android - java.lang.RuntimeException : An error occured while executing doInBackground() 错误

Question

我正在使用下面的代码。它在 Android Studio 中出错。你能帮忙吗？根据我的理解，args[0] 没有填充某些值。这是为什么？如果 args[0] 没有为此选择任何其他实现的任何值。

import android.app.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.provider.DocumentsContract;
import android.renderscript.Element;
import android.util.Log;
import android.widget.TextView;

import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import java.io.IOException;
import java.io.InputStream;
import java.lang.annotation.ElementType;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

public class StockInfoActivity  extends Activity{
    private static final String TAG="StockQoute";

    static final String KEY_ITEM="quote";
    static final String KEY_YEAR_LOW="YearLow";
    static final String KEY_YEAR_HIGH="YearHigh";
    static final String KEY_DAYS_LOW="DaysLow";
    static final String KEY_DAYS_HIGH="DaysHigh";
    static final String KEY_CHANGE="Change";
    static final String KEY_LAST_TRADE="LastTradePriceOnly";
    static final String KEY_DAYS_CHANGE="DaysRange";

    TextView companyNameView;
    TextView yearLowView    ;
    TextView yearHighView   ;
    TextView daysLowView    ;
    TextView daysHighView   ;
    TextView LastPriceView  ;
    TextView changeView     ;
    TextView dailyPriceRangeView;

    String name="";
    String yearLow="";
    String yearHigh="";
    String daysLow="";
    String daysHigh="";
    String lastTradePrice="";
    String change="";
    String daysRange="";

    String yahooURLFirst="https://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.quote%20where%20symbol%20in%20(%22";
    String yahooURLSecond="%22)&diagnostics=true&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys";

    protected void onCreate (Bundle savedInstanceState){

        super.onCreate(savedInstanceState);
        setContentView(R.layout.get_stock_qoute);
        Intent intent=getIntent();
        String stockSymbol=intent.getStringExtra(MainActivity.STOCK_SYMBOL);

        companyNameView =(TextView)findViewById(R.id.companyNameView);
        yearLowView =(TextView)findViewById(R.id.yearLow);
        yearHighView    =(TextView)findViewById(R.id.yearHigh);
        daysLowView =(TextView)findViewById(R.id.daysLow);
        daysHighView    =(TextView)findViewById(R.id.daysHigh);
        LastPriceView   =(TextView)findViewById(R.id.lastPrice);
        changeView      =(TextView)findViewById(R.id.change);
        dailyPriceRangeView =(TextView)findViewById(R.id.dailyPriceRange);
        //Log.d(TAG, "Before URL creation" + stockSymbol);
        final String yqlURL=yahooURLFirst+stockSymbol+yahooURLSecond;
       //Log.d(TAG, "Before URL creation" + yqlURL);
        new MyAsyncTask().execute();
    }

    private class MyAsyncTask extends AsyncTask<String,String,String>{

        protected String doInBackground(String... args) {
                try{
                    String newstr=args[0];
                    Log.d("Sync",newstr);
                    URL url= new URL(args[0]);

                    //Log.d("Sync1","We are here");
                    URLConnection conn=url.openConnection();

                    HttpURLConnection httpconn=(HttpURLConnection)conn;

                    int responseCode=httpconn.getResponseCode();

                    if(responseCode==HttpURLConnection.HTTP_OK){
                        InputStream in=httpconn.getInputStream();
                        DocumentBuilderFactory dbf= DocumentBuilderFactory.newInstance();
                        DocumentBuilder db=dbf.newDocumentBuilder();
                        Document dom=db.parse(in);
                        org.w3c.dom.Element docEl= (org.w3c.dom.Element) dom.getDocumentElement();
                        NodeList nl = docEl.getElementsByTagName("qoute");
                        Log.d("Sync3","We are here");
                        if(nl!=null && nl.getLength() > 0){
                            for(int i=0;i<=nl.getLength();i++){
                                StockInfo theStock=getStockInfo(docEl);
                                name=theStock.getName();
                                yearLow=theStock.getYearLow();
                                yearHigh=theStock.getYearHigh();
                                daysLow=theStock.getDaysLow();
                                daysHigh=theStock.getDaysHigh();
                                lastTradePrice=theStock.getLastTradePriceonly();
                                change=theStock.getChange();
                                daysRange=theStock.getDaysRange();
                            }
                        }
                    }

            } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } catch (ParserConfigurationException e) {
                    e.printStackTrace();
                } catch (SAXException e) {
                    e.printStackTrace();
                }
finally {       }
            return null;
        }

        protected void onPostExecute(String result){
            companyNameView.setText(name);
            yearHighView.setText("Year High: " +yearHigh);
            yearLowView.setText("Year Low: "+yearLow);
            daysHighView.setText("Days High: "+daysHigh);
            daysLowView.setText("Days Low:"+ daysLow );
            LastPriceView.setText("Last Price"+ lastTradePrice);
            changeView.setText("Change: "+change);
            dailyPriceRangeView.setText("Daily Price Range: "+daysRange) ;
        }

private StockInfo getStockInfo(org.w3c.dom.Element entry){
    String stockName=getTextValue(entry,"Name");
    String stockYearLow=getTextValue(entry,"YearLow");
    String stockYearHigh=getTextValue(entry,"YearHigh");
    String stockDaysLow=getTextValue(entry,"DaysLow");
    String stockDaysHigh=getTextValue(entry,"DaysHigh");
    String stockLastTradePrice=getTextValue(entry,"LastTradePriceOnly");
    String stockChange=getTextValue(entry,"Change");
    String stockDaysRange=getTextValue(entry,"DaysRange");

    StockInfo theStock=new StockInfo(stockDaysLow
            ,stockDaysHigh  ,stockYearLow ,stockYearHigh ,stockName,stockLastTradePrice ,stockChange ,stockDaysRange);
return theStock;
}
private String getTextValue(org.w3c.dom.Element Entry, String tagName)
{
    String tagValueToReturn=null;
    NodeList nl=Entry.getElementsByTagName(tagName);
    if(nl!=null && nl.getLength() > 0){
        org.w3c.dom.Element ele=(org.w3c.dom.Element)nl.item(0);
        tagValueToReturn=ele.getFirstChild().getNodeValue();
        }
    return tagValueToReturn;
}
}
}

低于错误

FATAL EXCEPTION: AsyncTask #1
Process: com.shravan.stockinfo, PID: 2188
java.lang.RuntimeException: An error occured while executing doInBackground()
    at android.os.AsyncTask$3.done(AsyncTask.java:304)
    at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
    at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
    at java.util.concurrent.FutureTask.run(FutureTask.java:242)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
    at java.lang.Thread.run(Thread.java:818)
 Caused by: java.lang.ArrayIndexOutOfBoundsException: length=0; index=1
    at com.shravan.stockinfo.StockInfoActivity$MyAsyncTask.doInBackground(StockInfoActivity.java:89)
    at com.shravan.stockinfo.StockInfoActivity$MyAsyncTask.doInBackground(StockInfoActivity.java:85)
    at android.os.AsyncTask$2.call(AsyncTask.java:292)
    at java.util.concurrent.FutureTask.run(FutureTask.java:237)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
    at java.lang.Thread.run(Thread.java:818) 

Answer 1

您正在像 new MyAsyncTask().execute(); 一样运行 AsyncTask，这意味着您没有向它传递任何参数。

但是在 doInBackground 方法中，您试图在 String newstr=args[0]; 处获取一个值，但是 args 数组的长度为 0 .

你需要像这样启动AsycTask

new MyAsyncTask().execute(yqlURL);