how to refresh viewForFooterInSection

- (UIView *)tableView:(UITableView *)tableView viewForFooterInSection:(NSInteger)section {  

    if(footerView == nil) {
        //allocate the view if it doesn't exist yet
        footerView  = [[UIView alloc] init];


        UIImage *imag开发者_如何学JAVAe = [[UIImage imageNamed:@"update.png"]
                          stretchableImageWithLeftCapWidth:8 topCapHeight:8];

        //create the button
        UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
        [button setBackgroundImage:image forState:UIControlStateNormal];

        //the button should be as big as a table view cell
        [button setFrame:CGRectMake(100, 3, 300, 50)];

        NSDate *today = [NSDate date];
        NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
        // display in 12HR/24HR (i.e. 11:25PM or 23:25) format according to User Settings
        [dateFormatter setTimeStyle:NSDateFormatterShortStyle];
        NSString *currentTime = [dateFormatter stringFromDate:today];


        [dateFormatter release];
        NSLog(@"User's current time in their preference format:%@",currentTime);

        NSString *btnString;


        NSDate* now = [NSDate date];
                btnString = [NSString stringWithFormat:@"%@:%@",@"Update",currentTime];     


        //set title, font size and font color
        [button setTitle:btnString forState:UIControlStateNormal];
        [button.titleLabel setFont:[UIFont boldSystemFontOfSize:20]];
        [button setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];

        //set action of the button
        [button addTarget:self action:@selector(update:)
         forControlEvents:UIControlEventTouchUpInside];

        [footerView addSubview:button];

    }
    return footerView;  
}  

here i am trying to add button in footer section of view and button contain text as "Update:currentTime"-> e.g."Update:4.30 PM"

so user will understand when he did last update but now when i am pressing this button update is done in view but i want to update(refresh) text of button too e.g if i press button after 15 minutes the it sould show "Update:4:45 PM"...how to refresh this text

thank you very much

Your "update:" method will receive the button as the sender. Sender should be as an id object, you can then cast it to a UIButton * and update its text as you want like this :

void update:(id)sender {    
[(UIButton)*sender setTitle:@"NEW TEXT" forState:UIControlStateNormal];
//rest of your update code
}