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我试图在加载到 assets 文件夹中并在 Android 活动中显示在 WebView 中的 xhtml 页面中调用一个简单的 highlight-this-text javascript 函数。使用以下功能：
1.loadUrl("javascript:myFunc(param)");不工作。
2. 在工作中内联整个函数也不行loadUrl。
3. 我还尝试在单独的文件（highlighter.js）和 xhtml 正文部分（使用 CDATA 标记）中使用突出显示功能。

上述方法都没有奏效。我需要帮助来弄清楚我做错了什么。

The code:  
/* JSWebview:
 * 1. Loads a webpage in the external sdcard.
 * 2. enables javascript and runs a small script.
 */

package com.sriram.jswebview;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.webkit.WebView;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends Activity {

    private WebView wv = null;
    private String url = null;
    private JSInterface myJSI;
    private Button fromMain;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        loadPage();

        //wv.loadUrl("javascript:doecho(\"Hello World!\");");
        //wv.loadUrl("javascript:tostring());");
        String toFind = "Hello";

        Log.v(this.toString(), "Finding string = " + toFind);

        //find string and highlight.
        if(android.os.Build.VERSION.SDK_INT < 16) {
            Log.v(this.toString(), "Launching findAll.");   
            int num = wv.findAll(toFind);
            Log.v(this.toString(), num + " instances found.");
        } else {
            Log.v(this.toString(), "Searching with findAllAsync.");
            wv.findAllAsync(toFind);
        }

        fromMain = (Button) findViewById(R.id.fromMain);        
        fromMain.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                String message = "This is a test.";
                wv.loadUrl("javascript:callFromActivity(\""+message+"\")");
                //wv.loadUrl("javascript:function (msg) { var oldHTML = document.getElementById(\"highlightbegin\"); var newHTML = \"<span style=\'color:#ffa000\'>\" + msg + \"</span>\"; document.getElementById(\"highlightbegin\").innerHTML = newHTML;}");
        }
        });
    }

    @SuppressLint("SetJavaScriptEnabled")
    @SuppressWarnings("deprecation")
    public void loadPage() {
        //loads the index.xhtml page from /mnt/sdcard.
        Log.v(this.toString(), "Inside loadPage().");
        if(Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
            //external media is mounted.
            url = Environment.getExternalStorageDirectory().getAbsolutePath() + "/" + "index.xhtml";
            Log.v(this.toString(), "URL = " + url);
        }

        wv = (WebView) findViewById(R.id.wv);
        wv.getSettings().setJavaScriptEnabled(true);   //enable javascript.

        myJSI = new JSInterface(this.getApplicationContext(), wv);
        wv.addJavascriptInterface(myJSI, "JSInterface");
        if((wv != null) && (url != null)) {
            Log.v(this.toString(), "Inside loadurl.");
            //wv.loadUrl(url);
            wv.loadUrl("file:///android_asset/mypage.xhtml");
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
}

//this class is used to call Javascript functions that act on the html page.
class JSInterface {

    private WebView wv = null;
    private Context c;

    public JSInterface(Context context, WebView w) {
        Log.v(this.toString(), "Inside JSInterface constructor.");
        c = context;
        wv = w;
    }

    public String tostring() {
        //Log.v(this.toString(), "Inside toString()");
        String result = "injected Object";
        return result;
    }

    public void doecho(String x) {
        Log.v(this.toString(), "Inside doEcho of JSInterface.");
        Toast.makeText(wv.getContext(), x, Toast.LENGTH_SHORT).show();
    }

    public void showToast(String message) {
        Toast.makeText(c, message, Toast.LENGTH_LONG).show();
    }

    public void openAndroidDialog() {
         AlertDialog.Builder myDialog = new AlertDialog.Builder(c);
          myDialog.setTitle("DANGER!");
          myDialog.setMessage("You can do what you want!");
          myDialog.setPositiveButton("ON", null);
          myDialog.show();
    }
}

活动主.xml： 

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <Button
        android:id="@+id/fromMain"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:text="fromMain" />

    <WebView
        android:id="@+id/wv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="@string/hello_world"
        android:layout_above="@id/fromMain" />

</RelativeLayout>

mypage.xhtml（存在于 assets 文件夹中： 

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
 "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta content="application/xhtml+xml;charset=UTF-8" />
<title>My HTML</title>
</head>
<body>
<h1>MyHTML</h1>
<p id="highlightbegin">Hello World! This is a test.</p>
<div> <input type="button" value="Alert" onclick="displayAlert()" /> </div>
<div> <input type="button" value="Say hello" onclick="showAndroidToast('Hello Android!')" /> </div>
<div> <input type="button" value="Open Dialog" onclick="openAndroidDialog()" /> </div>
<div> <input type="button" value="Add highlight" onclick="changeColor()" /> </div>

<script type="text/javascript">
//<![CDATA[
   function showAndroidToast(toast) {
       JSInterface.showToast(toast);
   }

   function openAndroidDialog() {
       JSInterface.openAndroidDialog();
   }

   function displayAlert() {
        window.alert("I am here!");
    }

//]]>
</script>

<script src="doecho.js" type="text/javascript"> </script>
<script src="tostring.js" type="text/javascript"> </script>
<script src="highlighter.js" type="text/javascript"> </script>

</body>
</html>

highlighter.js（包含 javascript 函数）： 

function callFromActivity(msg) {
        alert(msg);
        var oldHTML = document.getElementById("highlightbegin");
        alert(oldHTML);
        var newHTML = "<span style='color:#ffa000'>" + msg + "</span>";
        alert(newHTML);
        document.getElementById("mytext").innerHTML = newHTML;
    }
4

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