react native get TextInput value

Question

I am stuck with a very simple problem. I have login form with username, password and button. In my button handler, I try to get the textinput value. But always get undefined

Answer 1

You should use States to store the value of input fields. https://facebook.github.io/react-native/docs/state.html

• To update state values use setState

onChangeText={(value) => this.setState({username: value})}

• and get input value like this

this.state.username

Sample code

export default class Login extends Component {

    state = {
        username: 'demo',
        password: 'demo'
    };

    User Name
     this.setState({username: value})}
        value={this.state.username}
    />

    Password
     this.setState({password: value})}
        value={this.state.password}
    />

     
            {
                if(this.state.username.localeCompare('demo')!=0){
                    ToastAndroid.show('Invalid UserName',ToastAndroid.SHORT);
                    return;
                }

                if(this.state.password.localeCompare('demo')!=0){
                    ToastAndroid.show('Invalid Password',ToastAndroid.SHORT);
                    return;
                }

                //Handle LOGIN

            }
        }
    />