[Android] Fix minDistance being reset by partial config updates

[m-bert]

Description

Follow-up to #4327

On Android, Pan's updateConfig derived hasCustomActivationCriteria from a local variable recomputed from the keys present in the incoming config map. Config updates can be partial a SharedValue used in the config sends { [key]: value } through updateGestureHandlerConfig, which doesn't reset the handler first - so the flag reflected a single update message instead of the accumulated configuration. Any criteria-key update (velocity/offset) then hit the "custom criteria and no explicit minDist" branch and masked an explicitly configured minDistance with Float.MAX_VALUE, disabling distance-based activation entirely.

hasCustomActivationCriteria is now a field on the handler, together with hasExplicitMinDist tracking whether minDist was explicitly configured; both are cleared in resetConfig. This mirrors how the other platforms already model this state (web: instance field + stored minDist; iOS: flag recomputed from stored recognizer state in updateHasCustomActivationCriteria), which is why they don't exhibit the bug. Full-config paths (createGestureHandler / setGestureHandlerConfig) go through resetConfig first, so their behavior is unchanged.

Test plan

Tested on the following code:

import React, { useState } from 'react';
import { Button, StyleSheet, Text, View } from 'react-native';
import { GestureDetector, usePanGesture } from 'react-native-gesture-handler';
import { useSharedValue } from 'react-native-reanimated';

export default function MinDistReset() {
  const [log, setLog] = useState<string[]>([]);
  const minVelocityY = useSharedValue(10000);

  const append = (entry: string) =>
    setLog((prev) => [...prev.slice(-8), entry]);

  const pan = usePanGesture({
    minDistance: 50,
    minVelocityY,
    runOnJS: true,
    onActivate: () => {
      append('ACTIVATED');
    },
    onFinalize: (e) => {
      if (e.canceled) {
        append('finished without activation');
      }
    },
  });

  return (
    <View style={styles.container}>
      <Text style={styles.title}>
        minDistance = 50, minVelocityY = SharedValue(10000)
      </Text>
      <Text style={styles.hint}>
        Slow 50pt+ drag should ACTIVATE — also after poking the shared value.
      </Text>
      <Button
        title="poke shared value"
        onPress={() => {
          // Render-silent on purpose - see the note at the top of the file.
          minVelocityY.value = minVelocityY.value === 9000 ? 9001 : 9000;
          console.log('poked: minVelocityY ->', minVelocityY.value);
        }}
      />
      <GestureDetector gesture={pan}>
        <View style={styles.box} testID="panBox">
          <Text style={styles.boxLabel}>drag here</Text>
        </View>
      </GestureDetector>
      <View style={styles.log}>
        {log.map((entry, i) => (
          <Text key={i} style={styles.logLine}>
            {entry}
          </Text>
        ))}
      </View>
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    alignItems: 'center',
    paddingTop: 16,
  },
  title: {
    fontSize: 16,
    fontWeight: 'bold',
  },
  hint: {
    textAlign: 'center',
    marginVertical: 12,
    color: '#666',
  },
  box: {
    width: 300,
    height: 300,
    backgroundColor: 'tomato',
    borderRadius: 16,
    justifyContent: 'center',
    alignItems: 'center',
    marginTop: 12,
  },
  boxLabel: {
    color: 'white',
    fontSize: 18,
  },
  log: {
    marginTop: 20,
    minHeight: 160,
    alignSelf: 'stretch',
    paddingHorizontal: 24,
  },
  logLine: {
    fontFamily: 'monospace',
    fontSize: 13,
  },
});

[Copilot]

Pull request overview

Fixes an Android-specific PanGestureHandler configuration bug where partial updateConfig calls (e.g., from SharedValue-driven updates) could incorrectly treat a single update payload as the full config, causing an explicitly set minDistance to be masked and distance-based activation to stop working.

Changes:

• Persist hasCustomActivationCriteria across partial updateConfig calls to avoid recomputing state from only the incoming keys.
• Track whether minDist was explicitly configured via a new hasExplicitMinDist flag.
• Clear both flags in resetConfig to keep full-config paths (setGestureHandlerConfig / creation) behavior unchanged.

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