Handlerthread use

When inter-thread communication, such as Android in common update UI, related to the communication between the child thread and the main thread, implementation is Handler + Looper, but to their own manual Looper, is not recommended, so Google encapsulates HandlerThread class (similar to AsyncTask class).

Child thread executing the task to send a message to the sub-handler thread, the child thread Handler reuse HandlerThread send a message to the main thread update ui 

public  class the MainActivity the extends AppCompatActivity { 

    the TextView the textView; 
    the Button Button; 
    MainHandler MainHandler; 
    protected  void the onCreate (the Bundle savedInstanceState) {
         Super .onCreate (savedInstanceState); 
        the setContentView (R.layout.activity_main); 
        the textView = the findViewById (R.id.text); 
        the Button = findViewById (R.id.button);
         // this is the main thread Handler instance if there is a knowledge that is passed when there is no new Handler looper to her, he would go to the default contact looper thread currently running 
        mainHandler = new new MainHandler ( the this );


        HandlerThread HandlerThread = new new HandlerThread ( "First" ); 
        handlerThread.start (); 
        // This is the handler child thread the looper handlerThread incoming links of 
        Final Handler childHandler = new new Handler (handlerThread.getLooper ()) {
             int COUNT = 0 ; 

            @Override 
            public  void the handleMessage (the Message MSG) {
                 Super .handleMessage (MSG); 
                System.out.println ( "child threads Handler received data will now send data to the main thread of execution" + . Thread.currentThread () getName ( ));
                 // send a message to the main thread of her handler ui update
                Message.obtain (MainHandler,. 1, ++ COUNT) .sendToTarget (); 
            } 
        }; 


        // Open a thread of the call information transmission childHandler 
        button.setOnClickListener ( new new View.OnClickListener () { 
            @Override 
            public  void the onClick (View V) { 

                new new the thread ( new new the Runnable () { 
                    @Override 
                    public  void RUN () { 
                        System.out.println ( "child thread sending data" + Thread.currentThread () getName ());.
                         // transmitted to the handler handlerThread
                        childHandler.sendEmptyMessage (. 1 ); 
                    } 
                .}) Start (); 
            } 
        }); 

    } 
        // This is the main thread of this form defined Handler, memory leaks can be prevented 
        class MainHandler the extends Handler {
             Private WeakReference <the MainActivity> mainActivityWeakReference; 

            MainHandler (the MainActivity MainActivity) { 
                the this .mainActivityWeakReference = new new WeakReference <> (MainActivity); 
            } 

            @Override 
            public  void the handleMessage (the Message MSG) {
                super.handleMessage(msg);
                mainActivityWeakReference.get().textView.setText(msg.obj + "");
            }
        }
    }