Android的网络浏览:注入本地JavaScript文件到远程网页 [英] Android Web-View : Inject local Javascript file to Remote Webpage
问题描述
这已经被问过很多次,我通过一切浏览,没有明确的解答。
It has been asked many times before, I browsed through everything, no clear answers yet.
问题简化为:是否有可能要在Android网络浏览加载远程页面本地JavaScript文件(从资产或存储)注资?我知道,这是可能的,例如文件注入到在Web-查看装入本地网页(资产的HTML)。
Question simplified: Is it possible to inject local Javascript file (from asset or storage) to remote webpage loaded in an Android Web-View? I know that it is possible to inject such files to local Webpages (Assets HTML) loaded in a Web-View.
为什么我需要这个工作? :为了让浏览体验更快,避免了更大的文件,如JS和CSS文件下载每次。我想避免网络视图缓存。
Why do I need this to work? : To make browsing experience faster, by avoiding downloading of bigger files such as Js and CSS files every time. I want to avoid Web-View Caching.
推荐答案
有一种方法来力的注入,从本地资产(如资产/ JS /的script.js)本地JavaScript文件,并规避在不允许加载本地资源:文件:///android_assets/js/script.js ...'。问题
There is a way to 'force' the injection of your local Javascript files from local assets (e.g., assets/js/script.js), and to circumvent the 'Not allowed to load local resource : file:///android_assets/js/script.js ...' issue.
这是类似于在另一个线程描述(<一href="http://stackoverflow.com/questions/5649111/android-webview-loading-javascript-file-in-assets-folder">Android web视图,加载JavaScript资产文件夹文件),额外的BASE64编码/解码再presenting你的Javascript文件打印字符串。
It is similar to what described in another thread (Android webview, loading javascript file in assets folder), with additional BASE64 encoding/decoding for representing your Javascript file as a printable string.
我使用的是Android 4.4.2,API级别19的虚拟设备。
I am using an Android 4.4.2, API level 19 Virtual Device.
下面是一些code片段:
Here are some code snippets:
[资产/ JS /的script.js]:
[assets/js/script.js]:
'use strict';
function test() {
// ... do something
}
// more Javascript
[MainActivity.java]:
[MainActivity.java]:
...
WebView myWebView = (WebView) findViewById(R.id.webView);
WebSettings webSettings = myWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
webSettings.setAllowUniversalAccessFromFileURLs(true);
myWebView.setWebViewClient(new WebViewClient() {
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
return false;
}
@Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
injectScriptFile(view, "js/script.js"); // see below ...
// test if the script was loaded
view.loadUrl("javascript:setTimeout(test(), 500)");
}
private void injectScriptFile(WevView view, String scriptFile) {
InputStream input;
try {
input = getAssets().open(scriptFile);
byte[] buffer = new byte[input.available()];
input.read(buffer);
input.close();
// String-ify the script byte-array using BASE64 encoding !!!
String encoded = Base64.encodeToString(buffer, Base64.NO_WRAP);
view.loadUrl("javascript:(function() {" +
"var parent = document.getElementsByTagName('head').item(0);" +
"var script = document.createElement('script');" +
"script.type = 'text/javascript';" +
// Tell the browser to BASE64-decode the string into your script !!!
"script.innerHTML = window.atob('" + encoded + "');" +
"parent.appendChild(script)" +
"})()");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
myWebView.loadUrl("http://www.example.com");
...
我希望它能帮助!
I hope it helps!
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