如何捕获自定义tableViewCell中更改的开关事件？

Question

I have a question ...

I have Custom TableViewCell class:

// Class for Custom Table View Cell.
@interface CustomTableViewCell : UITableViewCell {
    // Title of the cell.
    UILabel*     cellTitle;
    // Switch of the cell.
    UISwitch*    cellSwitch;
}

How you can see in my custom UITableViewCell I have Label and Switch controller.

- (id)initWithStyle: (UITableViewCellStyle)style reuseIdentifier: (NSString *)reuseIdentifier tableType:(TableTypeEnumeration)tabletypeEnum {
        // Get Self.
        self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
        if (self) {
            // Create and initialize Title of Custom Cell.
            cellTitle = [[UILabel alloc] initWithFrame:CGRectMake(10, (44 - TAGS_TITLE_SIZE)/2, 260, 21)];
            cellTitle.backgroundColor      = [UIColor clearColor];
            cellTitle.opaque               = NO;
            cellTitle.textColor            = [UIColor blackColor];
            cellTitle.highlightedTextColor = [UIColor whiteColor];
            cellTitle.font                 = [UIFont boldSystemFontOfSize:TAGS_TITLE_SIZE];
            cellTitle.textAlignment        = UITextAlignmentLeft;
            // Create and Initialize Switch of Custom Cell.
            cellSwitch = [[UISwitch alloc] initWithFrame:CGRectMake(185, 10, 10, 10 )];

            [self.contentView addSubview:cellTitle];
            [self.contentView addSubview:cellSwitch];

            [cellTitle release];
            [cellSwitch release];
        }
        return self;
}

Now when I use my custom cell in TableView I want to catch event when user change the state of switch . How can I do that ?

Answer 1

You have to write method for value change as below:

[cellSwitch addTarget:self action:@selector(valueChange:) forControlEvents:UIControlEventValueChanged];

Then you have to implement delegate

@protocol SwitchDelegate <NSObject>
- (void)valueChangeNotify:(id)sender;
@end

then you have to make object id delegate and synthesis with (nonatomic, assign) propertly and method as below:

- (void)valueChange:(id)sender{
  if ([delegate respondToSelector:@selector(valueChangeNotify:)])
    [delegate valueChangeNotify:sender];
}

By this way, you can get notify state change in view controller.

Answer 2

Set up a target action for the switch to be notified of changes.

To do this call

- (void)addTarget:(id)target action:(SEL)action forControlEvents:(UIControlEvents)controlEvents;

when you create the cell.

Answer 3

@protocol SwitchDelegate
- (void)valueChangeNotify:(id)sender;
@end

// Class for Custom Table View Cell.
@interface CustomTableViewCell : UITableViewCell {
    // Title of the cell.
    UILabel*     cellTitle;
    // Switch of the cell.
    UISwitch*    cellSwitch;

    id<SwitchDelegate> delegate;
}

@property (nonatomic, assign) id <SwitchDelegate> delegate;

@end


- (id)initWithStyle: (UITableViewCellStyle)style reuseIdentifier: (NSString *)reuseIdentifier tableType:(TableTypeEnumeration)tabletypeEnum {
    // Get Self.
    self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
    if (self) {
        // Create and initialize Title of Custom Cell.
        cellTitle = [[UILabel alloc] initWithFrame:CGRectMake(10, (44 - TAGS_TITLE_SIZE)/2, 260, 21)];
        cellTitle.backgroundColor      = [UIColor clearColor];
        cellTitle.opaque               = NO;
        cellTitle.textColor            = [UIColor blackColor];
        cellTitle.highlightedTextColor = [UIColor whiteColor];
        cellTitle.font                 = [UIFont boldSystemFontOfSize:TAGS_TITLE_SIZE];
        cellTitle.textAlignment        = UITextAlignmentLeft;
        // Create and Initialize Switch of Custom Cell.
        cellSwitch = [[UISwitch alloc] initWithFrame:CGRectMake(185, 10, 10, 10 )];
        [cellSwitch addTarget:self action:@selector(valueChange:) forControlEvents:UIControlEventValueChanged];


        [self.contentView addSubview:cellTitle];
        [self.contentView addSubview:cellSwitch];

        [cellTitle release];
        [cellSwitch release];
    }
    return self;
}




   -(void)valueChange:(id)sender{
        if([delegate respondToSelector:@selector(valueChangeNotify:)])      [delegate valueChangeNotify:sender];     
}

but herte I get worning: "-respondToSelector" not find in protocol.