Get TextInput value from different component - react-native

Question

I have 2 react native components in my app, one is a toolbar that has a "Done" button, pressed when a user is done filling a form.
The other is the form itself from where I need to get the data.
When the user clicks "Done" I send a post request with the parameters, but I can't find a neat way to get the data.
What is best practice for this?
My toolbar:
<TopToolbar text='Upload new item'
navigator={this.props.navigator} state={this.state} donePage={'true'}/>
In the toolbar component I have the done button:
<TouchableHighlight style={styles.done} onPress={() =>{this.state.text=this.props.state.data.price}} underlayColor='#4b50f8'>
<Image source={require('./Images/Path 264.png')}/>
</TouchableHighlight>
and one of the text inputs is:
<TextInput placeholder='Price*' style={styles.text} onChangeText={(text) => { this.state.data.price = text }}></TextInput>

Answer 1

Use state. You need to bind the view to the model => (state). Please add your code for a better guide.
Each time that you press and new character need be saved in your state using onChangeText
Example:
class UselessTextInput extends Component {
constructor(props) {
super(props);
this.state = { text: 'Useless Placeholder' };
}
render() {
return (
<TextInput
style={{height: 40, borderColor: 'gray', borderWidth: 1}}
onChangeText={(text) => this.setState({text})}
value={this.state.text}
/>
);
}
}
When you press in Done button. The TextInput value will be stored in this.state.text
For more info: https://facebook.github.io/react-native/docs/textinput.html
I think your main problem is that you need to read more about the states in the react documentation
https://facebook.github.io/react-native/docs/state.html
When you needs set the state. You should use setState not this.state.data.price = text. The state is a object with multiple keys y your needs modify one internal key inside data you need modify all data key and replace it.
Example:
In your constructor declare
this.state = { data: {price: 10, name: xxxx} };
if need modify data you should do something like.
var dataM = this.state.data;
dataM.price = 200
this.setState({ data: dataM});