greact-largelist v0.5.2

greact-largelist

Install

npm i --save greact-largelist

Stable version

v0.5.0

Using it like this:

import { LargeList } from "greact-largelist";

//other code
...
<LargeList
  style={{ flex: 1 }}
  bounces={true}
  refreshing={this.state.refreshing}
  onRefresh={() => {
    this.setState({ refreshing: true });
    setTimeout(() => this.setState({ refreshing: false }), 2000);
  }}
  safeMargin={600}
  numberOfRowsInSection={section => this.props.numberOfEachSection}
  numberOfSections={()=>this.props.numberOfSections}
  heightForCell={(section, row) => row % 2 ? this.minCellHeight : this.maxCellHeight}
  renderCell={this.renderItem.bind(this)}
  heightForSection={section =>section % 2 ? this.minSectionHeight : this.maxSectionHeight}
  renderHeader={this.renderHeader.bind(this)}
  renderFooter={this.renderFooter.bind(this)}
  renderSection={section => {
    return (
      <View
        style={{
          flex: 1,
          backgroundColor: section % 2 ? "grey" : "yellow",
          justifyContent: "center",
          alignItems: "center"
        }}
      >
        <Text>
           I am section {section}
        </Text>
      </View>
    );
  }}
/>
...

Usage

import { LargeList } from "greact-largelist"

Props:

Notice:

• If your data source change and it affects the number of sections or the number of cells in section, or the height of any sections or cells, you must call reloadData

Principle

Before we learn advanced usage, we must first understand the basic principles:

Every Cell/Item is reused just like UITableView/RecyclerView. The top Cell/Item which is Slided to the outside of the visible region does not need to show. So, I move it bottom, render it with the new datasource.

But,as you know, It is different with native UITableView/RecyclerView. They are not one thread between Main Thread(UI Thread) and JavaScript Thread. And They are asynchronous, and the communication between them may take not a few time. So, I try to render more Cells/Items at the upper and lower ends of the visual area. I call it safeArea. And I use it to buffer, to avoid the user slide suddenly and the visual view of the upper and lower edges is flickering.

Look up the design of greact-largelist:

Advanced Usage

safeMargin

• type: number
• default: 600
• The height of rendering children out side of visible area. The greater the value is, the less easily you see the blank in the fast sliding process, but the longer the first time it is loaded

dynamicMargin

• type: number
• default: 500
• The height of dynamic safe margin when sliding too fast. For example, if safeMargin=600 and dynamicMargin=500, it will render 100 height on top and 1100 height on bottom out side of the visible area when sliding down too fast.

Notice:

1. It does not work when the speed of sliding is slow.
2. It can not be set larger than safeMargin

scrollEventThrottle

• type: number
• default: ios:16
• It is the same as scrollEventThrottle on ScrollView

onIndexPathDidEnterSafeArea

• type: (indexPath:IndexPath)=>any
• default: ()=>null
• The callback when an indexpath did enter safeArea.

onIndexPathDidLeaveSafeArea

• type: (indexPath:IndexPath)=>any
• default: ()=>null
• The callback when an indexpath did leave safeArea.

showsVerticalScrollIndicator

• type: bool
• default: true
• Show vertical scroll indicator.

onSectionDidHangOnTop

• type: section=>any
• default: ()=>null
• The callback when a new Section hang on the top of the LargeList.

speedLevel1

• type: number
• default: 4
• If the speed of scrolling is faster than speedLevel1, LargeList will not rerender, just use "setNativeProps" to move the position. Unit is logic pixels/ms.

speedLevel2

• type: number
• default: 10
• It does not work for the current version.

nativeOptimize

• type: bool
• default: false
• Use native optimize, iOS only. This is an experimental prop.If it is set, safeArea doesn't make sense. To use the prop, you should add "${YourProject}/node_modules/greact-largelist/ios/STTVTableView.xcodeproj" to your iOS project. And make sure link it.

onLoadMore

• type: ()=>any
• default: null
• The callback when pull up on the bottom

heightForLoadMore

• type: ()=>number
• default: ()=>70
• function: return the height of Loading More View.

allLoadCompleted

• type: bool
• default: false
• Did all data source load completed?

renderLoadingMore

• type: ()=>React.Element
• default: ()=> < ActivityIndicator style={{ marginTop: 10, alignSelf: "center" }} size={"large"}/ >
• The render of custom Loading More View,The parent is fixed,you can use flex=1

renderLoadCompleted

• type: ()=>React.Element
• default: ()=> < Text style={{ marginTop: 20, alignSelf: "center", fontSize: 16 }}>No more data< /Text >
• The render of custom Loading Completed View.The parent is fixed,you can use flex=1

numberOfCellPoolSize

• type: number
• default: (ScreenHeight + 2 * SafeMargin)/minCellHeight+0.5
• Max size of Cell pool

Notice：

1. LargeList does not create cell when sliding, they are reused.

2. If numberOfCellPoolSize is too large, it takes more time when initialing and reloadData.

3. If it is too small, LargeList will not work well.

numberOfSectionPoolSize

• type: number
• default: 6
• Max size of Section pool, Refer to numberOfCellPoolSize as a matter of attention.

renderEmpty

• type: ()=>React.Element
• default: ()=>null
• The empty view render

Notice：

1. It must have a bounded height in order to work
2. It is empty when numberOfSections===0 || (numberOfSections===1 && numberOfRowsInSection===0)

widthForRightWhenSwipeOut

• type: (section,row)=>number
• default: ()=>0
• Swipe left, the width of right View. To swipe out to delete/config cell, you must set this prop.

renderRightWhenSwipeOut

• type: (section,row)=>React.Element
• default: ()=>null
• Swipe left, the render of right View. To swipe out to delete/config cell, you must set this prop.

widthForLeftWhenSwipeOut

• type: (section,row)=>number
• default: ()=>0
• Swipe right, the width of left View. To swipe out to config cell, you can set this prop.

renderLeftWhenSwipeOut

• type: (section,row)=>number
• default: ()=>null
• Swipe right, the render of left View. To swipe out to config cell, you can set this prop.

Notice: It is not recommended to use widthForLeftWhenSwipeOut and renderLeftWhenSwipeOut, it will shake sometimes when rotating screen.

colorForSwipeOutBgColor

• type: (section,row)=>Color
• default: ()=>"#AAA"
• Background color for swipe out.

initialOffsetY

• type: number
• default: 0
• Initial offset. It works only on init.

renderItemSeparator

• type: (section,row)=>React.Element
• default: ()=>< View style={{height:1,backgroundColor:"#EEE",marginLeft: 16}} / >
• The render of item separator. It will not work on the last cell of any sections.And notice that the heightForCell contains its height.

onLargeListDidUpdate

• type: ()=>any
• default: ()=>null
• Callback when LargeList render completed and reloadData completed.

keyboardShouldPersistTaps

• type: enum('always', 'never', 'handled', false, true)
• default: 'never'
• Same as keyboardShouldPersistTaps on ScrollView

refreshControl

• type: () =>
• default: null
• use this to add a RefreshControl with more customzation
• will override the RefreshControl created by onRefresh and refreshing

onRefresh && refreshing

• type: onRefresh: function
• type: refreshing: bool
• use to create simple

Method

scrollTo(offset:Offset, animated:boolean=true)

Scroll to offset.

scrollToIndexPath(indexPath:IndexPath, animated:boolean = true)

Scroll to an indexpath.

scrollToEnd(animated:boolean=true)

Scroll to the end of the LargeList.

visibleIndexPaths():IndexPath[]

Get the visible indexpaths at this time.

renderedIndexPaths():IndexPath[]

Get the rendered indexpaths at this time.

freeCount(): number

Get the count of free views at this time.

reloadIndexPath(indexPath: IndexPath)

Reload datasource on indexpath partially.

reloadIndexPaths(indexPaths: IndexPath[])

Reload datasource in some indexpaths partially.

reloadAll()

Reload all datasource partially.

Notice:

1. reloadIndexPath, reloadIndexPaths, reloadAll work partially. They do not work well when the numberOfSections ,numberOfRowsInSection,heightForSection,heightForCell change.Use reloadData instead.

reloadData()

Reload all datasource globally.

Notice:

1. If the numberOfSections ,numberOfRowsInSection,heightForSection,heightForCell change, you must use this method to reload.
2. Do not use this method often, because it is bad performance.

Dynamic variable

size:Size

Current size of LargeList. Size：{width:number,height:number}

contentOffset:Offset

Current contentOffset of LargeList. Offset：{x:number,y:number}

safeArea: Range

Current safeArea of LargeList.. Range:{top:number,bottom:number}

topIndexPath: IndexPath

Current topIndexPath of LargeList. IndexPath:{section:number,row:number}

bottomIndexPath: IndexPath

Current bottomIndexPath of LargeList. IndexPath:{section:number,row:number}

contentSize:Size

Current contentSize of LargeList. Size:{width:number, height:number}

currentSection:number

Current section index of LargeList.

headerHeight:number

Get LargeList's header height

footerHeight:number

Get LargeList's footer height

approximation

The approximation to use when calculation in OnLoadMore event

License

greact-largelist is released under the MIT license. See LICENSE for details.