4

嗨，我想在我的 android 应用程序中使用 Mathjax，因为我在这里找到了一个示例表单。
我想在活动启动时显示一个公式，而不是按下显示按钮时的示例，但这不起作用。我错过了我的代码中的某些内容吗？
谢谢你的帮助。

private String doubleEscapeTeX(String s) {
    String t="";
    for (int i=0; i < s.length(); i++) {
        if (s.charAt(i) == '\'') t += '\\';
        if (s.charAt(i) != '\n') t += s.charAt(i);
        if (s.charAt(i) == '\\') t += "\\";
    }
    return t;
}

private int exampleIndex = 0;

private String getExample(int index) {
    return getResources().getStringArray(R.array.tex_examples)[index];
}

public void onClick(View v) {
    if (v == findViewById(R.id.button2)) {
        WebView w = (WebView) findViewById(R.id.webview);
        EditText e = (EditText) findViewById(R.id.edit);
        w.loadUrl("javascript:document.getElementById('math').innerHTML='\\\\["
                   +doubleEscapeTeX(e.getText().toString())+"\\\\]';");
        w.loadUrl("javascript:MathJax.Hub.Queue(['Typeset',MathJax.Hub]);");
    }
    else if (v == findViewById(R.id.button3)) {
        WebView w = (WebView) findViewById(R.id.webview);
        EditText e = (EditText) findViewById(R.id.edit);
        e.setText("");
        w.loadUrl("javascript:document.getElementById('math').innerHTML='';");
        w.loadUrl("javascript:MathJax.Hub.Queue(['Typeset',MathJax.Hub]);");
    }
    else if (v == findViewById(R.id.button4)) {
        WebView w = (WebView) findViewById(R.id.webview);
        EditText e = (EditText) findViewById(R.id.edit);
        e.setText(getExample(exampleIndex++));
        if (exampleIndex > getResources().getStringArray(R.array.tex_examples).length-1) 
            exampleIndex=0;
        w.loadUrl("javascript:document.getElementById('math').innerHTML='\\\\["
                  +doubleEscapeTeX(e.getText().toString())
                  +"\\\\]';");
        w.loadUrl("javascript:MathJax.Hub.Queue(['Typeset',MathJax.Hub]);");
    }
}

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    WebView w = (WebView) findViewById(R.id.webview);
    w.getSettings().setJavaScriptEnabled(true);
    w.getSettings().setBuiltInZoomControls(true);
    w.loadDataWithBaseURL("http://bar", "<script type='text/x-mathjax-config'>"
                          +"MathJax.Hub.Config({ " 
                            +"showMathMenu: false, "
                            +"jax: ['input/TeX','output/HTML-CSS'], "
                            +"extensions: ['tex2jax.js'], " 
                            +"TeX: { extensions: ['AMSmath.js','AMSsymbols.js',"
                              +"'noErrors.js','noUndefined.js'] } "
                          +"});</script>"
                          +"<script type='text/javascript' "
                          +"src='file:///android_asset/MathJax/MathJax.js'"
                          +"></script><span id='math'></span>","text/html","utf-8","");
    EditText e = (EditText) findViewById(R.id.edit);
    e.setBackgroundColor(Color.LTGRAY);
    e.setTextColor(Color.BLACK);
    e.setText("");
    Button b = (Button) findViewById(R.id.button2);
    b.setOnClickListener(this);
    b = (Button) findViewById(R.id.button3);
    b.setOnClickListener(this);
    b = (Button) findViewById(R.id.button4);
    b.setOnClickListener(this);
    TextView t = (TextView) findViewById(R.id.textview3);
    t.setMovementMethod(LinkMovementMethod.getInstance());
    t.setText(Html.fromHtml(t.getText().toString()));   

// Here is my added code.
 w.loadUrl("javascript:document.getElementById('math').innerHTML='\\\\["
               +doubleEscapeTeX("\\frac{1}2")+"\\\\]';");
 w.loadUrl("javascript:MathJax.Hub.Queue(['Typeset',MathJax.Hub]);");

}
4

2 回答 2

2

您必须将 assets 文件夹复制到您的应用程序的 assets 文件夹中。

于 2013-12-14T11:29:49.750 回答
2

永远不要webView.loadWithBaseUrl(..)与webView.loadUrl(..). 因为如果在完成webView.loadUrl(..)之前加载webView.loadWithBaseUrl(..)，它将引发错误并且 webView 将不显示任何内容

解决方案是使用以下代码将它们分开：`

private void initiateWebView(){

    webViewEquationDisplay.setWebViewClient(new WebViewClient() {
        @Override
        public void onPageFinished(WebView view, String url) {
            super.onPageFinished(view, url);

            if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT){
                loadUrlKitKat(equationSymbolFinal+equationToBeDisplayedFinal);
            }
            else{
                webViewEquationDisplay.loadUrl("javascript:document.getElementById('math').innerHTML='<font color=\"yellow\">`"+equationToBeDisplayedFinal+"`</font>';");
            }

            webViewEquationDisplay.loadUrl("javascript:MathJax.Hub.Queue(['Typeset',MathJax.Hub]);");
        }
    });

    final String mathJaxOfflineUrl = "file:///android_asset/MathJax/MathJax.js";            
    webViewEquationDisplay.loadDataWithBaseURL("http://bar/", "<script type='text/x-mathjax-config'>"
            +"MathJax.Hub.Config({ " 
                +"showMathMenu: false, "
                +"jax: ['input/AsciiMath','output/HTML-CSS'], "
                +"extensions: ['asciimath2jax.js'], " 
                +"AsciiMath: { fixphi: true, useMathMLspacing: true, displaystyle: false, decimalsign: \".\" }, "
              +"});</script>"
            +"<script type='text/javascript' "
              +"src='"+mathJaxOfflineUrl+"'"
              +"></script><span id='math'></span>","text/html","utf-8","");
}


@TargetApi(Build.VERSION_CODES.KITKAT)
private void loadUrlKitKat(String param){
    webViewEquationDisplay.evaluateJavascript("javascript:document.getElementById('math').innerHTML='<font color=\"#97FD97\">`"+param+"`</font>';",null);
}

`

不要忘记通过使用evaluateJavascript而不是添加 KITKAT 支持loadUrl

祝你好运

于 2014-11-19T04:36:54.760 回答