在Android 下写一个检测软件版本号 以自动升级APP 的插件

直接上图上代码：

1、插件类的编写

　　工程目录结构图：

　　代码如下：

package org.apache.cordova.versionupdate;

import org.apache.cordova.CallbackContext;
import org.apache.cordova.CordovaPlugin;
import org.apache.cordova.PluginResult;
import org.json.JSONArray;
import org.json.JSONException;

import android.content.pm.PackageInfo;
import android.content.pm.PackageManager.NameNotFoundException;

public class GCAppPlugin extends CordovaPlugin {

    @Override
    public boolean execute(String action, JSONArray args, CallbackContext callbackContext) throws JSONException {
        if ("version".equals(action)) {
            version(callbackContext);
            return true;
        }
        return false; 
    }

    private synchronized void version(CallbackContext callbackContext) {
        PackageInfo packInfo;
        try {
            packInfo = this.cordova.getActivity().getPackageManager().getPackageInfo(this.cordova.getActivity().getPackageName(),0);
            String version = packInfo.versionName +"_"+packInfo.versionCode+"";
            callbackContext.sendPluginResult(new PluginResult(PluginResult.Status.OK, version));
        } catch (NameNotFoundException e) {    }
    }
}

　　Javascript如何得到插件调用后的返回结果？主要通过类似 callbackContext.sendPluginResult(new PluginResult(PluginResult.Status.OK, version)); 代码返回PluginResult，失败和成功都可以触发Javascript执行对应的自定义函数。

2、插件的配置

　　打开res/xml/config.xml文件，添加feature，必须匹配类名，因为源码中是通过这些去配对的。上面我们写了更新插件，现在就是要配置一下这个插件类到功能名称，我在配置文件中加入了下文粗体部分内容（最后面）。

<?xml version='1.0' encoding='utf-8'?>
<widget id="com.lambda.client.cordova.washcarshopmanager" version="0.0.1" xmlns="http://www.w3.org/ns/widgets" xmlns:cdv="http://cordova.apache.org/ns/1.0">
    <preference name="loglevel" value="DEBUG" />
    <allow-intent href="market:*" />
    <name>WashCarShopManager</name>
    <description>
        A sample Apache Cordova application that responds to the deviceready event.
    </description>
    <author email="dev@cordova.apache.org" href="http://cordova.io">
        Apache Cordova Team
    </author>
   <!--  <content src="index.html" /> -->
   <!-- <content src="test/check_version.html" />  -->
   <content src="vipapp/index.html" /> 
    <access origin="*" />
    <allow-intent href="http://*/*" />
    <allow-intent href="https://*/*" />
    <allow-intent href="tel:*" />
    <allow-intent href="sms:*" />
    <allow-intent href="mailto:*" />
    <allow-intent href="geo:*" />
    <allow-navigation href="http: //*/*" /> 
    <feature name="Whitelist">
        <param name="android-package" value="org.apache.cordova.whitelist.WhitelistPlugin" />
        <param name="onload" value="true" />
    </feature>
    <feature name="Device">
        <param name="android-package" value="org.apache.cordova.device.Device" />
    </feature>
    <feature name="NetworkStatus">
        <param name="android-package" value="org.apache.cordova.networkinformation.NetworkManager" />
    </feature>
    <feature name="Geolocation">
        <param name="android-package" value="org.apache.cordova.geolocation.Geolocation" />
    </feature>
    <feature name="Camera">
        <param name="android-package" value="org.apache.cordova.camera.CameraLauncher" />
    </feature>
    <feature name="File">
        <param name="android-package" value="org.apache.cordova.file.FileUtils" />
        <param name="onload" value="true" />
    </feature>
    <feature name="Notification">
        <param name="android-package" value="org.apache.cordova.dialogs.Notification" />
    </feature>
    <feature name="SplashScreen">
        <param name="android-package" value="org.apache.cordova.splashscreen.SplashScreen" />
        <param name="onload" value="true" />
    </feature>
    <feature name="Gcapp"> 
        <param name="android-package" value="org.apache.cordova.versionupdate.GCAppPlugin" />
    </feature>  
</widget>

代码贴完了，我还是要再多说一下，

　　① org.apache.cordova.versionupdate.GCAppPlugin 是插件的全类名。

　　② Gcapp是 feature 名称，下面大家就知道在哪里会用到了

　　以上文件就是告诉cordova，我们新增了一个Gcapp功能，这个功能会调用我们的原生插件Java对象，接下来就是Javascript如何能调用到这个类了，最重要的就是这个Gcapp功能名称。

　　我们接着就要写Javascript代码来调用这个功能了，如何写呢？继续往下看，我在assets/www/plugins/下新增目录并建立了文件gcapp.js，完整路径是 assets/www/plugins/cordova-plugin-versionupdate/gcapp.js，代码如下：

cordova.define('org.apache.cordova.versionupdate.gcapp', function(require, exports, module) {
        var exec = require("cordova/exec");

        function Gcapp() {};
        
        Gcapp.prototype.version = function (getversion) {
            exec(getversion, null, 'Gcapp', 'version', []);
        };   
       
   　　 Gcapp.prototype.checkUpdate = function () {
            exec(null, null, 'Gcapp', 'checkUpdate', []);
        };   
                
        var gcapp = new Gcapp();
        module.exports = gcapp;
});

　　exec是cordova.js中内部的函数，当插件返回 PluginResult.Status.OK 时会执行exec的成功回调函数，如果插件返回的是错误，则会执行exec的错误回调函数。这里我们解释一下 

exec(null, null, 'Gcapp', 'checkUpdate', []);

　　其中Gcapp就是我们在上一步骤加的feature名称，大小写匹配着写，通过这个名称，cordova才能找到调用那个java插件类，然后通过checkUpdate知道调用这个插件类的哪个方法，后面[]中则是参数。因为我这个插件不需要参数，所以为空。

　　Javascript插件类也配对成功了，那如何调用呢？你可以直接在html中包括这个js，不过我们一般会再配置一个js，那就是assets/www/cordova_plugins.js(如下代码标蓝部分)，这样就不用对每个插件类都去写一遍了，cordova会遍历你的配置去加载它们。

cordova.define('cordova/plugin_list', function(require, exports, module) {
module.exports = [
    {
        "file": "plugins/cordova-plugin-whitelist/whitelist.js",
        "id": "cordova-plugin-whitelist.whitelist",
        "runs": true
    },
    {
        "file": "plugins/cordova-plugin-device/www/device.js",
        "id": "cordova-plugin-device.device",
        "clobbers": [
            "device"
        ]
    },
    {
        "file": "plugins/cordova-plugin-network-information/www/network.js",
        "id": "cordova-plugin-network-information.network",
        "clobbers": [
            "navigator.connection",
            "navigator.network.connection"
        ]
    },
    {
        "file": "plugins/cordova-plugin-network-information/www/Connection.js",
        "id": "cordova-plugin-network-information.Connection",
        "clobbers": [
            "Connection"
        ]
    },
    {
        "file": "plugins/cordova-plugin-geolocation/www/android/geolocation.js",
        "id": "cordova-plugin-geolocation.geolocation",
        "clobbers": [
            "navigator.geolocation"
        ]
    },
    {
        "file": "plugins/cordova-plugin-geolocation/www/PositionError.js",
        "id": "cordova-plugin-geolocation.PositionError",
        "runs": true
    },
    {
        "file": "plugins/cordova-plugin-camera/www/CameraConstants.js",
        "id": "cordova-plugin-camera.Camera",
        "clobbers": [
            "Camera"
        ]
    },
    {
        "file": "plugins/cordova-plugin-camera/www/CameraPopoverOptions.js",
        "id": "cordova-plugin-camera.CameraPopoverOptions",
        "clobbers": [
            "CameraPopoverOptions"
        ]
    },
    {
        "file": "plugins/cordova-plugin-camera/www/Camera.js",
        "id": "cordova-plugin-camera.camera",
        "clobbers": [
            "navigator.camera"
        ]
    },
    {
        "file": "plugins/cordova-plugin-camera/www/CameraPopoverHandle.js",
        "id": "cordova-plugin-camera.CameraPopoverHandle",
        "clobbers": [
            "CameraPopoverHandle"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/DirectoryEntry.js",
        "id": "cordova-plugin-file.DirectoryEntry",
        "clobbers": [
            "window.DirectoryEntry"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/DirectoryReader.js",
        "id": "cordova-plugin-file.DirectoryReader",
        "clobbers": [
            "window.DirectoryReader"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/Entry.js",
        "id": "cordova-plugin-file.Entry",
        "clobbers": [
            "window.Entry"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/File.js",
        "id": "cordova-plugin-file.File",
        "clobbers": [
            "window.File"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/FileEntry.js",
        "id": "cordova-plugin-file.FileEntry",
        "clobbers": [
            "window.FileEntry"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/FileError.js",
        "id": "cordova-plugin-file.FileError",
        "clobbers": [
            "window.FileError"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/FileReader.js",
        "id": "cordova-plugin-file.FileReader",
        "clobbers": [
            "window.FileReader"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/FileSystem.js",
        "id": "cordova-plugin-file.FileSystem",
        "clobbers": [
            "window.FileSystem"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/FileUploadOptions.js",
        "id": "cordova-plugin-file.FileUploadOptions",
        "clobbers": [
            "window.FileUploadOptions"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/FileUploadResult.js",
        "id": "cordova-plugin-file.FileUploadResult",
        "clobbers": [
            "window.FileUploadResult"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/FileWriter.js",
        "id": "cordova-plugin-file.FileWriter",
        "clobbers": [
            "window.FileWriter"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/Flags.js",
        "id": "cordova-plugin-file.Flags",
        "clobbers": [
            "window.Flags"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/LocalFileSystem.js",
        "id": "cordova-plugin-file.LocalFileSystem",
        "clobbers": [
            "window.LocalFileSystem"
        ],
        "merges": [
            "window"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/Metadata.js",
        "id": "cordova-plugin-file.Metadata",
        "clobbers": [
            "window.Metadata"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/ProgressEvent.js",
        "id": "cordova-plugin-file.ProgressEvent",
        "clobbers": [
            "window.ProgressEvent"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/fileSystems.js",
        "id": "cordova-plugin-file.fileSystems"
    },
    {
        "file": "plugins/cordova-plugin-file/www/requestFileSystem.js",
        "id": "cordova-plugin-file.requestFileSystem",
        "clobbers": [
            "window.requestFileSystem"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/resolveLocalFileSystemURI.js",
        "id": "cordova-plugin-file.resolveLocalFileSystemURI",
        "merges": [
            "window"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/browser/isChrome.js",
        "id": "cordova-plugin-file.isChrome",
        "runs": true
    },
    {
        "file": "plugins/cordova-plugin-file/www/android/FileSystem.js",
        "id": "cordova-plugin-file.androidFileSystem",
        "merges": [
            "FileSystem"
        ]
    },
    {
        "file": "plugins/cordova-plugin-file/www/fileSystems-roots.js",
        "id": "cordova-plugin-file.fileSystems-roots",
        "runs": true
    },
    {
        "file": "plugins/cordova-plugin-file/www/fileSystemPaths.js",
        "id": "cordova-plugin-file.fileSystemPaths",
        "merges": [
            "cordova"
        ],
        "runs": true
    },
    {
        "file": "plugins/cordova-plugin-dialogs/www/notification.js",
        "id": "cordova-plugin-dialogs.notification",
        "merges": [
            "navigator.notification"
        ]
    },
    {
        "file": "plugins/cordova-plugin-dialogs/www/android/notification.js",
        "id": "cordova-plugin-dialogs.notification_android",
        "merges": [
            "navigator.notification"
        ]
    },
    {
        "file": "plugins/cordova-plugin-splashscreen/www/splashscreen.js",
        "id": "cordova-plugin-splashscreen.SplashScreen",
        "clobbers": [
            "navigator.splashscreen"
        ]
    },
    {
        "file": "plugins/cordova-plugin-versionupdate/gcapp.js",
        "id": "org.apache.cordova.versionupdate.gcapp",
        "clobbers": [
            "gcapp"
        ]
    }
];
module.exports.metadata = 
// TOP OF METADATA
{
    "cordova-plugin-whitelist": "1.2.1",
    "cordova-plugin-device": "1.1.1",
    "cordova-plugin-network-information": "1.2.0",
    "cordova-plugin-geolocation": "2.1.0",
    "cordova-plugin-camera": "2.1.1",
    "cordova-plugin-file": "4.1.1",
    "cordova-plugin-dialogs": "1.1.0",
    "cordova-plugin-splashscreen": "2.1.0"
}
// BOTTOM OF METADATA
});

　　file表示我们去哪里找脚本插件定义js，id是之前我们在gcapp.js中开头cordova.define中写的标识，cordova通过这个标志去找到我们的Javascript插件定义，而clobbers则是我们在前端通过什么对象名来调用这个插件。这里我写的是gcapp，则后面调用则只需要写成gcapp.checkUpdate 即可。

三、插件的调用

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 
    <title>Camera Example</title>

    <script type="text/javascript" charset="utf-8" src="../../cordova.js"></script>
    <script type="text/javascript" charset="utf-8" src="../js/jquery.min.js"></script>
    <script type="text/javascript" charset="utf-8">
    // 等待PhoneGap连接设备
    document.addEventListener("deviceready",onDeviceReady,false);
    
    // PhoneGap准备就绪，可以使用！
    function onDeviceReady() {
        gcapp.version(function(version){
            $("#version").html("当前软件版本号为：  "+version);
        });
    }
</script>
</head>
<body>
    <p id="version">version is ?</p><br/>
</body>

</html>

　　此时已经能获取APP的版本信息了，需要在服务器端设置一个最新的版本号，每次用本地的版本号和服务器端的最新版本号比较，如果本地版本号小，则提示用户升级。

　　本文参考：http://www.cnblogs.com/zhoujg/p/4629162.html

　　因为只弄通了获取软件的版本号，而检测更新那块没弄懂，所以就没写，只写了获取版本号的内容。也算是大概了解了一下cordova自定义插件编写的流程。