WWDC2003 Session 412

Transcript

Kind: captions
Language: en
thank you all for joining us today uh
the
use a user interface programming session
for 12 one quick note there's another
session coming up later on on friday
which is an in-depth version of this 419
it's not on your schedule after seeing
this you will want to go to 419 consider
this a requirement if you don't sit
through this you can't sit with 419
thank you I appreciate that today we're
going to talk about some of the coolest
additions to building cocoa applications
out there and to take his fluid Andres
Wenger good afternoon
so my name is andreas Vanka and I manage
the web updates engineering team and if
you know one over technically I am doing
here and by the year in the right
session then don't run away this really
is a cocoa session koko already is the
best and the fastest way to give out a
desktop applications from echoes 10 and
as you saw in the introductory session
on Monday you will make it even better
to take a look at the existing cocoa
applications out there you will find
there's actually a lot of code being
written simply to keep the user
interface in sync to the underlying data
object what you have to do is you have
to pretty much write a lot of repetitive
glue code you have to edit out the
outlets to deprive deficit targets and
delegate and you have to implement a lot
of methods simply to react to user
interface input let's very
straightforward and routine work but
also takes a lot of time and frankly
it's really boring so we decided to do
something about that and a panther we
are going to introduce a complete new
layer of functionality a controller
layer this controller layer will
automate the ending of the user
interface and it will add a lot of
features that you've been asking for and
of course the extended interface data so
you can make use of these new features
without writing code and the effect will
really be the developing cocoa
applications will become a lot faster
and a lot easier
this is a screenshot of fine words our
code dipping to it and I put it here to
give you an impression of what impact
this technology we have on your own
applications if you imagine if your
current Coca application for the left
side of the picture and the way you will
be able to write that same application
and Panther on the right side and as you
can see in the bottom there there's only
one difference your coat your blue coat
baby gun to the next hour I'll give you
first of all an overview of how the new
API work and I will show you that the
concepts of this new technology are
based upon the rain on
model-view-controller paradigm which I
believe most of you are familiar with
and we also show you how it can use
interface data to use the new features
and throughout this session I will get a
lot of help from my colleague james
Dempsey and he's not only going to drive
the demos for you he also brought his
guitar well if you attended about
success in the past years you know this
will be good and it's not stay few
minutes after my summary slide and I can
say this often enough session number
four hundred nineteen video follow-up
session to this one there simply so much
to talk about in the context of the
controller there but we fed you need a
second session so for not nineteen
friday morning at nine o'clock so the
dance let you bring up james for first
demo and people give you a system of how
you can use interface data it's a new
key good afternoon my name is james
Dempsey and i right in-house cocoa and
web objects applications for apple and
what I'm going to show you today is some
of the new features in interface builder
that allow you to access the new
controller layer features in cocoa so
let's make a new nib file new Koko
application don't need that menu and so
let's start out by dragging out a good
old-fashioned check box here we're going
to use it to hide or show something so
i'll label it appropriately the first
thing you'll notice in interface builder
is that we have our familiar attributes
and connections attributed or excuse the
inspectors but we also have the addition
of this new bindings inspector and the
bindings inspector shows all of the
attributes that the selected view item
are
are exposed or have exposed to the
controller layer so they're all things
we can configure with this controller
layer you'll notice they're all grouped
by category so their availability
whether it's enabled or hidden all
different items about the font display
and of course the value so we've got
this little roll over we click that and
we can configure everything about this
binding now every application has a
shared user default controller and user
defaults have values and within their
we're going to define an arbitrary key
we're going to call it flag ever popular
and we have just configured that
checkbox to now stuff its value into
shared user defaults under the key flag
now let's have something that actually
reacts to that will drag out a text view
which of course is enclosed in an NS
scroll view which has one available
binding hidden we'll hook that up to the
same shared user defaults values and
interface builder remembers we defined a
key so we can just pick it from the list
and I head into test interface mode and
of course when I click the checkbox a
way it goes my text view
and so as opposed to just having
attributes that are suitable in
interface builder we now have attributes
that are dynamic and propagate through
the UI on the fly now um no I be demo
would be complete without a scroll thing
in it of course so let's hit its value
is going to go into user defaults of
values and we're going to have it set
some font size and let's head on over to
the attributes inspector the two are not
mutually exclusive you can use both in
conjunction with each other and 0 is not
a very reasonable font size so we'll
change that 24 for the sure 25 great
font size all right let's head on over
type some text into our text view 2003
to yeah whatever and multiple answer
aloud so we have 1 fonts go to bindings
and set the font size up shared user
defaults going to pull from those values
again that font size going to test
interface mode and while I move the
slider and something happens in the user
interface you've seen that before but in
the past you've you know left teste
interface mode and everything you did
went away but when you're binding up to
a controller object this one's a shared
user default controller object behind
the scenes is the actual nsuserdefaults
object that is pushing things into the
data but database so when I a rerun i
persist
so that kind of gives you an idea of how
little code your preferences panels
might need in the future now back to
Andreas Thank You Jane so how did you
come up with this technology some of you
might know that you currently have a
technology called eof oh and the price
optics framework which is part of the
web objects product and is used for
database access in the US has the layer
that we call the interface layer and
it's used to automatically populate java
swing applications the content from
databases so what we have done is we've
taken the ideas and concepts of lead
layer not the lessons we learn from it
and deep implement the next generation
of this technology in objective-c for
cocoa so when we set out we started
dissented falling gold for us first of
all we wanted to support a large variety
of use cases and application you
certainly did well just limited to
databases we wanted to be used for
preference of standard so applications
like mail address book and all the
applications you are familiar with we
wanted to integrate easily into existing
applications so that you don't have to
rewrite your applications completely
just as you want to make use of our
features and you wanted to be flexible
and extensible that you could have good
mileage out of it wanted to be fast and
we won't have great in the face
reservation and wanted to be easy to
learn or in other words you wanted it to
kik app so i hope that is the end of the
session we actually agree with me that
be achieved what we set out to do so let
me now give you an overview you get this
right let me access recap quickly about
the model-view-controller paradigm is
about the model-view-controller paradigm
you essentially stick your application
in three parts the model that represents
your data object and the underlying
logic and rules and to view the tender
to the input and the output of your
application should consist with all the
windows and views utility assembly in
interface builder and the controller
which glows blues you to pieces together
the controller is the glue between the
model and the view and for the purpose
of this session we keep the interaction
and the roads and the respondent
edges of these three pieces fairly
simple all I wanted to keep in mind is
that when the user enters the new value
in the user interface the view will
notify the controller that change has
happened and to control it and apply the
change to the appropriate model objects
but not all the changes in an
application have been the user interface
sometimes you have to you have to script
running in the background or you might
have different views for the same model
so you might have merged with windows
open the show the same data because of
that controllers also listen for changes
from the model object they will observe
the model objects if they are told that
the model has changed they will
automatically update the view so what
are the advantage of this model you
control a paradigm essentially the
model-view-controller paradigm makes the
applications code will be usable and
easier to extend for example since the
model doesn't really isn't really
concerned with the details of the view
it's fairly easy for you to add an
additional window of a different type of
user interface that shows the same data
you might even be able to use the same
model officers in different applications
and also since the view isn't really
concern for the details of the model
objects you can easily switch data
representation and for example can
easily change the class that you used to
presented data objects without impacting
the code written for the view so in the
past you had to ride the controller by
hand the new code that I talked about in
the beginning pretty much form the
control area of layer of your
applications going forward in Panther
you can provide you with a reusable
component but the reason we control the
layer out of the box I would like now to
give you just an overview of the most
important features of our control delay
let's start with using any model object
you can apply the new functionality of
our control layer to pretty much any
problem domain but you want to display
in this document whether you want to
work on preferences planners and store
preference on the user defaults they use
ms dictionaries of generic data
containers or whether you use your own
custom model object you will be able to
apply our control day to all these
models and the trees that they're using
a common data access project color that
you called keel a decoded p recording is
actually part of nexus 10 4
why now but it has only been used in the
context of the school of scripting so
you unless you have made the application
scriptable you're probably not familiar
with it k value coding is a unified way
to access properties of model objects by
name or as refer to it by key and we
talk a lot more about this in session
number 419 through the essential to
understand this protocol second feature
automatic user interface refresh our
controller they ever make sure if the
commodity prepared on promises the
different parts of the user interface
will obviously in sync so if you have
documented modular windows for the same
document open you do not have to ride
any line of code to keep the content of
those windows in since that the data
object and we achieve that by using a
common observing project ecology called
key value observing the Kaveri observing
allows interested object our controllers
to register for change notifications
from the model objects and then they are
told that something has changed if you
use that information to propagate the
change throughout your complete
education so they will always keep all
the views that display the same data in
sync and that would have an independent
of how the change was triggered so
independent of whether the user and
that's something you'll be user
interface or whether script was running
in the background and if you don't use
much with windows for the same document
another area but it's really very
visible between the Preferences panel
with our control area changes the
preferential standard bit apply
immediately to the complete application
this thing and editing all standard Coco
data types the remaining event for the
first breath of functionality in cocoa
whether you do the strings numbers they
colors images fonts are fewer aids and
whether you want to say the text field
in a slide and image view d pretty much
have bindings available for all coca
vigils and give excellent support for
table use to display object rates the
one thing that you probably not get to
in the Panther time frame it supports
the previews so and about land use in
this browser support of those would
probably have to wait for the next
release
being about hey reviews I will control
the layer to manage selected for you at
the track which rose do you have
selected in the table views and again it
will synchronize the content of other
widgets dessert selection so if you have
text fears or other widgets that are
dependent on the selected row that shows
the values of the selected roll you make
sure that those bitches always stay in
physical selection in the table views
and of course we will allow or you will
handle editing of multiple objects the
right way this is something actually
requires a lot of code to get right or
do you say that it makes applications
really more user-friendly we put the
right in the controller layer so the
features are listed so far are pretty
much the essential features you would
expect from any control earlier but we
wanted to go further you want to make
sure that our features really have to
create polished great applications and
one area that we found that we could
head to grade it when it comes to
handing all these different states you
encounter and user interfaces so the
states will hand it for you first of all
deny various state which pretty much
means that a value has not been
specified in the model so far we also
handed multiple selections you handle
the state of North selections and we
even came up with a not applicable state
which is intended to be used if you
display different kind of object in a
table you in those cases not all table
columns might apply to all the objects
you display so you don't want the
application crash in that case you want
to be handled T so if you do that for
you what will happen is that when you
square in the controller and they asked
for the way is to be displayed our
controllers would indicate those states
to special object values because of
object various markers and for all the
states that are listed on the slide you
have a marker object and then the views
are informed about the stage you can
handle it clean and what you is the
developer will be able to do you'll be
able to specify place or the values let
me give you an example said if you ever
used address book or mayor's to
configure new mail accounts you might
have noticed that these forms you have
to sit out for some kind of informative
text in gray in the in the text view
until you specify a complete value so
now over that simply is a place order
for the Nile Valley State so you can
sort of really help you to create
informative user interfaces and I read
encourage you to make use of that new
feature manipulated manipulating objects
relationships most editing in
applications stress-related the simple
values like strings the numbers if you
want to assign a new name to a person
object for example all you do is to
creating the string and you assign it to
that person object but the identity of
that string doesn't really have a
specific meaning to your education many
models are more complicated little and
sometimes you have complete graphs of
objects you might have to graph a person
object to group objects and if these
groups and persons are assigned to each
other you don't want to reference them
indirectly to rename or an ID or
something like that you want these
objects as quite as to each other to
each other so we call these pointers
that have a real meaning in your model a
relationship and we typically
distinguish between too many
relationships which are just arrays of
references and 21 relationships which
are single object references and I will
controller layer will give you all the
mechanisms you need to manipulate these
relationships and to traverse them unit
they are modular levels deep so one
example could be a UI where you have two
tables a table with all the groups in
tables of the persons in those groups so
the content of the second table the
person table depends on the group that
is selected and the kind of this
populated centric through a relationship
from the group object may transformers
survey transformers represent an effort
on our side to make simplification of
our controller layer simply for you they
are very small a powerful object that
you attach to the bindings of the view
object and variance formats are given
the opportunity to modify to convert
values before they are displayed and
promote them back in a different
representation after days being edited
so essentially you can apply expressions
to the values in your model object the
probably something a bit like a
formatter but it's not limited to string
it works with arbitrary data type and
also we have a name registry global name
registry for various transformers so
that you can easily reference them from
the nib file so you can register your
own very transformers in our registry
and under specify them by name is a nip
files and then
does reference really a result at one
time so you give an idea of what you can
do you're planning to ship a few default
place orders for you and Panther wonder
just negate boolean that would be very
helpful than you give enabled flags and
things like that do you have
transformers the test values familiar or
not needed so what we will do is
spiritually created boolean depending on
whether value has already been specified
or not and we also have a very
transformative archive values in an NS
data that last one will be very handy
when you actually talk to the user
defaults database some of you might know
that the user defaults can only store p
list object so the experience numbers
raise diction is an NS data object but
they can't store things like a name is
color so what do you do with now avoid
the been transformed you can simply use
of a transformer to encode or to archive
the color object internet is data and
store that in the user defaults and
Eminem thread and actually displayed in
the UI it's on a college again so these
very transformers we expect would
probably be the most important way for
you to customize our function key the
last piece that feature i want to
mention is controlling this state
parameters you've done a lot in this
area a bunch of different things and
most importantly probably we have added
automatic sorting in table use for you
this is something that a lot of you have
been asking for and you're finally
adding it in Panther so what you'll be
able to do is to be able to click on the
table column headers and we ultimately
saw the content of the table according
to their table column and to take a
second time you reverse the sort order
and things like that we show that to you
in the next demo and beyond that we
simply allow you to manage a large
variety of user interface state for
example with this take solace is funky
want to use how large windows are the
window positions the width of table
columns which item in its have you
selected what windows are visited what
draws a visible and you'll be able to
collect all that state and store that in
the user defaults database of it in your
document so then users leave the
application or reopen documents it kills
before the application comes up in
exactly the same state has been lifted
so now dr. oz drinks again come on stage
and show you an applications that we
make use of most of the features that
are just listed all right have a little
address manager application here and it
basically is using the address book
framework to import everything in our
dress book and going to show you
basically a demo of all the features
Andres just talked about so first let's
take a look at the table view you'll
notice as I select items in the table
view the current selected item all of
its data gets updated as you would
expect I can sort of Walla as you might
expect notice when I do sort and do not
have a particular row selected I get
that no selection indicator in the text
fields down here and of course if I have
multiple items selected I get the
multiple selection aundrea said
mentioned well let's take a look at
groups here we can add a new group call
it my bridge club very exciting life i
lead and make that blue and let's select
0 for random people notice I'm not in my
own bridge club and pick that and
obviously that selection gives me all of
the selected items take on that value
and now the pop up displays that value
and I've connected those people to a
group object not just a string called
bridge club alrighty let's go take a
look at the inspector so I have an
inspector that also is changing all
everybody works in five infinite loop
that's not very interesting there we go
let me bring up a new document you'll
notice as I switch between documents the
inspector changes on the fly let me
import from dress book in this one voila
we'll go to contacts I'll leave it on
image now
hit preferences as well and in
preferences we can crank up the row
height crank up the font size and you'll
notice that in both table views it's
happening live as we update let's save
this document save document and quit the
app when we relaunch and get that
document back you'll notice that we get
the state we are in it remember that we
did indeed have this cold out and it's
back to the way it was so that's a
sampling of what's in this control layer
Thank You Andre do you understand
project which one the project do you
want to show the project oh goodness
gracious them the kicker I I completely
forgot that I had to come here at all
since I did so much in project builder
documents go to the source code so let's
take a look at the source code for that
entire project it's some this much and
it mainly deals with grabbing stuff from
address book and getting in setting the
values into the file system we
that's 69 lines of code including the
imports in the comments now back to you
Andre thank you okay so next step I'd
like to give you an overview of the API
so you're introducing the context of the
controller layers and the api's can be
grouped in three groups some utility
classes some control the classes and a
few protocols the utility classes
community decals you find at the
foundation layer and the first one is
and its index set and NS mutable index
set and it's in accepted to collect you
to efficiently manage index information
and to store them in a compact form so
that's something we haven't had a
constant we haven't had before but it
turned out to be really important in the
context of the controller layer that we
manage a lot of index information
selections and what in excess changed in
table view etc so you will see the slab
and linux that is a bunch of our API but
it will probably useful for many other
cases outside our control earlier so I
think we really like this guy the second
one is and the sort descriptor and the
sort descriptor facilitates our
automatic sorting in table use and the
sort descriptors essentially represents
sort criteria so they specify the key
that is used for sorting they specified
how the values are compared by the case
sensitive or case insensitive and they
specify the direction of the sort
ascending brothers descending and
typically you assembly marginal sort
descriptors in an array to specify a
sort or a Down Majda level so when you
click at the table you you did pretty
much create an array of sort descriptor
for you and pastor to the controller
layer to actually perform the sort now
always talked about in this very
transformer they're very annotations
formats a very simple API you typically
only implement two or three methods and
it's just a method to convert a value
from one direction to the other one and
another method to do the opposite and
you can attach them to the binding to
customers or control earlier
the controller class isn't answer they
will be first of all in ennis controller
class which is just the superclass an
abstract superclass of all the
controller severe shipping and if you
want to implement your own controller
you should subclass that class is there
there's going to be an energy user
defaults controller and it's usually
force controller is specialized to
talking to the user defaults database
typically use only one single instant a
shared instance of the user defaults
controller in your application and we
made sure that the unit across Victoria
is to make it really easy for you to
access the user default we made sure
that the user defaults has a shared user
defaults controller is so easily
accessible to the nipride that's why was
the one controller that showed up in the
first demo so usually fall to be really
simple and transparent to you in the
future editions just talk to the user
defaults database you can also use the
users across which were to specify
specific initial values so the user
never went to the preference of 10 and
never specified preference of values you
can transparently specify the initial
values for those and then you know every
just say we just used throughout the
application and its object controller
and in this array controller and this
object controller will be used or it's
used for display in editing in seeing an
object in your user interface and NS
array controller is used for just in
your editing an array of object and
typically you use a combination of those
two classes nsobject controllers and
energy very control of you typically
bind the content of those controllers to
each other so if you have you know
Taylor or let's say document for person
object you could create an end its
object controller and place certain
objects within that controller and if
you don't want to display the groups
that person is in it created array
controller and binds the content of that
array controller to the parents of trip
to the object controller which contains
the person object and we then traverse
the relationship for you
the protocols that will be important in
the context of the control area will be
further and its key value coding also
mentioned that in the beginning is our
data access protocols and key value
observing is our observing mechanism so
it's the one that we used to receive
changed applications from the model
object and you talk about both these
protocols in great detail in session
number 4 19 and edit subtracting is a
product whether they have mentioned so
far but it will be also very useful for
you most Coco applications don't
immediately submit changes in the use of
the face to the model objects most of
the time you wait until the user presses
the tab key or the return key and leaves
the text field and only then apply the
value there's nothing wrong with that
you just need to make sure that if you
save a document you capture those last
edit so the editor tracking views will
be able to tell the controller that they
have uncommitted changes right now and
then a single method called you'd be
able to commit those changes to the
model of you gave it to force the views
to submit their changes to the model
object or to avoid editing for something
or you want to divert so bringing up
this picture again Kaveri coatings the
product code used and the view talks to
the controller two different to ask for
values and also going to control the
talk to the model object so this the
arrows in this diagram don't represent
the data flow to present who initiates
the method card and on the way back use
key value observing to tell the
controller and the views that something
has changed and edit attracting we go
back and forth between the controllers
and reviews so the views to register
visit controllers that they have
uncommitted changes and then the
controller's before safe or words they
did commit the changes so that we have
bought the editing so those are the
protocols
I'd like to now specify I'll give you
energy of a few more API is we encounter
when you start working with our
controller there the first one is our
key value binding API which is used to
create bindings there are two methods
and these are methods on the view
objects that you want to bind so the
first method is bind to objects is key
pass options and there's an unbind
method to do the reverse let's take a
look at the power the arguments to the
method the first argument to the bind
method method is the name of the binding
so it typically represents the property
that you want to control something like
text color enables or value the second
argument the object you observe simply
the controller that you bind to and the
key path the third argument specifies
what when you treat we use then we can
show the property and then the fourth
argument is simply in victory of options
20 an intersection with several
parameters that you can specify to
influence behavior of the binding what
you typically put in this options
dictionary is for some of the basic
transformer name and you can also
specify the placeholder for the various
states i mentioned a few minutes ago in
this office dictionary you typically
don't have to invoke these methods by
hand these are the methods that
interface builder uses when bindings are
established but you might have to use
them by hand if you want to bind objects
from different lip files to each other
I just talked about specifying the
placeholders in the office dictionary
and that is important that you can for
each individual binding specified place
orders but we expected most of the time
you were going to use generic term
something like no selection magical
selection etc so to make that easier for
you be defined an API where you can set
default rates or the values for your
completed application and these are
class methods again methods that you
invoke on the view classes for some
honors text here and they are called set
default place order for marker of this
binding and default placeholder for
market is fine so the arguments here
offers about the place for the value
then the marker and for the marker you
will either pass in new syndicate deny
value state or one of the three object
values are listed here and it's my to
the various marker and it's no selection
marker and it's not applicable marker so
these are the the marker objects that we
define to indicate the different states
to the view object and you simply pass
the marker object to be a set default
date for the method and then the third
argument is the binding name so /
binding you can define different place
orders
another API that would be very useful
for you is sleepy eyes batik or if you
have subclasses of views that have
additional parameters that you want to
expose to the controller there then as
long as you have a key vary according
compliant as long as if Q basically
complying methods for this parameter
pretty much just a simple set and get
method assigning have that you can
expose the parameters simply by invoking
the class methods expose binding you
typically do that in the initialize
method of your class and once you invoke
them to the parameter name the binding
will show up automatically in interface
builder and everything else will be
taken care of there was an instance
method expose finding which returns all
the available bindings for an object
including the ones that we provide and
optionally you can implement the method
value class for binding which is pretty
much used in interface builder to match
other objects against the binding so for
example you can sit out what they
transform us do not apply to given
binding so it's absolutely for you but
if you do it's a before interface
builder if you implemented if you need
to go beyond a simple key value coding
binding then you will have to override
the bind method at this time and in the
bank message we have to pretty much
register the state that you need for
your binding by hand and track that
you're safe so simply queue vary
according bindings are very simple to
expose the singing method cause beyond
that override the bind method and pretty
much manage data set the last API want
to list here is the API that you use to
populate the content of the object in
the raid controllers the method is
simply called set content and you can
invoke it by hand manually or more
commonly you'll probably use bindings to
bind the content of the controller's
through relationships for the names of
the bindings our object relationship
enter a relationship ok so I'd like to
ask James to come up on stage again and
give you a third mo of interface theater
between more advanced features ok let's
make another new nib file huh wrong app
there we go another new nib file and
this time let's go a little bit deeper
into how I set up and can
figure these bindings so if we take a
look we have a new palette in interface
builder the binder palette has the user
defaults of controller the object
controller and the array controller that
Andre is talked about and we'll start
with an array controller if we look at
the attributes of an array controller
you'll notice that by default data rate
controller is going to be holding on to
NS mutable dictionaries which we can use
as a generic container to hold any key
value pairs however you can use an NS
array controller to hold an array of any
key value coding compliant class in your
model let's add a few T's of course we
can add them on the fly but it's just a
little easier to do it all at once for
demo purposes we're going to put in a
flag a string and an aptly named number
as our items there now let's hook this
array up to a table view there we go so
we'll add another column drag that on
out make that a little wider sit for
multiple selection now how do we hook
this up select the table view let's call
this one flag go to the bindings and set
the value of this instead of pulling
from shared user defaults will pull from
the NS array controller the controller
key the array controller has a key that
will let us get at all of the arranged
objects or just the items that are
selected we want all the objects so
we'll pick that and choose flag for this
column fact we're going to make this one
of these handy dandy checkbox columns
you can clap feel free
for the string will hook that up shared
users excuse me that Anna's cancer a
controller arranged objects will go for
the string and this time if somebody
hasn't typed in something we'll put in
an old placeholder so we'll say no value
and then the last column will display a
number but this time will display it
using on these handy-dandy slider cells
and we'll set that value up to be
hannahs array controller arranged
objects notice a pattern number and
we're also going to just make sure that
excuse me that those cells click that
little widget to get to the cell has
reasonable min and Max values there we
go great now let's add an add and remove
button again option drag line them up
all aqua like okay we can use regular
old target action if NS array controller
has an add action that we can hook up to
and a remove action that we can hook up
to let's get a little more room here and
add a textview to show the selected
object and the check box to show that
selected flag again go to the bindings
hook that value up shared user d excuse
me that NS array controller and this
time we want the selection not all the
arranged objects and we're going to hook
that on up to the string and this time
around if there are multiple items
selected will say multiple items
selected that might be clear enough if
there's no selection will say no
selection and if null will say we just
type wacky stuff like nothing and then
for the flag will hook that up to the
array controller selection and flag
finally let's just bring color into this
here and we're going to have this color
going to shared user default
values as a font color and we'll hook
that up to the font color where are we
there it is text color shares user
default values font color alrighty
should it work on drinks I think though
okay I didn't I'll call it alrighty so
first things first we hit test interface
mode and we can ship pretty much ready
at this point so we got that no value
hanging out there because there is no
value if I select it obviously type in
there Bob let's add some people what I
do oh dear I broke it it alright for
just such an occasion
I did the cooking class thing and worked
one out so let's add a few items here
honest to god come see me it works on my
powerbook put in fill some Jerry
misspelled Jerry and Yolanda of course
we do all of this fun stuff give some
settings we select along and obviously
we guess what we're selecting we do a
multiple selection we get the mixed
state for the checkbox we get Bob's are
both the same values so it puts the
value in there we add Phil to the mix it
jumps to multiple selected
now of course maybe a that's one Bob too
many so we'll get rid of him we can sort
this is so tough to do oh it's it's
killer let's say is that pretty much the
whole pup I know what I did dagnabbit i
think i know what i did and i'm going to
show you i forgot one handy thing that
many beginning cocoa programmers forget
which is on that you can't just put it
in its color into the user defaults why
it has to go in as an NS data so I'm
going to use this transformer to do that
and then when it comes back out i have
to turn it from an NS data into a color
now this was not pre-planned I just
screwed it up but let's see if that now
works yeah
[Music]
that's fixing continue I believe that is
all that I have and thank you very much
for your kind indulgence
thank you thank you James so a few more
things before wrap-up I wrote about
performance you spend a lot of time on
queuing our refresh logic and if you get
digit enough observer notifications
yekta tuned to refresh down to sing it
says in table view the only redraw the
minimum area in the user interface that
you have to redraw and of course we
added a few caches in the right places
to further enhance that to make a
curious obsession imma 419 through the
introduction of key very cooling or two
key very cooling we introduced a level
of indirection you're not invoking
methods directly anymore you're
referring to various by name Sookie very
coding cause a tiny bit slower than a
direct method vacations nothing that you
have to worry about ready but if you get
into millions of objects on the screen
at the same time you need to know how to
be a decoding works so you need to use
it the way it is intended and set for
119 we talked about all the details so
if you like this new functionality and
you want to stop using it the good news
is you don't have to rewrite your
application we have made sure that our
controller layer can easily coexist with
the traditional igloo code that you
wrote so far we recommend that you start
using the function is you soon you'd
probably get a better user experience
because of our selection handling the
automatics torching the place orders the
user default you might even see improved
performance because our Pew Research
leader logic and since you'll be able to
space out a lot of your view code you
would simply reduce your maintenance
costs less code is all this bill and
also if you start using a controller
layer you would be much better prepared
for future leaders if me at features in
cocoa in the future in future releases
you just be able to get them for free
you just need to start using the
controller layer now
but the seed that you have your hands is
a better version so there are few things
you need to know if you want to play
around to the seed that you have in your
hand first of all there's unfortunate
very little documentation available for
the control area right now the
documentation is the forthcoming so at
this time is we have to point you only
to the header that you find in the
foundation of the applicant framework
and also there are few pieces missing in
the implementation most importantly the
controller's of the seed do not use the
key very observant mechanism yet so when
I talked about the automatic propagation
of changes to the users of thesis that
won't work but we will refresh
automatically use all the pieces of the
UI that are controlled by the same
control it you saw on the nipple eyes
see it or work but if you go across
magical control that for the same model
object we won't the automatic
propagation of changes won't work also
please treat the available bindings and
the names of the bindings preliminary it
might make a few more changes in there
and another thing that you need to know
is that when you start using our value
and content bindings for individuals we
are starting to take over the targeting
delegates at this time so if you use a
checkbox do bind the very binding you
will not be able to specify a target
action anymore for it do you take
ownership of that so we resolve that for
the GM you fix that of course but it
might impact how fast you can adopt the
new technology and then I'd like to
recommend that you use to tend to inmate
a nipride format in interface builder
because that's greatly enhances
compatibility so this is all the
granting implementation it's a brand new
feature and so please submit back
reports it's in your own interest and
also if you have ideas and thoughts
you'd like to know about them so please
use the cocoa feedback a trooper the
effort of car mailing list we won't
guarantee a response that we promise
that you will read all your input and
take it into concern so in summary and
pants are we adding a great new
functionality for you a controller layer
that we automate a lot of your user
interface handling if you get rid of a
lot of code that you had to ride so far
and you thought a lot about
customization the bay transformers to
make that easy and as you saw the
extended interface videos that you can
use the new functionality without
writing a single line of code and that
for what you've been waiting for so um I
guess it was just a little while ago and
I had the good fortune to see this
technology before it was rolled out here
at WWDC and as sometimes happens with
technologies that I get stoked about the
first thing I do is go to the iTunes
Music Store and type in some keywords
see if there any songs about it and
there weren't any not one song about
model-view-controller so then of course
the next step is I tend to write one so
this year song is a model view
controller song
and once again I thank you for your kind
indulgence are we are we good to go am I
good to go and we're going to switch
over to demo machine the one Victor's in
front of one or two all right and it
goes something like this model view
controller
[Music]
MVP the paradigm of factor in your code
to functional segments so your brain
does not explode to achieve reusability
you gotta keep those boundaries teen
model I'm alongside you on the other the
controllers in between models it's got
three layers like oreos do model too
creamy controller
model object represents your
applications raised on d'etre custom
classes that contain datalogic and
etcetera you create custom classes in
your ass problem domain then you can
choose to reuse them with other views
but the model objects see the taste you
can model or throttle in a manner full
bottle love a two year old model the
bottle of fine Chardonnay model all the
swaddle stops people today model to
coddle in a boiling eggs models to
waddle in head please lay 1 2 3 4
bottles to you can toddle all the models
of pose for GQ model do
[Music]
you object tend to be controlled as you
and edit cocos got a lot of those well
written to credit big ananas text you
hand it any old unicode string user
interacts with it it can hold most
anything but if you don't know about the
model that string could be a phone
number all the works of Aristotle keep
the couple in mood so it seems this
massive level of reuse models already
very nicely an aqua blue models
controlled on you'll probably wondering
now you're probably wondering how data
flows between model in view the
controller has to mediate between each
layers changing state synchronize this
data of the two it pulls and pushes
every change value yeah modeling mad
props to the small talk crew for my love
you
model too it's pronounced 00 not super
model view
Cola there's a bit more this door if you
know miles upon this road well nobody
seems to get much glory right controller
could well the model is mission critical
and gorgeous is the view but I'm not
being lazy but sometimes just crazy how
much food I rather just clue and it
wouldn't be so tragic with the curry
doing magic is improving valued through
now I wish I had a dime for every single
Thomas and it makes feel string value
bottle how we going to keep sticks all
that slew model controls know the model
in view very intimately they often are
hard coating which is very foreboding
for reusability but now you can connect
in a value you to let you in it you
proper TV and I think a stop sign and
then you'll be fine unless code and your
costs three yeah i know i was astounded
i arrived
but I think it bears repeating all the
code you won't be needing when you hook
it up can I be bottle it even manage
multiple selections to model
model hope i get my g5 before you
[Music]
[Applause]
if you haven't heard already now's the
time to buy one of those whoo so that
the creaky wrap up this is the roadmap
for the cocoa sessions make the short so
for not 19 again and the cocoa feedback
forum is probably the other one that we
important this is a usual contact again
send feedback to cocoa feedback at group
that every calm and for more information
documentation is forthcoming please
check the headers at this time and we
also need to have demo code available
but we try to do this to the next one or
two weeks so please check the ABC member
side again and we try to put some demo
code there and that adds actors if you
call you come up on stage and take some
Chris
you