Supported types of user input▲
The Qt Quick module provides support for the most common types of user input, including mouse and touch events, text input, and key-press events. Other modules provide support for other types of user input for example, the Qt Sensors module provides support for shake-gestures in QML applications.
This article covers how to handle basic user input; for further information about motion-gesture support, see the Qt Sensors documentation. For information about audio-visual input, see the Qt Multimedia documentation.
Mouse and touch events▲
The input handlers let QML applications handle mouse and touch events. For example, you could create a button by adding a TapHandler to an Image, or to a Rectangle with a Text object inside. The TapHandler responds to taps or clicks on any type of pointing device.
import QtQuick 2.12
Item {
id: root
width: 320
height: 480
Rectangle {
color: "#272822"
width: 320
height: 480
}
Rectangle {
id: rectangle
x: 40
y: 20
width: 120
height: 120
color: "red"
TapHandler {
onTapped: rectangle.width += 10
}
}
}For more advanced use cases such as, drag, pinch and zoom gestures, see documentation for the DragHandler and PinchHandler types.
Some types have their own built-in input handling. For example, Flickable responds to mouse dragging and mouse wheel scrolling. It handles touch dragging and flicking via synthetic mouse events that are created when the touch events are not handled.
Keyboard and button events▲
import QtQuick 2.3
Item {
id: root
width: 320
height: 480
Rectangle {
color: "#272822"
width: 320
height: 480
}
Rectangle {
id: rectangle
x: 40
y: 20
width: 120
height: 120
color: "red"
focus: true
Keys.onUpPressed: rectangle.y -= 10
Keys.onDownPressed: rectangle.y += 10
Keys.onLeftPressed: rectangle.x += 10
Keys.onRightPressed: rectangle.x -= 10
}
}For text input, we have several QML types to choose from. TextInput provides an unstyled single-line editable text, while TextField is more suitable for form fields in applications. TextEdit can handle multi-line editable text, but TextArea is a better alternative as it adds styling.
The following snippet demonstrates how to use these types in your application:
import QtQuick 2.12
import QtQuick.Controls 2.4
import QtQuick.Layouts 1.3
ApplicationWindow {
width: 300
height: 200
visible: true
ColumnLayout {
anchors.fill: parent
TextField {
id: singleline
text: "Initial Text"
Layout.alignment: Qt.AlignHCenter | Qt.AlignTop
Layout.margins: 5
background: Rectangle {
implicitWidth: 200
implicitHeight: 40
border.color: singleline.focus ? "#21be2b" : "lightgray"
color: singleline.focus ? "lightgray" : "transparent"
}
}
TextArea {
id: multiline
placeholderText: "Initial text\n...\n...\n"
Layout.alignment: Qt.AlignLeft
Layout.fillWidth: true
Layout.fillHeight: true
Layout.margins: 5
background: Rectangle {
implicitWidth: 200
implicitHeight: 100
border.color: multiline.focus ? "#21be2b" : "lightgray"
color: multiline.focus ? "lightgray" : "transparent"
}
}
}
}