Not able to identify the subview of TableView in Iphone - ios

Question

I added a header view with a button & a imageview but I can not Identify the Imageview for changed the Image.
My code is as follow:
My HaderView class .h file (HeaderSection.h)
#import <UIKit/UIKit.h>
#interface HeaderViewSection : UIView
#property(nonatomic,retain)UIButton *btn;
#property(nonatomic,retain)UIImageView *arrow_img;
#end
My HaderView class .m file (HeaderSection.m)
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
self.backgroundColor = [UIColor brownColor];
_arrow_img=[[UIImageView alloc]init];
_arrow_img.frame=CGRectMake(280, 15, 20, 20);
_arrow_img.image=[UIImage imageNamed:#"Arrow_down_section.png"];
_arrow_img.backgroundColor=[UIColor clearColor];
[self addSubview:_arrow_img];
btn = [UIButton buttonWithType:UIButtonTypeCustom];
btn.frame = CGRectMake(20, 15, 35, 25);
[btn setTitle:#"R" forState:UIControlStateNormal];
btn.backgroundColor = [UIColor blackColor];
[self addSubview:btn];
}
return self;
}
.h file
#import "HeaderViewSection.h"
#property (nonatomic,retain)HeaderViewSection *header_view;
.m file
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section{
_header_view = [[HeaderViewSection alloc] initWithFrame:CGRectMake(0, 0, 320, 50)];
_header_view.tag = section+5000;
_header_view.btn.tag = section+5000;
[_header_view.btn addTarget:self action:#selector(expandTableHeaderView:) forControlEvents:UIControlEventTouchUpInside];
_header_view.arrow_img.tag=section+2000;
return _header_view;
}
-(void)expandTableHeaderView:(id)sender{
[self.tblView beginUpdates];
NSInteger section = [sender tag];
UIView *view = (UIView *)[_header_view viewWithTag:[sender tag]]; //RETURNS nil
NSArray *arr = [view subviews]; //RETURNS nil
}
I don't know why this happen? Please Help me to solve this.

Answer 1

In this method you are creating new headerView. Now at this time there is no subView in headerView.
You are setting headerView.btn.tag but you did not add button in headerView, same is the case with image.
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section{
_header_view = [[HeaderViewSection alloc] initWithFrame:CGRectMake(0, 0, 320, 50)];
_header_view.tag = section+5000;
UIButton *button = [UIButton alloc] init];//set frame also
button.tag = section+5000;
[button addTarget:self action:#selector(expandTableHeaderView:) forControlEvents:UIControlEventTouchUpInside];
[header_view addSubView:button];
//Do same like image view
}
Edied:
As -(void)expandTableHeaderView:(id)sender{ } method will call only when you tap on button. Button is a subView of headerView. You can have header view by calling its superView method like this
UIView *view = (UIView*)[sender superView];
view.frame = // new frame
now view is you headerView, you can change its frame to expand or what ever you want.
You can get its subViews like this
NSArray *array = [view subViews];
for(UIView *v in array){
if([v isKindOfClass:[UIImage class]]){
//v is imageview change image if you want
}