TabController:控制器
void _changeIndex(int value, { Duration duration, Curve curve }) {
assert(value !=null);
assert(value >=0 && (value
assert(duration !=null || curve ==null);
assert(_indexIsChangingCount >=0);
if (value ==_index ||length <2)
return;
_previousIndex =index;
_index = value;
if (duration !=null) {
_indexIsChangingCount +=1;
notifyListeners();// Because the value of indexIsChanging may have changed.
_animationController
.animateTo(_index.toDouble(), duration: duration, curve: curve)
.whenCompleteOrCancel(() {
_indexIsChangingCount -=1;
notifyListeners();
});
}else {
_indexIsChangingCount +=1;
_animationController.value =_index.toDouble();
_indexIsChangingCount -=1;
notifyListeners();
}
}
TabBar:
const TabBar({
Key key,
@required this.tabs,//子标签
this.controller,//控制器
this.isScrollable =false,//能否滑动
this.indicatorColor,//指示器颜色
this.indicatorWeight =2.0,//指示器高度
this.indicatorPadding = EdgeInsets.zero,//指示器padding
this.indicator,//指示器的形状
this.indicatorSize,//指示器宽度
this.labelColor,//选中颜色
this.labelStyle,//选中样式
this.labelPadding,//标签padding
this.unselectedLabelColor,//未选中颜色
this.unselectedLabelStyle,//未选中样式
this.dragStartBehavior = DragStartBehavior.start,//确定处理拖动开始行为的方式
this.onTap,//点击事件
})
TabBarView：
const TabBarView({
Key key,
@required this.children,//子widget
this.controller,//控制器
this.physics,//可以设置NeverScrollableScrollPhysics()禁止滑动，
this.dragStartBehavior = DragStartBehavior.start,//确定处理拖动开始行为的方式
})