<itemvalue="Creates an animation controller with no upper or lower bound for its value. [value] is the initial value of the animation. [duration] is the length of time this animation should last. [debugLabel] is a string to help identify this animation during debugging (used by [toString]). `vsync` is the [TickerProvider] for the current context. It can be changed by calling [resync]. It is required and must not be null. See [TickerProvider] for advice on obtaining a ticker provider. This constructor is most useful for animations that will be driven using a physics simulation, especially when the physics simulation has no pre-determined bounds."/>
<itemvalue="transitive"/>
@ -53,12 +54,11 @@
<itemvalue="菜谱"/>
<itemvalue="RenderBox.size accessed beyond the scope of resize, layout, or permitted parent access. RenderBox can always access its own size, otherwise, the only object that is allowed to read RenderBox.size is its parent, if they have said they will. It you hit this assert trying to access a child's size, pass "parentUsesSize: true" to that child's layout()."/>