我正在使用Flutter开发Google地图标记。
在每个标记的点击事件中,我想展示一个自定义信息窗口,可以包含按钮、图片等内容。但是在Flutter中,有一个TextInfoWindow
属性,只能接受String
类型的值。
我该如何为地图标记的InfoWindow
添加按钮、图片等内容呢?
我正在使用Flutter开发Google地图标记。
在每个标记的点击事件中,我想展示一个自定义信息窗口,可以包含按钮、图片等内容。但是在Flutter中,有一个TextInfoWindow
属性,只能接受String
类型的值。
我该如何为地图标记的InfoWindow
添加按钮、图片等内容呢?
我遇到了这个问题,找到了适用于我的解决方案:
为了解决它,我编写了一个自定义信息小部件,可随意定制。例如,通过ClipShadowPath添加一些阴影。
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'custom_info_widget.dart';
void main() => runApp(MyApp());
class PointObject {
final Widget child;
final LatLng location;
PointObject({this.child, this.location});
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
initialRoute: "/",
routes: {
"/": (context) => HomePage(),
},
);
}
}
class HomePage extends StatefulWidget {
@override
_HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
PointObject point = PointObject(
child: Text('Lorem Ipsum'),
location: LatLng(47.6, 8.8796),
);
StreamSubscription _mapIdleSubscription;
InfoWidgetRoute _infoWidgetRoute;
GoogleMapController _mapController;
@override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
color: Colors.green,
child: GoogleMap(
initialCameraPosition: CameraPosition(
target: const LatLng(47.6, 8.6796),
zoom: 10,
),
circles: Set<Circle>()
..add(Circle(
circleId: CircleId('hi2'),
center: LatLng(47.6, 8.8796),
radius: 50,
strokeWidth: 10,
strokeColor: Colors.black,
)),
markers: Set<Marker>()
..add(Marker(
markerId: MarkerId(point.location.latitude.toString() +
point.location.longitude.toString()),
position: point.location,
onTap: () => _onTap(point),
)),
onMapCreated: (mapController) {
_mapController = mapController;
},
/// This fakes the onMapIdle, as the googleMaps on Map Idle does not always work
/// (see: https://github.com/flutter/flutter/issues/37682)
/// When the Map Idles and a _infoWidgetRoute exists, it gets displayed.
onCameraMove: (newPosition) {
_mapIdleSubscription?.cancel();
_mapIdleSubscription = Future.delayed(Duration(milliseconds: 150))
.asStream()
.listen((_) {
if (_infoWidgetRoute != null) {
Navigator.of(context, rootNavigator: true)
.push(_infoWidgetRoute)
.then<void>(
(newValue) {
_infoWidgetRoute = null;
},
);
}
});
},
),
),
);
}
/// now my _onTap Method. First it creates the Info Widget Route and then
/// animates the Camera twice:
/// First to a place near the marker, then to the marker.
/// This is done to ensure that onCameraMove is always called
_onTap(PointObject point) async {
final RenderBox renderBox = context.findRenderObject();
Rect _itemRect = renderBox.localToGlobal(Offset.zero) & renderBox.size;
_infoWidgetRoute = InfoWidgetRoute(
child: point.child,
buildContext: context,
textStyle: const TextStyle(
fontSize: 14,
color: Colors.black,
),
mapsWidgetSize: _itemRect,
);
await _mapController.animateCamera(
CameraUpdate.newCameraPosition(
CameraPosition(
target: LatLng(
point.location.latitude - 0.0001,
point.location.longitude,
),
zoom: 15,
),
),
);
await _mapController.animateCamera(
CameraUpdate.newCameraPosition(
CameraPosition(
target: LatLng(
point.location.latitude,
point.location.longitude,
),
zoom: 15,
),
),
);
}
}
import 'package:flutter/material.dart';
import 'package:flutter/painting.dart';
import 'package:meta/meta.dart';
class _InfoWidgetRouteLayout<T> extends SingleChildLayoutDelegate {
final Rect mapsWidgetSize;
final double width;
final double height;
_InfoWidgetRouteLayout(
{@required this.mapsWidgetSize,
@required this.height,
@required this.width});
/// Depending of the size of the marker or the widget, the offset in y direction has to be adjusted;
/// If the appear to be of different size, the commented code can be uncommented and
/// adjusted to get the right position of the Widget.
/// Or better: Adjust the marker size based on the device pixel ratio!!!!)
@override
Offset getPositionForChild(Size size, Size childSize) {
// if (Platform.isIOS) {
return Offset(
mapsWidgetSize.center.dx - childSize.width / 2,
mapsWidgetSize.center.dy - childSize.height - 50,
);
// } else {
// return Offset(
// mapsWidgetSize.center.dx - childSize.width / 2,
// mapsWidgetSize.center.dy - childSize.height - 10,
// );
// }
}
@override
BoxConstraints getConstraintsForChild(BoxConstraints constraints) {
//we expand the layout to our predefined sizes
return BoxConstraints.expand(width: width, height: height);
}
@override
bool shouldRelayout(_InfoWidgetRouteLayout oldDelegate) {
return mapsWidgetSize != oldDelegate.mapsWidgetSize;
}
}
class InfoWidgetRoute extends PopupRoute {
final Widget child;
final double width;
final double height;
final BuildContext buildContext;
final TextStyle textStyle;
final Rect mapsWidgetSize;
InfoWidgetRoute({
@required this.child,
@required this.buildContext,
@required this.textStyle,
@required this.mapsWidgetSize,
this.width = 150,
this.height = 50,
this.barrierLabel,
});
@override
Duration get transitionDuration => Duration(milliseconds: 100);
@override
bool get barrierDismissible => true;
@override
Color get barrierColor => null;
@override
final String barrierLabel;
@override
Widget buildPage(BuildContext context, Animation<double> animation,
Animation<double> secondaryAnimation) {
return MediaQuery.removePadding(
context: context,
removeBottom: true,
removeLeft: true,
removeRight: true,
removeTop: true,
child: Builder(builder: (BuildContext context) {
return CustomSingleChildLayout(
delegate: _InfoWidgetRouteLayout(
mapsWidgetSize: mapsWidgetSize, width: width, height: height),
child: InfoWidgetPopUp(
infoWidgetRoute: this,
),
);
}),
);
}
}
class InfoWidgetPopUp extends StatefulWidget {
const InfoWidgetPopUp({
Key key,
@required this.infoWidgetRoute,
}) : assert(infoWidgetRoute != null),
super(key: key);
final InfoWidgetRoute infoWidgetRoute;
@override
_InfoWidgetPopUpState createState() => _InfoWidgetPopUpState();
}
class _InfoWidgetPopUpState extends State<InfoWidgetPopUp> {
CurvedAnimation _fadeOpacity;
@override
void initState() {
super.initState();
_fadeOpacity = CurvedAnimation(
parent: widget.infoWidgetRoute.animation,
curve: Curves.easeIn,
reverseCurve: Curves.easeOut,
);
}
@override
Widget build(BuildContext context) {
return FadeTransition(
opacity: _fadeOpacity,
child: Material(
type: MaterialType.transparency,
textStyle: widget.infoWidgetRoute.textStyle,
child: ClipPath(
clipper: _InfoWidgetClipper(),
child: Container(
color: Colors.white,
padding: EdgeInsets.only(bottom: 10),
child: Center(child: widget.infoWidgetRoute.child),
),
),
),
);
}
}
class _InfoWidgetClipper extends CustomClipper<Path> {
@override
Path getClip(Size size) {
Path path = Path();
path.lineTo(0.0, size.height - 20);
path.quadraticBezierTo(0.0, size.height - 10, 10.0, size.height - 10);
path.lineTo(size.width / 2 - 10, size.height - 10);
path.lineTo(size.width / 2, size.height);
path.lineTo(size.width / 2 + 10, size.height - 10);
path.lineTo(size.width - 10, size.height - 10);
path.quadraticBezierTo(
size.width, size.height - 10, size.width, size.height - 20);
path.lineTo(size.width, 10.0);
path.quadraticBezierTo(size.width, 0.0, size.width - 10.0, 0.0);
path.lineTo(10, 0.0);
path.quadraticBezierTo(0.0, 0.0, 0.0, 10);
path.close();
return path;
}
@override
bool shouldReclip(CustomClipper<Path> oldClipper) => false;
}
今天我不小心遇到了同样的问题,我无法在TextInfoWindow中正确显示多行字符串。最终,我通过实现一个模态底部表单(https://docs.flutter.io/flutter/material/showModalBottomSheet.html)来规避这个问题,当您点击标记时,它会显示出来,对于我的情况效果很好。
我还可以想象许多使用情况需要完全自定义标记的信息窗口,但是阅读GitHub上的此问题(https://github.com/flutter/flutter/issues/23938),看起来目前还不可能,因为InfoWindow不是Flutter widget。
您可以将小部件制作的标记显示为自定义的“信息窗口”。基本上,您正在创建您的小部件的png图像,并将其显示为标记。
import 'dart:typed_data';
import 'dart:ui';
import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';
class MarkerInfo extends StatefulWidget {
final Function getBitmapImage;
final String text;
MarkerInfo({Key key, this.getBitmapImage, this.text}) : super(key: key);
@override
_MarkerInfoState createState() => _MarkerInfoState();
}
class _MarkerInfoState extends State<MarkerInfo> {
final markerKey = GlobalKey();
void initState() {
super.initState();
WidgetsBinding.instance.addPostFrameCallback((_) => getUint8List(markerKey)
.then((markerBitmap) => widget.getBitmapImage(markerBitmap)));
}
Future<Uint8List> getUint8List(GlobalKey markerKey) async {
RenderRepaintBoundary boundary =
markerKey.currentContext.findRenderObject();
var image = await boundary.toImage(pixelRatio: 2.0);
ByteData byteData = await image.toByteData(format: ImageByteFormat.png);
return byteData.buffer.asUint8List();
}
@override
Widget build(BuildContext context) {
return RepaintBoundary(
key: markerKey,
child: Container(
padding: EdgeInsets.only(bottom: 29),
child: Container(
width: 100,
height: 100,
color: Color(0xFF000000),
child: Text(
widget.text,
style: TextStyle(
color: Color(0xFFFFFFFF),
),
),
),
),
);
}
}
return Stack(
children: <Widget>[
MarkerInfo(
text: tripMinutes.toString(),
getBitmapImage: (img) {
customMarkerInfo = img;
}),
GoogleMap(
markers: markers,
...
最后一步是创建一个标记。从小部件传递的数据保存在customMarkerInfo - bytes中,因此将其转换为位图。
markers.add(
Marker(
position: position,
icon: BitmapDescriptor.fromBytes(customMarkerInfo),
markerId: MarkerId('MarkerID'),
),
);
Stack(
children: <Widget>[
Positioned.fill(child: GoogleMap(...),),
Positioned(
top: {offsetY},
left: {offsetX},
child: YourCustomInfoWidget(...),
)
]
)
screenCoordinate = await _mapController.getScreenCoordinate(currentPosition.target)
步骤3:计算器的offsetY、offsetX和setState。
相关问题:https://github.com/flutter/flutter/issues/41653
devicePixelRatio = Platform.isAndroid ? MediaQuery.of(context).devicePixelRatio : 1.0;
offsetY = (screenCoordinate?.y?.toDouble() ?? 0) / devicePixelRatio - infoWidget.size.width;
offsetX = (screenCoordinate?.x?.toDouble() ?? 0) / devicePixelRatio - infoWidget.size.height;
Marker(
...
consumeTapEvents: true,)
void paintTappedImage() async {
final ui.PictureRecorder recorder = ui.PictureRecorder();
final Canvas canvas = Canvas(recorder, Rect.fromPoints(const Offset(0.0, 0.0), const Offset(200.0, 200.0)));
final Paint paint = Paint()
..color = Colors.black.withOpacity(1)
..style = PaintingStyle.fill;
canvas.drawRRect(
RRect.fromRectAndRadius(
const Rect.fromLTWH(0.0, 0.0, 152.0, 48.0), const Radius.circular(4.0)),
paint);
paintText(canvas);
paintImage(labelIcon, const Rect.fromLTWH(8, 8, 32.0, 32.0), canvas, paint,
BoxFit.contain);
paintImage(markerImage, const Rect.fromLTWH(24.0, 48.0, 110.0, 110.0), canvas,
paint, BoxFit.contain);
final Picture picture = recorder.endRecording();
final img = await picture.toImage(200, 200);
final pngByteData = await img.toByteData(format: ImageByteFormat.png);
setState(() {
_customMarkerIcon = BitmapDescriptor.fromBytes(Uint8List.view(pngByteData.buffer));
});
}
void paintText(Canvas canvas) {
final textStyle = TextStyle(
color: Colors.white,
fontSize: 24,
);
final textSpan = TextSpan(
text: '18 mins',
style: textStyle,
);
final textPainter = TextPainter(
text: textSpan,
textDirection: TextDirection.ltr,
);
textPainter.layout(
minWidth: 0,
maxWidth: 88,
);
final offset = Offset(48, 8);
textPainter.paint(canvas, offset);
}
void paintImage(
ui.Image image, Rect outputRect, Canvas canvas, Paint paint, BoxFit fit) {
final Size imageSize =
Size(image.width.toDouble(), image.height.toDouble());
final FittedSizes sizes = applyBoxFit(fit, imageSize, outputRect.size);
final Rect inputSubrect =
Alignment.center.inscribe(sizes.source, Offset.zero & imageSize);
final Rect outputSubrect =
Alignment.center.inscribe(sizes.destination, outputRect);
canvas.drawImageRect(image, inputSubrect, outputSubrect, paint);
}
void _onMarkerTapped(MarkerId markerId) async {
final Marker tappedMarker = markers[markerId];
if (tappedMarker != null) {
if (markers.containsKey(selectedMarker)) {
final Marker resetOld =
markers[selectedMarker].copyWith(iconParam: _markerIconUntapped);
setState(() {
markers[selectedMarker] = resetOld;
});
}
Marker newMarker;
selectedMarker = markerId;
newMarker = tappedMarker.copyWith(iconParam: _customMarkerIcon);
setState(() {
markers[markerId] = newMarker;
});
tappedCount++;
}
}
参考资料:
ChangeNotifierProvider
、ChangeNotifier
和Consumer
的帮助,即使摄像机在Google地图上移动,您也可以轻松重建小部件。
InfoWindowModel类:
class InfoWindowModel extends ChangeNotifier {
bool _showInfoWindow = false;
bool _tempHidden = false;
User _user;
double _leftMargin;
double _topMargin;
void rebuildInfoWindow() {
notifyListeners();
}
void updateUser(User user) {
_user = user;
}
void updateVisibility(bool visibility) {
_showInfoWindow = visibility;
}
void updateInfoWindow(
BuildContext context,
GoogleMapController controller,
LatLng location,
double infoWindowWidth,
double markerOffset,
) async {
ScreenCoordinate screenCoordinate =
await controller.getScreenCoordinate(location);
double devicePixelRatio =
Platform.isAndroid ? MediaQuery.of(context).devicePixelRatio : 1.0;
double left = (screenCoordinate.x.toDouble() / devicePixelRatio) -
(infoWindowWidth / 2);
double top =
(screenCoordinate.y.toDouble() / devicePixelRatio) - markerOffset;
if (left < 0 || top < 0) {
_tempHidden = true;
} else {
_tempHidden = false;
_leftMargin = left;
_topMargin = top;
}
}
bool get showInfoWindow =>
(_showInfoWindow == true && _tempHidden == false) ? true : false;
double get leftMargin => _leftMargin;
double get topMargin => _topMargin;
User get user => _user;
}
完整的示例代码可以在我的博客上找到!
onCameraMove
?谢谢。 - Jessica