Objective-C : Always display 3 rows in UITableView - objective-c

Question

After scrolling i want my TableView to display like this :
not like this :
and i have set my rowHeight = tableViewHeight / 3:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return CGRectGetHeight(self.tableView.frame)/3;
}

Answer 1

There are a couple things you need for this. Firstly, you need to detect when the table view has stopped scrolling:
How to know exactly when a UIScrollView's scrolling has stopped?
Next, you need to set the scroll view position:
How can I set the scrolling position of an UIScrollView?
The position you're going to want to set it might be the tableview contentOffset - (contentOffset % rowHeight) to move it up to show the row partially shown at the top.

Answer 2

Follow this steps:
In .h , declare
NSMutableArray *arrayForBool;
NSMutableArray *arrPastOrder;
In .m ,
- (void)viewDidLoad {
arrPastOrder=[[NSMutableArray alloc] init];
int range=1+arc4random()%10;
for(int i=0;i<range;i++)
{
NSMutableArray *arrinside=[[NSMutableArray alloc] init];
for(int j=0;j<3;j++)
{
if(j==0)
[arrinside addObject:[NSString stringWithFormat:#"Some Header %i",i]];
else
[arrinside addObject:[NSString stringWithFormat:#"Subindex %i",j]];
}
[arrPastOrder addObject:arrinside];
}
arrayForBool=[[NSMutableArray alloc]init];
for (int i=0; i<[arrPastOrder count]; i++)
{
[arrayForBool addObject:[NSNumber numberWithBool:YES]];
}
}
#pragma mark -
#pragma mark TableView DataSource and Delegate Methods
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if ([[arrayForBool objectAtIndex:section] boolValue])
{
return [[arrPastOrder objectAtIndex:section] count]-1;
}
else
return 0;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath: (NSIndexPath *)indexPath
{
static NSString *cellid=#"hello";
UITableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:cellid];
if (cell==nil)
{
cell=[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellid];
}
BOOL manyCells = [[arrayForBool objectAtIndex:indexPath.section] boolValue];
/********** If the section supposed to be closed *******************/
if(!manyCells)
{
cell.backgroundColor=[UIColor clearColor];
NSLog(#"cellForRowAtIndexPath---if");
cell.textLabel.text=#"";
}
/********** If the section supposed to be Opened *******************/
else
{
//cell.textLabel.text=[NSString stringWithFormat:#"%# %ld",[sectionTitleArray objectAtIndex:indexPath.section],indexPath.row+1];
// ic_keyboard_arrow_up_48pt_2x ic_keyboard_arrow_down_48pt_2x.png
cell.textLabel.text=[NSString stringWithFormat:#"%#",[[arrPastOrder objectAtIndex:indexPath.section] objectAtIndex:indexPath.row+1]];
}
cell.textLabel.textColor=[UIColor blackColor];
return cell;
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return [arrPastOrder count];
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"%li--%li",(long)indexPath.section, (long)indexPath.row);
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
if ([[arrayForBool objectAtIndex:indexPath.section] boolValue]) {
return 40;
}
return 0;
}
- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
return 100;
}
#pragma mark - Creating View for TableView Section
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
UIView *sectionView=[[UIView alloc]initWithFrame:CGRectMake(0, 0, 540,100)];
sectionView.backgroundColor=[UIColor whiteColor];
sectionView.tag=section;
UILabel *viewLabel=[[UILabel alloc]initWithFrame:CGRectMake(10, 30, 530, 40)];
viewLabel.backgroundColor=[UIColor whiteColor];
viewLabel.textColor=[UIColor blackColor];
viewLabel.font=[UIFont boldSystemFontOfSize:20];
viewLabel.text=[NSString stringWithFormat:#"%#",[[arrPastOrder objectAtIndex:section] objectAtIndex:0]];
[sectionView addSubview:viewLabel];
/********** Add UITapGestureRecognizer to SectionView **************/
UITapGestureRecognizer *headerTapped = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(sectionHeaderTapped:)];
[sectionView addGestureRecognizer:headerTapped];
return sectionView;
}
#pragma mark - Table header gesture tapped
- (void)sectionHeaderTapped:(UITapGestureRecognizer *)gestureRecognizer{
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:gestureRecognizer.view.tag];
//Get which section is open, from here Set the value of arrafool. and expand collapse. Normally whole table is expanded.
}
Just run it. You will get the same structure. happy Coding !!