UKFirstResponder.m

   1 //
   2 //  UKFirstResponder.m
   3 //  Shovel
   4 //
   5 //  Created by Uli Kusterer on 04.10.04.
   6 //  Copyright 2004 M. Uli Kusterer. All rights reserved.
   7 //
   8
   9 #import "UKFirstResponder.h"
  10
  11 @interface UKFirstResponder (PrivateMethods)
  12
  13 -(id)   responderForAction: (SEL)itemAction;
  14
  15 @end
  16
  17 static UKFirstResponder*        sFirstResponder = nil;
  18
  19
  20 @implementation UKFirstResponder
  21
  22 +(id)   firstResponder
  23 {
  24         if( !sFirstResponder )
  25                 sFirstResponder = [[[self class] alloc] init];
  26
  27         return sFirstResponder;
  28 }
  29
  30
  31 // This is a singleton:
  32 +(id)   init
  33 {
  34         if( !sFirstResponder )
  35         {
  36                 self = [super init];
  37                 sFirstResponder = self;
  38
  39                 return self;
  40         }
  41         else
  42         {
  43                 [self autorelease];
  44                 return sFirstResponder;
  45         }
  46 }
  47
  48 // -----------------------------------------------------------------------------
  49 //      Finding out what messages the first responder understands/sending messages:
  50 // -----------------------------------------------------------------------------
  51
  52 -(id)   performSelector: (SEL)itemAction withObject: (id)obj
  53 {
  54         BOOL    does = [super respondsToSelector: itemAction];
  55         if( does )
  56                 return [super performSelector: itemAction withObject: obj];
  57
  58         id      resp = [self responderForAction: itemAction];
  59         if( !resp )
  60                 [self doesNotRecognizeSelector: itemAction];
  61         return [resp performSelector: itemAction withObject: obj];
  62 }
  63
  64 -(id)   performSelector: (SEL)itemAction
  65 {
  66         BOOL    does = [super respondsToSelector: itemAction];
  67         if( does )
  68                 return [super performSelector: itemAction];
  69
  70         id      resp = [self responderForAction: itemAction];
  71         if( !resp )
  72                 [self doesNotRecognizeSelector: itemAction];
  73         return [resp performSelector: itemAction];
  74 }
  75
  76 -(BOOL) respondsToSelector: (SEL)itemAction
  77 {
  78         BOOL    does = [super respondsToSelector: itemAction];
  79
  80         return( does || ([self responderForAction: itemAction] != nil) );
  81 }
  82
  83
  84 // -----------------------------------------------------------------------------
  85 //      Forwarding unknown methods to the first responder:
  86 // -----------------------------------------------------------------------------
  87
  88 -(NSMethodSignature*)   methodSignatureForSelector: (SEL)itemAction
  89 {
  90         NSMethodSignature*      sig = [super methodSignatureForSelector: itemAction];
  91         id                                      friend = [self responderForAction: itemAction];
  92
  93         if( sig )
  94                 return sig;
  95
  96         if( friend )
  97                 return [friend methodSignatureForSelector: itemAction];
  98
  99         return nil;
 100 }
 101
 102 -(void) forwardInvocation: (NSInvocation*)invocation
 103 {
 104     SEL itemAction = [invocation selector];
 105         id      friend = [self responderForAction: itemAction];
 106
 107     if( friend )
 108         [invocation invokeWithTarget: friend];
 109     else
 110         [self doesNotRecognizeSelector: itemAction];
 111 }
 112
 113 @end
 114
 115
 116 @implementation UKFirstResponder (PrivateMethods)
 117
 118 -(id)   responderForAction: (SEL)itemAction
 119 {
 120         NSResponder*    resp = [[NSApp keyWindow] firstResponder];
 121         id                              actualResponder = nil;
 122
 123         do
 124         {
 125                 if( [resp respondsToSelector: itemAction] )
 126                         actualResponder = resp;
 127                 else if( [resp respondsToSelector: @selector(delegate)] )
 128                 {
 129                         id del = [(id)resp delegate];
 130                         if( [del respondsToSelector: itemAction] )
 131                                 actualResponder = del;
 132                 }
 133         }
 134         while( !actualResponder && (resp = [resp nextResponder]) );
 135
 136         if( !actualResponder )
 137         {
 138                 if( [NSApp respondsToSelector: itemAction] )
 139                         actualResponder = NSApp;
 140                 else
 141                 {
 142                         id del = [NSApp delegate];
 143                         if( [del respondsToSelector: itemAction] )
 144                                 actualResponder = del;
 145                 }
 146         }
 147
 148         return actualResponder;
 149 }
 150
 151 @end