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

}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
if (keyCode == KeyEvent.KEYCODE_BACK )
{
// 创建退出对话框
AlertDialog isExit = new AlertDialog.Builder(this).create();
// 设置对话框标题
isExit.setTitle("系统提示");
// 设置对话框消息
isExit.setMessage("确定要退出吗");
// 添加选择按钮并注册监听
isExit.setButton("确定", listener);
isExit.setButton2("取消", listener);
// 显示对话框
isExit.show();

}

return false;

}
/**监听对话框里面的button点击事件*/
DialogInterface.OnClickListener listener = new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
switch (which)
{
case AlertDialog.BUTTON_POSITIVE:// "确认"按钮退出程序
finish();
break;
case AlertDialog.BUTTON_NEGATIVE:// "取消"第二个按钮取消对话框
break;
default:
break;
}
}
};
}