unity累加計時和倒計時實現

/// <summary>
/// 倒計時文本
/// </summary>
private Text RedRainTimerText;

int hour;
int minute;
int second;
int millisecond;
// 1小時  時 分 秒
float timeSpend = 4*60*60;
private void FixedUpdate()
{
    // 倒計時刷新
    if (RedRainTimerText.gameObject.activeInHierarchy)
    {
        // 累加計時 timeSpend += Time.deltaTime;
        // 倒計時
        timeSpend -= Time.deltaTime;

        hour = (int)timeSpend / 3600;
        minute = ((int)timeSpend - hour * 3600) / 60;
        second = (int)timeSpend - hour * 3600 - minute * 60;
        millisecond = (int)((timeSpend - (int)timeSpend) * 1000);

        RedRainTimerText.text = string.Format ("{0:D2}:{1:D2}:{2:D2}.{3:D3}", hour, minute, second, millisecond);
    }

}