long previous = 0L;            ...            {                Calendar c = Calendar.getInstance();                long now = c.getTimeInMillis();     //获取当前时间                Log.d(TAG, "now-->" + now + ",,previous-->"+previous + ",,now - previous -->" + (now - previous));                    if(now - previous>= 5000){                      // 两次点击时间差大于5秒                    // do something                    previous = now ;      //更新 previous                    }    //            previous = now ;                }               return true;