Java android下载.csv文件时出错

我正在尝试制作一个从雅虎下载股票数据的应用程序！并显示它

这是我的代码：

MainActivity.java：

package frank.com.myapplication;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import org.apache.http.util.ByteArrayBuffer;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;


public class MainActivity extends ActionBarActivity {

TextView symbolOut;
TextView priceOut;
TextView changePrecentageOut;
Button getQuote;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    symbolOut = (TextView) findViewById(R.id.stockSymbolOutput);
    priceOut = (TextView) findViewById(R.id.stockPriceOutput);
    changePrecentageOut = (TextView) findViewById(R.id.stockChangePercentageOutput);

    getQuote = (Button) findViewById(R.id.get_quote_button);

    getQuote.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {

            URL url;

            try {
                url = new URL("http://download.finance.yahoo.com/d/quotes.csv?s=goog&f=sl1p2");

                InputStream stream = url.openStream();
                BufferedInputStream bis = new BufferedInputStream(stream);
                ByteArrayBuffer baf = new ByteArrayBuffer(50);

                int current = 0;

                    while ((current = bis.read()) != -1){
                        baf.append((byte) current);
                    }

                String stockTxt = new String(baf.toByteArray());

                String[] tokens = stockTxt.split(",");

                String stockSymbol =            tokens[0];
                String stockPrice  =            tokens[1];
                String stockChangePercentage =  tokens[2];

                String fstockSymbol = stockSymbol.substring(1, stockSymbol.length( ) -1);
                String fstockChangePercentage = stockChangePercentage.substring(1, stockChangePercentage.length() -3);

                symbolOut.setText(fstockSymbol);
                priceOut.setText(stockPrice);
                changePrecentageOut.setText(fstockChangePercentage);

            } catch (MalformedURLException e) {
                e.printStackTrace();

            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    });
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}
}

AndroidManifest.xml：

<?xml version="1.0" encoding="utf-8"?>

---

如果您有任何帮助，我将不胜感激，我已经为此困扰了很长一段时间。

您的问题是您正在Android的UI/主线程中下载（进行网络操作）。这是不允许的，因为这将导致UI挂起。因此，Android将不允许您执行此操作

您可以在此处找到有关它的详细信息：

对于应用程序响应性，以下是您应该知道的：

在应用程序执行可能很长的操作的任何情况下，您都不应该在UI线程上执行工作，而应该创建一个工作线程并在那里执行大部分工作。

如果您有任何长时间运行的任务，如下载或任何网络连接，您应该在一个新的线程中完成。正确的方法是在AsyncTask中实现代码

检查此处的文档：

要了解有关应用程序响应性的更多信息，请查看此链接：

---

的确切副本。令人惊讶的是，询问者在谷歌搜索此异常时发现StackOverflow，却没有找到相关的答案。请尝试AsyncTask或生成一个新线程来完成您的工作。我不知道为什么答案被否决了。

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>
<uses-permission android:name="android.permission.INTERNET"></uses-permission>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

<Button
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Get Quote"
    android:id="@+id/get_quote_button"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/stockSymbolOutput"
    android:layout_below="@+id/get_quote_button"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/stockPriceOutput"
    android:layout_below="@+id/stockSymbolOutput"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/stockChangePercentageOutput"
    android:layout_below="@+id/stockPriceOutput"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

01-18 15:20:23.959    1532-1532/frank.com.myapplication E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: frank.com.myapplication, PID: 1532
android.os.NetworkOnMainThreadException
        at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1147)
        at java.net.InetAddress.lookupHostByName(InetAddress.java:418)
        at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
        at java.net.InetAddress.getAllByName(InetAddress.java:215)
        at com.android.okhttp.HostResolver$1.getAllByName(HostResolver.java:29)
        at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:232)
        at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:124)
        at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:272)
        at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:211)
        at com.android.okhttp.internal.http.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:373)
        at com.android.okhttp.internal.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:323)
        at com.android.okhttp.internal.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:190)
        at java.net.URL.openStream(URL.java:470)
        at frank.com.myapplication.MainActivity$1.onClick(MainActivity.java:48)
        at android.view.View.performClick(View.java:4756)
        at android.view.View$PerformClick.run(View.java:19749)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5221)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)