React Native Animation undefined is not an object 错误

Question

我正在尝试为按下按钮时向右滑动的视图设置动画，我目前有以下代码，但不断得到

undefined is not an object (evaluation this.state.panelPos) 错误。我不明白代码有什么问题。有什么建议吗？

constructor(props){
    super(props)
    this.state = {
        initialLife : 200,
        panelPos: new Animated.Value(0),
    };
};


slideOutPanel(){
Animated.timing( this.state.panelPos,{
            toValue: 300,
            duration: 1000,
        }).start();
};

render(){return(
<View style = {styles.container}>

    <View style = {styles.lContainer}>

        <View style = {styles.playerLife}>

            <View style = {styles.lifeButtonRow}>
                <LifeButton/>
                <LifeButton/>
            </View>
            <View style = {styles.lifeButtonRow}>
                <LifeButton/>
                <LifeButton/>
            </View>     

            <Text>text</Text>
        </View>

        <Animated.View style = {[styles.panel,{transform: [{translateX: this.state.panelPos}]}]}>
            <Image style = {styles.cmd_panel} source={require('image')}/>
        </Animated.View>
    </View>
    <View style = {styles.portrait}>
        <Button title = {'push'} onPress = {this.slideOutPanel}/>
    </View>
</View>);

Answer 1

否则一切似乎都是正确的，但 this 的上下文未正确设置为：onPress={this.slideOutPanel}。

要么：onPress={() => this.slideOutPanel()}

或：onPress={this.slideOutPanel.bind(this)}