Text Relatives II

[Text Relatives II]

　　When your app determines that the user has requested the edit menu—which could be the action of making a selection—you should complete the following steps to display the menu:

1. Call the sharedMenuController class method of UIMenuController to get the global menu-controller instance.

2. Compute the boundaries of the selection and with the resulting rectangle call the setTargetRect:inView: method. The edit menu is displayed above or below this rectangle, depending how close the selection is to the top or bottom of the screen.

3. Call the setMenuVisible:animated: method (with YES for both arguments) to animate the display of the edit menu above or below the selection.

　　Displaying the edit menu:

 - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
     UITouch *theTouch = [touches anyObject];

     if ([theTouch tapCount] ==   && [self becomeFirstResponder]) {

         // selection management code goes here...

         // bring up edit menu.
         UIMenuController *theMenu = [UIMenuController sharedMenuController];
         CGRect selectionRect = CGRectMake (currentSelection.x, currentSelection.y, SIDE, SIDE);
         [theMenu setTargetRect:selectionRect inView:self];
         [theMenu setMenuVisible:YES animated:YES];

     }
 }

　　Before the menu is displayed, however, the system sends a canPerformAction:withSender: message to the first responder, which in many cases is the custom view itself.

　　Conditionally enabling menu commands:

 - (BOOL)canPerformAction:(SEL)action withSender:(id)sender {
     BOOL retValue = NO;
     ColorTile *theTile = [self colorTileForOrigin:currentSelection];

     if (action == @selector(paste:) )
         retValue = (theTile == nil) &&
              [[UIPasteboard generalPasteboard] containsPasteboardTypes:
              [NSArray arrayWithObject:ColorTileUTI]];
     else if ( action == @selector(cut:) || action == @selector(copy:) )
         retValue = (theTile != nil);
     else
         retValue = [super canPerformAction:action withSender:sender];
     return retValue;
 }

　　Implementing a Change Color menu item:

 - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {}
 - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {}
 - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
     UITouch *theTouch = [touches anyObject];
     if ([theTouch tapCount] == ) {
         [self becomeFirstResponder];
         UIMenuItem *menuItem = [[UIMenuItem alloc] initWithTitle:@"Change Color" action:@selector(changeColor:)];
         UIMenuController *menuCont = [UIMenuController sharedMenuController];
         [menuCont setTargetRect:self.frame inView:self.superview];
         menuCont.arrowDirection = UIMenuControllerArrowLeft;
         menuCont.menuItems = [NSArray arrayWithObject:menuItem];
         [menuCont setMenuVisible:YES animated:YES];
     }
 }
 - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {}

 - (BOOL)canBecomeFirstResponder { return YES; }

 - (void)changeColor:(id)sender {
     if ([self.viewColor isEqual:[UIColor blackColor]]) {
         self.viewColor = [UIColor redColor];
     } else {
         self.viewColor = [UIColor blackColor];
     }
     [self setNeedsDisplay];
 }

　　Dismiss the Edit Menu:

 [UIMenuController sharedMenuController].menuVisible = YES;