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] == 2  && [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] == 2) {
        [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;