Question

在我的React Native应用程序的标题中，我有一个条件图标和一个Searchbar。

static navigationOptions = ({ navigation }) => {
const { params = {} } = navigation.state;
return {
  headerTitle: (
    <View
      style={{
        flex: 1,
        backgroundColor: Platform.OS === 'ios' ? '#e54b4d' : '',
        alignItems: 'center',
        flexDirection: 'row',
        paddingHorizontal: 10,
        height: StatusBar.currentHeight,
      }}>
      {params.isIconTriggered && <Icon name="chevron-left" size={28} />}
      <SearchBar
        round
        platform={'default'}
        placeholder="Search"
        containerStyle={{
          flex: 1,
          backgroundColor: 'transparent',
        }}
      />
    </View>
  ),
  headerStyle: {
    backgroundColor: '#e54b4d',
  },
};
};

通常，搜索栏将采用标题的全部宽度，这正是我想要的。如果条件isIconTriggered为真，则图标将出现在搜索栏的前面，并且搜索栏的宽度将缩小到足以使其旁边可见的程度。

但是，发生这种情况时没有过渡或动画，并且感觉也不好。我想在搜索栏中添加动画，以便在触发条件并显示图标时宽度逐渐平滑地缩小。

那有可能实现吗，我该如何实现呢？

Answer 1

尝试学习react native的动画API。

这是我通过按钮触发器完成的操作。

import React, {Component} from 'react';
import {StyleSheet, View, TextInput , Button, SafeAreaView, Animated} from 'react-native';
import FA from 'react-native-vector-icons/FontAwesome5'

const AnimatedIcon = Animated.createAnimatedComponent(FA)
// make your icon animatable using createAnimatedComponent method

export default class Application extends Component {

  animVal = new Animated.Value(0);
   // initialize animated value to use for animation, whereas initial value is zero

  interpolateIcon = this.animVal.interpolate({inputRange:[0,1], outputRange:[0,1]})
  interpolateBar = this.animVal.interpolate({inputRange:[0,1],outputRange:['100%','90%']})
  // initialize interpolation to control the output value that will be passed on styles
  // since we will animate both search bar and icon. we need to initialize both 
  // on icon we will animate the scale whereas outputRange starts at 0 end in 1
  // on search bar we will animate width. whereas outputRange starts at 100% end in 90%

  animatedTransition = Animated.spring(this.animVal,{toValue:1})
  // we use spring to make the animation bouncy . and it will animate to Value 1

  clickAnimate = () => {
    this.animatedTransition.start()
  }
  // button trigger for animation

  //Components that will use on Animation must be Animated eg. Animted.View
  render() {
    return (
      <SafeAreaView>
      <View style={styles.container}>
        <View style={styles.search}>
        {/* our icon */}

        <Animated.View style={{width: this.interpolateBar}}>
        <TextInput placeholder='search here' style={styles.input}/>
        </Animated.View>

        <AnimatedIcon name='search' size={28} style={{paddingLeft: 10,paddingRight:10, transform:[{scale: this.interpolateIcon}]}}/>
        </View>

          <Button title='animate icon' onPress={this.clickAnimate}/>
      </View>
      </SafeAreaView>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    backgroundColor:'#F79D42',
    // flex: 1,
    height:'100%',
    paddingTop:20,
    flexDirection: 'column',
    // justifyContent: 'center',
    alignItems:'center'
  },
  input:{
    width: '100%',
    height:40,
    backgroundColor:'gray',
    textAlign:'center'
  },
  search:{
    flexDirection:'row-reverse',
    width:'90%',
    height:40,
    alignItems:'center'
  }
});

使用react-native-elements SearchBar组件的解决方案。将SearchBar组件包装在Animated.View中。明确为搜索栏设置动画

赞！

 <Animated.View style={{width: this.interpolateBar}}>
    <SearchBar
    placeholder="Type Here..."
    containerStyle={{width: '100%'}}
  />
    </Animated.View>

Answer 2

您可以使用React Native的Animated API来实现。

您可以检查此tutorial，以获取有关通过动画更改元素大小的概述。

Answer 3

React-Native-Animatable非常酷！试试这个：

创建自定义动画对象

import * as Animatable from 'react-native-animatable';

Animatable.initializeRegistryWithDefinitions({
   const myAnimation = {
      from: {
          width: 200 
      },
      to: {
          width: 100
      }
   }
})

在视图中用作动画值或在函数调用中用作引用。

在视图内：

   <Animatable.View useNativeDriver animation={myAnimation}/>

作为参考变量：

   <Animatable.View useNativeDriver ref={ref=>(this.testAnimation = ref)}/>

方法：

   testMethod = () => {
       this.testAnimation.myAnimation();
   }

React Native-动画宽度缩小

3 个答案: