Java android wolfram alpha异常下载URL

我尝试在我的应用程序中使用walfram alpha我已经在java项目中使用了我的代码，但是当我尝试在android中使用它时，我得到了“异常下载URL”

这是我的密码

public class AlphaAPISample extends Activity{

// PUT YOUR APPID HERE:
private static String appid = MYAPPID;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    String input = "who is the president";
    WAEngine engine = new WAEngine();
    engine.setAppID(appid);
    engine.addFormat("plaintext");
    WAQuery query = engine.createQuery();
    query.setInput(input);
    try {
        System.out.println("Query URL:");
        System.out.println(engine.toURL(query));
        WAQueryResult queryResult = engine.performQuery(query);

        if (queryResult.isError()) {
            System.out.println("Query error");
            System.out.println("  error code: " + queryResult.getErrorCode());
            System.out.println("  error message: " + queryResult.getErrorMessage());

        } else if (!queryResult.isSuccess()) {
            System.out.println("Query was not understood; no results available.");

        } else {

            // Got a result.
            System.out.println("Successful query. Pods follow:\n");
            for (WAPod pod : queryResult.getPods()) {
                if (!pod.isError()) {
                    if(pod.getTitle().equals("Result")) {
                        System.out.println(pod.getTitle());
                        for (WASubpod subpod : pod.getSubpods()) {
                            for (Object element : subpod.getContents()) {
                                if (element instanceof WAPlainText) {
                                    System.out.println(((WAPlainText) element).getText());
                                }
                            }
                        }
                    }
                }
            }
            // We ignored many other types of Wolfram|Alpha output, such as warnings, assumptions, etc.
            // These can be obtained by methods of WAQueryResult or objects deeper in the hierarchy.
        }
    } catch (WAException e) {
        e.printStackTrace();
    }


   }
}

这是我的原木猫

    07-21 05:13:23.276  30688-30688/com.assist.me I/System.out﹕ Query URL:
07-21 05:13:23.276  30688-30688/com.assist.me I/System.out﹕ http://api.wolframalpha.com/v2/query?appid=MYAPPID&input=who+is+the+president&format=plaintext&async=false&reinterpret=true
07-21 05:13:23.276  30688-30688/com.assist.me I/URLFetcher﹕ Downloading url http://api.wolframalpha.com/v2/query?appid=MYAPPID&input=who+is+the+president&format=plaintext&async=false&reinterpret=true
07-21 05:13:23.286  30688-30688/com.assist.me W/URLFetcher﹕ Exception downloading URL http://api.wolframalpha.com/v2/query?appid=MYAPPID&input=who+is+the+president&format=plaintext&async=false&reinterpret=true. com.wolfram.alpha.net.WAHttpException: android.os.NetworkOnMainThreadException
07-21 05:13:23.286  30688-30688/com.assist.me I/URLFetcher﹕ Finished downloading URL http://api.wolframalpha.com/v2/query?appid=MYAPPID&input=who+is+the+president&format=plaintext&async=false&reinterpret=true. Elapsed millis: 8
07-21 05:13:23.286  30688-30688/com.assist.me W/System.err﹕ com.wolfram.alpha.WAException: com.wolfram.alpha.net.WAHttpException: android.os.NetworkOnMainThreadException
07-21 05:13:23.286  30688-30688/com.assist.me W/System.err﹕ at com.wolfram.alpha.WAEngine.performQuery(WAEngine.java:128)
07-21 05:13:23.286  30688-30688/com.assist.me W/System.err﹕ at com.pin.assistme.AlphaAPISample.onCreate(AlphaAPISample.java:83)

代码中每个带有我的应用程序id的地方都被替换为短语“MYAPPID”

已解决：

问题是我试图从主线程获取internet数据，而我本应该使用AsyncTask，正如您在异常中看到的那样

android.os.NetworkOnMainThreadException

请参阅下面的代码，以了解正确的操作方法。

好的，我知道了

public class AlphaAPISample extends Activity {

// PUT YOUR APPID HERE:
private static String appid = "APPID";

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    new YourTask().execute();
}


WAQueryResult queryResult;

private class YourTask extends AsyncTask<WAQueryResult, Void, WAQueryResult> {


    protected void onPreExecute() {

    }

    @Override
    protected WAQueryResult doInBackground(WAQueryResult... urls) {
        String input = "who is the president";
        WAEngine engine = new WAEngine();
        engine.setAppID(appid);
        engine.addFormat("plaintext");

        // Create the query.
        WAQuery query = engine.createQuery();
        query.setInput(input);
        queryResult = null;
        try {
            queryResult = engine.performQuery(query);
        } catch (WAException e) {
            e.printStackTrace();
        }
        return queryResult;
    }

    @Override
    protected void onPostExecute(WAQueryResult response) {
        if (queryResult.isError()) {
            System.out.println("Query error");
            System.out.println("  error code: " + queryResult.getErrorCode());
            System.out.println("  error message: " + queryResult.getErrorMessage());

        } else if (!queryResult.isSuccess()) {
            System.out.println("Query was not understood; no results available.");

        } else {

            // Got a result.
            System.out.println("Successful query. Pods follow:\n");
            for (WAPod pod : queryResult.getPods()) {
                if (!pod.isError()) {
                    if (pod.getTitle().equals("Result")) {
                        System.out.println(pod.getTitle());
                        for (WASubpod subpod : pod.getSubpods()) {
                            for (Object element : subpod.getContents()) {
                                if (element instanceof WAPlainText) {
                                    System.out.println(((WAPlainText) element).getText());
                                    Toast.makeText(getApplicationContext(),((WAPlainText) element).getText(),Toast.LENGTH_SHORT).show();
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}

公共类alphapisample扩展活动{
//将您的APPID放在此处：
私有静态字符串appid=“appid”；
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
新建YourTask（）.execute（）；
}
WAQueryResult queryResult；
私有类YourTask扩展了AsyncTask{
受保护的void onPreExecute（）{
}
@凌驾
受保护的WAQueryResult doInBackground（WAQueryResult…URL）{
String input=“谁是总裁”；
WAEngine engine=新WAEngine（）；
engine.setAppID（appid）；
engine.addFormat（“纯文本”）；
//创建查询。
WAQuery query=engine.createQuery（）；
query.setInput（输入）；
queryResult=null；
试一试{
queryResult=engine.performQuery（查询）；
}捕获（WAE例外）{
e、 printStackTrace（）；
}
返回查询结果；
}
@凌驾
受保护的void onPostExecute（WAQueryResult响应）{
if（queryResult.isError（））{
System.out.println（“查询错误”）；
System.out.println（“错误代码：+queryResult.getErrorCode（））；
System.out.println（“错误消息：+queryResult.getErrorMessage（））；
}如果（！queryResult.isSuccess（）），则为else{
System.out.println（“查询未被理解；没有可用的结果”）；
}否则{
//我得到了一个结果。
System.out.println（“成功查询。Pods跟随：\n”）；
for（WAPod:queryResult.getPods（））{
如果（！pod.isError（））{
if（pod.getTitle（）.equals（“结果”））{
System.out.println（pod.getTitle（））；
for（WASubpod subpod:pod.getSubpods（））{
for（对象元素：subpod.getContents（））{
if（WAPlainText的元素实例）{
System.out.println（（（WAPlainText）元素）.getText（））；
Toast.makeText（getApplicationContext（），（（WAPlainText）元素）.getText（），Toast.LENGTH_SHORT.show（）；
}
}
}
}
}
}
}
}
}

---

}

您是否介意记下到底哪里出了问题，以及您是如何解决的？如果将来有人引用此内容，请不要立即注意到您的问题是

NetworkOnMainThreadException

。