java EditText（文本字段）在报警应用程序中不工作？

Question

以下是我的代码：

import java.util.Calendar;

import 安卓.app.Activity;
import 安卓.app.AlarmManager;
import 安卓.app.PendingIntent;
import 安卓.content.Intent;
import 安卓.os.Bundle;
import 安卓.view.View;
import 安卓.view.Window;
import 安卓.widget.Button;
import 安卓.widget.EditText;

public class AlarmMainActivity extends Activity {
    Calendar cal = Calendar.getInstance();
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
            this.requestWindowFeature(Window.FEATURE_NO_TITLE);
       setContentView(R.layout.main);

   Button set = (Button)findViewById(R.id.button1);
   EditText Time = (EditText)findViewById(R.id.time);
   int n =Integer.parseInt(Time.getText().toString());

    //Create an offset from the current time in which the alarm will go off.   
    cal.add(Calendar.SECOND, 10);

    //Create a new PendingIntent and add it to the AlarmManager
    Intent intent = new Intent(this, AlarmReceiverActivity.class);
    PendingIntent pendingIntent = PendingIntent.getActivity(this,
        n, intent, PendingIntent.FLAG_CANCEL_CURRENT);
    AlarmManager am = 
        (AlarmManager)getSystemService(Activity.ALARM_SERVICE);
    am.set(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(),
            pendingIntent);     
}

}

这段代码中发生的是，这个应用程序在当前时间自动设置10秒的警报。我希望用户在需要多少秒后输入。我试着用cal.add(Calendar.SECOND, 10);代替10。但它不起作用