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PhoneGap 之 Android 端插件开发
2011年11月02日 移动开发 评论数 1 ⁄ 被围观 4,089+

前面一篇文章 《移动 APP 之跨平台解决方案》介绍了一种跨平台的解决方案,即用开发web app的方式来编写mobile app。鉴于PhoneGap才刚刚新起,还有许多功能因为平台的差异性无法很好的解决,所以我们在实际的开发中,发现有很多功能还需要完善,一种比较好的方式就是编写平台依赖的插件,进而扩展PhoneGap的功能。

lunny

本文介绍一下开发和使用插件的一个流程,以 VideoPlayer 为例。

  1. 环境搭建,下载 phonegap-android 的源码,下载地址 https://github.com/phonegap/phonegap-plugins
  2. 编写video.js,提供给web开发端的接口定义,定义了一个VideoPlayer类和play函数,参数为要播放的文件视频地址,代码如下:
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    /**
     * Constructor
     */
    function VideoPlayer() {
    };
     
    /**
     * Starts the video player intent
     *
     * @param url           The url to play
     */
    VideoPlayer.prototype.play = function(url) {
        PhoneGap.exec(null, null, "VideoPlayer", "playVideo", [url]);
    };
     
    /**
     * Load VideoPlayer
     */
    PhoneGap.addConstructor(function() {
        PhoneGap.addPlugin("videoPlayer", new VideoPlayer());
    });
    /**
     * Constructor
     */
    function VideoPlayer() {
    };
    
    /**
     * Starts the video player intent
     *
     * @param url           The url to play
     */
    VideoPlayer.prototype.play = function(url) {
        PhoneGap.exec(null, null, "VideoPlayer", "playVideo", [url]);
    };
    
    /**
     * Load VideoPlayer
     */
    PhoneGap.addConstructor(function() {
        PhoneGap.addPlugin("videoPlayer", new VideoPlayer());
    });
  3. 编写 Android VideoPlayer 的具体实现代码,VideoPlayer/src/com/phonegap/plugins/video/VideoPlayer.java
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    package com.phonegap.plugins.video;
     
    import org.json.JSONArray;
    import org.json.JSONException;
    import android.content.Intent;
    import android.net.Uri;
    import com.phonegap.api.Plugin;
    import com.phonegap.api.PluginResult;
     
    public class VideoPlayer extends Plugin {
        private static final String YOU_TUBE = "youtube.com";
     
        @Override
        public PluginResult execute(String action, JSONArray args, String callbackId) {
            PluginResult.Status status = PluginResult.Status.OK;
            String result = "";
     
            try {
                if (action.equals("playVideo")) {
                    playVideo(args.getString(0));
                }
                else {
                    status = PluginResult.Status.INVALID_ACTION;
                }
                return new PluginResult(status, result);
            } catch (JSONException e) {
                return new PluginResult(PluginResult.Status.JSON_EXCEPTION);
            }
        }
     
        private void playVideo(String url) {
            // Create URI
            Uri uri = Uri.parse(url);
     
            Intent intent = null;
            // Check to see if someone is trying to play a YouTube page.
            if (url.contains(YOU_TUBE)) {
                // If we don't do it this way you don't have the option for youtube
                intent = new Intent(Intent.ACTION_VIEW, uri);
            } else {
                // Display video player
                intent = new Intent(Intent.ACTION_VIEW);
                intent.setDataAndType(uri, "video/*");
            }
     
            this.ctx.startActivity(intent);
        }
    }
    package com.phonegap.plugins.video;
    
    import org.json.JSONArray;
    import org.json.JSONException;
    import android.content.Intent;
    import android.net.Uri;
    import com.phonegap.api.Plugin;
    import com.phonegap.api.PluginResult;
    
    public class VideoPlayer extends Plugin {
        private static final String YOU_TUBE = "youtube.com";
    
        @Override
        public PluginResult execute(String action, JSONArray args, String callbackId) {
            PluginResult.Status status = PluginResult.Status.OK;
            String result = "";
    
            try {
                if (action.equals("playVideo")) {
                    playVideo(args.getString(0));
                }
                else {
                    status = PluginResult.Status.INVALID_ACTION;
                }
                return new PluginResult(status, result);
            } catch (JSONException e) {
                return new PluginResult(PluginResult.Status.JSON_EXCEPTION);
            }
        }
    
        private void playVideo(String url) {
            // Create URI
            Uri uri = Uri.parse(url);
    
            Intent intent = null;
            // Check to see if someone is trying to play a YouTube page.
            if (url.contains(YOU_TUBE)) {
                // If we don't do it this way you don't have the option for youtube
                intent = new Intent(Intent.ACTION_VIEW, uri);
            } else {
                // Display video player
                intent = new Intent(Intent.ACTION_VIEW);
                intent.setDataAndType(uri, "video/*");
            }
    
            this.ctx.startActivity(intent);
        }
    }
  4. 配置插件, res/xml/plugins.xml 添加如下代码
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    <plugin name="VideoPlayer" value="com.phonegap.plugins.video.VideoPlayer"/>
    <plugin name="VideoPlayer" value="com.phonegap.plugins.video.VideoPlayer"/>
  5. 编写代码进行调用,文件开头引入js代码框架,然后进行VideoPlayer类的play函数调用
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    <script type="text/javascript" charset="utf-8" src="phonegap.js"></script>
    <script type="text/javascript" charset="utf-8" src="video.js"></script>
     
     //Sample use:
     /**
        * Display an intent to play the video.
        *
        * @param url           The url to play
        */
     //play(url)
     
    window.plugins.videoPlayer.play("http://path.to.my/video.mp4");
    window.plugins.videoPlayer.play("file:///path/to/my/video.mp4");
    <script type="text/javascript" charset="utf-8" src="phonegap.js"></script>
    <script type="text/javascript" charset="utf-8" src="video.js"></script>
    
     //Sample use:
     /**
        * Display an intent to play the video.
        *
        * @param url           The url to play
        */
     //play(url)
    
    window.plugins.videoPlayer.play("http://path.to.my/video.mp4");
    window.plugins.videoPlayer.play("file:///path/to/my/video.mp4");
  6. 到此为止,插件的开发和部署,以及调用就都ok了,是不是很简单( ⊙ o ⊙ )啊!

最后向大家推荐一本书籍《PhoneGap Beginner's Guide》,相信通过本书的学习,就知道了怎样利用PhoneGap来开发跨平台的mobile app了,同时也可以关注https://github.com/phonegap项目的最新进展情况和新特性,如果可以的话,贡献自己的力量来进行完善和扩充,O(∩_∩)O~!

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