[android] Fix state manager on unregistered gestures

[akwasniewski]

Description

The new StateManager is global and given handlerTag it can manually set the states of an arbitrary gesture. This causes errors, when the gesture, which state is being set, has not been yet recorded in the orchestrator. Recording gestures in the orchestrator on android is done lazily, thus if it never received touches it is not recorded.

Test plan

Tested on the following example

Details

import React from 'react';
import { View, Text, StyleSheet } from 'react-native';
import { GestureHandlerRootView, GestureDetector, useLongPressGesture, GestureStateManager, usePanGesture, useSimultaneousGestures, useTapGesture } from 'react-native-gesture-handler';

export default function TwoPressables() {
  const longPress = useLongPressGesture({
    onTouchesDown: (e) => {
      'worklet';
      console.log("touches down")
    },
    onActivate: () => {
      'worklet';
      console.log("long pressed")
    },
    minDuration: 100000000,
    disableReanimated: true
  })
  const pan = useTapGesture({
    onTouchesDown: () => {
      'worklet';
      console.log("tap")

      GestureStateManager.activate(longPress.tag)
    },
    disableReanimated: true
  });
  return (
    <GestureHandlerRootView>
      <View style={styles.root}>
        <GestureDetector gesture={longPress}>
          <View style={styles.outer}>
            <Text style={styles.label}>Long Press</Text>
          </View>
        </GestureDetector>
        <GestureDetector gesture={pan}>
          <View style={styles.outer}>
            <Text style={styles.label}>Pan</Text>
          </View>
        </GestureDetector>

      </View>
    </GestureHandlerRootView>
  );
}

const styles = StyleSheet.create({
  root: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#f7f7f7',
  },
  outer: {
    padding: 20,
    backgroundColor: '#ddd',
    borderRadius: 12,
    marginBottom: 50
  },
  label: {
    fontSize: 18,
    marginBottom: 10,
  },
})

[m-bert]

As said in the first comment, I'm not a big fan of ForManual suffix. I think we could either use overloading (where possible) or add more descriptive suffix.

[m-bert]

Shouldn't it be this.orchestrator != null? Especially that the condition that starts all this process is if (orchestrator == null).

Also, the only way to end up here is from orchestrator itself, right?

[akwasniewski]

The check works differently than if, this throws the provided message when the orchestrator was already set.

[m-bert]

I'm not a fan of this name. First of all, if it has the same purpose we could overload prepare (maybe with little comment when it is useful). If we want to keep it different, then I guess it should be more descriptive, like prepareForManualStateChange, prepareForManualManagement, or some other form.

Also, it seems to share most of the logic with prepare - we could extract it into separate function if needed so that we don't have this redundancy.

[akwasniewski]

Cleaned up in 27b2aa0. prepare works fine if we pass null as view, so we can just do that.

[m-bert]

Same here, most of the logic is repeated.

[akwasniewski]

As above

[m-bert]

I think we should throw error when both, orchestrator and hostDetectorView are null. This may happen if gesture is defined, but is not assigned to any of the detectors. In that case I believe it will still crash, but with other, less descriptive error (probably NullPointerException).

[akwasniewski]

Thanks, f3c1e93, I will check whether this works on other platforms

[akwasniewski]

On web the error is more fitting, Expected delegate view to be HTMLElement and on iOS it fails silently