executes. Standard actions descending from TObjectViewAction are TVirtualKeyboard and TViewAction:
  • TVirtualKeyboard--This standard action is executed by an associated virtual (on-screen) keyboard and it shows this virtual keyboard when it is executing.
    • TVirtualKeyboard extends TCustomViewAction by redeclaring some public properties and events as having published visibility.
    • TVirtualKeyboard keeps a virtual keyboard object in the FmxObject property. The virtual keyboard component is shown, while it executes the action.
    • Virtual keyboard components are supported by so called Platform Services. Therefore, this standard action might not be supported under all platforms.

      See FMX.ScrollableForm Sample, FMX.KeyboardTypes Sample, and FMX.KeyboardToolbar Sample examples for more details.

  • TViewAction--This standard action is executed by an associated component and it shows this component when it is being executed.
    • TViewAction extends TCustomViewAction by redeclaring some public properties and events as having published visibility.
    • TViewAction keeps the component object of the TFmxObject type in the FmxObject property. This component is shown, while it executes the action.

Code Examples

• FMX.ActionsDemo Sample
• FMX.KeyboardToolbar Sample
• FMX.ScrollableForm Sample

See Also

• FMX.ActnList.TAction
• FMX.ActnList.TActionLink
• FMX.ActnList.TActionList
• Vcl.ActnList.TAction
• Vcl.ActnList.TCustomAction
• Vcl.ActnList.TActionLink
• Vcl.ActnList.TActionList
• FireMonkey Actions
• FMX.StdActns.TSysCommonAction.CustomText
• FMX.StdActns.TSysCommonAction.Enabled
• FMX.StdActns.TSysCommonAction.HelpContext
• FMX.StdActns.TSysCommonAction.HelpKeyword
• FMX.StdActns.TSysCommonAction.HelpType
• FMX.StdActns.TSysCommonAction.Hint
• FMX.StdActns.TSysCommonAction.SecondaryShortCuts
• FMX.StdActns.TSysCommonAction.ShortCut
• FMX.StdActns.TSysCommonAction.Visible
• FMX.StdActns.TSysCommonAction.UnsupportedArchitectures.
• FMX.StdActns.TFileExit
• FMX.StdActns.TWindowClose
• FMX.StdActns.TFileHideApp
• FMX.StdActns.TFileHideAppOthers
• FMX.VirtualKeyboard.IFMXVirtualKeyboardService
• FMX.Platform.TPlatformServices
• FMX.StdActns.TViewAction.FmxObject
• FMX.ActnList.TCustomViewAction.Component