Xcode如何将界面构建器中的更改链接到实际的应用程序（代码）？

Question

I'm a newbie to ios developement. I'm using storyboards with xcode 5.1, and doing much of my designing using the interface builder.

Firstly, I wanted to know if xcode actually translates the interface builder config into (objective C) code. If yes, can such code be accessed (easily)?

Secondly, when exactly does xcode create the view? Before initwithnibname() or within some of these predefined methods? Actually, I wanted to know if for example a button which set as hidden from interface builder will be hidden when viewdidload() is called again at some point in time or not? If not, how can I reinitialise a view programmatically?

Answer 1

• (Firstly) No. It translates the "interface builder config" into instances . To put it another way, what's in the nib are instances, and you can readily see them:

   <tableViewCell clearsContextBeforeDrawing="NO" contentMode="scaleToFill" selectionStyle="blue" indentationWidth="10" reuseIdentifier="TrackCell" id="2" userLabel="Cell" customClass="MyCell"> <rect key="frame" x="0.0" y="0.0" width="320" height="147"/> <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/> <tableViewCellContentView key="contentView" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" tableViewCell="2" id="WVn-Ij-tEm"> <rect key="frame" x="0.0" y="0.0" width="320" height="146"/> <autoresizingMask key="autoresizingMask"/> <subviews> <label opaque="NO" clipsSubviews="YES" userInteractionEnabled="NO" tag="1" contentMode="scaleToFill" text="Zumalama" lineBreakMode="middleTruncation" numberOfLines="10" minimumFontSize="10" preferredMaxLayoutWidth="308" translatesAutoresizingMaskIntoConstraints="NO" id="8" userLabel="LabelTag1"> <rect key="frame" x="6" y="3" width="308" height="38"/> <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/> <constraints> <constraint firstAttribute="height" relation="greaterThanOrEqual" constant="21" id="56"/> <constraint firstAttribute="height" priority="1" constant="38" id="95"/> </constraints> <fontDescription key="fontDescription" name="Georgia-Bold" family="Georgia" pointSize="14"/> <color key="textColor" cocoaTouchSystemColor="darkTextColor"/> <nil key="highlightedColor"/> </label> <!-- and so on ... --> 

• (Secondly) I assume you are talking about a view controller's main view. It creates that view when (ie because) it loads the nib containing it, namely, when the view is first needed - either because code refers to it directly or (more usually) because the moment is approaching when it is to be put it into the interface. So, this is some time after initWithNibName: - all that did was make and prepare a view controller, which is quite a different matter. The moment itself is usually marked by (get this) viewDidLoad .

• (Actually) If the nib loads again, you get fresh instances out of the nib, unaffected by anything that happened to any previous instances that came from previous loadings of this nib. Thus loading a nib multiple times is a good way to get fresh pristine copies of a view - as happens, for example, with a table view cell that comes from a nib. But, just the other way, if you push a view controller, pop it, and push it again, all state has been lost, since this is a new instance of this view controller and its view; restoring state, if that is your goal, is up to you.