import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.KeyEvent;


public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
    	switch (keyCode) {
    	 case KeyEvent.KEYCODE_BACK:
             AlertDialog.Builder builder = new AlertDialog.Builder(this);
             builder.setIcon(R.drawable.ic_launcher)
                     .setTitle("提示！")
                     .setMessage("確認退出程式？")
                     .setPositiveButton("確定", new DialogInterface.OnClickListener() {
                         @Override
                         public void onClick(DialogInterface dialog, int which) {
                             finish();
                         }
                     })
                     .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                         @Override
                         public void onClick(DialogInterface dialog, int which) {

                         }
                     })
                     .show();
             break;
    	}
    	return false;	
    }
}