react native - How to change state when Button pressed? -


i'm new react native , unfamiliar js.

i want program show wrote in textinput when pressed button (there's text below button). figured maybe should make 2 state: put state1 text text input, , put state2 mimin textinput input, , when button pressed, put state2 mimin state1 text.

i've tried code below gave me red page when click button.

import react, { component } 'react'; import {   appregistry,   stylesheet,   text,   button,   textinput,   alert,   view } 'react-native';  export default class hella extends component {  constructor(props) {     super(props);     this.state = {text: '', mimin: ''}; }  render() {    return (        <view style={styles.container}>          <textinput           style={{height: 40}}           placeholder="type here translate!"           onchangetext={(mimin) => this.setstate({mimin})}         />         <button           onpress={onbuttonpress}           title="learn more"           color="#841584"           accessibilitylabel="learn more purple button"         />         <text style={styles.instructions}>           {this.state.text}         </text>       </view>     );   } }  const styles = stylesheet.create({   container: {     backgroundcolor: '#f5fcff',   } });  const onbuttonpress = () => {   hella.setstate({       text: hella.state.mimin  -------> error happened     }); };  appregistry.registercomponent('hella', () => hella);

the error was

undefined not object (evaluating 'hella.state.mimin')  onbuttonpress <project location>/index.android.js:61

what did wrong? how should declare it? can learn more?

your onbuttonpress should inside class since want setstate

export default class hella extends component {   constructor(props) {     ...   }    onbuttonpress = () => {     this.setstate({       text: this.state.mimin     });   }    render() {     return (       ...       <button         onpress={this.onbuttonpress}         ...       />       ...     );   } }

react native uses lot of react concepts. learning basics of react lot https://facebook.github.io/react/tutorial/tutorial.html


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