Select Photo from Gallery

Goal

Allow users to select one or more photos from their device gallery.

Actions Required

Action	Purpose
MediaServicesGetGalleryAccessStatus	Read current gallery permission status (Read mode)
MediaServicesSelectContent	Open gallery picker
MediaServicesGetSelectContentSuccessResult	Get selection count
MediaServicesGetContentTexture	Convert selected photo to Texture2D
MediaServicesGetSelectContentError	Read cached error after failure (optional)

Variables Needed

• galleryStatus (Enum: GalleryAccessStatus)

• contentCount (Int)

• selectedTexture (Texture2D)

• contentIndex (Int) = 0

Implementation Steps

1. State: CheckGalleryPermission

Action: MediaServicesGetGalleryAccessStatus

• Inputs:

  • accessMode: Read

• Outputs:

  • status → galleryStatus

• Next: Use an Enum Switch/Compare on galleryStatus:

  • Authorized / NotDetermined / Limited → SelectPhoto

  • Denied / Restricted → ShowPermissionError

2. State: SelectPhoto

Action: MediaServicesSelectContent

• Inputs:

  • mediaType: Image

  • allowsMultipleSelection: false

  • maxCount: 1 (ignored when multiple selection is off)

• Events:

  • successEvent → GetSelectionResult

  • failureEvent → HandleCancellationOrError

Note: Opens native photo picker UI.

3. State: GetSelectionResult

Action: MediaServicesGetSelectContentSuccessResult

• Outputs:

  • contentCount → contentCount

  • hasContent → (bool)

• Next: contentCount is always >= 1 here (the select action fires FAILURE when nothing is selected). Go to ConvertToTexture.

4. State: ConvertToTexture

Action: MediaServicesGetContentTexture

• Inputs:

  • contentIndex: contentIndex (0 for single selection)

• Outputs:

  • texture → selectedTexture

• Next: This action finishes when conversion completes. Use the state’s FINISHED transition → DisplayPhoto.

5. State: DisplayPhoto

Assign selectedTexture to UI Image component.

Selection Flow

CheckGalleryPermission
    └─ SelectPhoto (allowsMultipleSelection: false)
        └─ GetSelectionResult
            └─ ConvertToTexture (index: 0)
                └─ DisplayPhoto

Multi-Select Variation

For selecting multiple photos:

SelectPhoto with:

• allowsMultipleSelection: true

• maxCount: 5 (or desired limit)

Loop through selections:

Loop i from 0 to (contentCount - 1):
    MediaServicesGetContentTexture (contentIndex: i)
    Add texture to gallery UI

Common Issues

• No Permission: iOS users must grant Photos access

• User Cancelled / No selection: this typically triggers failureEvent. MediaServicesGetSelectContentError may be empty depending on platform callback.

• Large Images: Selected photos can be multi-megabyte; consider compression

• contentCount = 0: User may have deselected all photos before confirming

Platform Differences

iOS:

• Shows native Photos app picker

• "Privacy - Photo Library Usage Description" required in Info.plist

• iOS 14+: User can grant limited access to specific photos

Android:

• Shows system photo picker or gallery app

• READ_EXTERNAL_STORAGE permission required (older Android versions)

Performance Tips

• Lazy Loading: For multi-select, load textures on-demand as user scrolls

• Thumbnail Generation: Create smaller thumbnails for gallery views

• Background Loading: Convert large images to textures off main thread if possible