Triggers and Responses
Every interactive element in a prototype has triggers that listen for user actions and responses that execute when those actions occur. A button has a tap trigger linked to a navigation response. A hover trigger on a tooltip container reveals additional content. A timer trigger on a splash screen auto-advances after three seconds.
The trigger-response model is how PrototypeTool turns static screens into interactive experiences.
How triggers and responses model real user behavior
Real applications respond to user actions. Tapping a button submits a form. Hovering over an element shows a tooltip. Scrolling down loads more content. Triggers and responses replicate this input-output relationship in the prototype.
The simplest interaction is one trigger linked to one response — tap this button, navigate to that screen. But real applications often require multiple responses from a single trigger — tap the submit button, show a loading spinner, send an API request, hide the form, and display a confirmation message. Response chains handle this by executing multiple responses in sequence from a single trigger.
This model keeps interactions declarative and visual. Instead of writing event handlers in code, you configure triggers and drag response steps into a chain. The interaction logic is visible in the editor without opening a code file.
Configuring triggers and response chains
- Select any element and open the triggers panel. Add a trigger by choosing the event type: tap, double tap, long press, hover enter, hover exit, page load, page scroll, timer, or variable change.
- Add a response to the trigger. Choose from navigation (go to screen), state change (switch layer state), variable update (set or modify a value), animation (move, resize, fade), or webhook (fire an external event).
- Chain multiple responses on a single trigger by adding them in order. Responses execute sequentially from top to bottom. Use the drag handle to reorder them.
- Insert delay responses between other responses when you need timing gaps. A common pattern is: show loading spinner, delay 800ms, hide spinner, show content — simulating an asynchronous operation.
- Add conditions to responses to make them fire only when certain criteria are met. A submit button can navigate to a success screen if the form is valid or show an error message if a required field is empty.
- Test response chains in preview mode. Step through each response in the chain and verify that the timing, order, and visual result match your intent. Pay attention to transitions between responses.
Trigger configuration mistakes
- Attaching triggers to elements that users do not perceive as interactive. If an element has no visual affordance (like a hover state or cursor change), users will not discover the trigger.
- Creating response chains with too many steps. Chains longer than five responses are hard to debug and may produce unexpected visual results. Split complex interactions into separate trigger-response pairs.
- Not handling both success and failure paths. A form submission trigger should have responses for both valid and invalid states, not just the happy path.
- Using hover triggers on mobile-first prototypes. Hover does not exist on touch devices. Use tap, long press, or swipe triggers for mobile interactions.
- Forgetting that page load triggers fire every time the screen is visited, including when the user navigates back. If the trigger should fire only once, add a variable-based condition.
Measuring interaction coverage
- Trigger coverage: The percentage of interactive elements in the prototype that have at least one trigger configured. Untriggered interactive elements create dead zones.
- Response chain depth: The average and maximum number of responses per trigger. Deep chains may indicate overly complex interactions that should be simplified.
- Interaction test coverage: The percentage of triggers that have been activated during at least one preview or test session. Unexercised triggers may contain configuration errors.
- User discovery rate: The percentage of configured interactions that test participants find and use without prompting. Low discovery rates indicate affordance or discoverability problems.
When to use trigger-based interactions
- For every interactive element that should respond to user action. Triggers are the fundamental mechanism for making prototypes interactive.
- When simulating asynchronous operations like API calls, file uploads, or processing steps. Use response chains with delays to represent the loading and completion states.
- When building micro-interactions like button press feedback, form validation, tooltip display, and accordion expand/collapse that make prototypes feel polished and realistic.
- When creating guided prototype walkthroughs using timer and page-load triggers that auto-advance through screens for presentation purposes.
Key concepts
- Trigger: An event that initiates a prototype action, such as a tap, hover, page load, or timer completion.
- Response: The action executed when a trigger fires, such as navigating to a screen, changing a state, or starting an animation.
- Response chain: A sequence of responses that execute in order from a single trigger, enabling multi-step interactions.
FAQ
- Can a single element have multiple triggers? Yes. An element can respond to tap, hover, long press, and other triggers independently, each with its own response chain.
- How do I add a delay between responses? Insert a delay response between other responses in the chain. Set the duration in milliseconds.
- Can responses trigger other elements? Yes. A response can change the state of any element on the current screen, not just the element that received the trigger.
Next steps
Add one trigger-response pair to your current prototype and test it with a colleague. Focus on whether the interaction communicates intent clearly, then layer in additional triggers as the flow requires them.