Cordova WP8 插件开发

　　前面博客中介绍了Cordova WP8平台上的安装部署，Cordova扩展可以利用WP8本地代码扩展WebApp的功能，调用本地能力需要开发相应的插件，下面以闪光灯作为实例来描述创建一个WP8插件的详细步骤，对于闪光灯实现打开和关闭两个接口函数。

　　

1.  创建插件类

　　创建闪光灯插件类FlashLight需继承BaseCommand，通常我们会在工程目录下创建Plugins目录用于存放插件类。即在Plugins目录下创建FlashLight.cs文件。

　　编写FlashLight.cs文件，添加如下代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.Phone.Media.Capture;
using WPCordovaClassLib.Cordova;
using WPCordovaClassLib.Cordova.Commands;

namespace TestCordova.Plugins
{
    class FlashLight : BaseCommand
    {
        /// <summary>
        /// 闪光灯实例
        /// </summary>
        protected static AudioVideoCaptureDevice Device { get; set; }

        /// <summary>
        /// 打开闪光灯
        /// </summary>
        /// <returns></returns>
        public async Task trunOn(string options)
        {
            var sensorLocation = CameraSensorLocation.Back;

            try
            {
                if (Device == null)
                {
                    //取得 AudioViceoCaptureDevice
                    Device = await AudioVideoCaptureDevice.OpenAsync(sensorLocation, AudioVideoCaptureDevice.GetAvailableCaptureResolutions(sensorLocation).First());
                }

                // 打开闪光灯
                var supportedCameraModes = AudioVideoCaptureDevice.GetSupportedPropertyValues(sensorLocation, KnownCameraAudioVideoProperties.VideoTorchMode);
                if (supportedCameraModes.ToList().Contains((UInt32)VideoTorchMode.On))
                {
                    Device.SetProperty(KnownCameraAudioVideoProperties.VideoTorchMode, VideoTorchMode.On);

                    // 设定亮度为最大
                    Device.SetProperty(KnownCameraAudioVideoProperties.VideoTorchPower, AudioVideoCaptureDevice.GetSupportedPropertyRange(sensorLocation, KnownCameraAudioVideoProperties.VideoTorchPower).Max);
                }

                //返回状态
                DispatchCommandResult(new PluginResult(PluginResult.Status.OK, "{data: "ok"}"));
            }
            catch (Exception ex)
            {
                // 无法控制闪光灯,返回错误状态
                DispatchCommandResult(new PluginResult(PluginResult.Status.JSON_EXCEPTION));
            }
        }

        /// <summary>
        /// 关闭闪光灯
        /// </summary>
        public void trunOff(string options)
        {
            var sensorLocation = CameraSensorLocation.Back;

            try
            {
                var supportedCameraModes = AudioVideoCaptureDevice
                    .GetSupportedPropertyValues(sensorLocation, KnownCameraAudioVideoProperties.VideoTorchMode);
                // 关闭闪光灯
                if (Device != null && supportedCameraModes.ToList().Contains((UInt32)VideoTorchMode.Off))
                {
                    Device.SetProperty(KnownCameraAudioVideoProperties.VideoTorchMode, VideoTorchMode.Off);
                }

                //返回状态
                DispatchCommandResult(new PluginResult(PluginResult.Status.OK, "{data: "ok"}"));
            }
            catch (Exception ex)
            {
                // 无法控制闪光灯,返回错误状态
                System.Diagnostics.Debug.WriteLine(ex);
                DispatchCommandResult(new PluginResult(PluginResult.Status.JSON_EXCEPTION));
            }
        }
    }
}

　　由于调用闪光灯需要打开硬件的部分能力，所以需要配置WMAppManifest.xml文件勾选ID_CAP_ISV_CAMERA和ID_CAP_MICROPHONE。

2.  配置config.xml

　　打开config.xml文件在widget元素内加入配置：

  <feature name="FlashLight">
    <param name="wp-package" value="FlashLight" />
  </feature>

　　说明：以上配置是基于FlashLight类的命名空间为Cordova.Extension.Commands，如果将命名空间修改为其他，例如：TestCordova.Plugins，那么上述配置需修改为：

  <feature name="FlashLight">
    <param name="wp-package" value="TestCordova.Plugins.FlashLight" />
  </feature>

3.  编写js代码

　　打开index.html，编写js代码如下：

    <script type="text/javascript">
        app.initialize();

        function trunOn() {
            cordova.exec(
                function (data) {
                    //调用C#代码成功的回调函数
                    alert("Sucess:" + data);
                },
                function (data) {
                    //调用C#代码失败的回调函数
                    alert("Fail" + data);
                }
                , "FlashLight", "trunOn", ["input string"]);
        }

        function trunOff() {
            cordova.exec(
                function (data) {
                    //调用C#代码成功的回调函数
                    alert("Sucess:" + data);
                },
                function (data) {
                    //调用C#代码失败的回调函数
                    alert("Fail" + data);
                }
                , "FlashLight", "trunOff", ["input string"]);
        }
    </script>

　　添加两个button按钮，代码如下：

    <div class="app">
        <h1>Apache Cordova</h1>
        <div id="deviceready" class="blink">
            <p class="event listening">Connecting to Device</p>
            <p class="event received">Device is Ready</p>
        </div>
        <div>
            <button type="button" value="打开" style=" 100px; height: 50px; color: black; font-size: larger;" onclick="trunOn()">打开</button>
            <button type="button" value="关闭" style=" 100px; height: 50px; color: black; font-size: larger;" onclick="trunOff()">关闭</button>
        </div>
    </div>

4.  运行

　　编译并运行wp8工程，界面显示效果如下图：