this.setstate react code example
Example 1: react native class component constructor
import React from 'react';
import { View, TextInput } from "react-native";
class App extends React.Component {
constructor(props){
super(props);
this.state = {
name: ""
}
this.handleChange = this.handleChange.bind(this);
}
handleChange(text){
this.setState({ name: text })
console.log(this.props);
}
render() {
return (
<View>
<TextInput
value={this.state.name}
onChangeText={(text) =>this.handleChange(text)}
/>
</View>
}
}
export default App;
Example 2: state with react functions
import React, { useState } from 'react';
function Example() {
const [count, setCount] = useState(0);
return (
<div>
<p>You clicked {count} times</p>
<button onClick={() => setCount(count + 1)}>
Click me
</button>
</div>
);
}
Example 3: set state
class App extends React.Component {
state = { count: 0 }
handleIncrement = () => {
this.setState({ count: this.state.count + 1 })
}
handleDecrement = () => {
this.setState({ count: this.state.count - 1 })
}
render() {
return (
<div>
<div>
{this.state.count}
</div>
<button onClick={this.handleIncrement}>Increment by 1</button>
<button onClick={this.handleDecrement}>Decrement by 1</button>
</div>
)
}
}
Example 4: state with react functions
class Example extends React.Component {
constructor(props) {
super(props);
this.state = {
count: 0
};
}
render() {
return (
<div>
<p>You clicked {this.state.count} times</p>
<button onClick={() => this.setState({ count: this.state.count + 1 })}>
Click me
</button>
</div>
);
}
}
Example 5: react lifecycle example
class Test extends React.Component {
constructor() {
console.log('Constructor')
super();
this.state = {
count: 0
};
}
componentDidMount() {
console.log("component did mount");
}
componentDidUpdate() {
console.log("component did update");
}
onClick = () => {
this.setState({ count: this.state.count + 1 });
};
render() {
console.log("render");
return (
<div>
Hello Test
<button onClick={this.onClick}>
{this.state.count}
</button>
</div>
);
}
}
Example 6: this.setstate prevstate
this.setState(prevState => ({ n: !prevState.n }))