qml demo分析(clocks-时钟)

一、效果展示

　　效果如图1所示，时钟列表支持鼠标左右拖动，带有黑色背景的是晚上时钟，无黑色背景的是白天时钟

二、源码分析

1、main.cpp文件中只包含了一个宏，该宏的具体解释请看qml 示例中的关键宏文章

2、时钟项

  1 Item {
  2     id : clock
  3      {
  4         if (ListView.view && ListView.view.width >= 200)
  5             return ListView.view.width / Math.floor(ListView.view.width / 200.0);
  6         else
  7             return 200;
  8     }
  9 
 10     height: {
 11         if (ListView.view && ListView.view.height >= 240)
 12             return ListView.view.height;
 13         else
 14             return 240;
 15     }
 16 
 17     property alias city: cityLabel.text//属性别名，方便在外部使用
 18     property int hours//自定义属性
 19     property int minutes
 20     property int seconds
 21     property real shift
 22     property bool night: false//是否是晚上  来决定是否显示黑色实心圈
 23     property bool internationalTime: true //Unset for local time
 24 
 25     //js函数
 26     function timeChanged() {
 27         var date = new Date;
 28         hours = internationalTime ? date.getUTCHours() + Math.floor(clock.shift) : date.getHours()
 29         night = ( hours < 7 || hours > 19 )
 30         minutes = internationalTime ? date.getUTCMinutes() + ((clock.shift % 1) * 60) : date.getMinutes()
 31         seconds = date.getUTCSeconds();
 32     }
 33 
 34     Timer {
 35         interval: 100; running: true; repeat: true;//一个每隔100ms重复执行的定时器，默认启动
 36         onTriggered: clock.timeChanged()//定时器槽函数
 37     }
 38 
 39     Item {
 40         anchors.centerIn: parent
 41          200; height: 240
 42         
 43         Image { id: background; source: "clock.png"; visible: clock.night == false }//最外层白色圈
 44         Image { source: "clock-night.png"; visible: clock.night == true }//黑色实心圈，带有白色实心圆球的刻度点   
 45 
 46         //时针
 47         Image {
 48             x: 92.5; y: 27
 49             source: "hour.png"
 50             transform: Rotation {
 51                 id: hourRotation
 52                 origin.x: 7.5; origin.y: 73;
 53                 angle: (clock.hours * 30) + (clock.minutes * 0.5)
 54                 Behavior on angle {
 55                     SpringAnimation { spring: 2; damping: 0.2; modulus: 360 }
 56                 }
 57             }
 58         }
 59 
 60         //分针
 61         Image {
 62             x: 93.5; y: 17
 63             source: "minute.png"
 64             transform: Rotation {
 65                 id: minuteRotation
 66                 origin.x: 6.5; origin.y: 83;
 67                 angle: clock.minutes * 6
 68                 Behavior on angle {
 69                     SpringAnimation { spring: 2; damping: 0.2; modulus: 360 }
 70                 }
 71             }
 72         }
 73 
 74         //秒针
 75         Image {
 76             x: 97.5; y: 20
 77             source: "second.png"
 78             transform: Rotation {
 79                 id: secondRotation
 80                 origin.x: 2.5; origin.y: 80;
 81                 angle: clock.seconds * 6
 82                 Behavior on angle {
 83                     SpringAnimation { spring: 2; damping: 0.2; modulus: 360 }
 84                 }
 85             }
 86         }
 87         //中心白色圆圈
 88         Image {
 89             anchors.centerIn: background; source: "center.png"
 90         }
 91 
 92         Text {
 93             id: cityLabel//该属性已经被导出，在clocks.qml文件中指定该属性值
 94             y: 210; anchors.horizontalCenter: parent.horizontalCenter
 95             color: "white"
 96             font.family: "Helvetica"
 97             font.bold: true; font.pixelSize: 16
 98             style: Text.Raised; styleColor: "black"
 99         }
100     }
101 }

3、时钟列表

 1 import "content" as Content  //导入目录  该目录底下的所有qml自定义控件均可以直接使用
 2 
 3 Rectangle {
 4     id: root
 5      640; height: 320
 6     color: "#646464"
 7 
 8     ListView {//列表视图
 9         id: clockview//唯一id
10         anchors.fill: parent//填充整个父窗口
11         orientation: ListView.Horizontal//列表朝向为水平方向
12         cacheBuffer: 2000//左右2000个像素以内的委托项都不会被析构
13         snapMode: ListView.SnapOneItem//拖拽模式
14         highlightRangeMode: ListView.ApplyRange//高亮模式，高亮尽可能在可是区间内
15 
16         delegate: Content.Clock { city: cityName; shift: timeShift }//设置Clock控件的导出属性值
17         model: ListModel {//静态model
18             ListElement { cityName: "New York"; timeShift: -4 }
19             ListElement { cityName: "London"; timeShift: 0 }
20             ListElement { cityName: "Oslo"; timeShift: 1 }
21             ListElement { cityName: "Mumbai"; timeShift: 5.5 }
22             ListElement { cityName: "Tokyo"; timeShift: 9 }
23             ListElement { cityName: "Brisbane"; timeShift: 10 }
24             ListElement { cityName: "Los Angeles"; timeShift: -8 }
25         }
26     }
27     //左下角上一个箭头
28     Image {
29         anchors.left: parent.left
30         anchors.bottom: parent.bottom
31         anchors.margins: 10
32         source: "content/arrow.png"
33         rotation: -90
34         opacity: clockview.atXBeginning ? 0 : 0.5//当视图滚动到第一个时透明度为0(使用行为动画)
35         Behavior on opacity { NumberAnimation { duration: 500 } }//在透明度属性上添加动画(数字动画)
36     }
37     //右下角下一个箭头
38     Image {
39         anchors.right: parent.right
40         anchors.bottom: parent.bottom
41         anchors.margins: 10
42         source: "content/arrow.png"
43         rotation: 90
44         opacity: clockview.atXEnd ? 0 : 0.5
45         Behavior on opacity { NumberAnimation { duration: 500 } }
46     }
47 }