如何在Android中使用ScriptEngineManager? [英] How to use ScriptEngineManager in Android?

问题描述

import android.widget.Toast;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

 public void bEqual(View v) throws ScriptException {

       ScriptEngineManager mgr = new ScriptEngineManager();
       ScriptEngine engine = mgr.getEngineByName("JavaScript");
        String value = inputText.getText().toString();
        Toast.makeText(this,value,Toast.LENGTH_LONG).show();
        try{
            result = (double)engine.eval(value);
            Toast.makeText(this,String.format("%f",result),Toast.LENGTH_SHORT).show();
        }catch(Exception e){
            Toast.makeText(this,"Exception Raised",Toast.LENGTH_SHORT).show();
        }

    }

这有什么问题?执行此操作时，应用程序正在退出. 它没有显示任何错误，但应用程序正在关闭

What is wrong in it? App is exiting when perform this action. It is not showing any errors but app is closing

推荐答案

最简单的方法是改为在Android中使用Mozilla Rhino

Easiest way is to use Mozilla Rhino in Android instead[1] because ScriptEngine and it's dependencies would require time consuming setup and headache.

导入ff:

import org.mozilla.javascript.Context;
import org.mozilla.javascript.Scriptable;
import android.util.Log;

您在方法中放置的代码:

Code you put somewhere in your method:

    Context context = Context.enter(); // 
    context.setOptimizationLevel(-1); // this is required[2]
    Scriptable scope = context.initStandardObjects();
    Object result = context.evaluateString(scope, "18 > 17 and 18 < 100", "<cmd>", 1, null);
    Log.d("your-tag-here", "" + result);

将其添加到您的gradle依赖项中.

Add it in your gradle dependencies.

implementation group: 'org.mozilla', name: 'rhino', version: '1.7.10'

参考:

1. Mozilla Rhino
2. 说明为何需要该行代码
3. Mozilla Rhino的Maven存储库

1. Mozilla Rhino
2. Explanation why that line of code is needed
3. Mozilla Rhino's Maven Repository

这篇关于如何在Android中使用ScriptEngineManager?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！