1. iOS:
Custom
Views
Jussi
Pohjolainen

2. About
Views
• UIBu;on,
UILabel,
all
these
controls
are
views
• Views
is
an
– Instance
of
UIView
or
one
of
its
subclasses
– Can
be
drawn
on
applica-ons’
window
– Exists
in
hierarchy
of
views,
root
is
app
window
– Can
handle
events

3. AppDelegate
Creates
the
window,
puts
it
to
screen.
You
can
add
other
views
to
window!

4. CreaKng
Custom
View
• Subclass
UIView
• Allocate
and
iniKalize
the
UIView
• Pass
View
Frame
to
UIView
• Add
the
view
as
subview
of
Window

6. Subview
inside
of
Subview
MyCustomView* view =
[[MyCustomView alloc]
initWithFrame: viewFrame];
MyCustomView* view2 =
[[MyCustomView alloc]
initWithFrame: viewFrame2];
[view addSubview:view2];

7. drawRect
• Override
drawRect
–
method
in
custom
view
• Default:
does
not
do
anything

11. Redraw
and
Events
• To
redraw
a
view,
call
method
setNeedsDisplay
– [view setNeedsDisplay]
• To
receive
events
– 1)
Say
that
your
custom
view
can
do
that
• Return
YES
in
method
- (BOOL)
canBecomeFirstResponder
– 2)
Say
to
the
view
that
you
are
the
one
to
receive
events
• [view becomeFirstResponder];

12. MoKon
Event
to
Custom
View
• Override
moKonX
methods
in
custom
view
– moKonBegan
– moKonEnded
– moKonCancelled

13. Custom
View
Shake
- (BOOL) canBecomeFirstResponder
{
return YES;
}
- (void) motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event
{
if(motion == UIEventSubtypeMotionShake)
{
// New color
[self setCircleColor:[UIColor redColor]];
// Refresh!
[self setNeedsDisplay];
}
}

14. And
set
the
View
to
receive
events
// Create the view with given size
MyCustomView* view = [[MyCustomView alloc] initWithFrame:
viewFrame];
// Set view to become the one who is receiving events!
[view becomeFirstResponder];

15. Scrolling
• Set
view
larger
than
screen
• Draw
a
porKon
of
that
view
– Viewing
port
that
you
move
around
• UIScrollView
– contentSize
–
the
size
of
the
area
that
is
visible

16. UIScrollView
Example

17. UIScrollView
Example

18. Panning
and
Paging

19. Example

20. Hide
Status
Bar
• To
hide
status
bar
either:
– [[UIApplication sharedApplication]
setStatusBarHidden:YES
withAnimation:UIStatusBarAnimationFade];
• Or
in
info
property
list
of
your
project