_handlePanGestureStateChange = ({ nativeEvent }) => {
if (nativeEvent.oldState === State.ACTIVE) {
// Gesture was cancelled! For example, some navigation state update
// arrived while the gesture was active that cancelled it out
if (this.positionSwitch.__getValue() === 1) {
return;
}
if (this._isMotionVertical()) {
this._handleReleaseVertical(nativeEvent);
} else {
this._handleReleaseHorizontal(nativeEvent);
}
} else if (nativeEvent.state === State.ACTIVE) {
// Switch to using gesture position
this.positionSwitch.setValue(0);
// By enabling the gesture switch and ignoring the position here we
// end up with a quick jump to the initial value and then back to the
// gesture. While this isn't ideal, it's preferred over preventing new
// gestures during the animation (all gestures should be interruptible)
// and we will properly fix it (interruptible and from the correct position)
// when we integrate reanimated. If you prefer to prevent gestures during
// transitions, then fork this library, comment the positionSwitch value set above,
// and uncomment the following two lines.
// if (!this.props.transitionProps.position._animation) {
// this.positionSwitch.setValue(0);
// }
}
};
_prepareGesture() {
if (!this._isGestureEnabled()) {
if (this.positionSwitch.__getValue() !== 1) {
this.positionSwitch.setValue(1);
}
this.gesturePosition = undefined;
return;
}
// We can't run the gesture if width or height layout is unavailable
if (this.props.transitionProps.layout.width.__getValue() === 0 || this.props.transitionProps.layout.height.__getValue() === 0) {
return;
}
if (this._isMotionVertical()) {
this._prepareGestureVertical();
} else {
this._prepareGestureHorizontal();
}
}