iOS - cellForRowAtIndexPath Code Explanation - ios

Question

Here is the entire Code:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"DetailCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue2
reuseIdentifier:CellIdentifier];
NSUInteger sectionIndex = [indexPath section];
NSUInteger rowIndex = [indexPath row];
NSDictionary *section = [self.sections objectAtIndex:sectionIndex];
NSArray *rows = [section objectForKey:#"rows"];
NSDictionary *row = [rows objectAtIndex:rowIndex];
cell.textLabel.text = [row objectForKey:#"label"];
cell.detailTextLabel.text = [[self.myManagedObject valueForKey:[row objectForKey:#"key"]] description];
return cell;
}
My question is about:
cell.textLabel.text = [row objectForKey:#"label"];
cell.detailTextLabel.text = [[self.myManagedObject valueForKey:[row objectForKey:#"key"]] description]; //This is NSDate
Why is this code using two different formats: objectForKey & valueForKey?
why is there not a need to call self.myManagedObject with objectForKey?
What's the purpose of description?

Answer 1

Why is this code using two different formats: objectForKey &
valueForKey?
why is there not a need to call self.myManagedObject with
objectForKey?
self.myManagedObject is an NSManagedObject. There is no objectForKey: method for NSManagedObject.
row is an NSDictionary type. objectForKey: is a dictionary method.
What's the purpose of description?
[self.myManagedObject valueForKey:[row objectForKey:#"key"]] should be returning an object which will contain a NSString type property as description.
They just as a single line. you can split up it to multiple lines as follows
YourCustomClass *customclassObj = [self.myManagedObject valueForKey:[row objectForKey:#"key"]];
cell.detailTextLabel.text = customclassObj.description;

Answer 2

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath;
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
//create new cell
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
[tableView setRowHeight: 50.00];
UILabel *name=[[UILabel alloc]initWithFrame:CGRectMake(10, 5, 70, 30)];
name.text=#"Ajay";
[cell.contentView addSubview:name];
[name release];
// cell.selectionStyle = UITableViewCellSelectionStyleNone;
//cell.contentView.backgroundColor=[UIColor whiteColor];
UIButton *btn1=[[UIButton alloc]initWithFrame:CGRectMake(80, 5, 70, 30)];
//UIButton *btn1=[UIButton buttonWithType:UIButtonTypeRoundedRect];
//btn1.frame=CGRectMake(80, 5, 40, 30);
[btn1 setTitle:#"Name" forState:UIControlStateNormal];
[btn1 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
//[btn1 addTarget:self action:#selector(Nam:) forControlEvents:UIControlEventTouchUpInside];
btn1.backgroundColor=[UIColor greenColor];
[[btn1 layer]setCornerRadius:8.0f];
[[btn1 layer]setBorderWidth:1.0f];
[cell.contentView addSubview:btn1];
[btn1 release];
UILabel *add=[[UILabel alloc]initWithFrame:CGRectMake(10, 56, 70, 50)];
add.text=#"Biliya";
[cell.contentView addSubview:add];
[add release];
// cell.selectionStyle = UITableViewCellSelectionStyleNone;
//cell.contentView.backgroundColor=[UIColor whiteColor];
UIButton *btn2=[[UIButton alloc]initWithFrame:CGRectMake(80, 56, 70, 30)];
//UIButton *btn1=[UIButton buttonWithType:UIButtonTypeRoundedRect];
//btn1.frame=CGRectMake(80, 5, 40, 30);
[btn2 setTitle:#"Address" forState:UIControlStateNormal];
[btn2 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
//[btn1 addTarget:self action:#selector(Nam:) forControlEvents:UIControlEventTouchUpInside];
btn2.backgroundColor=[UIColor greenColor];
[[btn2 layer]setCornerRadius:8.0f];
[[btn2 layer]setBorderWidth:1.0f];
[cell.contentView addSubview:btn2];
[btn2 release];
return cell;
}