android 定时广播，做定时器

        //定义AlarmManager 
        private AlarmManager am = null;
        //实例化AlarmManager 
        am = (AlarmManager) getSystemService(ALARM_SERVICE);
        // 注册广播
        IntentFilter filter1 = new IntentFilter();
        filter1.addAction("com.xx.alarm");
        registerReceiver(alarmReceiver, filter1);

        Intent intent = new Intent();
        intent.setAction("com.xx.alarm");
        PendingIntent pi = PendingIntent.getBroadcast(this, 0, intent, 0);


        am.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(),

                1000*60, pi);// 马上开始，每分钟触发一次



 BroadcastReceiver alarmReceiver = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {
//            Toast.makeText(context, ++i, 0).show();
            if(canUpload){
                UploadFile();
            }
        }
            //判断是否同一个时间内
    };