UIImagePickerController Class Reference

Inherits from
Conforms to
Framework
/System/Library/Frameworks/UIKit.framework
Availability
Available in iOS 2.0 and later.
Companion guide
Declared in
UIImagePickerController.h
Related sample code

Overview

The UIImagePickerController class manages customizable, system-supplied user interfaces for taking pictures and movies on supported devices, and for choosing saved images and movies for use in your app. An image picker controller manages user interactions and delivers the results of those interactions to a delegate object.

The role and appearance of an image picker controller depend on the source type you assign to it before you present it.

To use an image picker controller containing its default controls, perform these steps:

  1. Verify that the device is capable of picking content from the desired source. Do this by calling the isSourceTypeAvailable: class method, providing a constant from the “UIImagePickerControllerSourceType” enumeration.

  2. Check which media types are available for the source type you’re using, by calling the availableMediaTypesForSourceType: class method. This lets you distinguish between a camera that can be used for video recording and one that can be used only for still images.

  3. Tell the image picker controller to adjust the UI according to the media types you want to make available—still images, movies, or both—by setting the mediaTypes property.

  4. Present the user interface. On iPhone or iPod touch, do this modally (full-screen) by calling the presentViewController:animated:completion: method of the currently active view controller, passing your configured image picker controller as the new view controller.

    On iPad, the correct way to present an image picker depends on its source type, as summarized in this table:

    Camera

    Photo Library

    Saved Photos Album

    Use full screen

    Must use a popover

    Must use a popover

    The table indicates that on iPad, if you specify a source type of UIImagePickerControllerSourceTypePhotoLibrary or UIImagePickerControllerSourceTypeSavedPhotosAlbum, you must present the image picker using a popover controller, as described in “Presenting and Dismissing the Popover” in UIPopoverController Class Reference. If you attempt to present an image picker modally (full-screen) for choosing among saved pictures and movies, the system raises an exception.

    On iPad, if you specify a source type of UIImagePickerControllerSourceTypeCamera, you can present the image picker modally (full-screen) or by using a popover. However, Apple recommends that you present the camera interface only full-screen.

  5. When the user taps a button to pick a newly-captured or saved image or movie, or cancels the operation, dismiss the image picker using your delegate object. For newly-captured media, your delegate can then save it to the Camera Roll on the device. For previously-saved media, your delegate can then use the image data according to the purpose of your app.

For details on these steps, refer to “Taking Pictures and Movies”.

You can customize an image picker controller to manage user interactions yourself. To do this, provide an overlay view containing the controls you want to display, and use the methods described in “Capturing Still Images or Movies.” You can display your custom overlay view in addition to, or instead of, the default controls. Custom overlay views for the UIImagePickerController class are available in iOS 3.1 and later by way of the cameraOverlayView property. For a code example, see the Using UIImagePickerController to Select Pictures and Take Photos sample code project.

Providing a Delegate Object

To use an image picker controller, you must provide a delegate that conforms to the UIImagePickerControllerDelegate protocol. Starting in iOS 4.1, you can use the delegate to save still-image metadata to the Camera Roll along with the image. See UIImagePickerControllerDelegate Protocol Reference.

Adjusting Flash Mode

In iOS 4.0 and later, you can provide custom controls to let the user adjust flash mode (on devices that have a flash LED), pick which camera to use (on devices that have a front and rear camera), and switch between still image and movie capture. You can also manage these settings programmatically. You can also manipulate the flash directly to provide effects such as a strobe light. Present a picker interface set to use video capture mode. Then, turn the flash LED on or off by setting the cameraFlashMode property to UIImagePickerControllerCameraFlashModeOn or UIImagePickerControllerCameraFlashModeOff.

Working with Movies

Movie capture has a default duration limit of 10 minutes but can be adjusted using the videoMaximumDuration property. When a user taps the Share button to send a movie to MMS, MobileMe, YouTube, or another destination, an appropriate duration limit and an appropriate video quality are enforced.

The default camera interface supports editing of previously-saved movies. Editing involves trimming from the start or end of the movie, then saving the trimmed movie. To display an interface dedicated to movie editing, rather than one that also supports recording new movies, use the UIVideoEditorController class instead of this one. See UIVideoEditorController Class Reference.

Fully-Customized Media Capture and Browsing

To perform fully-customized image or movie capture, instead use the AV Foundation framework as described in “Media Capture and Access to Camera” in AV Foundation Programming Guide. Camera access using the AV Foundation framework is available starting in iOS 4.0.

To create a fully-customized image picker for browsing the photo library, use classes from the Assets Library framework. For example, you could create a custom image picker that displays larger thumbnail images, that makes use of EXIF metadata including timestamp and location information, or that integrates with other frameworks such as Map Kit. For more information, see Assets Library Framework Reference. Media browsing using the Assets Library framework is available starting in iOS 4.0

Tasks

Setting the Picker Source

Configuring the Picker

Configuring the Video Capture Options

Customizing the Camera Controls

Capturing Still Images or Movies

Configuring the Camera

Properties

allowsEditing

A Boolean value indicating whether the user is allowed to edit a selected still image or movie.

@property (nonatomic) BOOL allowsEditing
Discussion

If you allow the user to edit still images or movies, the delegate may receive a dictionary with information about the edits that were made. The protocol for the delegate is described in UIImagePickerControllerDelegate Protocol Reference.

This property is set to NO by default.

Availability
  • Available in iOS 3.1 and later.
Related Sample Code
Declared In
UIImagePickerController.h

cameraCaptureMode

The capture mode used by the camera.

@property (nonatomic) UIImagePickerControllerCameraCaptureMode cameraCaptureMode
Discussion

The various capture modes are listed in the “UIImagePickerControllerCameraCaptureMode” enumeration. The default value is UIImagePickerControllerCameraCaptureModePhoto.

Availability
  • Available in iOS 4.0 and later.
Related Sample Code
Declared In
UIImagePickerController.h

cameraDevice

The camera used by the image picker controller.

@property (nonatomic) UIImagePickerControllerCameraDevice cameraDevice
Discussion

The default is UIImagePickerControllerCameraDeviceRear.

Availability
  • Available in iOS 4.0 and later.
Related Sample Code
Declared In
UIImagePickerController.h

cameraFlashMode

The flash mode used by the active camera.

@property (nonatomic) UIImagePickerControllerCameraFlashMode cameraFlashMode
Discussion

The various flash modes are listed in the “UIImagePickerControllerCameraFlashMode” enumeration. The default value is UIImagePickerControllerCameraFlashModeAuto.

The value of this property specifies the behavior of the still-image flash when the value of the cameraCaptureMode property is UIImagePickerControllerCameraCaptureModePhoto, and specifies the behavior of the video torch when cameraCaptureMode is UIImagePickerControllerCameraCaptureModeVideo.

Availability
  • Available in iOS 4.0 and later.
Related Sample Code
Declared In
UIImagePickerController.h

cameraOverlayView

The view to display on top of the default image picker interface.

@property (nonatomic, retain) UIView *cameraOverlayView
Discussion

You can use an overlay view to present a custom view hierarchy on top of the default image picker interface. The image picker layers your custom overlay view on top of the other image picker views and positions it relative to the screen coordinates. If you have the default camera controls set to be visible, incorporate transparency into your view, or position it to avoid obscuring the underlying content.

You can access this property only when the source type of the image picker is set to UIImagePickerControllerSourceTypeCamera. Attempting to access this property for other source types results in throwing an NSInvalidArgumentException exception.

Availability
  • Available in iOS 3.1 and later.
Declared In
UIImagePickerController.h

cameraViewTransform

The transform to apply to the camera’s preview image.

@property (nonatomic) CGAffineTransform cameraViewTransform
Discussion

This transform affects the live preview image only and does not affect your custom overlay view or the default image picker controls. You can use this property in conjunction with custom controls to implement your own electronic zoom behaviors.

You can access this property only when the source type of the image picker is set to UIImagePickerControllerSourceTypeCamera. Attempting to access this property for other source types results in the throwing of an NSInvalidArgumentException exception.

Availability
  • Available in iOS 3.1 and later.
Related Sample Code
Declared In
UIImagePickerController.h

delegate

The image picker’s delegate object.

@property (nonatomic, assign) id<UINavigationControllerDelegate, UIImagePickerControllerDelegate> delegate
Discussion

The delegate receives notifications when the user picks an image or movie, or exits the picker interface. The delegate also decides when to dismiss the picker interface, so you must provide a delegate to use a picker. If this property is nil, the picker is dismissed immediately if you try to show it.

For information about the methods you can implement for your delegate object, see UIImagePickerControllerDelegate Protocol Reference.

Availability
  • Available in iOS 2.0 and later.
Declared In
UIImagePickerController.h

mediaTypes

An array indicating the media types to be accessed by the media picker controller.

@property (nonatomic, copy) NSArray *mediaTypes
Discussion

Depending on the media types you assign to this property, the picker displays a dedicated interface for still images or movies, or a selection control that lets the user choose the picker interface. Before setting this property, check which media types are available by calling the availableMediaTypesForSourceType: class method.

If you set this property to an empty array, or to an array in which none of the media types is available for the current source, the system throws an exception.

When capturing media, the value of this property determines the camera interface to display. When browsing saved media, this property determines the types of media presented in the interface.

By default, this property is set to the single value kUTTypeImage, which designates the still camera interface when capturing media, and specifies that only still images should be displayed in the media picker when browsing saved media. To designate the movie capture interface, or to indicate that only movies should be displayed when browsing saved media, use the kUTTypeMovie identifier in a statement like this:

myImagePickerController.mediaTypes =
    [[NSArray alloc] initWithObjects: (NSString *) kUTTypeMovie, nil];

To designate all available media types for a source, use a statement like this:

myImagePickerController.mediaTypes =
    [UIImagePickerController availableMediaTypesForSourceType:
        UIImagePickerControllerSourceTypeCamera];
Availability
  • Available in iOS 3.0 and later.
Declared In
UIImagePickerController.h

showsCameraControls

Indicates whether the image picker displays the default camera controls.

@property (nonatomic) BOOL showsCameraControls
Discussion

The default value of this property is YES, which specifies that the default camera controls are visible in the picker. Set it to NO to hide the default controls if you want to instead provide a custom overlay view using the cameraOverlayView property.

If you set this property to NO and provide your own custom controls, you can take multiple pictures before dismissing the image picker interface. However, if you set this property to YES, your delegate must dismiss the image picker interface after the user takes one picture or cancels the operation.

You can access this property only when the source type of the image picker is set to UIImagePickerControllerSourceTypeCamera. Attempting to access this property for other source types results in the throwing of an NSInvalidArgumentException exception. Depending on the value you assign to the mediaTypes property, the default controls display the still camera or movie camera interface, or a selection control that lets the user choose the picker interface.

Availability
  • Available in iOS 3.1 and later.
Declared In
UIImagePickerController.h

sourceType

The type of picker interface to be displayed by the controller.

@property (nonatomic) UIImagePickerControllerSourceType sourceType
Discussion

Prior to running the picker interface, set this value to the desired source type. The source type you set must be available and an exception is thrown if it is not. If you change this property while the picker is visible, the picker interface changes to match the new value in this property.

The various source types are listed in the “UIImagePickerControllerSourceType” enumeration. The default value is UIImagePickerControllerSourceTypePhotoLibrary.

Availability
  • Available in iOS 2.0 and later.
Declared In
UIImagePickerController.h

videoMaximumDuration

The maximum duration, in seconds, for a video recording.

@property (nonatomic) NSTimeInterval videoMaximumDuration
Discussion

The default value for this property is 10 minutes (600 seconds). When a user taps the Share button to send a movie to MMS, MobileMe, YouTube, or another destination, an appropriate duration limit and an appropriate video quality are enforced.

This property is available only if the mediaTypes property’s value array includes the kUTTypeMovie media type.

Availability
  • Available in iOS 3.1 and later.
Declared In
UIImagePickerController.h

videoQuality

The video recording and transcoding quality.

@property (nonatomic) UIImagePickerControllerQualityType videoQuality
Discussion

The video quality setting specified by this property is used during video recording. It is also used whenever picking a recorded movie. Specifically, if the video quality setting is lower than the video quality of an existing movie, displaying that movie in the picker results in transcoding the movie to the lower quality.

The various video qualities are listed in the “UIImagePickerControllerQualityType” enumeration. The default value is UIImagePickerControllerQualityTypeMedium. To capture or transcode a movie using a video quality other than the default value, you must set the quality explicitly.

This property is available only if the mediaTypes property’s value array includes the kUTTypeMovie media type.

Availability
  • Available in iOS 3.1 and later.
Related Sample Code
Declared In
UIImagePickerController.h

Class Methods

availableCaptureModesForCameraDevice:

Returns an array of NSNumber objects indicating the capture modes supported by a given camera device.

+ (NSArray *)availableCaptureModesForCameraDevice:(UIImagePickerControllerCameraDevice)cameraDevice
Parameters
cameraDevice

A “UIImagePickerControllerCameraDevice” constant indicating the camera you want to interrogate.

Return Value

An array of NSNumber objects indicating the capture modes supported by cameraDevice.

Discussion

See “UIImagePickerControllerCameraCaptureMode” for possible values.

Availability
  • Available in iOS 4.0 and later.
Declared In
UIImagePickerController.h

availableMediaTypesForSourceType:

Returns an array of the available media types for the specified source type.

+ (NSArray *)availableMediaTypesForSourceType:(UIImagePickerControllerSourceType)sourceType
Parameters
sourceType

The source to use to pick an image.

Return Value

An array whose elements identify the available media types for the specified source type.

Discussion

Some iOS devices support video recording. Use this method, along with the isSourceTypeAvailable: method, to determine if video recording is available on a device. The availability of video recording is indicated by the presence of the kUTTypeMovie media type for the UIImagePickerControllerSourceTypeCamera source type.

Availability
  • Available in iOS 3.0 and later.
Declared In
UIImagePickerController.h

isCameraDeviceAvailable:

Returns a Boolean value that indicates whether a given camera is available.

+ (BOOL)isCameraDeviceAvailable:(UIImagePickerControllerCameraDevice)cameraDevice
Parameters
cameraDevice

A “UIImagePickerControllerCameraDevice” constant indicating the camera whose availability you want to check.

Return Value

YES if the camera indicated by cameraDevice is available, or NO if it is not available.

Availability
  • Available in iOS 4.0 and later.
Declared In
UIImagePickerController.h

isFlashAvailableForCameraDevice:

Indicates whether a given camera has flash illumination capability.

+ (BOOL)isFlashAvailableForCameraDevice:(UIImagePickerControllerCameraDevice)cameraDevice
Parameters
cameraDevice

A “UIImagePickerControllerCameraDevice” constant indicating the camera whose flash capability you want to know.

Return Value

YES if cameraDevice can use flash illumination, or NO if it cannot.

Availability
  • Available in iOS 4.0 and later.
Declared In
UIImagePickerController.h

isSourceTypeAvailable:

Returns a Boolean value indicating whether the device supports picking media using the specified source type.

+ (BOOL)isSourceTypeAvailable:(UIImagePickerControllerSourceType)sourceType
Parameters
sourceType

The source to use to pick an image or movie.

Return Value

YES if the device supports the specified source type; NO if the specified source type is not available.

Discussion

Because a media source may not be present or may be unavailable, devices may not always support all source types. For example, if you attempt to pick an image from the user’s library and the library is empty, this method returns NO. Similarly, if the camera is already in use, this method returns NO.

Before attempting to use an UIImagePickerController object to pick an image, you must call this method to ensure that the desired source type is available.

Availability
  • Available in iOS 2.0 and later.
Declared In
UIImagePickerController.h

Instance Methods

startVideoCapture

Starts video capture using the camera specified by the UIImagePickerControllerCameraDevice property.

- (BOOL)startVideoCapture
Return Value

YES on success or NO on failure. This method may return a value of NO for various reasons, among them the following:

  • Movie capture is already in progress

  • The device does not support movie capture

  • The device is out of disk space

Discussion

Use this method in conjunction with a custom overlay view to initiate the programmatic capture of a movie. You can take more than one movie without leaving the interface, but to do so requires you to hide the default image picker controls.

Calling this method while a movie is being captured has no effect. You must call the stopVideoCapture method, and then wait until the associated delegate object receives an imagePickerController:didFinishPickingMediaWithInfo: message, before you can capture another movie.

Calling this method when the source type of the image picker is set to a value other than UIImagePickerControllerSourceTypeCamera results in the throwing of an NSInvalidArgumentException exception.

If you require additional options or more control over movie capture, use the movie capture methods in the AV Foundation framework. Refer to AV Foundation Framework Reference.

Availability
  • Available in iOS 4.0 and later.
Declared In
UIImagePickerController.h

stopVideoCapture

Stops video capture.

- (void)stopVideoCapture
Discussion

After you call this method to stop video capture, the system calls the image picker delegate’s imagePickerController:didFinishPickingMediaWithInfo: method.

Availability
  • Available in iOS 4.0 and later.
Declared In
UIImagePickerController.h

takePicture

Captures a still image using the camera.

- (void)takePicture
Discussion

Use this method in conjunction with a custom overlay view to initiate the programmatic capture of a still image. This supports taking more than one picture without leaving the interface, but requires that you hide the default image picker controls.

Calling this method while an image is being captured has no effect. You must wait until the associated delegate object receives an imagePickerController:didFinishPickingMediaWithInfo: message before you can capture another picture.

Calling this method when the source type of the image picker is set to a value other than UIImagePickerControllerSourceTypeCamera results in the throwing of an NSInvalidArgumentException exception.

Availability
  • Available in iOS 3.1 and later.
Declared In
UIImagePickerController.h

Constants

UIImagePickerControllerSourceType

The source to use when picking an image or when determining available media types.

enum {
   UIImagePickerControllerSourceTypePhotoLibrary,
   UIImagePickerControllerSourceTypeCamera,
   UIImagePickerControllerSourceTypeSavedPhotosAlbum
};
typedef NSUInteger UIImagePickerControllerSourceType;
Constants
UIImagePickerControllerSourceTypePhotoLibrary

Specifies the device’s photo library as the source for the image picker controller.

Available in iOS 2.0 and later.

Declared in UIImagePickerController.h.

UIImagePickerControllerSourceTypeCamera

Specifies the device’s built-in camera as the source for the image picker controller. Indicate the specific camera you want (front or rear, as available) by using the cameraDevice property.

Available in iOS 2.0 and later.

Declared in UIImagePickerController.h.

UIImagePickerControllerSourceTypeSavedPhotosAlbum

Specifies the device’s Camera Roll album as the source for the image picker controller. If the device does not have a camera, specifies the Saved Photos album as the source.

Available in iOS 2.0 and later.

Declared in UIImagePickerController.h.

Discussion

A given source may not be available on a given device because the source is not physically present or because it cannot currently be accessed.

UIImagePickerControllerQualityType

Video quality settings for movies recorded with the built-in camera, or transcoded by displaying in the image picker.

enum {
   UIImagePickerControllerQualityTypeHigh            = 0,
   UIImagePickerControllerQualityTypeMedium          = 1,  // default value
   UIImagePickerControllerQualityTypeLow             = 2,
   UIImagePickerControllerQualityType640x480         = 3,
   UIImagePickerControllerQualityTypeIFrame1280x720  = 4,
   UIImagePickerControllerQualityTypeIFrame960x540   = 5
};
typedef NSUInteger UIImagePickerControllerQualityType;
Constants
UIImagePickerControllerQualityTypeHigh

If recording, specifies that you want to use the highest-quality video recording supported for the active camera on the device.

Recorded files are suitable for on-device playback and for wired transfer to the Desktop using Image Capture; they are likely to be too large for transfer using Wi-Fi.

If displaying a recorded movie in the image picker, specifies that you do not want to reduce the video quality of the movie.

Available in iOS 3.1 and later.

Declared in UIImagePickerController.h.

UIImagePickerControllerQualityType640x480

If recording, specifies that you want to use VGA-quality video recording (pixel dimensions of 640x480).

If displaying a recorded movie in the image picker, specifies that you want to transcode higher-quality movies to VGA video quality.

Available in iOS 4.0 and later.

Declared in UIImagePickerController.h.

UIImagePickerControllerQualityTypeMedium

If recording, specifies that you want to use medium-quality video recording.

Recorded files can usually be transferred using Wi-Fi. This is the default video quality setting.

If displaying a recorded movie in the image picker, specifies that you want to transcode higher-quality movies to medium video quality.

Available in iOS 3.1 and later.

Declared in UIImagePickerController.h.

UIImagePickerControllerQualityTypeLow

If recording, specifies that you want to use low-quality video recording.

Recorded files can usually be transferred over the cellular network.

If displaying a recorded movie in the image picker, specifies that you want to transcode higher-quality movies to low video quality.

Available in iOS 3.1 and later.

Declared in UIImagePickerController.h.

UIImagePickerControllerQualityTypeIFrame1280x720

If recording, specifies that you want to use 1280x720 iFrame format.

The Apple iFrame format supports video editing by keeping content in its native recorded format while editing.

Available in iOS 5.0 and later.

Declared in UIImagePickerController.h.

UIImagePickerControllerQualityTypeIFrame960x540

If recording, specifies that you want to use 960x540 iFrame format.

The Apple iFrame format supports video editing by keeping content in its native recorded format while editing.

Available in iOS 5.0 and later.

Declared in UIImagePickerController.h.

Discussion

The constants in this enumeration are for use as values of the videoQuality property.

The video quality setting applies to transcoding as well as to recording. Specifically, if the video quality setting is lower than the video quality of an existing movie, displaying that movie in the picker results in transcoding the movie to the lower quality.

UIImagePickerControllerCameraDevice

The camera to use for image or movie capture.

enum {
   UIImagePickerControllerCameraDeviceRear,
   UIImagePickerControllerCameraDeviceFront
};
typedef NSUInteger UIImagePickerControllerCameraDevice;
Constants
UIImagePickerControllerCameraDeviceRear

Specifies the camera on the rear of the device.

Available in iOS 4.0 and later.

Declared in UIImagePickerController.h.

UIImagePickerControllerCameraDeviceFront

Specifies the camera on the front of the device.

Available in iOS 4.0 and later.

Declared in UIImagePickerController.h.

Discussion

The constants in this enumeration are for use as values of the cameraDevice property.

UIImagePickerControllerCameraCaptureMode

The category of media for the camera to capture.

enum {
   UIImagePickerControllerCameraCaptureModePhoto,
   UIImagePickerControllerCameraCaptureModeVideo
};
typedef NSUInteger UIImagePickerControllerCameraCaptureMode;
Constants
UIImagePickerControllerCameraCaptureModePhoto

Specifies that the camera captures still images.

Available in iOS 4.0 and later.

Declared in UIImagePickerController.h.

UIImagePickerControllerCameraCaptureModeVideo

Specifies that the camera captures movies.

Available in iOS 4.0 and later.

Declared in UIImagePickerController.h.

Discussion

The constants in this enumeration are for use as values of the cameraCaptureMode property.

UIImagePickerControllerCameraFlashMode

The flash mode to use with the active camera.

enum {
   UIImagePickerControllerCameraFlashModeOff  = -1,
   UIImagePickerControllerCameraFlashModeAuto = 0,
   UIImagePickerControllerCameraFlashModeOn   = 1
};
typedef NSInteger UIImagePickerControllerCameraFlashMode;
Constants
UIImagePickerControllerCameraFlashModeOff

Specifies that flash illumination is always off, no matter what the ambient light conditions are.

Available in iOS 4.0 and later.

Declared in UIImagePickerController.h.

UIImagePickerControllerCameraFlashModeAuto

Specifies that the device should consider ambient light conditions to automatically determine whether or not to use flash illumination.

Available in iOS 4.0 and later.

Declared in UIImagePickerController.h.

UIImagePickerControllerCameraFlashModeOn

Specifies that flash illumination is always on, no matter what the ambient light conditions are.

Available in iOS 4.0 and later.

Declared in UIImagePickerController.h.

Discussion

The constants in this enumeration are for use as values of the cameraFlashMode property.

The behavior of the flash depends on the camera capture mode.

For a given camera on a device, flash may or may not be available. You specify the active camera by way of the cameraDevice property. You can determine if the active camera has flash available by calling the isFlashAvailableForCameraDevice: class method.

You can manipulate the flash directly to provide effects such as a strobe light. Present a picker interface set to use video capture mode. Then, turn the flash LED on or off by setting the cameraFlashMode property to UIImagePickerControllerCameraFlashModeOn or UIImagePickerControllerCameraFlashModeOff.