expo-image-header-scroll-view

This library originally from https://github.com/bamlab/react-native-image-header-scroll-view

I encountered some issues because it is still using outdated dependencies, especially it used childContextType, so I replaced it with the context provider.

I have confirmed that the modified library works well in my project.

A ScrollView-like component that:

• Has a fixed image header
• Keep the image as a nav bar
• Works on iOS and Android

Installation

$ yarn add expo-image-header-scroll-view

Demo

|

You can find this example code here : https://github.com/bamlab/react-native-image-header-scroll-view-example/blob/master/src/Pages/TvShow.js

Basic Usage

import { ImageHeaderScrollView, TriggeringView } from 'expo-image-header-scroll-view';

// Inside of a component's render() method:
render() {
  return (
    <ImageHeaderScrollView
      maxHeight={200}
      minHeight={MIN_HEIGHT}
      headerImage={require("../../assets/NZ.jpg")}
      renderForeground={() => (
        <View style={{ height: 150, justifyContent: "center", alignItems: "center" }} >
          <TouchableOpacity onPress={() => console.log("tap!!")}>
            <Text style={{ backgroundColor: "transparent" }}>Tap Me!</Text>
          </TouchableOpacity>
        </View>
      )}
    >
      <View style={{ height: 1000 }}>
        <TriggeringView onHide={() => console.log("text hidden")}>
          <Text>Scroll Me!</Text>
        </TriggeringView>
      </View>
    </ImageHeaderScrollView>
  );
}

Result :

You can find examples in a dedicated repository.

Usage (API)

All of the properties of ScrollView are supported. Please refer to the ScrollView documentation for more detail.

The ImageHeaderScrollView handle also the following props. None is required :

Header

Property	Type	Default	Description	Example
renderHeader	function	Empty view	Function which return the component to use as header. It can return background image for example.	example
headerImage	Image source Props (object or number)	undefined	Shortcut for renderHeader={() => <Image source={this.props.headerImage} style={{ height: this.props.maxHeight, width: Dimensions.get('window').width }} />}	example
maxHeight	number	125	Max height for the header	example
minHeight	number	80	Min height for the header (in navbar mode)	example
minOverlayOpacity	number	0	Opacity of a black overlay on the header before any scroll	example
maxOverlayOpacity	number	0.3	Opacity of a black overlay on the header when in navbar mode	example
overlayColor	string	black	Color of the overlay on the header	example
useNativeDriver	boolean	false	Use native driver for the animation for performance improvement. A few props are unsupported at the moment if useNativeDriver=true (onScroll, ScrollComponent, renderTouchableFixedForeground)	-
headerContainerStyle	Object	undefined	Optional styles to be passed to the container of the header component
disableHeaderGrow	boolean	undefined	Disable to grow effect on the header

Foreground

Property	Type	Default	Description	Example
renderForeground	function	Empty view	Function which return the component to use at foreground. The component is render in front of the header and scroll with the ScrollView. It can return a title for example.	example
renderFixedForeground	function	Empty view	Function which return the component to use as fixed foreground. The component is displayed with the header but not affected by the overlay.	example
foregroundExtrapolate	string	clamp	Optional prop that allows override extrapolate mode for foreground. Use null to allow extrapolation, which is usefull for using foreground as bottom title	-
foregroundParallaxRatio	number	1	Ration for parallax effect of foreground when scrolling. If 2, the header goes up two times faster than the scroll	example
fadeOutForeground	bool	false	If set, add a fade out effect on the foreground when scroll up	example
renderTouchableFixedForeground	function	Empty view	Same as renderFixedForeground but allow to use touchable in it. Can cause performances issues on Android	example
fixedForegroundContainerStyles	Object	undefined	Optional styles to be passed to the container of the fixed foreground component

Mixed

Property	Type	Default	Description	Example
ScrollViewComponent	Component	ScrollView	The component to be used for scrolling. Can be any component with an onScroll props (ie. ListView, FlatList, SectionList or ScrollView)	example
scrollViewBackgroundColor	string	white	Background color of the scrollView content	example

TriggeringView

The module also export a TriggeringView component. It is a spy View you put on the page that will can call various callback during the scroll. It accept callback called when it disappear or appear at the top of the ImageHeaderScrollView. You can see an exemple in the dedicated repository.

All of the properties of View are supported.

Property	Type	Description
onBeginHidden	function	Called when the component start to be hidden at the top of the scroll view.
onHide	function	Called when the component is not displayed any more after scroll up
onBeginDisplayed	function	Called when the component begin to be displayed again after scroll down
onDisplay	function	Called when the component finished to be displayed again.
onTouchTop	function	Called when the Top of the component touch the Top of the ScrollView. (onDisplay + onBeginHidden)
onTouchBottom	function	Called when the Bottom of the component touch the Top of the ScrollView. (onHide + onBeginDisplayed)

FAQ

How to remove the black image overlay

Just set the maxOverlayOpacity to 0.

<ImageHeaderScrollView
  minOverlayOpacity={0}
  maxOverlayOpacity={0}
  {/* ... */}
/>

How to remove the image zomming on scroll down

You have two solutions :

1. You can use the disableHeaderGrow props. It will keep the ios elastic scroll effect.
2. You can also use the bounces={false} props from the scroll view.

Results :

disableHeaderGrow	bounces={false}

Contributing

All contributions are welcomed, that might be either adding new features, doing some refaco of the exisiting code or fixing bugs.