Fix issue were pins stay on the map when you have maps on multiple pages #450

tomcurran · 2025-10-07T11:02:35Z

Clears all the annotations prior to adding new ones. We found it was needed as of .NET 9. Related code. Mirrors the behaviour in MauiMKMapView.

Summary by CodeRabbit

Bug Fixes
- On iOS, the map now clears existing annotations before rendering updates, preventing duplicate or outdated pins after data refreshes. This improves visual consistency and reliability of map markers during navigation, filtering, or live updates. No changes to public APIs or user interactions; pin updates are simply more accurate and consistent.

coderabbitai · 2025-10-07T11:02:57Z

Walkthrough

Adds a pre-condition in AddPins to clear existing annotations on iOS by calling RemoveAnnotations(PlatformView.Annotations) before iterating and adding new pins.

Changes

Cohort / File(s)	Summary
iOS Map Pin Refresh Logic `MauiMaps/Platforms/iOS/CustomMapHandler.cs`	Inserted an early branch in AddPins to remove existing annotations via RemoveAnnotations(PlatformView.Annotations) before processing mapPins; no public API changes.

Sequence Diagram(s)

sequenceDiagram
  autonumber
  actor Caller
  participant CustomMapHandler
  participant PlatformView as MKMapView (iOS)

  Caller->>CustomMapHandler: AddPins(mapPins)
  alt Existing annotations present
    CustomMapHandler->>PlatformView: RemoveAnnotations(PlatformView.Annotations)
    note right of PlatformView: Clears current markers
  end
  loop For each pin in mapPins
    CustomMapHandler->>PlatformView: AddAnnotation(pin)
  end
  CustomMapHandler-->>Caller: Return

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

I sweep the map, a tidy bun,
Old pins hop off—now zero, none.
Fresh carrots—erm, markers—line in rows,
A clean slate gleams where river flows.
With tidy paws and careful cheer,
Tap-tap, new pins—the path is clear! 🥕🗺️

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	You can run `@coderabbitai generate docstrings` to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title Check	✅ Passed	The title clearly describes the primary change by indicating that it fixes the issue of pins remaining on the map when navigating between multiple pages, which aligns directly with the pull request’s objective of clearing annotations before adding new ones.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

✨ Finishing touches

🔄 Docstrings generation in progress.

🧪 Generate unit tests (beta)

✅ Copyable Unit Test edits generated.

Create PR with unit tests
Commit unit tests in branch feature/map-pins
Post copyable unit tests in a comment

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Actionable comments posted: 1

📜 Review details

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📥 Commits

Reviewing files that changed from the base of the PR and between 519f54e and 66a2630.

📒 Files selected for processing (1)

MauiMaps/Platforms/iOS/CustomMapHandler.cs (1 hunks)

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GitHub Check: Codacy Static Code Analysis

coderabbitai · 2025-10-07T11:06:12Z

MauiMaps/Platforms/iOS/CustomMapHandler.cs

+		if (PlatformView.Annotations.Length > 0)
+		{
+			PlatformView.RemoveAnnotations(PlatformView.Annotations);
+		}


⚠️ Potential issue | 🟠 Major

Filter annotation removal to preserve system annotations.

Removing all annotations indiscriminately may unintentionally clear system-managed annotations such as the user location marker. Additionally, the async image loading for CustomPin (lines 144-157) can introduce a race condition: if AddPins is called again before image callbacks complete, those pending annotations might be added after the new clear operation, leaving stale pins on the map.

Consider filtering the removal to only target annotations added by this handler:

-if (PlatformView.Annotations.Length > 0) -{ - PlatformView.RemoveAnnotations(PlatformView.Annotations); -} +var annotationsToRemove = PlatformView.Annotations + .Where(a => a is CustomAnnotation || a is MKPointAnnotation) + .ToArray(); +if (annotationsToRemove.Length > 0) +{ + PlatformView.RemoveAnnotations(annotationsToRemove); +}

This preserves system annotations while still addressing the .NET 9 issue where pins persist across page navigations.

📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change

if (PlatformView.Annotations.Length > 0)

{

PlatformView.RemoveAnnotations(PlatformView.Annotations);

}

var annotationsToRemove = PlatformView.Annotations

.Where(a => a is CustomAnnotation || a is MKPointAnnotation)

.ToArray();

if (annotationsToRemove.Length > 0)

{

PlatformView.RemoveAnnotations(annotationsToRemove);

}

VladislavAntonyuk · 2025-10-11T15:08:31Z

MauiMaps/Platforms/iOS/CustomMapHandler.cs

 			return;
 		}

+		if (PlatformView.Annotations.Length > 0)


@tomcurran could you please explain why we need to clear all annotations? I see we removed annotations on line 116.

I found this to be needed to get the correct behaviour. See the description for information.

Could you please provide example to reproduce the issue?

coderabbitai · 2025-10-13T04:09:31Z

Note

Docstrings generation - SUCCESS
Generated docstrings for this pull request at #451

@VladislavAntonyuk

Docstrings generation was requested by @VladislavAntonyuk. * #450 (comment) The following files were modified: * `MauiMaps/Platforms/iOS/CustomMapHandler.cs`

coderabbitai · 2025-10-13T04:10:09Z

Note

Unit test generation is an Early Access feature. Expect some limitations and changes as we gather feedback and continue to improve it.

Generating unit tests... This may take up to 20 minutes.

coderabbitai · 2025-10-13T04:10:11Z

Note

Unit test generation is an Early Access feature. Expect some limitations and changes as we gather feedback and continue to improve it.

Generating unit tests... This may take up to 20 minutes.

coderabbitai · 2025-10-13T04:10:12Z

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coderabbitai · 2025-10-13T04:10:14Z

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coderabbitai · 2025-10-13T04:10:35Z

Note

Unit test generation is an Early Access feature. Expect some limitations and changes as we gather feedback and continue to improve it.

Generating unit tests... This may take up to 20 minutes.

coderabbitai · 2025-10-13T04:10:38Z

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Fix issue were pins stay on the map when you have maps on multiple pages

66a2630

coderabbitai bot reviewed Oct 7, 2025

View reviewed changes

VladislavAntonyuk reviewed Oct 11, 2025

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coderabbitai bot added a commit that referenced this pull request Oct 13, 2025

📝 Add docstrings to feature/map-pins

c80ab13

Docstrings generation was requested by @VladislavAntonyuk. * #450 (comment) The following files were modified: * `MauiMaps/Platforms/iOS/CustomMapHandler.cs`

coderabbitai bot mentioned this pull request Oct 13, 2025

📝 Add docstrings to feature/map-pins #451

Open

-		if (PlatformView.Annotations.Length > 0)
-		{
-			PlatformView.RemoveAnnotations(PlatformView.Annotations);
-		}
+var annotationsToRemove = PlatformView.Annotations
+    .Where(a => a is CustomAnnotation || a is MKPointAnnotation)
+    .ToArray();
+if (annotationsToRemove.Length > 0)
+{
+    PlatformView.RemoveAnnotations(annotationsToRemove);
+}

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Fix issue were pins stay on the map when you have maps on multiple pages #450

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Fix issue were pins stay on the map when you have maps on multiple pages #450

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Sequence Diagram(s)

Estimated code review effort

Poem

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