Qt Quick Input Handlers
Qt Quick Input Handlers are a set of QML types used to handle events from keyboard, touch, mouse, and stylus devices in a UI. In contrast to event-handling items, such as MouseArea and Flickable, input handlers are explicitly non-visual, require less memory and are intended to be used in greater numbers: one handler instance per aspect of interaction. Each input handler instance handles certain events on behalf of its parent Item. Thus the visual and behavioral concerns are better separated, and the behavior is built up by finer-grained composition.
In Qt 5.10, these handlers were introduced in a separate Qt.labs.handlers module. Now they are included with Qt Quick since 5.12. The pre-existing Keys attached property is similar in concept, so we refer to the pointing-device-oriented handlers plus Keys together as the set of Input Handlers. We expect to offer more attached-property use cases in future versions of Qt.
Input Handlers
Handler for dragging | |
Handler for mouse and tablet hover | |
Supports key navigation by arrow keys | |
Provides key handling to Items | |
Handler for pinch gestures | |
Handler for reacting to a single touchpoint | |
Handler for taps and clicks | |
Handler for the mouse wheel |
Key Features
Some of the key features are:
- Handle keystrokes within the focused Item
- Handle gestures such as tapping or dragging regardless which device it comes from
- Handle gestures from different classes of devices in different ways
- Each Item can have unlimited Handlers