I have a react native component which is connected to the store, whenever there is an update to the store, render method is invoked.
I want to know whether render finished rendering the page.
I tried componentDidUpdate() but is getting invoked for every update from the redux store.
componentDidMount will be called after the first initial render.
componentDidUpdate will be called after all other renders.
See here under lifecycle.
Related
I have put console log inside of my functional component file. In this file render whenever the API called. If I called API in some other file and the API not related to that file still got logs. I am not sure why. I have checked useEffect and usestate but no clue. Even search from google no clue.
I am using Usestate to store and useEffect to reloaded the the page when data change
I am using apisauce to call the API
React native navigation bottomtab to navigate the screen
Using React.memo but still page rendered.
Any one please help me to resolve this issue. because I am new to react native.
React components automatically re-render whenever there is a change in their state or props. A simple update of the state, from anywhere in the code, causes all the User Interface (UI) elements to be re-rendered automatically.
However, there may be cases where the render() method depends on some other data. After the initial mounting of components, a re-render will occur when:
A component’s setState() method is called.
A component’s forceUpdate() method is called.
Warning: You should normally try to avoid all uses of forceUpdate() and only read from this.props and this.state in render().
I'm trying to update a component after receiving props from redux using componentWillReceiveProps. On the next instance that props are sent to the component by redux componentWillReceiveProps does not fire a second time. Any idea why this is happening and the best lifecycle component to use in such a situation?.
I am using react-navigation:
If i change the login property of the redux state when redux rerenders the View my StackLogin resets to initial state (If i am in the SignIn view it goes back to Login). Its like its not maintaining its own state. Maybe its something im missing about this library.
Regards
When the login prop changes, React will re-render your component. To determine what to render, the render() method is executed. Your render() method creates a new StackNavigator every time it is run. Therefore your <StackLogin /> is effectively reset when the prop changes.
What you probably want to do is to define StackLogin outside of the Login class. You certainly want to do it outside of the render() method.
Currently, I read some state from AsyncStorage in componentWillMount. However, some screens modify what is in AsyncStorage, and it does not appear that componentWillMount is called when returning (this.props.navigation.goBack()) to a screen, so they don't receive the update.
What, if anything, is called? What are the component lifecyle functions that are called on the return to a screen? Are any of these only called once, when the screen is to be shown again?
componentDidFocus is currently in design not avaiable yet, see react-native open issue #51.
Try this alternative way react-navigation-addons.
I'm building an app which views are inside tabs.
Some of the views render lists from data fetched by a call to an api.
I noticed that the render method is callled every time I hit the tab.
This causes the render method to re-render the list, so there is a delay and this not user friendly at all, as it takes some time.
How can I render the views only once?
You should implement shouldComponentUpdate method for each react component
you don't want to re-render each time it's props or state changed