iOS CGRectmake problems

[blue-lion]

I'm really struggling to understand the CGRectMake. I understand its the position of the start and size of the rectangle, but i keep seeing examples where the X and Y positioning are always 0,0 . When i would expect different objects on a view to be positioned differently all all over screen ?. sorry if this is pretty basic stuff. The example beneath is has a header and footer sections both positioned at X0 and Y0 ,when i would have thought the footer would be down the screen with a higher Y value?

are the numbers relative to the view that contains the object ?, even so, i still don't really get it?


please help

// setup our table data
	self.tableArray = [NSArray arrayWithObjects:@"Camping", @"Water Skiing", @"Weight Lifting", @"Stamp Collecting", nil];
	
	// set up the table's header view based on our UIView 'myHeaderView' outlet
	CGRect newFrame = CGRectMake(0.0, 0.0, self.tableView.bounds.size.width, self.myHeaderView.frame.size.height);
	self.myHeaderView.backgroundColor = [UIColor clearColor];
	self.myHeaderView.frame = newFrame;
	self.tableView.tableHeaderView = self.myHeaderView;	// note this will override UITableView's 'sectionHeaderHeight' property
	
	// set up the table's footer view based on our UIView 'myFooterView' outlet
	newFrame = CGRectMake(0.0, 0.0, self.tableView.bounds.size.width, self.myFooterView.frame.size.height);
	self.myFooterView.backgroundColor = [UIColor clearColor];
	self.myFooterView.frame = newFrame;
	self.tableView.tableFooterView = self.myFooterView;	// note this will override UITableView's 'sectionFooterHeight' property

 

[jiminaus]

How a CGRect is interpreted depends on what property it's assigned to or read from. Read the details on the frame and the bounds properties in the UIView class reference.

 

[xStep]

Look at Apple's View Programming Guide for iOS

Cocoadevcentral has some older discussions on the subject. Just keep in mind the origin for iOS views are opposite OS X views. That would be referred to as a flipped view in the first discussion.
Introduction to Quartz
Intro to Quartz II