Android Looper update UI in non-UI threads

A toast was used in the test service to print the log.

Prompt cannot call Looper.prepare ()

After adding, the code executes normally.

Looper.prepare (); Toast.maketext (Getapplicationcontext (), "Services Thread", Toast.length_long). Show () Looper.loop ();

But then there was another toast, and then there was an error stating that each thread could have only one looper

caused by:java.lang.RuntimeException:Only one Looper may be created per thread

To view the data, prepared will create a looper.

So the other place no longer needs to be called again.

     //Looper    public static final void  Prepare ()  {        if  (Sthreadlocal.get ()  != null)  {            throw new  RuntimeException ("Only one looper may be created per thread");         }        sthreadlocal.set (New  looper ());   //Create a looper      }     in the current thread Private looper ()  {        mQueue = new  MessageQueue ();   //the key here, the creation of Looper has done nothing.   is actually creating a message queue           mRun = true;         mthread = thread.currentthread ();    &nbsP;}     looper    public static final void prepare ()  {        if  (Sthreadlocal.get ()  != null)  {             throw new runtimeexception (" Only one looper may be created per thread ");         }        sthreadlocal.set (New Looper ());   //Create a Looper    }    private looper () in the current thread  {         mqueue = new messagequeue ();   //the key here, Create what Looper have done.   is actually creating a message queue         mRun = true;         mthread = thread.currentthread ();     }

Android Looper update UI in non-UI threads