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.
This article covers how to handle basic user input. For information about audio-visual input, see the Qt Multimedia 文档编制。
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 采用 文本 object inside. The TapHandler responds to taps or clicks on any type of pointing device.
import QtQuick 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 } } }
注意: Some Item types have their own built-in input handling. For example, Flickable responds to mouse dragging, touch flicking, and mouse wheel scrolling.
Button and key presses, from buttons on a device, a keypad, or a keyboard, can all be handled using the 键 attached property. This attached property is available on all Item derived types, and works with the Item::focus property to determine which type receives the key event. For simple key handling, you can set the focus to true on a single Item and do all your key handling there.
import QtQuick 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 import QtQuick.Controls import QtQuick.Layouts 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" } } } }