反应原生圆变换翻译动画

Question

嗨，我希望animated.view 像圆圈一样移动。我想用鼻窦来解决这个问题，但它不起作用。有人知道怎么做吗？我不想旋转视图。它应该在圆圈中移动。我是新来的反应本地人。如果有人可以帮助我，那就太好了。

//import liraries
import React, { Component } from 'react';
import { View, Text, StyleSheet, Animated, Button, TouchableOpacity } from 'react-native';

// create a component
class MyClass extends Component {
  constructor() {
    super()
    this.animated = new Animated.Value(0);
  }

  animate() {    
    this.animated.setValue(0)
    Animated.timing(this.animated, {
      toValue: Math.PI *2,
      duration: 1000,
    }).start();
  }


  render() {
    const translateY = this.animated.interpolate({
      inputRange: [0, Math.PI *2],
      outputRange: [0, 200]
    });
    const translateX = translateY
    const transform = [{ translateY }, {translateX}];
    return (
      <View style={styles.container}>
        <Animated.View style={[{ transform }]}>
          <TouchableOpacity style={styles.btn}>
            <Text>hallo</Text>
          </TouchableOpacity>
        </Animated.View>
        <Button title="Test" onPress={() => { 
          this.animate() 
          }} />
      </View>
    );
  }
}

// define your styles
const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#2c3e50',
  },
  btn: {
    backgroundColor: 'red',
    justifyContent: 'center',
    alignItems: 'center',
    width: 50,
  }
});

//make this component available to the app
export default MyClass;

Answer 1

如果您正在寻找高性能的圆形旋转。 （没有颤抖/复杂的数学）

在这里

https://rn-animiations.web.app/component/circular-animation

完整代码：

import React, {Component} from 'react';
import {View, Text, Animated, StyleSheet, Easing} from 'react-native';

export default class Circle extends Component {
    constructor() {
        super();
        this.animated = new Animated.Value(0);
        var inputRange = [0, 1];
        var outputRange = ['0deg', '360deg'];
        this.rotate = this.animated.interpolate({inputRange, outputRange});
        outputRange = ['0deg', '-360deg'];
        this.rotateOpposit = this.animated.interpolate({inputRange, outputRange});
    }

    componentDidMount() {
        this.animate();
    }

    animate() {
      Animated.loop(
        Animated.timing(this.animated, {
            toValue: 1,
            duration: 4000,
            useNativeDriver: true,
            easing: Easing.linear,
        }),
      ).start();
    }
    render() {
        const transform = [{rotate: this.rotate}];
        const transform1 = [{rotate: this.rotateOpposit}];
        return (
          <View style={styles.container}>
            <Animated.View style={[styles.item, {transform}]}>
              <Animated.View style={[styles.dot, {transform: transform1}]}>
                <Text style={styles.text}>Test</Text>
              </Animated.View>
            </Animated.View>
          </View>
        );
    }
 }
 const styles = StyleSheet.create({
    container: {
        flex: 1,
        justifyContent: 'center',
        alignItems: 'center',
    },
    item: {
        position: 'absolute',
        width: 100,
        height: 200, // this is the diameter of circle
    },
    dot: {
        width: '100%',
        height: 20,
        backgroundColor: 'red',
        position: 'absolute',
        alignItems: 'center',
        justifyContent: 'center',
    },
    text: {
        color: '#fff',
    },
 });

结果：

Answer 2

你必须用Trigonometric Function计算translateX和translateY。

translateX对应Math.sin()，translateY对应Math.cos()。

虽然react-native animated.interpolate 不支持函数回调，但是你可以通过分成几个部分来模拟它（我在我的代码示例中选择了 50 个）：

完整代码：

export class App extends Component {
    constructor() {
        super()
        this.animated = new Animated.Value(0);

        var range = 1, snapshot = 50, radius = 100;
        /// translateX
        var inputRange = [], outputRange = [];
        for (var i=0; i<=snapshot; ++i) {
            var value = i/snapshot;
            var move = Math.sin(value * Math.PI * 2) * radius;
            inputRange.push(value);
            outputRange.push(move);
        }
        this.translateX = this.animated.interpolate({ inputRange, outputRange });

        /// translateY
        var inputRange = [], outputRange = [];
        for (var i=0; i<=snapshot; ++i) {
            var value = i/snapshot;
            var move = -Math.cos(value * Math.PI * 2) * radius;
            inputRange.push(value);
            outputRange.push(move);
        }
        this.translateY = this.animated.interpolate({ inputRange, outputRange });
    }

      animate() {
        this.animated.setValue(0)
        Animated.timing(this.animated, {
          toValue: 1,
          duration: 1000,
        }).start();
      }


      render() {
        const transform = [{ translateY: this.translateY }, {translateX: this.translateX}];
        return (
          <View style={styles.container}>
            <Animated.View style={[{ transform }]}>
              <TouchableOpacity style={styles.btn}>
                <Text>hallo</Text>
              </TouchableOpacity>
            </Animated.View>
            <Button title="Test" onPress={() => { 
              this.animate() 
              }} />
          </View>
        );
      }
    }

    // define your styles
    const styles = StyleSheet.create({
      container: {
        flex: 1,
        justifyContent: 'center',
        alignItems: 'center',
        backgroundColor: '#2c3e50',
      },
      btn: {
        backgroundColor: 'red',
        justifyContent: 'center',
        alignItems: 'center',
        width: 50,
      }
    });

结果：