場景：dialogfragment(tabLayout+viewpager) + 兩個Afragment

解決方案一：
class SafeMutableLiveData<T> : MutableLiveData<T>() {

private var weakLifecycleOwner: WeakReference<LifecycleOwner>? = null

override fun observe(owner: LifecycleOwner, observer: Observer<in T>) {
    weakLifecycleOwner?.get()?.let {
        removeObservers(it)
    }
    weakLifecycleOwner = WeakReference(owner)
    super.observe(owner, observer)
}

override fun setValue(value: T) {
    try {
        super.setValue(value)
    } catch (e: Exception) {
        super.postValue(value)
    }
}}

解決方案二
onViewCreated setUserVisibleHint 判斷 if (userVisibleHint && isVisible) viewmodel 實現(xiàn)observe 也可以解決這種問題