QML Introduction



  • 参考视频:Introduction to Qt - Intro to QML {tutorial}

    主要功能

    • 点击Sender,Receiver会变颜色,然后计数+1
    • 按+-键,Sender和Receiver会变大变小,按Esc键会复原

    源码

    Background.qml

    import QtQuick 2.11
    
    BackgroundForm {
        property Circle target: null
        focus: true
    
        Keys.onPressed: {
            if(event.key === Qt.Key_Plus || event.key === Qt.Key_Equal){
                target.width += 10
                target.visible = true
            }
            if(event.key === Qt.Key_Minus || event.key === Qt.Key_Underscore){
                if(target.width>0){
                    target.width -= 10
                    target.visible = true
                }else{
                    target.visible = false
                }
    
            }
            if(event.key === Qt.Key_Escape){
                target.width = 200
            }
        }
    }
    
    

    BackgroundForm.ui.qml

    import QtQuick 2.11
    
    Item {
        width: 400
        height: 400
    
        Rectangle {
            id: rectangle
            gradient: Gradient {
                GradientStop {
                    position: 0
                    color: "#80d5f6"
                }
    
                GradientStop {
                    position: 1
                    color: "#000000"
                }
            }
            anchors.fill: parent
        }
    }
    
    

    Circle.qml

    import QtQuick 2.11
    
    CircleForm {
    }
    
    

    CircleForm.ui.qml

    import QtQuick 2.11
    
    Item {
        width: 200
        height: 200
        property alias buttonColor: button.color
        property alias displayText: display.text
    
        Rectangle {
            id: button
            width: 200
            height: 200
            color: "#ff0000"
            radius: width * 0.5
            anchors.fill: parent
    
            Text {
                id: display
                x: 176
                y: 194
                text: qsTr("Hello Qt")
                anchors.horizontalCenter: parent.horizontalCenter
                anchors.verticalCenter: parent.verticalCenter
                font.family: "Times New Roman"
                font.pixelSize: 24
            }
        }
    }
    
    

    Receiver.qml

    import QtQuick 2.11
    Circle {
        id: receiveButton
    
        function receive(value){
            displayText = value
            clicknotify.running = true
        }
    
        SequentialAnimation on buttonColor {
            id: clicknotify
            running: false
    
    
            ColorAnimation {
                from: "red"
                to: "blue"
                duration: 500
            }
    
            ColorAnimation {
                from: "blue"
                to: "red"
                duration: 500
            }
        }
    }
    
    

    Sender.qml

    import QtQuick 2.11
    
    Circle {
        id: sendButton
    
        property int counter: 0
        property Receiver target: null
    
        signal send(string value)
        onTargetChanged: send.connect(target.receive)
    
        MouseArea{
            anchors.fill: parent
    
            onClicked: {
                counter++
                parent.send(counter)
            }
    
            onPressed: {
                parent.buttonColor = "green"
            }
            onReleased: {
                parent.buttonColor = "blue"
            }
        }
    }
    
    

    main.qml

    import QtQuick 2.11
    import QtQuick.Window 2.11
    
    Window {
        visible: true
        width: 640
        height: 480
        title: qsTr("QML Introduction")
    
        Background {
            id: background
            anchors.fill: parent
            target: sender
            Sender {
                id: sender
                y: 214
                displayText: "Sender"
                anchors.verticalCenterOffset: 0
                anchors.left: parent.left
                anchors.leftMargin: 50
                anchors.verticalCenter: parent.verticalCenter
                target: receiver
            }
    
            Receiver {
                id: receiver
                x: 532
                y: 240
                displayText: "Receiver"
                anchors.right: parent.right
                anchors.rightMargin: 50
                anchors.verticalCenter: parent.verticalCenter
                width: sender.width
                visible: sender.visible
            }
        }
    }
    
    

    截图

    最后的运行效果

    image

    自己做的时候留下的部分截图

    image
    image
    image

    思考与总结

    我刚刚看到视频中做Background和Circle组件时,感到非常奇怪,为什么要用一个Item,而不直接使用Rectangle呢?后来看到,先把这两个组件做好,最后进行组装,特别好用。用js做的一些简单逻辑也非常方便。

    GitHub: https://github.com/PikachuHy/qml-demo/tree/master/qml-introduction


 

走马观花

最近的回复

关注我们

微博
QQ群











召唤伊斯特瓦尔