自制MP3播放器 读取文件问题

Question

public boolean onOptionsItemSelected(MenuItem item) {
// TODO Auto-generated method stub
     if(item.getItemId()==UPDATE){
String xml=downloadXML("http://192.168.1.38:8080/mp3/resources.xml");
System.out.println("xml~~~~"+xml);
         }
打印的时候打印不出后面的xml
运行时报错：
 java.lang.IllegalStateException: problem parsing line: null at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1084)
在线等答案啊，求大神帮助~~

Answer 1

不是打印方面的问题，建议你发详细的Log信息上来，应该是在downloadXML里面下载文件里面的解析XML文件出错。

Answer 2

你好这是Log里的详细信息，麻烦你啦，帮我看看到底是什么问题，应该不是HttpDownloader解析XML文件出错了。。是不是我地址不对啊，或者TOMCAT有问题，MP3文件已经放在我TOMCAT中webapps文件夹下面了
public boolean onOptionsItemSelected(MenuItem item) {
// TODO Auto-generated method stub
     if(item.getItemId()==UPDATE){
String xml=downloadXML("http://192.168.1.38:8080/mp3/resources.xml");
System.out.println("xml"+"~~~~"+xml）；
}else if(item.getItemId()==ABOUT){

}
return super.onOptionsItemSelected(item);
}
    private String downloadXML(String urlStr){
     HttpDownloader httpdownloader=new HttpDownloader();
     String result=httpdownloader.download(urlStr);
     return result;
    }
 android.os.NetworkOnMainThreadException
 at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1084)
  at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:74)
    at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
     at libcore.io.IoBridge.connect(IoBridge.java:112)
     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
    at java.net.Socket.connect(Socket.java:842)
    at libcore.net.http.HttpConnection.<init>(HttpConnection.java:77)
    at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
     at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:351)
    at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:86)
     at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
    at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:308)
    at libcore.net.http.HttpEngine.connect(HttpEngine.java:303)
     at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:282)
     at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:232)
    at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:273)
    at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:168)
   at com.download.HttpDownloader.download(HttpDownloader.java:18)
     at com.kaikai.mp3play.Mp3ListActivity.downloadXML(Mp3ListActivity.java:48)
     at com.kaikai.mp3play.Mp3ListActivity.onOptionsItemSelected(Mp3ListActivity.java:37)
     at android.app.Activity.onMenuItemSelected(Activity.java:2502)
     at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:950)
    at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735)
   at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149)
    at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874)
     at com.android.internal.view.menu.ListMenuPresenter.onItemClick(ListMenuPresenter.java:163)
     at android.widget.AdapterView.performItemClick(AdapterView.java:292)
    at android.widget.AbsListView.performItemClick(AbsListView.java:1058)
    at android.widget.AbsListView$PerformClick.run(AbsListView.java:2514)
    at android.widget.AbsListView$1.run(AbsListView.java:3168)
   at android.os.Handler.handleCallback(Handler.java:605)
    at android.os.Handler.dispatchMessage(Handler.java:92)
    at android.os.Looper.loop(Looper.java:137)
     at android.app.ActivityThread.main(ActivityThread.java:4340)
     at java.lang.reflect.Method.invokeNative(Native Method)
     at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
    at dalvik.system.NativeStart.main(Native Method)
 java.lang.NullPointerException
    at com.download.HttpDownloader.download(HttpDownloader.java:26)
    at com.kaikai.mp3play.Mp3ListActivity.downloadXML(Mp3ListActivity.java:48)
     at com.kaikai.mp3play.Mp3ListActivity.onOptionsItemSelected(Mp3ListActivity.java:37)
    at android.app.Activity.onMenuItemSelected(Activity.java:2502)
     at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:950)
    at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735)
     at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149)
     at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874)
     at com.android.internal.view.menu.ListMenuPresenter.onItemClick(ListMenuPresenter.java:163)
     at android.widget.AdapterView.performItemClick(AdapterView.java:292)
    at android.widget.AbsListView.performItemClick(AbsListView.java:1058)
     at android.widget.AbsListView$PerformClick.run(AbsListView.java:2514)
    at android.widget.AbsListView$1.run(AbsListView.java:3168)
     at android.os.Handler.handleCallback(Handler.java:605)
   at android.os.Handler.dispatchMessage(Handler.java:92)
     at android.os.Looper.loop(Looper.java:137)
     at android.app.ActivityThread.main(ActivityThread.java:4340)
     at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:511)
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
    at dalvik.system.NativeStart.main(Native Method)
 Window already focused, ignoring focus gain of: com.android.internal.view.IInputMethodClient$Stub$Proxy@4127a0f0

Answer 3

Mp3ListActivity.java文件发上来看看。

Answer 4

package com.kaikai.mp3play;import android.app.ListActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;import com.download.HttpDownloader;public class Mp3ListActivity extends ListActivity {
private static final int UPDATE=1;
private static final int ABOUT=2;
/**
 * 在用户点击MENU按钮后会调用该方法
 */
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// TODO Auto-generated method stub
menu.add(0, UPDATE, 1, R.string.mp3list_update);
     menu.add(0, ABOUT, 2, R.string.mp3list_about);
return super.onCreateOptionsMenu(menu);
} /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
    }
       @Override
public boolean onOptionsItemSelected(MenuItem item) {
// TODO Auto-generated method stub
     if(item.getItemId()==UPDATE){
String xml=downloadXML("http://192.168.1.38:8080/mp3/resources.xml");
System.out.println("xml"+"~~~~"+xml);


}else if(item.getItemId()==ABOUT){

}
return super.onOptionsItemSelected(item);
}
    private String downloadXML(String urlStr){
     HttpDownloader httpdownloader=new HttpDownloader();
     String result=httpdownloader.download(urlStr);
     return result;
    }
    
}

Answer 5

package com.download;import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;public class HttpDownloader {

     public String download(String urlStr){
      
      StringBuffer sb=new StringBuffer();
      String line=null;
      BufferedReader buffer=null;
      try{
      URL url=new URL(urlStr);
      HttpURLConnection urlConn=(HttpURLConnection)url.openConnection();
      buffer=new BufferedReader(new InputStreamReader(urlConn.getInputStream()));
      while((line=buffer.readLine())!=null){
      sb.append(line);
      }
      }catch(Exception e){
      e.printStackTrace();
      }finally{
      try{
      buffer.close();
      }catch(Exception e){
      e.printStackTrace();
      }
      }
      return sb.toString();
     }
}

Answer 6

package com.kaikai.mp3play;import android.app.ListActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;import com.download.HttpDownloader;public class Mp3ListActivity extends ListActivity {
private static final int UPDATE=1;
private static final int ABOUT=2;
/**
 * 在用户点击MENU按钮后会调用该方法
 */
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// TODO Auto-generated method stub
menu.add(0, UPDATE, 1, R.string.mp3list_update);
     menu.add(0, ABOUT, 2, R.string.mp3list_about);
return super.onCreateOptionsMenu(menu);
} /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
    }
       @Override
public boolean onOptionsItemSelected(MenuItem item) {
// TODO Auto-generated method stub
     if(item.getItemId()==UPDATE){
String xml=downloadXML("http://192.168.1.38:8080/mp3/resources.xml");
System.out.println("xml"+"~~~~"+xml);


}else if(item.getItemId()==ABOUT){

}
return super.onOptionsItemSelected(item);
}
    private String downloadXML(String urlStr){
     HttpDownloader httpdownloader=new HttpDownloader();
     String result=httpdownloader.download(urlStr);
     return result;
    }
    
}

Answer 7

NetworkOnMainThreadException这个错误意思是在主线程中执行了网络操作，所以，将String xml=downloadXML("http://192.168.1.38:8080/mp3/resources.xml");这段代码放到单独的线程中执行。