如何在 Android Webview 菜单中添加高亮选项？

Question

我正在从文本字符串中加载我的 Webview，如下所示：

String encodedHtml = Base64.encodeToString(unencodedHtml.getBytes(), Base64.NO_PADDING);
webview.loadData(encodedHtml, "text/html", "base64");
WebSettings webSettings = webview.getSettings();
webSettings.setJavaScriptEnabled(true);

当用户长按一个单词时，我想在 菜单 中添加一个颜色 Highlight 选项。我在 StackOverflow 上搜索了许多其他类似的问题，但没有成功。您对一些示例代码的帮助将不胜感激。提前致谢！

更新： 我正在使用这个脚本来突出显示：

public static String HighlightScript = "<script language=\"javascript\">" +
        "function highlightSelection(){" +
        "var userSelection = window.getSelection();" +
        "for(var i = 0; i < userSelection.rangeCount; i++)"
        + "  highlightRange(userSelection.getRangeAt(i));" +
        "}" +
        "function highlightRange(range){"+
        "span = document.createElement(\"span\");"+
        "span.appendChild(range.extractContents());"+
        "span.setAttribute(\"style\",\"display:inline;background:#ffc570;\");"+
        "range.insertNode(span);}"+
        "</script> ";

Answer 1

基于这个Calculate Position of selected text javascript/JQuery?调用WebView的evulatejavascript来获取开始结束值

objWebView.evaluateJavascript("(function(){var start = 0, end = 0;\n" +
                                        "    var sel, range, priorRange;\n" +
                                        "    if (typeof window.getSelection != \"undefined\") {\n" +
                                        "        range = window.getSelection().getRangeAt(0);\n" +
                                        "        priorRange = range.cloneRange();\n" +
                                        "        priorRange.selectNodeContents(document.body);\n" +
                                        "        priorRange.setEnd(range.startContainer, range.startOffset);\n" +
                                        "        start = priorRange.toString().length;\n" +
                                        "        end = start + range.toString().length;\n" +
                                        "    } else if (typeof document.selection != \"undefined\" &&\n" +
                                        "            (sel = document.selection).type != \"Control\") {\n" +
                                        "        range = sel.createRange();\n" +
                                        "        priorRange = document.body.createTextRange();\n" +
                                        "        priorRange.moveToElementText(document.body);\n" +
                                        "        priorRange.setEndPoint(\"EndToStart\", range);\n" +
                                        "        start = priorRange.text.length;\n" +
                                        "        end = start + range.text.length;\n" +
                                        "    }\n" +
                                        "        console.log(\"Selection starts at: \" + start);\n" +
                                        "        console.log(\"Selection ends at: \" + end);\n" +
    
    
                                        "    return {\n" +
                                        "        start: start,\n" +
                                        "        end: end\n" +
                                        "    };})()",
                                new ValueCallback<String>()
                                {
                                    @Override
                                    public void onReceiveValue(String value)
                                    {
                                        Log.v(TAG, "Webview selected text: " + value);
                                    }
                                });

一旦您在数据库中保存了范围值。调用相同的方法来突出显示（仅在 WebView 加载完页面后才有效

    objWebView.loadDataWithBaseURL(null, yourstringobject, "text/html; charset=UTF-8", "UTF-8",
                        null);
                objWebView.post(new Runnable() {
                    @Override
                    public void run() {
     //here you can have logic to fetch the data from database and loop to update                   
objWebView.evaluateJavascript("javascript:selectAndHighlightRange('Amod', 250, 274)", null);
                    }
            });