MiscTargetActionView.rtf

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MiscTargetActionView

Inherits From: View : Responder : Object

Declared In: misckit/MiscTargetActionView.h

Class Description

MiscTargetActionView is an abstract superclass that implements a target action paradeigm for Views. It is not quite the same as the Control Class since there is no "value". MiscTargetActionView accepts keyboard and mouse events and converts them into target/action messages (potentially using a responder chain).

MiscTargetActionView takes it's lessons from several other classes. The target/action methods are similar to those of the Control Class; the actionMask support is similar and complimentary to the eventMask of Windows; and the event handling methods override (but may forward to) those of the Responder Class.

Only a handful of the methods in this class will ever be called directly by a user: all of the action mask methods; the target and action methods; initialization methods; possibly the diagnostic methods; and sometimes the setFirstResponder and setFirstMouse methods.

Note that events in the actionMask will only be recieved if the corresponding events are enabled in the window's event mask. The following code fragment shows how to use this class in an application in which one wants to have the user object's method attention: sent upon any key down, mouse down or mouse movement including the very first one. This is typical of code one might use to make a screensaver get out of the way:

myWindow = [[Window allocFromZone: [self zone]] init];
newView = [[MiscTargetActionView allocFromZone: [self zone]] init];
[newView setActionMask: NX_LMOUSEDOWNMASK | NX_RMOUSEDOWNMASK | \
NX_MOUSEMOVEDMASK | NX_KEYDOWNMASK];
[newView setFirstMouse: YES];
[newView setTarget: self];
[newView setAction: @selector(attention:)];
[[myWindow setContentView: newView] free];

oldMask = [myWindow addToEventMask:NX_KEYDOWNMASK | NX_MOUSEMOVEDMASK];
[newView setFirstResponder];
[myWindow makeKeyWindow];
[NXApp activateSelf: YES];

The setFirstResponder method will only be in effect until some other view is given firstResponder status by the Window, so in some applications it might be necessary to send it as part of the setup, just like the makeKeyWindow is sent to the Window.

Instance Variables

BOOL firstMouse;
int actionMask;
NXEvent * actionEvent;
id target;
SEL action;
BOOL debug;

firstMouse Yes if we accept first mouse click.
actionMask Mask of events that will fire the target/action.
actionEvent Event causing the current target/action.
target Id of the target object .
action Selector of the message to be sent to the target.
debug YES if a diagnostic trace is to be printed on the console or the gdb terminal.

Method Types

Initialization - initFrame:

Determining the first responder - acceptsFirstResponder
- setFirstResponder
- acceptsFirstMouse
- setFirstMouse:

Setting the action mask - setActionMask:
- addToActionMask:
- removeFromActionMask:
- actionMask

Target and action - setAction:
- action
- setTarget:
- target
- actionEvent

Processing event messages - mouseDown:
- rightMouseDown:
- mouseDragged:
- rightMouseDragged:
- mouseUp:
- rightMouseUp:
- mouseMoved:
- mouseEntered:
- mouseExited:
- keyDown:
- keyUp:
- flagsChanged:

Diagnostics - setDebug:
- debug:
- toggleDebug:

Archiving - awake
- read:
- write:

Instance Methods

acceptsFirstMouse
- (BOOL)acceptsFirstMouse

This returns YES if an initial mouse-down event in the View�an event that causes the View's Window to become the key window�is sent to the View (through a mouseDown: message). If only those mouse-downs that occur when the MiscTargetActionView's Window is already key are sent, this returns NO (the default). The default behavior may be changed with the setFirstMouse: method.