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:

 1 - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

 2     UITouch *theTouch = [touches anyObject];

 3  

 4     if ([theTouch tapCount] == 2  && [self becomeFirstResponder]) {

 5  

 6         // selection management code goes here...

 7  

 8         // bring up edit menu.

 9         UIMenuController *theMenu = [UIMenuController sharedMenuController];

10         CGRect selectionRect = CGRectMake (currentSelection.x, currentSelection.y, SIDE, SIDE);

11         [theMenu setTargetRect:selectionRect inView:self];

12         [theMenu setMenuVisible:YES animated:YES];

13  

14     }

15 }

View Code

　　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:

 1 - (BOOL)canPerformAction:(SEL)action withSender:(id)sender {

 2     BOOL retValue = NO;

 3     ColorTile *theTile = [self colorTileForOrigin:currentSelection];

 4  

 5     if (action == @selector(paste:) )

 6         retValue = (theTile == nil) &&

 7              [[UIPasteboard generalPasteboard] containsPasteboardTypes:

 8              [NSArray arrayWithObject:ColorTileUTI]];

 9     else if ( action == @selector(cut:) || action == @selector(copy:) )

10         retValue = (theTile != nil);

11     else

12         retValue = [super canPerformAction:action withSender:sender];

13     return retValue;

14 }

View Code

　　Implementing a Change Color menu item:

 1 - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {}

 2 - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {}

 3 - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

 4     UITouch *theTouch = [touches anyObject];

 5     if ([theTouch tapCount] == 2) {

 6         [self becomeFirstResponder];

 7         UIMenuItem *menuItem = [[UIMenuItem alloc] initWithTitle:@"Change Color" action:@selector(changeColor:)];

 8         UIMenuController *menuCont = [UIMenuController sharedMenuController];

 9         [menuCont setTargetRect:self.frame inView:self.superview];

10         menuCont.arrowDirection = UIMenuControllerArrowLeft;

11         menuCont.menuItems = [NSArray arrayWithObject:menuItem];

12         [menuCont setMenuVisible:YES animated:YES];

13     }

14 }

15 - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {}

16  

17 - (BOOL)canBecomeFirstResponder { return YES; }

18  

19 - (void)changeColor:(id)sender {

20     if ([self.viewColor isEqual:[UIColor blackColor]]) {

21         self.viewColor = [UIColor redColor];

22     } else {

23         self.viewColor = [UIColor blackColor];

24     }

25     [self setNeedsDisplay];

26 }

View Code

　　Dismiss the Edit Menu:

1 [UIMenuController sharedMenuController].menuVisible = YES;