首页 > 代码库 > PhoneGap 插件简介
PhoneGap 插件简介
PhoneGap 插件简介
#广州# OSC源创会第31期(12月27日)开始报名,OSC自曝家丑!
一、PhoneGap平台
前不久PhoneGap发布了1.0版本,这为移动开发大家族提供了又一个跨平台的解决方案。开发者只要有JavaScript、CSS3、Html5的基础就可以快速开发移动应用,并且一次开发支持iOS、iOS(xcode 4)、Android、WebOS、Blackberry、Symbian 六大平台。不过,JavaScript的速度虽然在近些年提高了100倍,其速度还是无法和原生代码相比。在编写复杂的业务逻辑时JavaScript显得力不从心。那么PhoneGap有没有办法解决这个问题呢?答案是肯定的。PhoneGap平台提供了插件功能,开发者可以将重量级的功能封装在原生代码开发的插件中,并将接口暴露给JavaScript,JavaScript在调用插件功能时都是非阻塞的,所以并不影响JavaScript层的性能。下面我们就看看如何编写和调用一个PhoneGap插件吧。
二、编写插件
由于要写原生代码,所以各个平台插件的编写略有不同。我们以Android为例吧。这个是PhoneGap官方的例子,原文网址: http://wiki.phonegap.com/w/page/36753494/How%20to%20Create%20a%20PhoneGap%20Plugin%20for%20Android 需要翻*墙。1.插件功能
PhoneGap提供了文件读写的Api,但没有提供列出文件清单的功能。我们编写一个名为 DirectoryListingPlugin 的插件来实现列表SDCARD上文件的功能吧。
2.创建一个Android工程
如下图所示:3.包含PhoneGap依赖
- 下载PhoneGap并解压
- 在工程根目录新建目录/libs
- 拷贝 phonegap.jar 到 /libs
4.实现插件类
代码:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
|
/**
* Example of Android PhoneGap Plugin
*/
packagecom.trial.phonegap.plugin.directorylisting;
importjava.io.File;
importorg.json.JSONArray;
importorg.json.JSONException;
importorg.json.JSONObject;
importandroid.util.Log;
importcom.phonegap.api.Plugin;
importcom.phonegap.api.PluginResult;
importcom.phonegap.api.PluginResult.Status;
/**
* PhoneGap plugin which can be involved in following manner from javascript
* <p>
* result example -
* {"filename":"/sdcard","isdir":true,"children":[{"filename":"a.txt"
* ,"isdir":false},{..}]}
* </p>
*
* <pre>
* {
@code
* successCallback = function(result){
* //result is a json
*
* }
* failureCallback = function(error){
* //error is error message
* }
*
* DirectoryListing.list("/sdcard",
* successCallback
* failureCallback);
*
* }
* </pre>
*
*
@author Rohit Ghatol
*
*/
publicclassDirectoryListPluginextendsPlugin {
/** List Action */
publicstaticfinalString ACTION ="list";
/*
* (non-Javadoc)
*
*
@see com.phonegap.api.Plugin#execute(java.lang.String,
* org.json.JSONArray, java.lang.String)
*/
@Override
publicPluginResult execute(String action, JSONArray data, String callbackId) {
Log.d("DirectoryListPlugin","Plugin Called");
PluginResult result =null;
if(ACTION.equals(action)) {
try{
String fileName = data.getString(0);
JSONObject fileInfo = getDirectoryListing(newFile(fileName));
Log
.d("DirectoryListPlugin","Returning "
+ fileInfo.toString());
result =newPluginResult(Status.OK, fileInfo);
}catch(JSONException jsonEx) {
Log.d("DirectoryListPlugin","Got JSON Exception "
+ jsonEx.getMessage());
result =newPluginResult(Status.JSON_EXCEPTION);
}
}else{
result =newPluginResult(Status.INVALID_ACTION);
Log.d("DirectoryListPlugin","Invalid action : "+ action
+" passed");
}
returnresult;
}
/**
* Gets the Directory listing for file, in JSON format
*
*
@param file
* The file for which we want to do directory listing
* @return JSONObject representation of directory list. e.g
* {"filename":"/sdcard"
* ,"isdir":true,"children":[{"filename":"a.txt"
* ,"isdir":false},{..}]}
* @throws JSONException
*/
privateJSONObject getDirectoryListing(File file)throwsJSONException {
JSONObject fileInfo =newJSONObject();
fileInfo.put("filename", file.getName());
fileInfo.put("isdir", file.isDirectory());
if(file.isDirectory()) {
JSONArray children =newJSONArray();
fileInfo.put("children", children);
if(null!= file.listFiles()) {
for(File child : file.listFiles()) {
children.put(getDirectoryListing(child));
}
}
}
returnfileInfo;
}
}
|
Eclipse中如下操作:
- 在要生成jar的项目上右击,选择菜单上的Export(导出)
- 导出类型选择Jar File
- 选择或者输入生成路径
- 选择要导出的类
6.实现JavaScript插件
- 创建一个名为DirectoryListing的类
- 创建一个成员函数list()
- 在成员函数中调用PhoneGap.exec(<<successCallback>>,<<failureCallback>>,<<Plugin Name>>,<<Action Name>>,<<Arguments Array>>);
- 将js文件保存为directorylisting.js
代码:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
|
/**
*
* @return Object literal singleton instance of DirectoryListing
*/
var DirectoryListing = {
/**
* @param directory The directory for which we want the listing
* @param successCallback The callback which will be called when directory listing is successful
* @param failureCallback The callback which will be called when directory listing encouters an error
*/
list: function(directory,successCallback, failureCallback) {
returnPhoneGap.exec(successCallback, //Success callback from the plugin
failureCallback, //Error callback from the plugin
‘DirectoryListPlugin‘, //Tell PhoneGap to run "DirectoryListingPlugin" Plugin
‘list‘, //Tell plugin, which action we want to perform
[directory]); //Passing list of args to the plugin
}
};
|
三、测试
1.创建一个PhoneGap应用 http://www.phonegap.com/start/#android
2.将 directorylisting.jar 加入工程依赖
3.将directorylisting.js放入到 /assets/www 目录下。
4.在 /res/xml/plugins.xml 文件中添加
1
2
|
<pluginname="DirectoryListPlugin"
value="http://www.mamicode.com/com.trial.phonegap.plugin.directorylisting.DirectoryListPlugin"/>
|
5.在index.html中调用DirectoryListing.list
代码:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
|
<!DOCTYPE HTML>
<html>
<head>
<title>PhoneGap</title>
</head>
<body>
<!-- Button -->
<input disabled id="list-sdcard"type="button"value="http://www.mamicode.com/List SDCard Contents" />
<hr>
<!-- Place Holderforplacing the SD Card Listing -->
<div id="result"></div>
<hr>
<script type="text/javascript"src="http://www.mamicode.com/phonegap-1.0.0.js"></script>
<script type="text/javascript"src="http://www.mamicode.com/directorylisting.js"></script>
<script type="text/javascript">
document.addEventListener(‘deviceready‘,function() {
varbtn = document.getElementById("list-sdcard");
btn.onclick =function() {
DirectoryListing.list( "/sdcard",
function(r){printResult(r)},
function(e){log(e)}
);
}
btn.disabled=false;
},true);
functionprintResult(fileInfo){
varinnerHtmlText=getHtml(fileInfo);
document.getElementById("result").innerHTML=innerHtmlText;
}
functiongetHtml(fileInfo){
varhtmlText="<ul><li>"+fileInfo.filename;
if(fileInfo.children){
for(varindex=0;index<fileInfo.children.length;index++){
htmlText=htmlText+getHtml(fileInfo.children[index]);
}
}
htmlText=htmlText+"</li></ul>";
returnhtmlText;
}
</script>
</body>
</html>
|
至此,一个PhoneGap Android插件就成完了。
文章转自 : http://blog.csdn.net/yyan/article/details/6664863
PhoneGap 插件简介