Adding Menu to Table

Operating system requirements: iOS 5.0 or later.

Mobile device: iPad.

Description

This example describes table menu implementation. After starting the example the following operations are executed:

Menu items are created and set.
Menu item text is aligned.
Position of popup window arrow and popup window plot area are determined.
A delegate and a table, for which it is called are set for menu.
Table cell press event is handled, after which menu is displayed. If a cell is not highlighted, the Select menu item is available, if it is not highlighted, the Deselect menu item.
A single-element pool instance is created for common access to element.

Source Files

Executing the example requires to add the following methods with their implementation in the ViewController class (see the Creating a Simple Data Grid section):

// Creates menu items
- (NSArray *)makeMenuItemsForCell:(NuGridCell *)cell {
    NSMutableArray *items = [[NSMutableArray new] autorelease];
    // Determine operation called after menu item selection
    SEL changeCellSelection = @selector(changeCellSelection:);
    if ([cell isHighLighted]) {
        // If a cell is not highlighted, display the Deselect menu item
        UIMenuItem *firstMenuItem = [[[UIMenuItem alloc] initWithTitle:@"Deselect" action:changeCellSelection] autorelease];
        [items addObject:firstMenuItem];
        } else {
        // If a cell is highlighted, display the Select menu item
        UIMenuItem *secondMenuItem = [[[UIMenuItem alloc] initWithTitle:@"Select" action:changeCellSelection] autorelease];
        [items addObject:secondMenuItem];
    }
    return items;
}
// Changes cell selection state
- (void)changeCellSelection:(id)sender {
    // Get last pressed cell
    NuGridCell *lastTouchedCell = [contr gridView].controller.lastTouchedCell;
    if (lastTouchedCell) {
        // Check if table cell is highlighted
        if ([lastTouchedCell isHighLighted]) {
            // Restore table cell initial background
            [lastTouchedCell setBackgroundColor:[[lastTouchedCell style] backgroundColor]];
            [lastTouchedCell setIsHighLighted:NO];
            } else {
            // Change table cell background
            [lastTouchedCell setBackgroundColor:[UIColor lightGrayColor]];
            [lastTouchedCell setIsHighLighted:YES];
        }
    }
}

Then handle table cell press event, after the event occurs the menu is displayed. Consider three methods of the handler implementation:

1. First method.

- (void)gridView:(NuGridView *)gridView wasTouchedInCell:(NuGridCell *)cell {
    // Create menu manager
    NuMenuController *menuCtrl = [NuMenuController sharedMenuController];
    // Create and set menu items
    [menuCtrl setMenuItems:[self makeMenuItemsForCell:cell]];
    // Determine menu settings
    [menuCtrl setRect:cell.frame inView:gridView forTarget:[gridView gridDelegate]];
    // Determine popup window arrow direction
    [menuCtrl setArrowDirection: UIPopoverArrowDirectionUp];
    // Align menu item text by center
    [[menuCtrl menu] setTextAlignment:UITextAlignmentCenter];
    // Display menu by using animation
    [menuCtrl setMenuVisible:YES animated:YES];
}

2. Second method.

- (void)gridView:(NuGridView *)gridView wasTouchedInCell:(NuGridCell *)cell {
    // Create menu manager
    NuMenuController *menuCtrl = [NuMenuController sharedInstance];
    // Create and set menu items
    [menuCtrl setMenuItems:[self makeMenuItemsForCell:cell]];
    // Set menu delegate
    [menuCtrl setTarget:[gridView gridDelegate]];
    // Create and set menu items
    [menuCtrl setTargetRect:[cell frame]];
    // Set table, for which menu is called
    [menuCtrl setTargetView:gridView];
    // Determine popup window arrow direction
    [menuCtrl setArrowDirection: UIPopoverArrowDirectionUp];
    // Align menu item text by center
    [[menuCtrl menu] setTextAlignment:UITextAlignmentCenter];
    // Display menu
    [menuCtrl setMenuVisible:YES];
}

3. Third method.

- (void)gridView:(NuGridView *)gridView wasTouchedInCell:(NuGridCell *)cell {
    // Display popup menu
    [self showPopoverForCell: cell];
}
// Displays popup window
- (void) showPopoverForCell:(NuGridCell*) cell {
    NuMenu *menu = [[[NuMenu alloc] init] autorelease];
    [menu setDelegate: self];
    [menu setItems:[self makeMenuItemsForCell:cell]];
    // Align menu item text by center
    [menu setTextAlignment:UITextAlignmentCenter];
    CGRect rect = [cell frame];
    popover = [[UIPopoverController alloc] initWithContentViewController:menu];
    [popover presentPopoverFromRect:rect inView:[contr gridView] permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];
    [popover setDelegate:self];
    if ([[contr gridView] respondsToSelector:@selector(setScrollEnabled:)]) {
        [(UIScrollView *)[contr gridView] setScrollEnabled:NO];
    }
}

After executing the example pressing any table cell displays a menu with the Select item:

After selecting this menu item the corresponding cell is highlighted. To clear selection, press again the cell and select the Deselect menu item.