How to call an async function in textinput?

How to call an async function with in textinput?

getTxt = async () => {

    filetxt = 'abc';
    currentFileName = this.props.navigation.getParam("currentFileName");
    console.log(currentFileName);

    try {

        filetxt = FileSystem.readAsStringAsync(`${FileSystem.documentDirectory}${currentFileName}.txt`, { encoding: FileSystem.EncodingTypes.UTF8 });

        console.log(filetxt);

    } catch (error) {
        console.log(error);
    }

    return filetxt;
}

render() {

    return (
        <View style={{ flex: 1 }}>
            <TextInput
                multiline = {true}
                style={{ margin : 10 }}
            >{ await this.getTxt() }
            </TextInput>
            <Button onPress = { this.FunctionToOpenFirstActivity } title = 'Save'/>
        </View>
    );
}

There is an error "await is a reserved words", anyknow knows?

You need to re-arrange the code to get desired result. You can't use await in render() which is not async function. If you call async function getTxt without await, it will return a promise. So the filetext will be empty at the time of rendering. You need to make use of state to automatically re-render when value changes.

// Initialise filetext with state
constructor(props) {
    super(props);
    this.state = {
      filetext: ""
    };
  }
// Make componentWillMount async and invoke getTxt with await
async componentWillMount() {
 let text = await this.getTxt();
 this.setState({ filetext: text });
}

//Access filetext from the state so that it will automatically re-render when value changes

render() {

    return (
        <View style={{ flex: 1 }}>
            <TextInput
                multiline = {true}
                style={{ margin : 10 }}
            >{ this.state.filetext }
            </TextInput>
            <Button onPress = { this.FunctionToOpenFirstActivity } title = 'Save'/>
        </View>
    );
}

async function, An async function is a function declared with the async keyword. wish to safely perform two or more jobs in parallel, you must await a call to� Now add the async method below in the code above , on the onPressSubmitButton property and un-comment the line.onFetchLoginRecords will call async http request. The async function will execute our code – It is the beauty of the React Native Library. async onFetchLoginRecords() { var data = { email: this.state.emailAddress,

You can call the function without await keyword

this.getTxt()

Your code will like:

getTxt = async () => {

    filetxt = 'abc';
    currentFileName = this.props.navigation.getParam("currentFileName");
    console.log(currentFileName);

    try {

        filetxt = FileSystem.readAsStringAsync(`${FileSystem.documentDirectory}${currentFileName}.txt`, { encoding: FileSystem.EncodingTypes.UTF8 });

        console.log(filetxt);

    } catch (error) {
        console.log(error);
    }

    return filetxt;
}

render() {

    return (
        <View style={{ flex: 1 }}>
            <TextInput
                multiline = {true}
                style={{ margin : 10 }}
            >{ this.getTxt() }
            </TextInput>
            <Button onPress = { this.FunctionToOpenFirstActivity } title = 'Save'/>
        </View>
    );
}

Async Operations in Redux. For any beginner with React and Redux , This inner function calls the saveUser API function in the mock API which has a TextInput (present in components/common/TextInput.js ) and� TextInput has by default a border at the bottom of its view. This border has its padding set by the background image provided by the system, and it cannot be changed. Solutions to avoid this is to either not set height explicitly, case in which the system will take care of displaying the border in the correct position, or to not display the border by setting underlineColorAndroid to trans

Render is not a async function , so you can not use await in render, you can do it in componentWillMount and keep it in a state the put that state in render method

async / await to avoid control flow, How to use async/await without disabling control flow (Promise spec', function() {; it('should find an element by text input model', function () arrange the above code as chain of promises to let it execute in a sequential way. :This creates a new TextInput that we will add to the application. Next, add an event listener to textInput for the creationComplete event. Using the static class Async call the method proceedOnEvent passing it the testCase, the target textInput, the event to listen for, and the timeout).

AsyncStorage - React Native By Example, Each of the methods in AsyncStorage can accept a callback function as an Call the _updateList method during the componentDidMount life cycle. Copy by updating listOfTasks and firing _changeTextInputValue to reset TextInput value. To use the async parts you need python 3.5+. I tested with python 3.5.2 on windows (it "should" not be OS specific). There are two possible approaches to add async support to kivy: Use kivy's event loop as an backend for an async event loop. That means that all the async task scheduling done externally go through the kivy event loop.

Example AsyncStorage React Native � GitHub, TextInput, export default class AsyncStorageExample extends Component { const value = await AsyncStorage. await AsyncStorage. @zawya Yes, you call that in the component you have that function defined and you� AsyncStorage is a key-value, asynchronous, simple, persistent, unencrypted, storage system that is global to the app. It is used as a LocalStorage in Apps similar to localstorage in browser.

Add a function to validate form fields using Yup and custom async , Today it is not possible to to mix async validations with Yup validations. schemas/SignupFormSchema"; import TextInput from "../. Changing value in one field does not trigger call to API to validate another field when its� It is sometimes necessary to make changes directly to a component without using state/props to trigger a re-render of the entire subtree. When using React in the browser for example, you sometimes need to directly modify a DOM node, and the same is true for views in mobile apps. `setNativeProps` is the React Native equivalent to setting properties directly on a DOM node.

Comments
  • That's exactly what the state is for