WKWebView Component for React Native

React Native comes with WebView component, which uses UIWebView on iOS. This component uses WKWebView introduced in iOS 8.0 and macOS 10.10 with all the performance boosts.

• Deployment Target >= iOS 8.0 is required (which is React Native's current minimum deployment target anyway) when deploying to iOS.
• Deployment Target >= macOS 10.10 is required when deploying to macOS.

Install

1. Install from npm (note the postfix in the package name): npm install react-native-wkwebview-reborn
2. run react-native link react-native-wkwebview-reborn

Manual alternative

1. Install from npm (note the postfix in the package name): npm install react-native-wkwebview-reborn
2. In the XCode's "Project navigator", right click on your project's Libraries folder ➜ Add Files to <...>
3. Go to node_modules ➜ react-native-wkwebview-reborn ➜ ios (or macos) ➜ select RCTWKWebView.xcodeproj
4. Go your build target ➜ Build Phases ➜ Link Binary With Libraries, click "+" and select libRCTWkWebView.a (or libRCTWkWebView-macos.a, when building for macOS) (see the following screenshot for reference)
5. Compile and profit (Remember to set Minimum Deployment Target to 8.0 for iOS, or 10.10 for macOS)

Usage

import WKWebView from 'react-native-wkwebview-reborn';

Try replacing your existing WebView with WKWebView and it should work in most cases.

If your React Native < 0.40, please use 0.x.x versions.

Compatibility with UIWebView

WKWebView aims to be a drop-in replacement for UIWebView. However, some legacy UIWebView properties are not supported.

Since 1.14.0, WkWebView supports onMessage and postMessage as in the default WebView. You can refer to the React Native documentation or the example project. For advanced or customized usage, please refer to Advanced Communication between React Native and WkWebView.

Additional props:

• onProgress

A callback to get the loading progress of WKWebView. Derived from estimatedProgress property.

<WKWebView onProgress={(progress) => console.log(progress)} />

progress is a double between 0 and 1.

• openNewWindowInWebView

If set to true, links with target="_blank" or window.open will be opened in the current webview, not in Safari. Default is false.

• sendCookies

Set sendCookies to true to copy cookies from sharedHTTPCookieStorage when calling loadRequest. This emulates the behavior of react-native's WebView component. You can set cookies using react-native-cookies Default is false.

• source={{file: '', allowingReadAccessToURL: '' }}

This allows WKWebView loads a local HTML file. Please note the underlying API is only introduced in iOS 9+. So in iOS 8, it will simple ignores these two properties. It allows you to provide a fallback URL for iOS 8 users.

<WKWebView source={{ file: RNFS.MainBundlePath + '/data/index.html', allowingReadAccessToURL: RNFS.MainBundlePath }} />

• userAgent="MyUserAgent" (or customUserAgent="...")

Set a custom user agent for WKWebView. Note this only works on iOS 9+. Previous version will simply ignore this props.

• hideKeyboardAccessoryView

This will hide the keyboard accessory view (< > and Done). Default is false.

• allowsLinkPreview

A Boolean value that determines whether pressing on a link displays a preview of the destination for the link. This props is available on devices that support 3D Touch. In iOS 10 and later, the default value is true; before that, the default value is false.

• contentInsetAdjustmentBehavior

This property specifies how the safe area insets are used to modify the content area of the scroll view. The default value of this property is "never". Available on iOS 11 and later. Possible values are "automatic", "scrollableAxes", "never", "always". New in 1.16.0

• keyboardDisplayRequiresUserAction

Enables focusing an input inside a webview and showing the keyboard programatically. New in 1.20.0

• injectJavaScript, injectJavaScriptForMainFrameOnly

Add JavaScript at document start, see WKUserScriptInjectionTimeAtDocumentStart. New in 1.20.0

• injectedJavaScript, injectedJavaScriptForMainFrameOnly

Add JavaScript at document end. Since 1.20.0, the implementation has been changed to use WKUserScript.

Currently supported props are:

• automaticallyAdjustContentInsets
• contentInset
• html (deprecated)
• injectJavaScript
• injectedJavaScript
• onError
• onLoad
• onLoadEnd
• onLoadStart
• onNavigationStateChange
• renderError
• renderLoading
• source
• startInLoadingState
• style
• url (deprecated)
• bounces
• onShouldStartLoadWithRequest
• pagingEnabled
• scrollEnabled
• directionalLockEnabled

Unsupported props are:

• mediaPlaybackRequiresUserAction
• scalesPageToFit
• domStorageEnabled
• javaScriptEnabled
• allowsInlineMediaPlayback
• decelerationRate

Incomplete APIs for macOS

Some iOS methods have not been fully implemented for macOS yet. This is because the macOS implementation of WKWebView has some differences, such as lacking a scrollView, and using AppKit instead of UIKit; and so I (@shirakaba) don't quite know what should be done in the macOS case. I therefore can't guarantee the success of the following methods for macOS:

• setHideKeyboardAccessoryView
• setContentInset
• setBackgroundColor
• refreshContentInset
• scrollViewDidScroll

mailto and tel schemes are also not supported yet because I don't know the macOS equivalent.

Advanced Communication between React Native and WkWebView

Communication from WKWebview to React Native

• onMessage

This utilizes the message handlers in WKWebView and allows you to post message from webview to React Native. For example:

<WKWebView onMessage={(e) => console.log(e)} />

Then in your webview, you can post message to React Native using

window.webkit.messageHandlers.reactNative.postMessage({message: 'hello!'});

or (since 1.14.0)

window.postMessage({message: 'hello!'});

Then you can access the nativeEvent in React Native using the event object returned

e.nativeEvent => {
  name: 'reactNative',
  data: {
    message: 'hello!'
  }
}

The data serialization flow is as follows:

 JS — (via WKWebView) --> ObjC --- (via React Native Bridge) ---> JS

So I recommend to keep your data simple and JSON-friendly.

Communication from React Native to WkWebView

There is a evaluateJavaScript method on WKWebView, which does exactly what its name suggests. To send message from React Native to WebView, you can define a callback method on your WebView:

window.receivedMessageFromReactNative = function(data) {
  // Code here
  console.log(data);
}

Then you can send message from React Native with this method call:

// <WKWebView ref={ref => { this.webview = ref; }} />
this.webview.evaluateJavaScript('receivedMessageFromReactNative("Hello from the other side.")');

If you look at the source, the JavaScript side is mostly derived from React Native's WebView. The Objective C side mostly deals with the API difference between UIWebView and WKWebView.

Contribute

We battle test this component against our app. However, we haven't use all the props so if something does not work as expected, please open an issue or PR.