android.os.NetworkOnMainThreadException [duplicate

问题:

This question already has an answer here:

• How do I fix 'android.os.NetworkOnMainThreadException'? 54 answers

I make simply rss reader in android. I have the errors (I searched and tried some solutions but nothing):

Couldn't open http://pogoda.wp.pl/rss.xml
java.io.IOException: Couldn't open http://pogoda.wp.pl/rss.xml
at org.apache.harmony.xml.ExpatParser.openUrl(ExpatParser.java:755)
at org.apache.harmony.xml.ExpatReader.parse(ExpatReader.java:292)
at javax.xml.parsers.SAXParser.parse(SAXParser.java:390)
at javax.xml.parsers.SAXParser.parse(SAXParser.java:266)
at com.newsreader.RssReader.getItems(RssReader.java:23)
at com.newsreader.MainActivity$1$1.run(MainActivity.java:48)
at android.os.Handler.handleCallback(Handler.java:605)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4340)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
at dalvik.system.NativeStart.main(Native Method)
 Caused by: android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1084)
at java.net.InetAddress.lookupHostByName(InetAddress.java:391)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:242)
at java.net.InetAddress.getAllByName(InetAddress.java:220)
at libcore.net.http.HttpConnection.<init>(HttpConnection.java:71)
at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
at libcore.net.http.HttpConnection$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 org.apache.harmony.xml.ExpatParser.openUrl(ExpatParser.java:753)

and activity:

public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    new Thread(){
        public void run(){
            MainActivity.this.runOnUiThread(new Runnable(){

                @Override
                public void run() {
                    try{
                    RssReader reader = new RssReader("http://pogoda.wp.pl/rss.xml");
                    ListView items = (ListView) findViewById(R.id.listView1);
                    ArrayAdapter<RssItem> adapter = new ArrayAdapter<RssItem>(MainActivity.this, android.R.layout.simple_list_item_1, reader.getItems());
                    items.setAdapter(adapter);
                    Log.i("", ""+reader);
                    items.setOnItemClickListener(new ListListener(reader.getItems(), MainActivity.this));
                    }catch(Exception e){
                        Log.e("blad", e.getMessage(), e);
                    }

                }

        });
        }
    }.start();

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main, menu);

    return true;
}

 }

I don't know what am I doing wrong. Maybe someone has got the same problem so please help. Thanks

回答1:

Always use AsyncTask to solve this issue.

BUT, if you're within the movie Swordfish, someone points a gun at you and say "fix it in 30 seconds", then change your targetSdkVersion to 9 in the Android Manifest and the exception will stop. Don't worry, it will run on devices with version higher than 9 too. Even so, correct your code later using AsyncTask.

回答2:

It is because you are performing network operation on main thread of activity. Using Async task will be a better option.

回答3:

Caused by: android.os.NetworkOnMainThreadException

This speaks for itself.

Don't do networking on the main Thread!

AsyncTask to the rescue. Try it out it will work.