How to Solve Poly Line Not Drawing on Google Map Flutter
Introduction
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Google Maps is a popular mapping service used in many mobile applications, including those built with Flutter. One common issue developers face when using Google Maps in their Flutter apps is the poly line not drawing on the map. This can be frustrating, especially when trying to display routes or boundaries on the map. In this article, we will explore the possible causes of this issue and provide a step-by-step solution to solve it.
Causes of Poly Line Not Drawing
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There are several reasons why poly lines may not be drawing on Google Maps in your Flutter app. Some of the most common causes include:
- Incorrect coordinates: If the coordinates used to draw the poly line are incorrect or out of order, the line will not be displayed on the map.
- Insufficient permissions: If the app does not have the necessary permissions to access the device’s location, the poly line will not be drawn.
- Map not initialized: If the Google Map is not properly initialized, the poly line will not be displayed.
Solving Poly Line Not Drawing
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To solve the issue of poly lines not drawing on Google Maps in your Flutter app, follow these steps:
Step 1: Ensure Correct Coordinates
Make sure the coordinates used to draw the poly line are correct and in the correct order. You can use the following code to create a poly line:
“`dart
List
LatLng(37.7749, -122.4194),
LatLng(37.7859, -122.4364),
LatLng(37.7963, -122.4574),
];
Polyline(
polylineId: PolylineId(‘polyline’),
color: Colors.blue,
width: 5,
points: coordinates,
);
“`
Step 2: Check Permissions
Ensure that the app has the necessary permissions to access the device’s location. You can use the `location` package to request the necessary permissions:
“`dart
import ‘package:location/location.dart’;
Location location = Location();
Future
bool serviceEnabled;
PermissionStatus permission;
serviceEnabled = await location.serviceEnabled();
if (!serviceEnabled) {
serviceEnabled = await location.requestService();
if (!serviceEnabled) {
return;
}
}
permission = await location.hasPermission();
if (permission == PermissionStatus.denied) {
permission = await location.requestPermission();
if (permission != PermissionStatus.granted) {
return;
}
}
}
“`
Step 3: Initialize Google Map
Ensure that the Google Map is properly initialized before trying to draw the poly line. You can use the following code to initialize the map:
“`dart
GoogleMap(
onMapCreated: (GoogleMapController controller) {
_controller = controller;
},
initialCameraPosition: CameraPosition(
target: LatLng(37.7749, -122.4194),
zoom: 12,
),
)
“`
Conclusion
———-
In conclusion, solving the issue of poly lines not drawing on Google Maps in your Flutter app requires ensuring correct coordinates, checking permissions, and initializing the Google Map. By following the steps outlined in this article, you should be able to resolve the issue and display poly lines on the map.
Frequently Asked Questions
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1. Q: Why is my poly line not drawing on the Google Map?
A: The most common reasons for poly lines not drawing on the Google Map include incorrect coordinates, insufficient permissions, and the map not being initialized.
2. Q: How do I ensure correct coordinates for my poly line?
A: Make sure the coordinates used to draw the poly line are correct and in the correct order.
3. Q: What permissions do I need to access the device’s location?
A: You need to request the `location` permission to access the device’s location.
4. Q: How do I initialize the Google Map in my Flutter app?
A: You can initialize the Google Map by creating a `GoogleMap` widget and setting the `onMapCreated` property.
5. Q: Can I use the `location` package to request permissions?
A: Yes, you can use the `location` package to request the necessary permissions to access the device’s location.
