Используйте разные значения состояния, по одному для каждого сборщика.
import React, { Component } from 'react';
import { View, Picker } from 'react-native';
class PickersComp extends Component {
state = {
val1 : '',
val2: '',
val3: '',
}
render(){
return (
<View>
<Picker
selectedValue={this.state.val1}
style={{ height: 50, width: 100 }}
onValueChange={(itemValue, itemIndex) => this.setState({ val1: itemValue })}>
<Picker.Item label="Java" value="java" />
<Picker.Item label="JavaScript" value="js" />
</Picker>
<Picker
selectedValue={this.state.val2}
style={{ height: 50, width: 100 }}
onValueChange={(itemValue, itemIndex) => this.setState({ val2: itemValue })}>
<Picker.Item label="foo" value="foo" />
<Picker.Item label="bar" value="bar" />
</Picker>
<Picker
selectedValue={this.state.val3}
style={{ height: 50, width: 100 }}
onValueChange={(itemValue, itemIndex) => this.setState({ val3: itemValue })}>
<Picker.Item label="test" value="test" />
<Picker.Item label="test2" value="js" />
</Picker>
</View>
);
}
};