Objective-c – Loading a Nib within a Nib

iphoneobjective c

I am new to interface builder and I would like to have a screen which contains a 3×3 grid of a UIView each of which contain a UIImageView, and 4 UILabels.

My logic is probably flawed but the way I am trying to achieve this was to:

Create a UIView Nib file MyUIView.nib and layout in IB with an imageView and 4 labels
Create a UIView subclass called MyUIView.m which contains 1 IBOutlet UIImageView and 4 IBOutlet UILabels. Link the MyUIView.nib and MyUIView.m as files owner and connect the outlets.
Then create another nib MyGridViewController.nib which has 9 MyUIView in it laid out in the 3×3 grid.
Create a UIViewController which has 9 IBOutlet MyUIView and connect them via Interface Builder.

Is it possible to load a nib into another nib graphically from within InterfaceBuilder, if so how do I do it? Do I drag a "standard" UIView onto the canvas and then change the class to be a MyUIView?

Or do I need to do this all programmatically within the MyGridViewController.m with something like:

for (int i=0; i<9; i++)
{
    NSArray* nibViews =  [[NSBundle mainBundle] loadNibNamed:@"MyUIView" owner:self options:nil];
   [myViewArray addObject:[ nibViews objectAtIndex: 1]];
}

The only other way I have gotten this to work was to have a single Nib and put 9 UIImageViews and 36 UILabels but this obviously is a pain when I want to change something as I need to update each one of the 3×3 "cells". I thought it would be easier to change it in one file and all 9 would be updated.

Best Answer

You cannot do it in Interface Builder.

What I would probably do is to make a custom view, say MyGridItem, that loads MyUIView.nib as a subview when it awakes, and then use 9 of them in your MyGridView.nib.

Be careful with awakeFromNib, as it can be called twice if the view is involved in the loading of two different nibs (eg, if MyGridItem is the owner when loading MyGridView.nib, then MyGridItem awakeFromNib will be called once when it is loaded as part of loading MyUIView.nib, and once when it loads the MyGridView.nib.

Also, since you're loading the nib 9 times, you may want to cache the nib once using

NSNib* theNib = [[NSNib alloc] initWithNibNamed:@"MyGridItem" bundle:nil];

load it with:

if ( [theNib instantiateNibWithOwner:self topLevelObjects:NULL] ) {

You then may want to deallocate it after you've loaded all nine subviews.

Related Solutions

Ios – How to load a UIView using a nib file created with Interface Builder

There is also an easier way to access the view instead of dealing with the nib as an array.

1) Create a custom View subclass with any outlets that you want to have access to later. --MyView

2) in the UIViewController that you want to load and handle the nib, create an IBOutlet property that will hold the loaded nib's view, for instance

in MyViewController (a UIViewController subclass)

  @property (nonatomic, retain) IBOutlet UIView *myViewFromNib;

(dont forget to synthesize it and release it in your .m file)

3) open your nib (we'll call it 'myViewNib.xib') in IB, set you file's Owner to MyViewController

4) now connect your file's Owner outlet myViewFromNib to the main view in the nib.

5) Now in MyViewController, write the following line:

[[NSBundle mainBundle] loadNibNamed:@"myViewNib" owner:self options:nil];

Now as soon as you do that, calling your property "self.myViewFromNib" will give you access to the view from your nib!

Ios – Correct way to load a Nib for a UIView subclass

MyViewClass *myViewObject = [[[NSBundle mainBundle] loadNibNamed:@"MyViewClassNib" owner:self options:nil] objectAtIndex:0]

I'm using this to initialise the reusable custom views I have.

Note that you can use "firstObject" at the end there, it's a little cleaner. "firstObject" is a handy method for NSArray and NSMutableArray.

Here's a typical example, of loading a xib to use as a table header. In your file YourClass.m

- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
    return [[NSBundle mainBundle] loadNibNamed:@"TopArea" owner:self options:nil].firstObject;
}

Normally, in the TopArea.xib, you would click on File Owner and set the file owner to YourClass. Then actually in YourClass.h you would have IBOutlet properties. In TopArea.xib, you can drag controls to those outlets.

Don't forget that in TopArea.xib, you may have to click on the View itself and drag that to some outlet, so you have control of it, if necessary. (A very worthwhile tip is that when you are doing this for table cell rows, you absolutely have to do that - you have to connect the view itself to the relevant property in your code.)

Best Answer

Related Solutions

Ios – How to load a UIView using a nib file created with Interface Builder

Ios – Correct way to load a Nib for a UIView subclass

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