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在前面的文章“使用golang来设计我们的Ubuntu Scope”中，我们已经介绍了如何利用golang来开发Ubuntu Scope。在今天的文章中，我们来简单介绍一下如何使用golang来开发QML应用。这对于一些熟悉golang语言的，但是不是很熟悉C++的开发这来说，无疑是一个好的选择。虽然我们大多数的QML应用只需要QML加上一些Javascript的脚本即可，但是我们可以使用Qt C++或Go语言来拓展它的功能，来做一些需要计算或特殊功能的部分。

首先，我们来查看我们中国开发者dawndiy所做的一个repository:

https://github.com/dawndiy/ubuntu-go-qml-template

这个repository是基于另外一个repository: https://github.com/go-qml/qml．有兴趣的开发者也可以参阅另外一个repository https://github.com/salviati/go-qt5．这也是一个非常有意思的一个项目．

首先就像dawndiy在它的github里描述的那样：

安装Ubuntu SDK

安装额外的包

$sudo apt-get install golang g++ qtdeclarative5-dev qtbase5-private-dev qtdeclarative5-private-dev libqt5opengl5-dev qtdeclarative5-qtquick2-plugin

设置chroots

$git clone https://github.com/nikwen/ubuntu-go-qml-template.git
$cd ubuntu-go-qml-template
$chroot-scripts/setup-chroot.sh

#!/bin/bashDIR=$(dirname $(readlink -f "$0"))echo "====================================="
echo "========== Creating chroot =========="
echo "====================================="
echosudo click chroot -a armhf -f ubuntu-sdk-14.10 -s utopic create
sudo click chroot -a armhf -f ubuntu-sdk-14.10 -s utopic upgradeecho
echo "====================================="
echo "=== Installing packages in chroot ==="
echo "====================================="
echosudo click chroot -a armhf -f ubuntu-sdk-14.10 -s utopic maint apt-get install git qtdeclarative5-dev:armhf qtbase5-private-dev:armhf qtdeclarative5-private-dev:armhf libqt5opengl5-dev:armhf qtdeclarative5-qtquick2-plugin:armhfGO_DIR=$DIR/../go-installationmkdir -p $GO_DIR
cd $GO_DIR$DIR/install-go-1-3-3.sh

在Desktop下运行应用

$./run.sh

应用中的qml文件可以在./share/ubuntu-go-qml-template/main.qml中找到：

main.qml

import QtQuick 2.0
import Ubuntu.Components 1.1/*!\brief MainView with a Label and Button elements.
*/MainView {// objectName for functional testing purposes (autopilot-qt5)objectName: "mainView"// Note! applicationName needs to match the "name" field of the click manifestapplicationName: "ubuntu-go-qml-template.nikwen"/*This property enables the application to change orientationwhen the device is rotated. The default is false.*///automaticOrientation: true// Removes the old toolbar and enables new features of the new header.useDeprecatedToolbar: falsewidth: units.gu(100)height: units.gu(75)Page {title: i18n.tr("Simple")Column {spacing: units.gu(1)anchors {margins: units.gu(2)fill: parent}Label {id: labelobjectName: "label"text: ctrl.message}Button {objectName: "button"width: parent.widthtext: i18n.tr("Tap me!")onClicked: ctrl.hello()}}}
}

package mainimport ("gopkg.in/qml.v1""log"
)func main() {err := qml.Run(run)if (err != nil) {log.Fatal(err)}
}func run() error {engine := qml.NewEngine()component, err := engine.LoadFile("share/ubuntu-go-qml-template/main.qml")if err != nil {return err}ctrl := Control{Message: "Hello from Go!"}context := engine.Context()context.SetVar("ctrl", &ctrl)win := component.CreateWindow(nil)ctrl.Root = win.Root()win.Show()win.Wait()return nil
}type Control struct {Root    qml.ObjectMessage string
}func (ctrl *Control) Hello() {go func() {if (ctrl.Message == "Hello from Go!") {ctrl.Message = "Hello from Go Again!"} else {ctrl.Message = "Hello from Go!"}qml.Changed(ctrl, &ctrl.Message)}()
}

部署到手机中

$./install-on-device.sh