android - 从 webview 中获取文本 [英] android - get Text out of webview

问题描述

在我的应用程序中，我使用 EPUBLIB 在 webview 中显示 epub HTML 文件.我的问题是我想为我的 epub 阅读器使用书签功能.为此，我想从 webview 中获取文本，该文本显示了我的 epub 的 HTML 文件中的页面，然后在我的书签活动中使用该文本向用户显示他们已添加书签的内容.我怎样才能做到这一点?

In my application, I am showing epub HTML files in webview using EPUBLIB. My problem is that I want to use bookmark functionality for my epub reader. For that I want to fetch text from webview which is showing page from my epub's HTML file and then use that text in my bookmark activity to show the user what they have bookmarked. How can I achieve this?

推荐答案

从 webview 获取纯文本内容相当困难.基本上，android 类不提供它，但 javascript 提供，并且 Android 提供了一种让 javascript 将信息传递回您的代码的方法.

Getting the plain text content from a webview is rather hard. Basically, the android classes don't offer it, but javascript does, and Android offers a way for javascript to pass the information back to your code.

在我进入细节之前，请注意，如果您的 html 结构很简单，您最好手动解析数据.

Before I go into the details, do note that if your html structure is simple, you might be better off just parsing the data manually.

也就是说，这就是你要做的:

That said, here is what you do:

1. 启用 javascript
2. 添加你自己的javascript接口类，让javascript与你的Android代码通信
3. 注册您自己的webviewClient，覆盖 onPageFinished 插入一些 javascript
4. 在javascript中，获取标签的element.innerText，并传入到您的 javascript 界面.

1. Enable javascript
2. Add your own javascript interface class, to allow the javascript to communicate with your Android code
3. Register your own webviewClient, overriding the onPageFinished to insert a bit of javascript
4. In the javascript, acquire the element.innerText of the tag, and pass it to your javascript interface.

为了澄清，我将在下面发布一个有效(但非常粗糙)的代码示例.它在顶部显示一个 webview，在底部显示一个基于文本的内容的 textview.

To clarify, I'll post a working (but very rough) code example below. It displays a webview on the top, and a textview with the text-based contents on the bottom.

package test.android.webview;

import android.app.Activity;
import android.os.Bundle;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.TextView;

public class WebviewTest2Activity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        WebView webView = (WebView) findViewById(R.id.webView);
        TextView contentView = (TextView) findViewById(R.id.contentView);

        /* An instance of this class will be registered as a JavaScript interface */ 
        class MyJavaScriptInterface 
        { 
            private TextView contentView;

            public MyJavaScriptInterface(TextView aContentView)
            {
                contentView = aContentView;
            }

            @SuppressWarnings("unused") 

            public void processContent(String aContent) 
            { 
                final String content = aContent;
                contentView.post(new Runnable() 
                {    
                    public void run() 
                    {          
                        contentView.setText(content);        
                    }     
                });
            } 
        } 

        webView.getSettings().setJavaScriptEnabled(true); 
        webView.addJavascriptInterface(new MyJavaScriptInterface(contentView), "INTERFACE"); 
        webView.setWebViewClient(new WebViewClient() { 
            @Override 
            public void onPageFinished(WebView view, String url) 
            { 
                view.loadUrl("javascript:window.INTERFACE.processContent(document.getElementsByTagName('body')[0].innerText);"); 
            } 
        }); 

        webView.loadUrl("http://shinyhammer.blogspot.com");
    }
}

使用以下 main.xml:

Using the following main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <WebView
        android:id="@+id/webView"
        android:layout_width="match_parent"
        android:layout_height="fill_parent"
        android:layout_weight="0.5" />

    <TextView
        android:id="@+id/contentView"
        android:layout_width="match_parent"
        android:layout_height="fill_parent"
        android:layout_weight="0.5" />


</LinearLayout>

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