在徽标点击上来回旋转动画，反应原生

Question

我正在尝试动画菜单徽标以便在单击时旋转。我在旋转时成功获得了旋转，但是在旋转时它直接转到0而不是通过旋转动画。

这是我的组成部分：

import React from 'react';
import { TouchableOpacity, Animated } from 'react-native';
import PropTypes from 'prop-types';

import styles from './styles';

const TabIcon = ({
  route,
  renderIcon,
  onPress,
  focused,
  menuToggled,
  activeTintColor,
  inactiveTintColor,
}) => {
  const isMenuLogo = route.params && route.params.navigationDisabled;
  const animation = new Animated.Value(0);

  Animated.timing(animation, {
    toValue: menuToggled ? 1 : 0,
    duration: 200,
    useNativeDriver: true,
  }).start();

  const rotateInterpolate = animation.interpolate({
    inputRange: [0, 1],
    outputRange: ['0deg', '180deg'],
  });
  const animatedStyles = { transform: [{ rotate: rotateInterpolate }] };
  const logoStyles = [animatedStyles, styles.logoStyle];

  return (
    <TouchableOpacity
      style={styles.tabStyle}
      onPress={onPress}
      activeOpacity={isMenuLogo && 1}
    >
      <Animated.View style={isMenuLogo ? logoStyles : null}>
        {
          renderIcon({
            route,
            focused,
            tintColor: focused
              ? activeTintColor
              : inactiveTintColor,
          })
        }
      </Animated.View>
    </TouchableOpacity>
  );
};

TabIcon.propTypes = {
  route: PropTypes.shape({
    key: PropTypes.string,
  }).isRequired,
  renderIcon: PropTypes.func.isRequired,
  onPress: PropTypes.func,
  focused: PropTypes.bool,
  menuToggled: PropTypes.bool,
  activeTintColor: PropTypes.string.isRequired,
  inactiveTintColor: PropTypes.string.isRequired,
};

TabIcon.defaultProps = {
  onPress: () => {},
  focused: false,
  menuToggled: false,
};

export default TabIcon;

我先检查它是否在实际旋转之前切换过来。此组件在另一个显示自定义底部选项卡导航的父组件中调用。

当它向下旋转或我在当前动画中缺少配置时，我应该为它做一个不同的动画吗？

任何帮助和建议将非常感谢。谢谢。

Answer 1

我认为这个问题与以下事实有关：当你设置animation的初始值因为它始终设置为0时，它不会反映切换菜单时的更改。

你需要改变：

const animation = new Animated.Value(0);

至

const animation = new Animated.Value(menuToggled ? 0 : 1);

虽然做出这种改变会导致不同的问题。因为menuToggled影响动画的开始和结束位置，所以Icon现在将从结束位置旋转到正确的起始位置。这不太理想。

但是我们可以通过为menuToggled设置默认值null来解决这个问题。然后将动画包装在if-statement中，只有当menuToggled不是null时才会运行。

以下是基于初始代码的示例：

import React from 'react';
import { View, StyleSheet, Animated, TouchableOpacity } from 'react-native';
import { Ionicons } from '@expo/vector-icons';

const TabIcon = ({
  onPress,
  menuToggled
}) => {
  const logoStyles = [styles.logoStyle];
  if (menuToggled !== null) {
    const animation = new Animated.Value(menuToggled ? 0 : 1);

    Animated.timing(animation, {
      toValue: menuToggled ? 1 : 0,
      duration: 200,
      useNativeDriver: true
    }).start();

    const rotateInterpolate = animation.interpolate({
      inputRange: [0, 1],
      outputRange: ['0deg', '180deg']
    });
    const animatedStyles = { transform: [{ rotate: rotateInterpolate }] };
    logoStyles.push(animatedStyles);
  }

  return (
    <TouchableOpacity
      style={styles.tabStyle}
      onPress={onPress}
    >
      <Animated.View style={logoStyles}>
        <Ionicons name="md-checkmark-circle" size={32} color="green" />
      </Animated.View>
    </TouchableOpacity>
  );
};
export default class App extends React.Component {
  state = {
    menuToggled: null
  }

  toggleMenu = () => {
    this.setState(prevState => {
      return { menuToggled: !prevState.menuToggled };
    });
  }

  render () {
    return (
      <View style={styles.container}>
        <TabIcon
          onPress={this.toggleMenu}
          menuToggled={this.state.menuToggled}
        />
      </View>
    );
  }
}

我删除了你的TabIcon组件，因为那里有很多与动画无关的东西。您应该能够轻松地将我所做的工作融入您自己的组件中。 https://snack.expo.io/@andypandy/rotating-icon

Answer 2

我已经尝试过上面的安德鲁解决方案并且它有效，但我选择将其转换为类组件。它的工作方式相同。请参阅下面的组件。

import React, { PureComponent } from 'react';
import { TouchableOpacity, Animated } from 'react-native';
import PropTypes from 'prop-types';

import styles from './styles';

class TabIcon extends PureComponent {
  constructor(props) {
    super(props);
    this.state = {
      animation: new Animated.Value(0),
    };
  }

  render() {
    const { animation } = this.state;
    const {
      route,
      renderIcon,
      onPress,
      focused,
      menuToggled,
      activeTintColor,
      inactiveTintColor,
    } = this.props;
    const isMenuLogo = route.params && route.params.navigationDisabled;

    Animated.timing(animation, {
      toValue: menuToggled ? 1 : 0,
      duration: 200,
      useNativeDriver: true,
    }).start();

    const rotateInterpolate = animation.interpolate({
      inputRange: [0, 1],
      outputRange: ['0deg', '180deg'],
    });
    const animatedStyles = { transform: [{ rotate: rotateInterpolate }] };
    const logoStyles = [animatedStyles, styles.logoStyle];

    return (
      <TouchableOpacity
        style={styles.tabStyle}
        onPress={onPress}
        activeOpacity={isMenuLogo && 1}
      >
        <Animated.View style={isMenuLogo ? logoStyles : null}>
          {
            renderIcon({
              route,
              focused,
              tintColor: focused
                ? activeTintColor
                : inactiveTintColor,
            })
          }
        </Animated.View>
      </TouchableOpacity>
    );
  }
}

TabIcon.propTypes = {
  route: PropTypes.shape({
    key: PropTypes.string,
  }).isRequired,
  renderIcon: PropTypes.func.isRequired,
  onPress: PropTypes.func,
  focused: PropTypes.bool,
  menuToggled: PropTypes.bool,
  activeTintColor: PropTypes.string.isRequired,
  inactiveTintColor: PropTypes.string.isRequired,
};

TabIcon.defaultProps = {
  onPress: () => {},
  focused: false,
  menuToggled: false,
};

export default TabIcon;