title: force close error occurs in my java class when I want to display it in XML Layout
body: <p>I've no idea why there's a force close error occurs.</p>
  
  <p>I would like to display the code in my XML Layout.
  However, there's an force close error occurs.
  I'm not sure what's the problem with it.</p>
  
  <p>Here is my logcat error.</p>
  
  <pre><code>07-27 15:44:51.030: E/AndroidRuntime(6171): FATAL EXCEPTION: main
  07-27 15:44:51.030: E/AndroidRuntime(6171): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.fambond/com.example.fambond.MainActivity}: java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at android.os.Handler.dispatchMessage(Handler.java:99)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at android.os.Looper.loop(Looper.java:130)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at android.app.ActivityThread.main(ActivityThread.java:3691)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at java.lang.reflect.Method.invokeNative(Native Method)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at java.lang.reflect.Method.invoke(Method.java:507)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:912)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:670)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at dalvik.system.NativeStart.main(Native Method)
  07-27 15:44:51.030: E/AndroidRuntime(6171): Caused by: java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:257)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at java.util.ArrayList.get(ArrayList.java:311)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at com.example.fambond.MainActivity.onCreate(MainActivity.java:144)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1050)
  07-27 15:44:51.030: E/AndroidRuntime(6171):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615)
  </code></pre>
  
  <p>MainActivity.java</p>
  
  <pre><code>public class MainActivity extends Activity {
      ArrayList&lt;String&gt; psi;
  
        public TextView psi_text;
  
      TextView weather;
       ImageView image;
       private static Handler mHandler = new Handler();
       class MyWeather{
  
  
        String conditiontext;
        String conditiontemp;
        String conditiondate;
  
  
  
        public String forecastToString(){
  
         return 
           conditiontext + "\n" + "        "  + conditiontemp + "°C"  ;
  
        } 
       }
  
       @Override
          protected void onCreate(Bundle savedInstanceState) {
              super.onCreate(savedInstanceState);
              setContentView(R.layout.activity_main);
              weather = (TextView)findViewById(R.id.weather);
              image = (ImageView)findViewById(R.id.image);
              psi = new ArrayList&lt;String&gt;();  
  
  
              psi_text = (TextView) findViewById(R.id.psi_text);
  
              try {
  
                  URL url = new URL(
                          "http://app2.nea.gov.sg/data/rss/nea_psi.xml");
                  DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
                  DocumentBuilder db = dbf.newDocumentBuilder();
                  Document doc = db.parse(new InputSource(url.openStream()));
                  doc.getDocumentElement().normalize();
  
                  NodeList nodeList = doc.getElementsByTagName("item");
                  for (int i = 0; i &lt; nodeList.getLength(); i++) {
  
                      Node node = nodeList.item(i);       
  
                      Element fstElmnt = (Element) node;                 
  
                      NodeList websiteList = fstElmnt.getElementsByTagName("psi");
                      Element websiteElement = (Element) websiteList.item(0);
                      websiteList = websiteElement.getChildNodes();
  
                      psi.add(""+ ((Node) websiteList.item(0)).getNodeValue());           
  
                  }
              } catch (Exception e) {
                  System.out.println("XML Pasing Excpetion = " + e);
              }
  
  
  
              String temp = Html.fromHtml(psi.get(0)).toString(); 
              String a[] = temp.split("\\)");
              psi_text.setText(""+a[0]+")");
  
  
              Thread myThread = new Thread(new Runnable(){
  
                   @Override
                     public void run() {
                      String weatherString = QueryYahooWeather();
                            Document weatherDoc = convertStringToDocument(weatherString);
  
                            final MyWeather weatherResult = parseWeather(weatherDoc);
                            runOnUiThread(new Runnable(){
  
                                @Override
                                   public void run() {
                                    weather.setText(weatherResult.forecastToString());
                                   }});
  
                                 }});
                                      myThread.start();
                                  }
  
       private MyWeather parseWeather(Document srcDoc){
  
           MyWeather myWeather = new MyWeather();
  
              //&lt;yweather:condition.../&gt;
           Node conditionNode = srcDoc.getElementsByTagName("yweather:condition").item(0);
  
  
           String weatherCode = conditionNode.getAttributes()
                 .getNamedItem("code")
                 .getNodeValue()
                 .toString();
  
           // thunderstorms
           if(weatherCode.equals("4")){
  
               mHandler.post(new Runnable() {
                  @Override
                  public void run() {
                      // This gets executed on the UI thread so it can safely modify
                      // Views
  
                       image.setImageResource(R.drawable.thunderstorm);
                  }
              });
           }
  
           //isolated thunderstorms
           else if ( weatherCode.equals("37")) {
                      mHandler.post(new Runnable() {
                          @Override
                          public void run() {
  
                              image.setImageResource(R.drawable.thunderstorm);
                          }
                      });
                  }
  
  
           //scattered thunderstorms
           else if ( weatherCode.equals("38")) {
                      mHandler.post(new Runnable() {
                          @Override
                          public void run() {
  
                              image.setImageResource(R.drawable.thunderstorm);
                          }
                      });
                  }
  
           //scattered thunderstorms
           else if ( weatherCode.equals("39")) {
                      mHandler.post(new Runnable() {
                          @Override
                          public void run() {
  
                              image.setImageResource(R.drawable.thunderstorm);
                          }
                      });
                  }
  
           //thundershowers
           else if ( weatherCode.equals("45")) {
                      mHandler.post(new Runnable() {
                          @Override
                          public void run() {
  
                              image.setImageResource(R.drawable.thunderstorm);
                          }
                      });
                  }
  
           //isolated thundershowers
           else if ( weatherCode.equals("47")) {
                      mHandler.post(new Runnable() {
                          @Override
                          public void run() {
  
                              image.setImageResource(R.drawable.thunderstorm);
                          }
                      });
                  }
  
           //drizzle
           else if ( weatherCode.equals("9")) {
                      mHandler.post(new Runnable() {
                          @Override
                          public void run() {
  
                              image.setImageResource(R.drawable.rainy);
                          }
                      });
                  }
  
           //showers
           else if ( weatherCode.equals("11")) {
                      mHandler.post(new Runnable() {
                          @Override
                          public void run() {
  
                              image.setImageResource(R.drawable.rainy);
                          }
                      });
                  }
  
   //showers
  else if ( weatherCode.equals("12")) {
      mHandler.post(new Runnable() {
          @Override
          public void run() {
  
              image.setImageResource(R.drawable.rainy);
          }
      });
  }
  
           //scattered showers
  else if ( weatherCode.equals("40")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.rainy);
              }
          });
      }
  
           //hail
  else if ( weatherCode.equals("17")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.hail);
              }
          });
      }
  
  
           //mixed rain and hail
  else if ( weatherCode.equals("35")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.hail);
              }
          });
      }
  
           //foggy
  else if ( weatherCode.equals("20")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.foggy);
              }
          });
      }
  
           //haze
  else if ( weatherCode.equals("21")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.foggy);
              }
          });
      }
  
           //smoky
  else if ( weatherCode.equals("22")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.foggy);
              }
          });
      }
  
           //windy
  else if ( weatherCode.equals("24")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.windy);
              }
          });
      }
  
           //cloudy
  else if ( weatherCode.equals("26")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.cloudy);
              }
          });
      }
  
           //fair (night)
  else if ( weatherCode.equals("33")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.cloudy);
              }
          });
      }
  
           //fair (day)
  else if ( weatherCode.equals("34")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.cloudy);
              }
          });
      }
  
           //partly cloudy
  else if ( weatherCode.equals("44")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.cloudy);
              }
          });
      }
  
           //mostly cloudy (night)
  else if ( weatherCode.equals("27")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.night_cloudy);
              }
          });
      }
  
           //partly cloudy (night)
  else if ( weatherCode.equals("29")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.night_cloudy);
              }
          });
      }
  
           //mostly cloudy (day)
  else if ( weatherCode.equals("28")) {
          mHandler.post(new Runnable() {
              @Override
              public void run() {
  
                  image.setImageResource(R.drawable.day_cloudy);
              }
          });
      }
  
  
           //partly cloudy (day)
      else if ( weatherCode.equals("30")) {
              mHandler.post(new Runnable() {
                  @Override
                  public void run() {
  
                      image.setImageResource(R.drawable.day_cloudy);
                  }
              });
          }
  
  
  
  
           //clear(night)
      else if ( weatherCode.equals("31")) {
              mHandler.post(new Runnable() {
                  @Override
                  public void run() {
  
                      image.setImageResource(R.drawable.moon);
                  }
              });
          }
  
  
           //sunny
      else {
              mHandler.post(new Runnable() {
                  @Override
                  public void run() {
  
                      image.setImageResource(R.drawable.sunny);
                  }
              });
          }
  
  
  
  
           myWeather.conditiontext = conditionNode.getAttributes()
         .getNamedItem("text")
         .getNodeValue()
         .toString();
  
           myWeather.conditiontemp = conditionNode.getAttributes()
                     .getNamedItem("temp")
                     .getNodeValue()
                     .toString();
  
  
  
  
       return myWeather; 
      }
  
      private Document convertStringToDocument(String src){
  
       Document dest = null;
       DocumentBuilderFactory dbFactory =
         DocumentBuilderFactory.newInstance();
       DocumentBuilder parser;
  
       try {
        parser = dbFactory.newDocumentBuilder();
        dest = parser.parse(new ByteArrayInputStream(src.getBytes())); 
       } catch (ParserConfigurationException e1) {
        e1.printStackTrace();
        Toast.makeText(MainActivity.this,
          e1.toString(), Toast.LENGTH_LONG).show(); 
       } catch (SAXException e) {
        e.printStackTrace();
        Toast.makeText(MainActivity.this,
          e.toString(), Toast.LENGTH_LONG).show(); 
       } catch (IOException e) {
        e.printStackTrace();
        Toast.makeText(MainActivity.this,
          e.toString(), Toast.LENGTH_LONG).show(); 
       }
  
       return dest; 
      }
  
      private String QueryYahooWeather(){
  
       String qResult = "";
       String queryString = "http://weather.yahooapis.com/forecastrss?w=1062617&amp;u=c";
  
       HttpClient httpClient = new DefaultHttpClient();
       HttpGet httpGet = new HttpGet(queryString);
  
       try {
        HttpEntity httpEntity = httpClient.execute(httpGet).getEntity();
  
        if (httpEntity != null){
         InputStream inputStream = httpEntity.getContent();
         Reader in = new InputStreamReader(inputStream);
         BufferedReader bufferedreader = new BufferedReader(in);
         StringBuilder stringBuilder = new StringBuilder();
  
         String stringReadLine = null;
  
         while ((stringReadLine = bufferedreader.readLine()) != null) {
          stringBuilder.append(stringReadLine + "\n"); 
         }
  
         qResult = stringBuilder.toString(); 
        } 
       } catch (ClientProtocolException e) {
        e.printStackTrace();
        Toast.makeText(MainActivity.this,
          e.toString(), Toast.LENGTH_LONG).show(); 
       } catch (IOException e) {
        e.printStackTrace();
        Toast.makeText(MainActivity.this,
          e.toString(), Toast.LENGTH_LONG).show(); 
       }
  
       return qResult; 
      }
  
  
  
  }
  </code></pre>
  
  <p>activity_main.xml</p>
  
  <pre><code>&lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
      android:orientation="vertical"
      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" &gt;
  
      &lt;Button
          android:id="@+id/button1"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignLeft="@+id/checkBox6"
          android:layout_alignParentBottom="true"
          android:layout_alignParentRight="true"
          android:text="Recommended" /&gt;
  
      &lt;CheckBox
          android:id="@+id/checkBox6"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignBaseline="@+id/checkBox3"
          android:layout_alignBottom="@+id/checkBox3"
          android:layout_alignParentRight="true"
          android:text="Neighbourhood" /&gt;
  
      &lt;CheckBox
          android:id="@+id/checkBox4"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignBaseline="@+id/checkBox1"
          android:layout_alignBottom="@+id/checkBox1"
          android:layout_alignLeft="@+id/checkBox5"
          android:text="Museum" /&gt;
  
      &lt;CheckBox
          android:id="@+id/checkBox3"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_above="@+id/button1"
          android:layout_alignParentLeft="true"
          android:layout_marginBottom="54dp"
          android:text="Sports" /&gt;
  
      &lt;EditText
          android:id="@+id/editText1"
          android:layout_width="182dp"
          android:layout_height="wrap_content"
          android:layout_above="@+id/checkBox4"
          android:layout_alignLeft="@+id/checkBox1"
          android:layout_marginBottom="22dp"
          android:ems="10" /&gt;
  
      &lt;TextView
          android:id="@+id/textView1"
          android:layout_width="78dp"
          android:layout_height="wrap_content"
          android:layout_above="@+id/editText1"
          android:layout_alignLeft="@+id/editText1"
          android:text="Location:" /&gt;
  
      &lt;CheckBox
          android:id="@+id/checkBox1"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_above="@+id/checkBox2"
          android:layout_alignLeft="@+id/checkBox2"
          android:layout_marginBottom="20dp"
          android:text="Education" /&gt;
  
      &lt;CheckBox
          android:id="@+id/checkBox2"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_above="@+id/checkBox3"
          android:layout_alignLeft="@+id/checkBox3"
          android:layout_marginBottom="18dp"
          android:text="Festival" /&gt;
  
      &lt;CheckBox
          android:id="@+id/checkBox5"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignLeft="@+id/checkBox6"
          android:layout_below="@+id/checkBox1"
          android:text="Performing Arts" /&gt;
  
      &lt;Button
          android:id="@+id/button2"
          style="?android:attr/buttonStyleSmall"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignBottom="@+id/button1"
          android:layout_alignLeft="@+id/checkBox3"
          android:layout_alignRight="@+id/imageView1"
          android:text="By Month" /&gt;
  
  
      &lt;ImageView
          android:id="@+id/imageView1"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignBottom="@+id/textView4"
          android:layout_alignLeft="@+id/textView1"
          android:layout_alignParentTop="true"
          android:layout_alignRight="@+id/checkBox1"
          android:layout_marginRight="16dp"
          android:src="@drawable/logo" /&gt;
  
    &lt;ImageView
          android:id="@+id/image"
          android:layout_width="60dp"
          android:layout_height="60dp"
                android:layout_alignParentRight="true"
                android:layout_above="@+id/weather"
                 android:layout_marginLeft="235dp"              
                /&gt;
  
          &lt;TextView
              android:id="@+id/weather"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:layout_alignBottom="@+id/imageView1"
              android:layout_alignRight="@+id/checkBox5"
              android:layout_marginLeft="29dp"
              android:layout_toRightOf="@+id/editText1"
              android:textColor="#000000" /&gt;
  
          &lt;TextView
              android:id="@+id/psi_text"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:layout_above="@+id/textView1"
              android:layout_alignRight="@+id/weather"
              android:layout_marginLeft="26dp"
              android:layout_toRightOf="@+id/editText1"
              android:textColor="#000000" /&gt;
  
  &lt;/RelativeLayout&gt;
  </code></pre>