Fix #5163: status-bar tap scrolls to top only once per Form

[shai-almog]

Problem

Reported in #5163: on device (iPhone 15 Pro Max, iOS 26.5), tapping the status bar scrolls the Form to the top, but only once after the Form is shown. Scroll down again and the next tap does nothing; switching to another Form and back re-enables exactly one more working tap. The simulator's "iOS Status Bar Tap" menu can't reproduce it because that path bypasses the proxy.

Root cause

The "tap status bar → scroll to top" feature uses a synthetic UIScrollView proxy (CN1StatusBarTapProxyView) pinned to the status-bar strip at the UIWindow level. iOS only routes UIStatusBarTapAction to a scroll view whose contentOffset.y > 0 (i.e. it looks "scrolled away from top"), so the proxy is kept at contentOffset = (0,1) to stay eligible.

cn1FireStatusBarTap() re-armed that offset synchronously — but it runs from inside scrollViewShouldScrollToTop: while UIKit is still mid-tap. UIKit settles the proxy back toward the top after the delegate returns, clobbering our reset, so the proxy ends up at offset 0 and is no longer eligible. iOS then stops delivering taps until the next viewDidAppear re-pins the offset — hence "works exactly once per Form appearance."

The Java half (Form.findScrollableChild + scrollRectToVisible) is stateless and would scroll on every invocation, which is what localizes the bug to the native re-arm.

Fix

Bounce the (0,1) re-arm to the next main-queue turn via dispatch_async, so UIKit finishes processing the gesture before we restore the offset. The re-arm then sticks and the proxy stays eligible for every subsequent tap. Low-risk: it only changes when the existing one-line reset runs, and dispatch_async to the main queue is safe regardless of which thread cn1FireStatusBarTap is invoked from (including the instrumented test path).

Verification

This is device-only (the simulator status-bar menu bypasses the proxy). The exposed diagnostic counter can confirm before/after:

Display.getInstance().getProperty("cn1.iosStatusBarTap.count", "0")

Before the fix the count stops incrementing on the second tap; after the fix it increments on every tap.

🤖 Generated with Claude Code

[github-actions]

✅ Continuous Quality Report

Test & Coverage

• ✅ Tests: 2895 total, 0 failed, 1 skipped
• 📊 Line coverage: 52.41% [HTML preview] [Download]
  • Lowest covered classes
    • com.codename1.io.oidc.OidcClient – 0.00%
    • com.codename1.ai.OpenAiClient – 0.00%
    • com.codename1.social.Auth0Connect – 0.00%
    • com.codename1.io.grpc.ProtoWriter – 0.00%
    • com.codename1.social.AppleSignIn – 0.00%
    • com.codename1.io.graphql.GraphQLSubscription – 0.00%
    • com.codename1.io.grpc.GrpcWeb – 0.00%
    • com.codename1.nfc.NdefMessage – 0.00%
    • com.codename1.io.grpc.ProtoReader – 0.00%
    • com.codename1.nfc.NdefRecord – 0.00%

Static Analysis

• SpotBugs [Report archive]
  • ✅ ByteCodeTranslator: 0 findings (no issues)
  • ✅ android: 0 findings (no issues)
  • ✅ codenameone-maven-plugin: 0 findings (no issues)
  • ✅ core-unittests: 0 findings (no issues)
  • ✅ ios: 0 findings (no issues)
• ✅ PMD: 0 findings (no issues) [Report archive]
• ✅ Checkstyle: 0 findings (no issues) [Report archive]

Generated automatically by the PR CI workflow.

[shai-almog]

Compared 122 screenshots: 122 matched.
✅ Native Mac screenshot tests passed.

Benchmark Results

• VM Translation Time: 0 seconds
• Compilation Time: 153 seconds

Detailed Performance Metrics

Metric	Duration
Base64 payload size	8192 bytes
Base64 benchmark iterations	6000
Base64 native encode	688.000 ms
Base64 CN1 encode	1343.000 ms
Base64 encode ratio (CN1/native)	1.952x (95.2% slower)
Base64 native decode	430.000 ms
Base64 CN1 decode	1136.000 ms
Base64 decode ratio (CN1/native)	2.642x (164.2% slower)
Base64 SIMD encode	499.000 ms
Base64 encode ratio (SIMD/native)	0.725x (27.5% faster)
Base64 encode ratio (SIMD/CN1)	0.372x (62.8% faster)
Base64 SIMD decode	449.000 ms
Base64 decode ratio (SIMD/native)	1.044x (4.4% slower)
Base64 decode ratio (SIMD/CN1)	0.395x (60.5% faster)
Image encode benchmark iterations	100
Image createMask (SIMD off)	65.000 ms
Image createMask (SIMD on)	15.000 ms
Image createMask ratio (SIMD on/off)	0.231x (76.9% faster)
Image applyMask (SIMD off)	184.000 ms
Image applyMask (SIMD on)	122.000 ms
Image applyMask ratio (SIMD on/off)	0.663x (33.7% faster)
Image modifyAlpha (SIMD off)	156.000 ms
Image modifyAlpha (SIMD on)	89.000 ms
Image modifyAlpha ratio (SIMD on/off)	0.571x (42.9% faster)
Image modifyAlpha removeColor (SIMD off)	177.000 ms
Image modifyAlpha removeColor (SIMD on)	125.000 ms
Image modifyAlpha removeColor ratio (SIMD on/off)	0.706x (29.4% faster)
Image PNG encode (SIMD off)	1275.000 ms
Image PNG encode (SIMD on)	1145.000 ms
Image PNG encode ratio (SIMD on/off)	0.898x (10.2% faster)
Image JPEG encode	616.000 ms

[shai-almog]

Compared 103 screenshots: 103 matched.
✅ Native iOS Metal screenshot tests passed.

Benchmark Results

• VM Translation Time: 0 seconds
• Compilation Time: 264 seconds

Build and Run Timing

Metric	Duration
Simulator Boot	93000 ms
Simulator Boot (Run)	1000 ms
App Install	13000 ms
App Launch	8000 ms
Test Execution	1504000 ms

[shai-almog]

Compared 122 screenshots: 122 matched.
✅ Native iOS screenshot tests passed.

Benchmark Results

• VM Translation Time: 0 seconds
• Compilation Time: 206 seconds

Build and Run Timing

Metric	Duration
Simulator Boot	72000 ms
Simulator Boot (Run)	0 ms
App Install	20000 ms
App Launch	6000 ms
Test Execution	351000 ms

Detailed Performance Metrics

Metric	Duration
Base64 payload size	8192 bytes
Base64 benchmark iterations	6000
Base64 native encode	1296.000 ms
Base64 CN1 encode	1521.000 ms
Base64 encode ratio (CN1/native)	1.174x (17.4% slower)
Base64 native decode	520.000 ms
Base64 CN1 decode	1920.000 ms
Base64 decode ratio (CN1/native)	3.692x (269.2% slower)
Base64 SIMD encode	509.000 ms
Base64 encode ratio (SIMD/native)	0.393x (60.7% faster)
Base64 encode ratio (SIMD/CN1)	0.335x (66.5% faster)
Base64 SIMD decode	605.000 ms
Base64 decode ratio (SIMD/native)	1.163x (16.3% slower)
Base64 decode ratio (SIMD/CN1)	0.315x (68.5% faster)
Image encode benchmark iterations	100
Image createMask (SIMD off)	73.000 ms
Image createMask (SIMD on)	13.000 ms
Image createMask ratio (SIMD on/off)	0.178x (82.2% faster)
Image applyMask (SIMD off)	215.000 ms
Image applyMask (SIMD on)	88.000 ms
Image applyMask ratio (SIMD on/off)	0.409x (59.1% faster)
Image modifyAlpha (SIMD off)	200.000 ms
Image modifyAlpha (SIMD on)	110.000 ms
Image modifyAlpha ratio (SIMD on/off)	0.550x (45.0% faster)
Image modifyAlpha removeColor (SIMD off)	323.000 ms
Image modifyAlpha removeColor (SIMD on)	188.000 ms
Image modifyAlpha removeColor ratio (SIMD on/off)	0.582x (41.8% faster)
Image PNG encode (SIMD off)	1386.000 ms
Image PNG encode (SIMD on)	1202.000 ms
Image PNG encode ratio (SIMD on/off)	0.867x (13.3% faster)
Image JPEG encode	619.000 ms