MeViewController and SuperClass Part 10

Loading...

From the course by University of California, Irvine

Toward the Future of iOS Development with Swift

71 ratings

University of California, Irvine

Toward the Future of iOS Development with Swift

71 ratings

Course 5 of 6 in the Specialization iOS Development for Creative Entrepreneurs

An introduction to the Swift programming language. This will prepare you for more extensive iOS app development and build a foundation for advanced iOS development topics. Upon completing this course, you will be able to: 1. Associate the relationship of Swift and Objective-C and their use in iOS and Mac (OS X) programming 2. Develop the ability to read and write Swift code 3. Distinguish how both programming languages can be used together in applications 4. Demonstrate how to write applications entirely in Swift with the help from several iOS programming samples 5. Determine how Swift can be used for development on new platforms such as Apple Watch and Apple TV 6. Create a working client-server iPhone application with location services that you can add to your portfolio.

From the lesson

iPhone Applications and More

In this last week of the course, you will follow along and create a more full-fledged application called HoBshare. This is a more complex application that is intended to help you use many of the different techniques and language features introduced in the previous weeks and see how they can be used as tools to develop an application. We will also explore some of the new and exciting consumer technologies that developers can now work with using Swift.

MeViewController and SuperClass Part 18:04

MeViewController and SuperClass Part 26:17

MeViewController and SuperClass Part 311:15

MeViewController and SuperClass Part 415:21

MeViewController and SuperClass Part 57:34

MeViewController and SuperClass Part 66:15

MeViewController and SuperClass Part 78:36

MeViewController and SuperClass Part 86:16

MeViewController and SuperClass Part 96:17

MeViewController and SuperClass Part 1011:42

Meet the Instructors

Justin-Nicholas Toyama
UCI Extension Instructor
Lead iOS Developer at Smilefish Corporation
Frank Ayars
UCI Extension Instructor
CTO and Director of Software Development at Smilefish Corporation
Ralf Brockhaus
UCI Extension Instructor
Founder and CEO at Smilefish Corporation

[MUSIC]

All right, let's return to the submit function inside of me view controller.

And so now that we have gotten our user back and

we can get the hobbies out of that user

that the server returned to us.

We also get back a user ID with that returnUser,

that's the whole point of creating a new user or signing in so

we have a user ID which we can use to identify

us when we ask the server to update our information inside of the database.

So we also want to cache that user ID into NSUserDefault so that it's available for

other classes in our application to use when they need them.

For example, the edit hobbies view controller will need our user ID in order

to tell the server edit the hobbies for a user with the ID such and such.

Again, we need to do the same thing and register a default value for

the current user ID key inside of NS user defaults.

So let's go do that, too.

All right.

Again, I check if there's nothing in that key yet.

Then I set an empty string as the value for my CurrentUserId field.

And then we say, synchronize.

Store that in there.

All right, let's go back to our submit function and finish that up.

So if we got our return status code

of zero that means everything went well.

The server gave us back our user and now we can save our hobbies and

save our user ID so that it's ready for use.

But what if something bad happened?

Let's go, we want to show the user hey,

the server is telling us something bad happens.

So let's display that to the user.

So if that's the case, then status.code will, oops.

Status.code will not equal 0.

So I can just say else, and then it would be nice to have some

function that will help us show errors where ever we need to in that application.

because a few lines of code to show something on the screen when an error

happens, so rather than typing those lines of code over and over and

over again, let's factor them into one function, and

then call that function whenever we need to show an error.

So let's go do that.

I'm going to implement that in the super class, hobby share view controller,

that way all of the subclasses can use it to show errors when they need to.

All right, so here we are inside of how user view controller and

we will implement this function called show error which takes

a string that contains the message that we want to show in the error.

So we'll say let alert equal UI alert controller, and

we'll use its init with title, message, and preferred style method.

So the title will be the app title.

So rather than me typing the app title everywhere and possibly misspelling it in

one place, let's save that into a constant so that we only have to type it in code

once, so if it is misspelled, we only have one place to correct the misspelling.

So I'm going to create a new file over here, called constants.

So I'll say new file, and I'll just this time create a new swift file and

call it constants, and create it.

Save it in the default location.

And here I will just say let kAppTitle

equal hoBshare.

All right so now if I go back to where I was trying to use

we'll notice that the error is resolved.

So the title will be the title of the app.

The message will be the message that was passed into us by the show error function.

And the preferred style will be dot alert.

All right, so now we need a way for the user to dismiss that alert so

that they can go on with whatever they want to do in the application, so

let's add an OK button.

We do that by adding on a UI alert action

to the UI alert controller which is called alert in our case.

So we say let OK action equal UI alert action, again in it with the title

dismiss, the style of this OK button should be the default style,

and then we have this handler argument which decides after the user, excuse me,

which we use to express what should happen when

the user actually taps that Dismiss button or the OK button as we're calling it.

So that's what this handler function is, and

you'll notice again it's another trailing closure.

So we'll say when the user presses the action button, and

by the way that action button is returned to us inside of the argument

of this closure, in case we need to look at it.

But we'll just say alert.dismissViewControllerAnimated true,

and we don't need anything to happen after the alert goes away, so we say nil for

the completion argument here.

So now we need to actually add that okAction into the alert itself, so

we say alert.addAction, the okAction.

And now we can show the alert on the screen now that it's set up.

So self.presentViewController.

We want to present the alert in animated fashion so we set this to True.

And once the alert gets onto the screen, we don't need anything else to happen

until the user presses the OK button so the completion can be nil here.

So now we have a nice function that will allow us to show alerts anywhere we need

to and if we return to the submit function on our meViewController,

remember, here we're trying to create a user or sign in.

So if something bad happens, we fall into this else and

then we'll call that showError statement.

What error do we show?

We want to show the error that the server told us happened so

luckily on the SFL base model class helps us look at that through

the status.statusDescription object or property.

So we can just pass in the returned user.status.statusDescription

which is a string into the showError function and

we'll see what the server told us went wrong on the screen.

Okay, so that finishes up our submit function.

We have a little error here because again, we haven't finished implementing our

user model on this initializer.

Let's go just quickly touch up the text field should return function.

We said if validate equals true, then call this admit function,

which we just finished implementing.

But what if validate equaled false.

We should show an error to the user and say hey,

you need to correct this, you need to correct this form.

So we could do something here like say else,

self.showError("Did you enter a user name?") and

this will help guide the user to correct the form

if they did something wrong before trying to submit it.

Okay, so now we have our form validation.

We have our submit function which we'll

ask our data provider to go call the server for us.

So we're pretty much almost ready to go actually and

make the call out to the internet.

We know that this will happen when the user pushes the return button

on the keyboard, but it would be really nice to have a very obvious submit button.

So let's go and add one now.

And I'm going to create this function

as an IP action that can be called when my Submit button gets pressed.

So, this is going to be called saveButtonPressed, and

we're going to say the same thing, if validate equals true,

then submit and it looks like I need one more curly brace here.

Okay good.

So now all we need to do is go put that submit button into our UI because we

haven't done that yet.

So let's return to our Main.storyboard.

Here it is.

And, go to our Me function.

And now I want to add that Submit button.

A nice place to do it will be up in this navigation bar in the top.

So we'll open up our Archive Office Library.

And this time we're going to look for a UI bar button.

So I'll drag that out into the navigation bar.

We don't want to use the regular button.

We want to use the bar button item, okay?

So we'll double click on this and make its text be the word submit.

And now, we can use the assistant editor again.

If I select this yellow object that represents our view controller and

set this to automatic, then we should get to the new view control class,

and I can, while holding down Control on my keyboard, drag

from that new submit button we created to the save button pressed function.

So now, when we type in our username and hit the submit button here or

again tap the return button on the keyboard, it will go and

ask the data provider to make the call to the server for us.

[MUSIC]

Explore our Catalog

Join for free and get personalized recommendations, updates and offers.

Coursera provides universal access to the world’s best education, partnering with top universities and organizations to offer courses online.

© 2018 Coursera Inc. All rights reserved.

Download on the App Store

Get it on Google Play