java - Android send data via socket -

i send simple date through tcp. working threads, dont know why when try run code stop imediatelly here that. have set permissons well.

what did wrong? beginner please me

package com.example.teszt;  import java.util.date;  import java.io.ioexception; import java.io.outputstream; import java.io.printwriter; import java.net.socket; import java.net.unknownhostexception;  import android.os.bundle; import android.app.activity; import android.view.menu; import android.view.view; import android.widget.edittext; import android.widget.textview;   public class mainactivity extends activity {      textview date;     edittext textout;     textview textin;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);         date=(textview)findviewbyid(r.id.text1);           //////////////////////////////////////////////////////////////////////////      }      public void shownewdate(view v)     {         date.settext(new date().tostring());     }      @override     public boolean oncreateoptionsmenu(menu menu) {         // inflate menu; adds items action bar if present.         getmenuinflater().inflate(r.menu.main, menu);         return true;     }  ///////////////////////////////////////////////////////////////////////////////////         public void send_socket(view arg0)     {           thread thread =  new thread(new runnable() {             public void run() {          try {           socket socket = new socket("10.38.248.121", 2101);            outputstream out = socket.getoutputstream();           printwriter output = new printwriter(out);                   output.println("hello android");                       date.settext(new date().tostring());               out.flush();         out.close();          socket.close();                                                 }          catch (unknownhostexception e) {e.printstacktrace();}          catch (ioexception e) { e.printstacktrace();}               }         });  thread.start();      }   } 

this xml:

<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:paddingbottom="@dimen/activity_vertical_margin"     android:paddingleft="@dimen/activity_horizontal_margin"     android:paddingright="@dimen/activity_horizontal_margin"     android:paddingtop="@dimen/activity_vertical_margin"     tools:context=".mainactivity" >      <textview         android:id="@+id/text1"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignbaseline="@+id/button1"         android:layout_alignbottom="@+id/button1"         android:layout_alignparentleft="true"         android:layout_marginleft="133dp"         android:text="katt"         tools:ignore="hardcodedtext" />      <button         android:id="@+id/button1"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignparentleft="true"         android:layout_alignparenttop="true"         android:layout_marginleft="32dp"         android:layout_margintop="40dp"         android:onclick="shownewdate"         android:text="dátum"         tools:ignore="hardcodedtext" />      <button         android:id="@+id/button2"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignleft="@+id/button1"         android:layout_below="@+id/button1"         android:layout_margintop="26dp"         android:onclick="send_socket"         android:text="send"         tools:ignore="hardcodedtext" />    </relativelayout> 

you can interact ui main thread. can´t do

date.settext(new date().tostring());