Permissions may be granted at install or asked at the moment of use

What it is

A mobile OS decides when to ask: a single install-time list of camera, contacts, and location with one Allow, or a system dialog at the moment that capability is first called. Those timings are platform rules, not two wordings of the same privacy principle. Install-time grant puts the decision before the person has seen the product. Ask-on-use ties the decision to a concrete action. This entry is where the ask sits on the timeline. It is not which sensors a permission named "location" covers on each OS, not whether a denial can be followed by another prompt, and not how cross-platform code should converge.

Why it happens

The install-time model writes permissions into a manifest that the store or installer shows at the moment of install. There is no task context such as "I need to photograph an invoice"; attention is on "do I install," and the list is easy to skim past. The runtime model binds the dialog to the first API call: the shutter, start navigation, attach a contact. Context gives "why" a place to land, and also interrupts the task. The same product on a still-install-time system will assume the permission already exists after launch; on a runtime-only system the same line of code will prompt on first call. Shipping iOS "ask at the shutter" onto an install-time environment feels like being asked twice. Shipping the long install list onto a runtime system fires several system dialogs before the task has started, and they get denied.

Studying it

Compare attention and comprehension on an install list versus a first-use dialog; do not stop at "would you grant this."

Independent variables: prompt timing (install list / burst at launch / first use of the capability), whether a comprehensible task goal is present. Dependent variables: whether permission items are looked at, ability to recall what was granted, completion and denial rates on the first related task.

The classic method measures attention on the install dialog (gaze, recall of list items) and contrasts it with runtime prompts that have task context. A lab "please install this app" raises diligence at install; real store swipe-installs are closer to skimming. A higher runtime denial rate is not automatically more privacy—it may be the interruption catching a mis-tap.

Where it stops holding

Sideloaded enterprise builds and preinstalled apps on some systems still grant at install or silently; there is no "first use" moment. Capabilities with no single use instant (notifications, background refresh) need a proxy moment even under a runtime model, and that proxy is not always clearer than install-time. Site permissions in a desktop browser (camera, location) are closer to runtime, but a site is not an install unit; the mobile install-time model does not map. After an OS upgrade moves a permission from install-time to runtime, old grants may reset; the product cannot assume last year's Allow still holds.

Applying it

• Ask on the target system's clock: on runtime systems, call the system dialog when the matching action happens. On still-install-time systems, keep the manifest short and add in-app context at first real use, rather than faking a second system dialog.
• Do not fire a burst of runtime dialogs on the launch screen for capabilities not needed yet.
• Verify the "photograph and upload" path on one install-time device and one runtime device. Runtime should show the system dialog near the shutter; install-time should finish granting during install and not ambush at capture. If the timings are swapped, one platform's clock was copied onto the other.

Related

• Within the group: K1.12.2 A permission with the same name does not grant the same capabilities on every OS · K1.12.3 After a denial, whether the app may prompt again is platform-specific · K1.12.4 A cross-platform app cannot treat one permission model as universal
• Adjacent: O2.01 Information design of permission prompts · O1.05 Usability dilemma of informed consent
• Search terms: install-time permission · runtime permission · ask on first use