Tài liệu Thủ thuật lập trình cho iPhone part 2 doc

Trong bài này các bạn sẽ được học về: - Create a New View Based Project Tạo một project với đối tượng được khởi tạo ban đầu là UIView - Opening the iPhone Simulator - Adding UI Elements

Bài 3: Beginner Interface Builder

Hello World

Bài này hướng dẫn cách xây dựng một ứng dụng "Hello world" bằng cách

kéo thả trong interface builder của XCode

Trong bài này các bạn sẽ được học về:

- Create a New View Based Project (Tạo một project với đối tượng được

khởi tạo ban đầu là UIView)

- Opening the iPhone Simulator

- Adding UI Elements to your home screen

- Executing the code (Cách thực thi chương trình)

In my last tutorial UITableView Hello World I said that there are many ways

to write a “Hello World” tutorial for the iPhone Here is one using Interface

Builder Last time, I demonstrated a simple way to populate one cell in a

UITableView with some text Today‟s tutorial is even simpler I will show you how to work with Interface Builder to create a simple layout for you

application In fact, you won‟t write any code at all! In my next tutorial, I will

detail how to interface with your UI components in code

In this tutorial you will learn:

 Create a New View Based Project

 Opening the iPhone Simulator

 Adding UI Elements to your home screen

 Executing the code

Create a New View Based Project

Let‟s start by opening up XCode and Creating a new View-Based

Application Do this by clicking on File > New Project Make sure that

So at this point, Apple has added some default files to get us started They

have added the main window for us to edit along with the code to launch

the window Now in iPhone terms, each window is called a View Since you

can only see one view at a time, you will need to create a new view for

each screen in your application In this tutorial, we will be sticking to editing

the view Apple has provided us In later tutorials, I will go into how to add

new views and transition between them Go ahead and click Build and Go

Opening the iPhone Simulator

The program should compile and launch the iPhone Simululator Your

screen should look something like this

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Not very interesting right? Excuse my crappy screenshot So let‟s add

some UI components to our view to make it more interesting To do this we

will be editing HelloWorldViewsViewController.xib A file with the xib

extension is known as a nib file These files open with Interface Builder and

are where you define the look and feel of your application Apple is nice

enough to have provided us with one

Adding UI Elements to You Home Screen

Once you open Interface Builder, you should see a few different windows…

You should see a blank window that has the same dimentions as the

iPhone that says View up in the top If not click the View icon in the smaller

box This is the main window we will be editing

To the right, you should see a tool box that contains many different UI

components Most of them should look familiar if you have ever used an

iPhone application So let‟s add a few of them to our view Just click on the

one‟s you want and drag them on to your view Make sure you at least use

a Label For this tutorial, I have used a Label, Search Bar, and a Tab Bar

Notice when you drag the search bar and tab bar onto the view, they size

correctly to the screen Also, if you move the items around, you will see

blue lines that guide you These are in place to help you line up

components and center them

After you have added the label, click on it Now let‟s open the Attributes

Inspector to change the text of the label To do this click Tools >

Attributes Inspector At the top of the Attributes Inspector you should see

a box labeled Text If you don‟t click on the label again to select it Put

whatever you would like the label to say in that box I put “Hello World”

You can update other properties of the label including color and font using

the Attributes Inspector You may need to resize the Label to accommodate

your new text To do this click on the label and you will see little boxes

around it that you can drag to resize the text area

After you are done, your interface should look something like this:

Now press Apple-S to save this file We are done with Interface Builder so

you can close it Your application should now be ready to execute

Executing the Code

There you have it! A simple iPhone application without writing a line of

code If you click in the search box, the iPhone will automatically pull up the

keyboard Thank you for reading this tutorial and I hope that you have

learned something In my next tutorial, I will show you how to use code to

interface with our UI components If you have any questions, feel free to

leave them in the comments Happy iCoding!