Android studio 颤振无法将00.00转换为秒，unseconds（）方法显示错误

我正在尝试制作音频播放器，但在查找歌曲当前持续时间的滑块时遇到问题， 谢谢,

@override
void initState() {
super.initState();
player.onAudioPositionChanged.listen((Duration duration) {
  setState(() {
    currenttime = duration;
  });
});
player.onDurationChanged.listen((Duration duration) {
  setState(() {
    totaltime = duration;
  });
});
}

这是捕获CURRENTTIME和TOTALTIME的滑块小部件

Slider(
                        value: currenttime.inSeconds.toDouble(),
                        max: totaltime.inSeconds.toDouble(),
                        min: 0.0,
                        activeColor: mycolor,
                        inactiveColor: Colors.grey,
                        onChanged: (double value) {
                          setState(() {
                            int second = value.toInt();
                            Duration seeked = Duration(seconds: second);
                            player.seek(seeked);
                            value = value;
                          });
                        }),

这就是错误所在

═╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
The following NoSuchMethodError was thrown building MyApp(dirty, state: _MyAppState#8e9ee):
The getter 'inSeconds' was called on null.
Receiver: null
Tried calling: inSeconds

---

使用三元运算符，因为

currenttime

最初似乎为空，或者调查它为何为空

Slider(
       value: currenttime != null? currenttime.inSeconds.toDouble() : 0.0,

---

看起来它是空的尝试调试该值，您将know@OMiShah如何调试？抱歉，如果这很愚蠢的话。我的意思是，试着打印那个变量的值。最有可能的情况是，您试图在初始化一个空变量之前转换它，这会导致问题