How to Dynamically Increase Marker Icon Size on Selection in Flutter Google Maps

Описание: Discover how to effectively change the size of marker icons on selection in Flutter Google Maps. This post provides a detailed solution to enhance your app's user experience.
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This video is based on the question https://stackoverflow.com/q/68023063/ asked by the user 'AgentRed' ( https://stackoverflow.com/u/7425940/ ) and on the answer https://stackoverflow.com/a/68091774/ provided by the user 'Simon Hutton' ( https://stackoverflow.com/u/4205425/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Dynamically Increase Marker Icon Size on Selection in Flutter Google Maps

Creating a visually engaging and interactive map experience in a Flutter application can often hinge on the effective use of markers. However, developers frequently encounter a challenge when trying to change the visual size of these markers upon selection. If you've ever wondered how to increase the icon size of a marker in Flutter's Google Maps when selected, you're in the right place.

Understanding the Problem

You might have attempted to utilize Flutter's capabilities by placing markers on the map and changing their appearance on tap. The typical approach involves using setState() to dynamically update the state of the widget. However, in the case of markers on Google Maps, this approach hits a roadblock because:

Markers are not Stateful Widgets: As they are instances of MapObject, they don't come with a setState() method.

Need for a Full Rebuild: To change the marker from a small to a large icon (or any other state change), it's necessary to replace the list of markers entirely, followed by a rebuild of the GoogleMap widget.

Implementing the Solution

To implement the desired functionality effectively, let's follow a structured approach. Here’s how you can manage marker sizes upon selection:

Step 1: Initialize Required Variables

First, you need to define the marker’s icons—both the small and large sizes. This is typically done using BitmapDescriptor.

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Create a Stateful Widget

Implement a StatefulWidget for your map. This allows you to rebuild your map and its markers when needed.

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Manage Marker State

Within your widget state, initialize the marker details and handle their status when selected. Create a method to generate the current state of your marker list.

[[See Video to Reveal this Text or Code Snippet]]

Step 4: Create Marker Generation Logic

This is where the power lies. You'll need a function that generates a list of markers. Depending on which marker is selected, the corresponding icon size will switch accordingly.

[[See Video to Reveal this Text or Code Snippet]]

Step 5: Build Your Google Map Widget

Finally, the code below constructs the GoogleMap widget which utilizes the marker data created:

[[See Video to Reveal this Text or Code Snippet]]

MarkerDetails Class

Moreover, define a class to encapsulate marker properties neatly:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

And there you have it! With this approach, tapping on a marker will switch its size dynamically, enhancing user interactivity within your application. Remember, the key takeaway here is to generate a new list of markers each time you select one, effectively leveraging Flutter's setState() to build your Google Map anew.

Implementing such dynamic features greatly improves usability and aesthetic appeal in your mobile app. Happy coding!