多選做法如下：
- (void)tableView:(UITableView *)tableViewdidSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[tableViewdeselectRowAtIndexPath:indexPath animated:YES];

Custom *cell= (Custom*)[tableView cellForRowAtIndexPath:indexPath];

NSUIntegerrow = [indexPath row];
NSMutableDictionary *dic = [contacts objectAtIndex:row];
if ([[dicobjectForKey:@"checked"] isEqualToString:@"NO"]) {
[dic setObject:@"YES" forKey:@"checked"];
[cell setChecked:YES];
}else{
[dic setObject:@"NO" forKey:@"checked"];
[cell setChecked:NO];
}
}

在cell類中添加BOOL屬性checked和設置方法setChecked...

全選做法如下：
NSArray *anArrayOfIndexPath = [NSArray arrayWithArray:[contactListindexPathsForVisibleRows]];
for (int i =0; i < [contacts count]; i++) {
NSIndexPath *indexPath= [anArrayOfIndexPath objectAtIndex:i];
Custom *cell = (Custom*)[contactListcellForRowAtIndexPath:indexPath];
NSUInteger row = [indexPath row];
NSMutableDictionary *dic = [contacts objectAtIndex:row];
if ([[[(UIButton*)sender titleLabel] text] isEqualToString:@"全選"]){
[dic setObject:@"YES" forKey:@"checked"];
[cell setChecked:YES];
}else {
[dic setObject:@"NO" forKey:@"checked"];
[cell setChecked:NO];
}
}