page property
The current page displayed in the controlled PageView.
There are circumstances that this PageController can't know the current page. Reading page will throw an AssertionError in the following cases:
- No PageView is currently using this PageController. Once a PageView starts using this PageController, the new page position will be derived:
- First, based on the attached PageView's BuildContext and the position saved at that context's PageStorage if keepPage is true.
- Second, from the PageController's initialPage.
- More than one PageView using the same PageController.
The hasClients property can be used to check if a PageView is attached prior to accessing page.
Implementation
double get page {
assert(
positions.isNotEmpty,
'PageController.page cannot be accessed before a PageView is built with it.',
);
assert(
positions.length == 1,
'The page property cannot be read when multiple PageViews are attached to '
'the same PageController.',
);
final _PagePosition position = this.position;
return position.page;
}