gistfile1.txt

  componentWillMount() {
    this._responder = PanOrTapResponder.create({
      onPressIn: () => {
        // Called after the ~30ms delay to make sure
        // this gesture is not a pan but rather a tap.
        this.setState({highlightUnderlay: true});
      },

      onPress: () => {
        this.setState({highlightUnderlay: false});
        this.navigateToFoo();
      },

      onPressOut: () => {
        this.setState({highlightUnderlay: false});
        // cancelled so do not navigate
      },

      onPanResponderGrant: (e, {dx, dy}) => {
        invariant(
          this.state.highlightUnderlay === false,
          'Cannot be called if press lifecycle is midway through',
        );

        this.state.pan.setOffset({x: dx, y: dy});
        this.state.pan.setValue({x: 0, y: 0});
      },

      onPanResponderMove: (e, {dx, dy}) => {
        this.state.pan.setValue({
          x: Math.min(0, dx),
        });
      },

      onPanResponderRelease: (e, {dx, dy, vx, vy}) => {
        // Fancy animation stuff.
        Animated.decay(this.state.pan.x, {
          velocity: vx,
          deceleration: 0.98,
        }).start();
      },