覆盖View.OnKeyListener中的onKey的问题

Question

I am new to Android programming and relatively new to programming in general so please bear with me here...

I am trying to implement an EditText field and I am having problems with overriding onKey.

I found a couple of errors and fixed them but when I compile I get the following error:

cs211d.hw03.HW03 is not abstract and does not override abstract method       onKey(android.view.View,int,android.view.KeyEvent) in android.view.View.OnKeyListener
[javac] public class HW03 extends Activity implements View.OnKeyListener

I tried moving the onKey method outside of the inner class and it worked but only if I commented out et.setOnKeyListener(...);

Somebody suggested in another forum that I remove the OnKeyListener and/or implements View.OnKeyListener but it seems like it should be possible to implement the interface and use the OnKeyListener ....otherwise what is the point of it's existence?

Here is my code:

import android.app.Activity;
import android.os.Bundle;
import android.view.*;
import android.widget.EditText;

public class HW03 extends Activity implements View.OnKeyListener
{
    final EditText et = (EditText) findViewById(R.id.penniesField);

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle b)
    {
        super.onCreate(b);
        setContentView(R.layout.main);

        et.setOnKeyListener(
            new View.OnKeyListener()
            {
                public boolean onKey(View v, int keyCode, KeyEvent ke)
                {
                    if( (ke.getAction() == KeyEvent.ACTION_DOWN) &&
                        (keyCode == KeyEvent.KEYCODE_ENTER) )
                    {
                        String pennies = et.getText().toString();
                        return true;
                    }
                    return true;
                }
            });
    }
}

Answer 1

I'm not sure what the problem is exactly. I ran this piece of code and if I typed "hello" in the EditText and pressed Enter, "pennies" would contain the word "hello".

    ScrollView sv = new ScrollView(this);
    LinearLayout ll = new LinearLayout(this);
    ll.setOrientation(LinearLayout.VERTICAL);
    sv.addView(ll);    
    ll.addView(et);
et.setOnKeyListener(
        new View.OnKeyListener()
        {
            public boolean onKey(View v, int keyCode, KeyEvent ke)
            {
                String pennies = "";
                boolean output = false;
                if( (ke.getAction() == KeyEvent.ACTION_DOWN) &&
                    (keyCode == KeyEvent.KEYCODE_ENTER) )
                {
                    pennies = et.getText().toString();
                    output = true;
                }
                System.out.println("output = " + output);
                System.out.println("Pennies = " + pennies);
                return output;
            }
        });


this.setContentView(sv);