从另一个活动取消具有相同Pending Intent的警报

Question

我有两项活动。在活动A上，我将闹钟设置为在5分钟后重复。在活动B上，我显示一个带有“贪睡”按钮和“关闭”按钮的对话框。但是，我可以从两个活动中获得相同的PendingIntent。我该如何解决这个问题？

MainActivity.java

public class MainActivity extends Activity {

    private static Context context;

    public static Context getAppContext(){
        return MainActivity.context;
    }

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

     MainActivity.context = getApplicationContext();

                /** Creating a calendar object corresponding to the date and time set by the user */
                for (int i = 0; i < alarm.size(); i++) {
                    GregorianCalendar calendar1 = new GregorianCalendar(alarm.get(i).getYear(), alarm.get(i).getMonth(), alarm.get(i).getDay(), alarm.get(i).getHour(), alarm.get(i).getMinute());
                    Intent alarmintent = new Intent("com.med.dic.alarmreceiveactivity");
                    alarmintent.putExtra("Title", alarm.get(i).getTime());
                    alarmintent.putExtra("Note", alarm.get(i).getAmount());
                    int _id = (int) System.currentTimeMillis();
                    alarmintent.putExtra("Id", _id);
                    PendingIntent sender = PendingIntent.getActivity(getApplicationContext(), _id, alarmintent, 0);

                    long cal = calendar1.getTimeInMillis();

                    /** Setting an alarm, which invokes the operation at alart_time */
                    alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, cal, 1000*60*1, sender);
                }
            }
        });
    }

AlarmReceiveActivity.java

public class AlarmReceiveActivity extends Activity {
private MediaPlayer mAlarmPlayer;
private Calendar calendar = Calendar.getInstance();
private String title;
private String note;
private int id;
private AlarmManager alarmManager;
private Context context;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Bundle extras = getIntent().getExtras();
    if (extras != null) {
        title = extras.getString("Title");
        note = extras.getString("Note");
        id = extras.getInt("Id");
        mAlarmPlayer = MediaPlayer.create(this, R.raw.test_alarm);
        mAlarmPlayer.setLooping(true);
        mAlarmPlayer.start();

        context = MainActivity.getAppContext();
        AlertDialog.Builder _builder = new AlertDialog.Builder(AlarmReceiveActivity.this);
        _builder.setTitle(title);
        _builder.setMessage(note);
        _builder.setPositiveButton("Nhắc lại(5')",
                new DialogInterface.OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        mAlarmPlayer.pause();
                        dialog.dismiss();

                });
        _builder.setNegativeButton("Bỏ qua",
                new DialogInterface.OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        mAlarmPlayer.pause();
                        Intent alarmintent = new Intent("com.med.dic.alarmreceiveactivity");
                        PendingIntent sender = PendingIntent.getActivity(context, id, alarmintent, 0);


                        alarmManager = (AlarmManager) getBaseContext().getSystemService(ALARM_SERVICE);
                        alarm.cancel(sender);
                        finish();
                    }
                });
        AlertDialog alert = _builder.create();
        alert.setCanceledOnTouchOutside(false);
        alert.setCancelable(false);
        alert.show();
    }
}