问题
I have an application that allows the user to pick a photo from their device. To do this, I'm using the UIImagePickerController, but the problem is that I'm unsure whether I should be using a source type of UIImagePickerControllerSourceTypePhotoLibrary or UIImagePickerControllerSourceTypeSavedPhotosAlbum.
On my iPhone 4 running iOS 5 the saved photos album gives a much better experience, but when I try to use my iPod Touch running iOS 4.3 using a photo that I synced from iTunes, it doesn't even show up. If I switch to PhotoLibrary my iPod works but my iPhone experience is worse. When I ask the UIImagePickerController it says the SavedPhotosAlbum is available on my iPod, but I don't seem to have a way to determine that it's empty.
What is the best way to determine which source type to use? If I have a way to determine if the Saved Photo Album is empty, I guess that would work, but I don't see one.
回答1:
UIImagePickerControllerSourceTypePhotoLibrary references the entire photo library, letting the user choose which album. UIImagePickerControllerSourceTypeSavedPhotosAlbum goes straight to the camera roll album without giving the user a choice as to which album to choose from. They're similar, but different. You can get to the camera roll from PhotoLibrary; you can access only the camera roll from UIImagePickerControllerSourceTypeSavedPhotosAlbum.
Reference.
来源：https://stackoverflow.com/questions/8087405/when-should-i-use-uiimagepickercontrollersourcetypephotolibrary-instead-of-uiima