task 1 of 3 handler

Question

Task 1 of 3We're currently creating a new Thread each time we want to update our Twitter app. Instead, let's now use a Handler. Start by creating a new inner class extending Handler, and move the call to 'twitterClient.update()' into this new Handler's 'handleMessage' method.

MainActivity.java

public class MainActivity extends Activity {
  Button button;
  TwitterClient twitterClient = new TwitterClient();

  @Override
  public void onCreate(Bundle savedInstanceState) {
    setContentView(R.layout.activity_main);

    final TwitterThread twitterThread = new TwitterThread();
    twitterThread.setName("TwitterThread");
    twitterThread.start();

    button = (Button) findViewById(R.id.update_button);
    button.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v){

      }
    });
  }

  class TwitterThread extends Thread {
    @Override
    public void run() {
      twitterClient.update();
    }
  }
}

Answer 1 · 2017-03-25T16:23:51Z

March 25, 2017 4:23pm

Hi there,

There are a few steps to this first task - it isn't a simple one to figure out! Let's break it down into small parts.

The first part of the question is Start by creating a new inner class extending Handler. This will look like the TwitterThread class that's there already, i.e. it is inside the MainActivity class. I've called it TwitterHandler. The skeleton of it will look like:

    class TwitterHandler extends Handler{

    }

So, we have a class now. The next part of the question is move the call to 'twitterClient.update()' into this new Handler's 'handleMessage' method. So, we need a method called handleMessage inside this new class. Let's just put an empty method in there and work our way through the errors that throws up:

    class TwitterHandler extends Handler{
      public handleMessage(){

      }
    }

That gives an error about the return type. Let's guess that it returns nothing, so add void to see if that's accepted.

    class TwitterHandler extends Handler{
      public void handleMessage(){

      }
    }

That clears the error in Preview but the code challenge says Bummer! Don't forget to override the 'handleMessage(Message msg)' method of you new Handler. Aha! So we're dealing with an overriden method from the extends Handler and we now it know it takes a parameter too, so let's add those two things - one is the @Override keyword and the other is the parameter, Message msg:

    class TwitterHandler extends Handler{
      @Override
      public void handleMessage(Message msg){

      }
    }

Now we're making some progress! Adding that clears any issues in Preview again, but the next error on checking the code is Bummer! Don't forget to move the 'twitterClient.update()' call out of the Thread and into the Handler. Tat's the last part of the task! So, move the update code out of TwitterThread and into this new method.

The final code looks like:

    class TwitterHandler extends Handler{
      @Override
      public void handleMessage(Message msg){
        twitterClient.update();
      }
    }

And that's Task 1 passed!! Good luck!

Steve.

Answer 2 · 2020-07-30T10:56:56Z

July 30, 2020 10:56am

public class MainActivity extends Activity { Button button; TwitterClient twitterClient = new TwitterClient();

@Override public void onCreate(Bundle savedInstanceState) { setContentView(R.layout.activity_main);

final TwitterThread twitterThread = new TwitterThread();
twitterThread.setName("TwitterThread");
twitterThread.start();

button = (Button) findViewById(R.id.update_button);
button.setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View v){

  }
});

}

class TwitterThread extends Thread { @Override public void run() {

}

  class TwitterHandler extends Handler{
  @Override
  public void handleMessage(Message msg){
    twitterClient.update();
  }
}
}

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Tapiwanashe Taurayi

Tapiwanashe Taurayi

task 1 of 3 handler

2 Answers

Steve Hunter

Steve Hunter

Gift Nyamapfene

Gift Nyamapfene