An application starts a system-level Picker component (such as DocumentViewPicker, PhotoViewPicker, or ContactsPicker). The user selects files, photos, or contacts on the component, and the application obtains the result returned by the component.
A system-level Picker component is implemented by an independent system process.
The system-level Picker components have been pre-authorized. When using such a component, you can temporarily access the corresponding resources without requesting the permissions. For example, before accessing a user's image, an application normally needs the permission for reading images. By using the photo Picker, the application can directly access the image selected by the user.
The system-level Picker component is integrated into system applications as a means to start system resources. For details, see Starting a System Application.