title: Activity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@46368a28 that was originally added here
body: <p>This problem drives me crazy. I miss some basic but very important knowledge about how to handle long operations in a new thread created within an activity and how to modify view components like text and such after the long operation's done. </p>
  
  <p>Let me first show you the part of my code where this problem happens:</p>
  
  <pre><code>mProgressDialog = ProgressDialog.show(mContext, "Tripplanner", "please wait...", true, false);
  connectAndGetRoute();
  
  
  private void connectAndGetRoute(){
  
      new Thread(){
          @Override
          public void run() {
              try {
              if(!connectTo9292ov()) return;// conncetto9292ov() connects to a website, parses the reasult into an arraylist. The arraylist contains route.
  
              } catch(UnknownHostException e){
                  Toast.makeText(mContext, "failed to connect to server", Toast.LENGTH_LONG).show();
              }catch (ClientProtocolException e) {
                 Toast.makeText(mContext, "failed to connect to server", Toast.LENGTH_LONG).show();                   
          } catch (IOException e) {
                  Toast.makeText(mContext, "failed to connect to server", Toast.LENGTH_LONG).show();
              }
  
              handler.post(runConnection);
          }
  
      }.start();
  
      handler = new Handler();
      runConnection = new Runnable(){
          @Override
          public void run() {
              mProgressDialog.dismiss();
              showOnScreen();
          }   
      };
  }
  </code></pre>
  
  <p>and this is the error I get:</p>
  
  <pre><code>ERROR/WindowManager(8297): Activity mp.tripplanner.OvPlanner has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@46368a28 that was originally added here
  ERROR/WindowManager(8297): android.view.WindowLeaked: Activity mp.tripplanner.OvPlanner has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@46368a28 that was originally added here
  ERROR/WindowManager(8297): at android.view.ViewRoot.&lt;init&gt;(ViewRoot.java:251)
  ERROR/WindowManager(8297): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148)
  ERROR/WindowManager(8297): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
  ERROR/WindowManager(8297): at android.view.Window$LocalWindowManager.addView(Window.java:424)
  ERROR/WindowManager(8297): at android.app.Dialog.show(Dialog.java:241)
  ERROR/WindowManager(8297): at android.app.ProgressDialog.show(ProgressDialog.java:107)
  ERROR/WindowManager(8297): at android.app.ProgressDialog.show(ProgressDialog.java:95)
  ERROR/WindowManager(8297): at mp.tripplanner.OvPlanner$3.onClick(OvPlanner.java:351)
  ERROR/WindowManager(8297): at android.view.View.performClick(View.java:2408)
  ERROR/WindowManager(8297): at android.view.View$PerformClick.run(View.java:8817)
  ERROR/WindowManager(8297): at android.os.Handler.handleCallback(Handler.java:587)
  ERROR/WindowManager(8297): at android.os.Handler.dispatchMessage(Handler.java:92)
  ERROR/WindowManager(8297): at android.os.Looper.loop(Looper.java:144)
  ERROR/WindowManager(8297): at android.app.ActivityThread.main(ActivityThread.java:4937)
  ERROR/WindowManager(8297): at java.lang.reflect.Method.invokeNative(Native Method)
  ERROR/WindowManager(8297): at java.lang.reflect.Method.invoke(Method.java:521)
  ERROR/WindowManager(8297): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
  ERROR/WindowManager(8297): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
  ERROR/WindowManager(8297): at dalvik.system.NativeStart.main(Native Method)
  </code></pre>
  
  <p>But another error message is written to the log before the above one, which is:</p>
  
  <pre><code>ERROR/AndroidRuntime(8297): FATAL EXCEPTION: Thread-9
  ERROR/AndroidRuntime(8297): java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
  ERROR/AndroidRuntime(8297): at android.os.Handler.&lt;init&gt;(Handler.java:121)
  ERROR/AndroidRuntime(8297): at android.widget.Toast.&lt;init&gt;(Toast.java:68)
  ERROR/AndroidRuntime(8297): at android.widget.Toast.makeText(Toast.java:231)
  ERROR/AndroidRuntime(8297): at mp.tripplanner.OvPlanner$4.run(OvPlanner.java:371)
  </code></pre>
  
  <p>Thank you for your help.</p>