# react-native-collapsing-toolbar

react-native wrapper for [CollapsingToolbarLayout](https://developer.android.com/reference/android/support/design/widget/CollapsingToolbarLayout.html),
easy to integrate with Animated.Event and FlatList out the box.

![collapsing-github](https://cloud.githubusercontent.com/assets/5366959/26673566/b68a1a1e-4693-11e7-9a7b-41227dde0ff3.gif)

[See the example](https://github.com/cesardeazevedo/react-native-collapsing-toolbar/blob/master/example/index.android.js)

## Getting started

Make sure to install both `react-native-collapsing-toolbar` and `react-native-nested-scroll-view`.

`$ npm install react-native-nested-scroll-view --save`
`$ npm install react-native-collapsing-toolbar --save`

### Installation

MainActivity.java

```diff

+   import com.rnnestedscrollview.RNNestedScrollViewPackage;
+   import com.rncollapsingtoolbar.RNCollapsingToolbarPackage;

    public class MainApplication extends Application implements ReactApplication {

      @Override
      protected List<ReactPackage> getPackages() {
        return Arrays.<ReactPackage>asList(
            new MainReactPackage(),
+           new RNCollapsingToolbarPackage(),
+           new RNNestedScrollViewPackage()
        );
      }
    }

```

android/app/build.gradle


```diff
    dependencies {
        implementation fileTree(dir: "libs", include: ["*.jar"])
        implementation "com.android.support:appcompat-v7:${rootProject.ext.supportLibVersion}"
        implementation "com.facebook.react:react-native:+"  // From node_modules
+       implementation project(':react-native-collapsing-toolbar')
+       implementation project(':react-native-nested-scroll-view')
    }

```

android/settings.gradle

```diff

include ':app'

+   include ':react-native-nested-scroll-view'
+   project(':react-native-nested-scroll-view').projectDir = new File(rootProject.projectDir, '../node_modules/react-native-nested-scroll-view/android')

+   include ':react-native-collapsing-toolbar'
+   project(':react-native-collapsing-toolbar').projectDir = new File(rootProject.projectDir, '../node_modules/react-native-collapsing-toolbar/android')


```

# Usage

This package depends of [react-native-nested-scroll-view](https://github.com/cesardeazevedo/react-native-nested-scroll-view).

**Note** This component is very easy to break, you should follows this exact component order to make it work.

```jsx

import {
  AppBarLayout,
  CoordinatorLayout,
  CollapsingToolbarLayout,
  CollapsingParallax,
} from 'react-native-collapsing-toolbar'

import NestedScrollView from 'react-native-nested-scroll-view'


render() {
  const HEADER_HEIGHT = 300
  return (
    <CoordinatorLayout>
      <AppBarLayout style={{height: HEADER_HEIGHT, backgroundColor: '#000'}}>
        <CollapsingToolbarLayout
          title='Collapsing Toolbar'
          contentScrimColor='#673AB7'
          expandedTitleColor='#ffffff'
          expandedTitleGravity='BOTTOM'
          scrimAnimationDuration={500}
          expandedTitleMarginStart={22}
          expandedTitleMarginBottom={22}
          scrollFlags={
              AppBarLayout.SCROLL_FLAG_SCROLL
            | AppBarLayout.SCROLL_FLAG_EXIT_UNTIL_COLLAPSED
            | AppBarLayout.SCROLL_FLAG_SNAP
          }>
          <CollapsingParallax parallaxMultiplier={0.6}>
            <View collapsable={false} style={{height: HEADER_HEIGHT, justifyContent: 'center' }}>
              <Text>Some Custom Text Inside the Parallax</Text>
            </View>
          </CollapsingParallax>
          <ToolbarAndroid actions={[{title: 'Settings'}]} />
        </CollapsingToolbarLayout>
      </AppBarLayout>
      <NestedScrollView>
      // Main Content
      </NestedScrollView>
    </CoordinatorLayout>
  )
}


```

## Usage with FlatList

To work with FlatList, you should just pass the `renderScrollComponent` props and render a NestedScrollView instead of the ScrollView.

**NOTE:** RefreshControl is **NOT** supported yet.

```jsx
renderScroll(props) {
  return (
    <NestedScrollView {...props} />
  )
}

render() {
  return (
    <CoordinatorLayout>
      <AppBarLayout>
      ....
      </AppBarLayout>
      <FlatList
        data={data}
        renderItem={this.renderItem}
        renderScrollComponent={this.renderScroll}
      />
    </CoordinatorLayout>
  )
}
```

## Usage with Animated.Events

In order to do custom animations when collapsing, you should use `onOffsetChanged` prop on the `AppBarLayout` and **not** `onScroll` from the `NestedScrollView`, the `onScroll` won't fire until the CollapsingToolbarLayout is entire collapsed.

```jsx

state = {
  scrollY: new Animated.Value(0),
};

handleOffsetChanged = (e) => {
  Animated.event(
    [{ nativeEvent: { offset: this.state.scrollY }}]
  )(e, this.state)
}

render() {
  const rotateZ = this.state.scrollY.interpolate({
    inputRange:  [0, 100],
    outputRange: ["0deg", "-50deg"],
  })
  return (
    <CoordinatorLayout>
      <AppBarLayout onOffsetChanged={this.handleOffsetChanged}>
        <CollapsingToolbarLayout>
          <Animated.Image
            source={require('./image.png')}
            style={{ transform: [{ rotateZ }] }}
          />
          <ToolbarAndroid />
        </CollapsingToolbarLayout>
      </AppBarLayout>
      <NestedScrollView>
      </NestedScrollView>
    </CoordinatorLayout>
  )
}

```

# API

AppBarLayout properties

| Prop                      | Description
|---------------------------|------------
| onOffsetChanged           | The actual scroll event when de toolbar is collasping

AppBarLayout Methods

| Method  | Description
|---------|------------
| show    | Expands the toolbar
| hide    | Collapses the toolbar
| redraw  | Redraw the toolbar (invokes requestLayout)

CollapsingToolbarLayout properties

| Prop                      | Description
|---------------------------|------------
| title                     | Title of the Toolbar
| titleEnable               | If false, it will show the title of the ToolbarAndroid Component
| height                    | Height when the component is expanded, could be set on the style prop
| scrimVisibleHeightTrigger | The trigger value when the animation transition should started
| scrimAnimationDuration    | The duration of the animation transition
| contentScrimColor         | The color of the Toolbar to show when the view is collapsing
| collapsedTitleTextColor   | The color of the title when the view is collapsed.
| collapsedTitleGravity     | The alignment of the title when collpased, can be "CENTER", "CENTER_VERTICAL", "TOP", "LEFT", "RIGHT", "BOTTOM", "START" or "END"
| collapsedTitleTypeface    | Name of the font when the title is collapsed.
| statusBarScrimColor       | The color to use for the status bar scrim, Only works on Lollipop with the correct setup
| expandedTitleColor        | The color of the title when the view is expanded
| expandedTitleMargin       | Object with start, top, end, bottom margins
| expandedTitleMarginStart  | The left margin when title is expanded
| expandedTitleMarginTop    | The top margin when title is expanded
| expandedTitleMarginEnd    | The right margin when title is expanded
| expandedTitleMarginBottom | The bottom margin when title is expanded
| expandedTitleGravity      | The alignment of the title when expanded, can be "CENTER", "CENTER_VERTICAL", "TOP", "LEFT", "RIGHT", "BOTTOM", "START" or "END"
| expandedTitleTypeface     | Name of the font when the title is expanded
| scrollFlags               | Defines the scroll behavior, the values are defined statically on the AppBarLayout, can be SCROLL_FLAG_SNAP, SCROLL_FLAG_SCROLL, SCROLL_FLAG_ENTER_ALWAYS, SCROLL_FLAG_ENTER_ALWAYS, SCROLL_FLAG_EXIT_UNTIL_COLLAPSED, SCROLL_FLAG_ENTER_ALWAYS_COLLAPSED

CollapsingParallax props

| Prop               | Description
|--------------------|------------
| parallaxMultiplier | The multiplier amount of parallax, a value higher than 1, the content will move against the scroll.

# License

[MIT](./LICENSE)