如何在 Flutter 中滚动或跳转到 PageView.builder 或 PageController 的位置?
How to scroll or jump to position of PageView.builder or PageController in Flutter?
问题:使用 PageController 加载综合浏览量后无法滚动到 POSITION *
like ViewPager scroll to specific page in Android
Widget _buildCarousel(BuildContext context, int selectedIndex) {
PageController controller = PageController(viewportFraction: 1, keepPage: true);
return Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
SizedBox(
// you may want to use an aspect ratio here for tablet support
height: 400.0,
width: 240,
child: PageView.builder(
itemCount: assetImageList.length,
controller: controller,
itemBuilder: (BuildContext context, int itemIndex) {
return _buildCarouselItem(context, selectedIndex, itemIndex);
},
),
)
],
);
}
您可以使用 jumpTo() 方法滚动 PageView 的位置。
我在下面的例子中创建了一个 changePageViewPostion() 方法:
import 'package:flutter/material.dart';
class MyPageView extends StatefulWidget {
createState() {
return StateKeeper();
}
}
class StateKeeper extends State<MyPageView> {
PageController controller = PageController(viewportFraction: 1, keepPage: true);
var currentPageValue = 0.0;
var mItemCount = 10;
@override
void initState() {
// TODO: implement initState
super.initState();
controller.addListener(() {
setState(() {
currentPageValue = controller.page;
});
});
}
void changePageViewPostion(int whichPage) {
if(controller != null){
whichPage = whichPage + 1; // because position will start from 0
double jumpPosition = MediaQuery.of(context).size.width / 2;
double orgPosition = MediaQuery.of(context).size.width / 2;
for(int i=0; i<mItemCount; i++){
controller.jumpTo(jumpPosition);
if(i==whichPage){
break;
}
jumpPosition = jumpPosition + orgPosition;
}
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('PageView position change'),
),
body: PageView.builder(
controller: controller,
itemBuilder: (context, position) {
return Container(
color: position % 2 == 0 ? Colors.blue : Colors.pink,
child: Column(
children: <Widget>[
Center(
child: Text(
"Page " + (position + 1).toString(),
style: TextStyle(color: Colors.white, fontSize: 22.0),
),
),
Align(
alignment: FractionalOffset.bottomCenter,
child: Padding(padding: EdgeInsets.only(bottom: 20),
child: FloatingActionButton(
elevation: 0.0,
child: new Icon(Icons.check),
backgroundColor: new Color(0xFFE57373),
onPressed: (){
changePageViewPostion(5);
}
),),
),
],
),
);
},
itemCount: mItemCount,
)
);
}
}
我们可以通过控制器获取当前位置,如下所示:
controller.addListener(() {
setState(() {
currentPageValue = controller.page.toInt();
print((currentPageValue + 1).toString());
});
});
希望对您有所帮助:)
终于找到答案了。只需设置 initialPage: mSelectedPosition 属性,如:
child: PageView.builder(
itemCount: mTemplateModelList.length,
controller: PageController(initialPage: mSelectedPosition, keepPage: true, viewportFraction: 1),
itemBuilder: (BuildContext context, int itemIndex) {
return _buildCarouselItem(context, selectedIndex, itemIndex);
},
),
或者如果你想在点击按钮后滚动页面,你可以使用 jumpTo() 方法使用 PageController另一个用户在下面清楚地提到了:@android.
目前有 2 个选项可以处理您的请求:
PageView.builder(
controller: _pageController,
itemCount: _list.length,
itemBuilder: (context, index) {
return GestureDetector(
onTap: () {
_pageController.jumpToPage(index); // for regular jump
_pageController.animateToPage(_position, curve: Curves.decelerate, duration: Duration(milliseconds: 300)); // for animated jump. Requires a curve and a duration
},
child: Container();
);
}
),
问题:使用 PageController 加载综合浏览量后无法滚动到 POSITION *
like ViewPager scroll to specific page in Android
Widget _buildCarousel(BuildContext context, int selectedIndex) {
PageController controller = PageController(viewportFraction: 1, keepPage: true);
return Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
SizedBox(
// you may want to use an aspect ratio here for tablet support
height: 400.0,
width: 240,
child: PageView.builder(
itemCount: assetImageList.length,
controller: controller,
itemBuilder: (BuildContext context, int itemIndex) {
return _buildCarouselItem(context, selectedIndex, itemIndex);
},
),
)
],
);
}
您可以使用 jumpTo() 方法滚动 PageView 的位置。 我在下面的例子中创建了一个 changePageViewPostion() 方法:
import 'package:flutter/material.dart';
class MyPageView extends StatefulWidget {
createState() {
return StateKeeper();
}
}
class StateKeeper extends State<MyPageView> {
PageController controller = PageController(viewportFraction: 1, keepPage: true);
var currentPageValue = 0.0;
var mItemCount = 10;
@override
void initState() {
// TODO: implement initState
super.initState();
controller.addListener(() {
setState(() {
currentPageValue = controller.page;
});
});
}
void changePageViewPostion(int whichPage) {
if(controller != null){
whichPage = whichPage + 1; // because position will start from 0
double jumpPosition = MediaQuery.of(context).size.width / 2;
double orgPosition = MediaQuery.of(context).size.width / 2;
for(int i=0; i<mItemCount; i++){
controller.jumpTo(jumpPosition);
if(i==whichPage){
break;
}
jumpPosition = jumpPosition + orgPosition;
}
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('PageView position change'),
),
body: PageView.builder(
controller: controller,
itemBuilder: (context, position) {
return Container(
color: position % 2 == 0 ? Colors.blue : Colors.pink,
child: Column(
children: <Widget>[
Center(
child: Text(
"Page " + (position + 1).toString(),
style: TextStyle(color: Colors.white, fontSize: 22.0),
),
),
Align(
alignment: FractionalOffset.bottomCenter,
child: Padding(padding: EdgeInsets.only(bottom: 20),
child: FloatingActionButton(
elevation: 0.0,
child: new Icon(Icons.check),
backgroundColor: new Color(0xFFE57373),
onPressed: (){
changePageViewPostion(5);
}
),),
),
],
),
);
},
itemCount: mItemCount,
)
);
}
}
我们可以通过控制器获取当前位置,如下所示:
controller.addListener(() {
setState(() {
currentPageValue = controller.page.toInt();
print((currentPageValue + 1).toString());
});
});
希望对您有所帮助:)
终于找到答案了。只需设置 initialPage: mSelectedPosition 属性,如:
child: PageView.builder(
itemCount: mTemplateModelList.length,
controller: PageController(initialPage: mSelectedPosition, keepPage: true, viewportFraction: 1),
itemBuilder: (BuildContext context, int itemIndex) {
return _buildCarouselItem(context, selectedIndex, itemIndex);
},
),
或者如果你想在点击按钮后滚动页面,你可以使用 jumpTo() 方法使用 PageController另一个用户在下面清楚地提到了:@android.
目前有 2 个选项可以处理您的请求:
PageView.builder(
controller: _pageController,
itemCount: _list.length,
itemBuilder: (context, index) {
return GestureDetector(
onTap: () {
_pageController.jumpToPage(index); // for regular jump
_pageController.animateToPage(_position, curve: Curves.decelerate, duration: Duration(milliseconds: 300)); // for animated jump. Requires a curve and a duration
},
child: Container();
);
}
),