06_键盘事件

import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnKeyListener;
import android.widget.TextView;

public class MainActivity extends Activity implements OnKeyListener {
    StringBuilder builder = new StringBuilder();
     TextView textView;

     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         textView = new TextView(this);
         textView.setText("Press keys (if you have some)!");
         textView.setOnKeyListener(this);
         textView.setFocusableInTouchMode(true);
         textView.requestFocus();
         setContentView(textView);
     }

     @Override
     public boolean onKey(View view, int keyCode, KeyEvent event) {
         builder.setLength(0);
         switch (event.getAction()) {
         case KeyEvent.ACTION_DOWN:
             builder.append("down, ");
             break;
         case KeyEvent.ACTION_UP:
             builder.append("up, ");
             break;
         }
         builder.append(event.getKeyCode());
         builder.append(", ");
         builder.append((char) event.getUnicodeChar());
         String text = builder.toString();
         Log.d("KeyTest", text);
         textView.setText(text);

         if (event.getKeyCode() == KeyEvent.KEYCODE_BACK)
             return false;
         else
             return true;
     }
 }