对象评估在Android Studio调试中始终为无效
在Android Studio调试时，我发现了一种奇怪的行为。我正在使用真实的设备（不是模拟器）。我有以下代码：
val currentFragment = supportFragmentManager.findFragmentById(R.id.act_navhost_fragment)
if (currentFragment is BottomNavFragment) {
...
在调试中，我看到以下内容：
如您所见，电流范围不是null。但是，如果我尝试仅评估表达式 supportFragmentManager.findFragmentById（r.id.act_navhost_fragment），结果为null。
怎么可能？我知道这可能是一个非常愚蠢的问题，但是我不明白为什么评估表达与运行时代码相比，会产生不同的结果，也许是因为片段ID？有没有办法评估这种表达方式？
I have found a weird behavior while debugging in Android Studio. I am using a real device (not an emulator). I have the following code:
val currentFragment = supportFragmentManager.findFragmentById(R.id.act_navhost_fragment)
if (currentFragment is BottomNavFragment) {
...
In debug I see the following:
As you may see, currentFragment is not null. However, if I try to evaluate only the expression
supportFragmentManager.findFragmentById(R.id.act_navhost_fragment), the result is null.
How is it possible? I know it's probably a very silly question but I don't understand why evaluate expression gives a different result compare to runtime code, maybe it's because of fragment id? Is there a way to evaluate such expressions?
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看来这是一个kotlin错误，R值无法正确解决。
https://youtrack.jetbrains.com/issue/issue/ktij-18232 发现的是复制正确的r.id。
It seems it's a kotlin bug, R values are resolved incorrectly.
https://youtrack.jetbrains.com/issue/KTIJ-18232
Workaround I have found is to copy the correct R.id.* int value (eg printing a log or directly from R file) and replace the R.id.* with the copied int.