In this recipe, we will
take a look at how we can use the UIImageView class to display images within a view.
In this recipe, we will start by creating a UIImageView object that will be used as a container to display our image. For this example, we will be using an image file named Blue-Aqua-Apple.png.
In order to see how this can be achieved, we need to modify the ViewObjectsExample application that we created in the previous recipe. Perform the following steps to do so:
- Open the
ViewObjectsExample.xcodeprojproject file. - Select the
ViewController.xibfile from the project navigator window. - From Object Library, drag a UIImageView object onto the subview and place it underneath the
Round Rect Buttonobject we added previously. - Resize the
UIImageViewcontrol so that it will be big enough to hold the image. - Next, create the outlet and property for this
UIImageView, and name itimgPicture. - Then, select Files | Add Files to "ViewObjectsExample"…, or alternatively press option + command + A.
- Select the Blue-Aqua-Apple.pngimage file to add and then click on the Add button.
Our next step is to create the code functionality that will be responsible for displaying the image within our imageView control:
- Open the
ViewController.mimplementation file from the project navigator. - Next, create the
displayImagemethod, as shown in the following code snippet:-(void)displayImage { [self.imgPicture setImage:[UIImage imageNamed:@"Blue-Aqua-Apple.png"]]; [self.imgPicture setContentMode:UIViewContentModeScaleAspectFit]; } - Then, add the following line of code within the
viewDidLoadmethod:[self displayImage];
- Then, build and run the application by selecting Product | Run from the Product menu, or alternatively by pressing command + R.
When the compilation completes, the iOS Simulator will appear, displaying the image that we just added to our project.
The UIImageView class is basically a view that has been customized for the purpose of displaying images. We then set the
contentMode property of the imageView class to UIViewContentModeScaleAspectFit, which scales and fills the image to fit the entire contents of UIImageView.
Note
If you would like to find out more information on the
UIImageView class, you can refer to the Apple Developer documentation located at http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIImageView_Class/Reference/Reference.html.
The contentMode property accepts an enumeration type named UIViewContentMode. The following table explains some of these types:
The UIImage class is the object that represents image-related information. The following table displays some of these file
formats that it currently supports:
|
File format |
File extension |
|---|---|
|
Portable Network Graphics |
|
|
Joint Photographic Experts Group |
|
|
Tagged Image File Format |
|
|
Graphics Interchange Format |
|
|
Windows Bitmap Format |
|
|
Windows Icon Format |
|