Summary:
The invariant condition doesn't allow scrolling to the last index
Here is a simple reproduction of the problem: https://snack.expo.io/BJ59gzWrZ
Surely, if the last item is rendered, we should be able to scroll to it without an invariant failing?
Tested locally that this change fixes the issue.
Closes https://github.com/facebook/react-native/pull/14934
Differential Revision: D5414535
Pulled By: shergin
fbshipit-source-id: 38dac4c0e2ae5e1e199a67ca0e98e8f7325e77f4
Summary:
(prior to the scroll metrics being set up, or prior to the view being scrolled to the right location).
I'm using a StackNavigator to push a FlatList secondary screen, and it was causing extraneous rendering (item X ->item 0 -> item X)
I've logged inside the render functions of my `renderItem` function, and verified that it no longer attempts to render item 0 anymore. And I've verified from the `VirtualizedList.state` no longer renders a `{first: 0, last: 0}`, but persistently stays at `{first: X, last: X}` from start until things stabilize.
Closes https://github.com/facebook/react-native/pull/14562
Reviewed By: bvaughn
Differential Revision: D5283771
Pulled By: sahrens
fbshipit-source-id: 0f70ac0b89922449bd20bfa69edbc8939eafdf1f
Summary:
Returning an object that doesn't have all the required properties from `getItemLayout` doesn't cause a flow error (maybe because we are using `createAnimatedComponent`) and caused ALL items to be rendered which caused perf issues that were hard to debug (typo lenght -> length -_-). This adds a simple warning in DEV mode using checkPropTypes.
**Test plan**
Tested in RNTester by passing a bad `getItemLayout` function.
Closes https://github.com/facebook/react-native/pull/14111
Differential Revision: D5283942
Pulled By: sahrens
fbshipit-source-id: 8909532dfddd8628b7fb3380c198f0dfa88f240a
Summary:
Curently FlatList does not implement setting native props directly like the old ListView did. This pr introduce the `setNativeProps` function which delegates to MetroListView or VirtualizedList. Thos don't have `setNativeProps` handling either, so, I delegated further to the respective ListView and Scroll components, which do have handling for it, thus, allowing to set the native props through FlatList.
Create a project with a FlatList and change a native property using `setNativeProps`:
```javascript
componentDidMount() {
setInterval(() => {
this.list.setNativeProps({ style: {backgroundColor:"white"} })
}, 1000)
}
render() {
return (
<View style={styles.container}>
<FlatList ref={component => this.list = component}
style={{backgroundColor:"black"}}
data={[{key: 'a'}, {key: 'b'}]}
renderItem={({item}) => <Text>{item.key}</Text>} />
</View>
)
}
```
Fixes#13501
Closes https://github.com/facebook/react-native/pull/13529
Differential Revision: D5283593
Pulled By: sahrens
fbshipit-source-id: 8f96f88e286042d82452fef924689b5a8a783987
Summary:
When rendering a large list without a getItemLayout (ie SectionList, where it's hard to compute), it freaks out and attempt to render them all, starving the rendering/layout engine from computing the size (and more accurately figurnge out how few it actually should render.)
Before this change, with <FlatList maxToRenderPerBatch={5} data={objectOfLengthN} />, I essentially saw it doing:
```
{first: 0, last: 0}
{first: 0, last: 5}
{first: 0, last: 10}
....
{first: 0, last: N}
```
(no more hiPri renders since all elements have been rendered)
(actually renders and lays out all N objects, and computes their sizes)
(realizes that it doesn't need to show all N for my current screen size and row size)
```{first: 0, last: 55}```
After this change, that whole first part where it keeps incrementing `last` to try to "keep up with the scrolling" disappears.
Closes https://github.com/facebook/react-native/pull/14563
Differential Revision: D5278796
Pulled By: sahrens
fbshipit-source-id: 5db117b40909ec4bc92fba9b5556c6a2add046ac
Summary:
This uses `context` to render inner lists of the same orientation to a plain `View` without
virtualization instead of rendering nested `ScrollView`s trying to scroll in the same direction,
which can cause problems.
Reviewed By: bvaughn
Differential Revision: D5174942
fbshipit-source-id: 989150294098de837b0ffb401c7f5679a3928a03
Summary:
This is necessary to fix an extraneous warning when a VirtualizedList is constructed on the first frame.
On the first frame, the dt is huge (ie, time since epoch).
On the second frame (which may legitimately be slow as a result of a lot to render), it will then assume there were two consecutive slow frames, and print a warning:
"VirtualizedList: You have a large list that is slow to update..."
Closes https://github.com/facebook/react-native/pull/14393
Differential Revision: D5210467
Pulled By: sahrens
fbshipit-source-id: 2e79218c3d66a4a9df4884f328a125047ef264ed
Summary:
Flashing scroll indicators is a standard behavior on iOS to show the user there's more content.
Launch RNTester on iOS, go to the ScrollView section, tap the "Flash scroll indicators" button.
You'll see this:
I've exposed the method `flashScrollIndicators` on all scrolling components that were already exposing a `scrollToXXX` method so it's usable from those components using a ref.
Let me know what you think.
Closes https://github.com/facebook/react-native/pull/14058
Differential Revision: D5103239
Pulled By: shergin
fbshipit-source-id: caad8474fbe475065418d771b17e4ea9766ffcdc
Summary:
I expanded the documentation of the scrollToOffset method a bit in FlatList
Thanks for submitting a PR! Please read these instructions carefully:
- [x] Explain the **motivation** for making this change.
- [x] Provide a **test plan** demonstrating that the code is solid.
- [x] Match the **code formatting** of the rest of the codebase.
- [x] Target the `master` branch, NOT a "stable" branch.
The documentation of the scrollToOffset method in FlatList was a bit confusing. Also, there was no documentation for this method on VirtualizedList. I added the doc block there and linked to it from the FlatList doc block.
Please check if the link on the FlatList scrollToOffset method links to the scrollToOffset method of the VirtualizedList docs page.
Sign the [CLA][2], if you haven't already.
Small pull requests are much easier to review and more likely to get merged. Make sure the PR does only one thing, otherwise please split it.
Make sure all **tests pass** on both [Travis][3] and [Circle CI][4]. PRs that break tests are unlikely to be merged.
For more info, see the ["Pull Requests"][5] section of our "Contributing" guidelines.
[1]: https://medium.com/martinkonicek/what-is-a-test-plan-8bfc840ec171#.y9lcuqqi9
[2]: https://code.facebook.com/cla
[3]: https://travis-ci.org/facebook/react-native
[4]: http://circleci.com/gh/facebook/react-native
[5]: https://github.com/facebook/react-native/blob/master/CONTRIBUTING.md#pull-requests
Closes https://github.com/facebook/react-native/pull/14317
Differential Revision: D5192378
Pulled By: hramos
fbshipit-source-id: 6131a8e5adb2a2f7cb84344541f4f8b999a232d2
Summary:
This is a simple bugfix. `_updateViewableItems` expects the `data` prop, as it calls `getItemCount` on it. Without this, `onViewableItemsChanged` updates twice for each scroll position, once from `_onScroll` with the incorrect results, and once from `_updateCellsToRender` with the correct results. This means the callback nigh-on unusable.
I simply logged the results of `onViewableItemsChanged` and made sure they were correct.
Closes https://github.com/facebook/react-native/pull/14162
Differential Revision: D5128363
Pulled By: sahrens
fbshipit-source-id: 3faef812068921a26ed871339da79870fd0d911c
Summary:
Hey there :)
Please let me know if the name `ListEmptyComponent` should be changed. I also thought about `ListNoItemsComponent`. Or maybe `ListPlaceholderComponent`?
- [x] Explain the **motivation** for making this change.
- [x] Provide a **test plan** demonstrating that the code is solid.
- [x] Match the **code formatting** of the rest of the codebase.
- [x] Target the `master` branch, NOT a "stable" branch.
In a FlatList, I wanted to show some placeholder when my data is empty (while keeping eventual Header/Footer/RefreshControl).
A way around this issue would be to do something like adding a `ListHeaderComponent` that checks if the list is empty, like so:
```js
ListHeaderComponent={() => (!data.length ? <Text style={styles.noDataText}>No data found</Text> : null)}
```
But I felt it was not easily readable as soon as you have an actual header.
This PR adds a `ListEmptyComponent` that is rendered when the list is empty.
I added tests for VirtualizedList, FlatList and SectionList and ran `yarn test -- -u`. I then checked that the snapshots changed like I wanted.
I also tested this against one of my project, though I had to manually add my changes because the project is on RN 0.43.
Here are the docs screenshots:
- [VirtualizedList](https://cloud.githubusercontent.com/assets/82368/25566000/0ebf2b82-2dd2-11e7-8b80-d8c505f1f2d6.png)
- [FlatList](https://cloud.githubusercontent.com/assets/82368/25566005/2842ab42-2dd2-11e7-81b4-32c74c2b4fc3.png)
- [SectionList](https://cloud.githubusercontent.com/assets/82368/25566010/368aec1e-2dd2-11e7-9425-3bb5e5803513.png)
Thanks for your work!
Closes https://github.com/facebook/react-native/pull/13718
Differential Revision: D4993711
Pulled By: sahrens
fbshipit-source-id: 055b40f709067071e40308bdf5a37cedaa223dc5
Summary:
The main reason to use **VirtualizedList** is to set the `getItem` and `getItemCount` props, so having default values for these props makes things error prone.
* In **VirtualizedList**, changed the `getItem` and `getItemCount` props from optional to required, and removed default values.
* Ensured that implementing classes **FlatList** and **SectionVirtualizedList** are always passing these props.
* Updated VirtualizedList-test.js accordingly.
Reviewed By: sahrens
Differential Revision: D4980236
fbshipit-source-id: ad1838931253bc61ff9068c40929f6e9c755b92c
Summary:
- If the initial render doesn't extend past `onEndReachedThreshold` it is likely that onEndReached won't get called until scroll, which can be a bad experience if the `initialNumToRender` is very close to the viewport height. This happens because when `onContentSizeChange`, `onLayout` may not have fired yet so we don't know what the `visibleLength` is. Fix is to also call `maybeCallOnEndReached` in `_onLayout` as well.
- We have an optimization that does hi-pri render window updates when scrolling quickly and the content reaches the edge of the viewport, but there is also an important case where the user has scrolled to the end of the content and is waiting for a network response. Once the new data comes in, we want to render it ASAP because the user is waiting for it. To solve this we refactor our scheduling code into a shared function that always checks if it should be a hi-pri update instead of just in `_onScroll`.
Reviewed By: bvaughn
Differential Revision: D4975314
fbshipit-source-id: 8d64832ecbcbdbac430a08a4018d7a32b2216a85
Summary:
These got smashed together with some weird rebase snafu. They are pretty intertwined anyway so the value of
separate commits is minimal (e.g. separate commits would not revert cleanly anyway).
== [lists] better fill rate logging (previously D4907958)
After looking through some production data, I think this will address all the issues we're seeing. Now:
- Header/Footer getting no longer counted as blank.
- Avoid floating point for Scuba.
- Compare actual time of blankness, not just samples.
- Include both "any" vs. "mostly" blank (similar to 1 and 4 frame drops).
- Include events where there is no blankness so we have a baseline.
- Remove events with too few samples
**Test Plan: **
A bunch of scrolling in FlatListExample
T17384966
== [Lists] Update SectionSeparatorItem docs (previously D4909526)
Forgot to update the language here when we modified the behavior with the introduction of separator
highlighting support.
** Test Plan: **
nope.
== [Lists] Add renderSectionFooter prop to SectionList (previously D4923353)
Handy for things like "see more" links and such.
The logic here is to render the footer last, *after* the bottom section separator. This is to preserve
the highlighting behavior of the section separator by keeping it adjacent to the items.
**Test Plan: **
Added to snapshot test and example:
{F66635525}
{F66635526}
== [SectionList] Add a bunch more info for rendering items and separators (previously D4923663)
This extra info can be helpful for rending more complex patterns.
**Test Plan: **
Made snapshot test more comprehensive and inspected the output.
== [Lists] reduce render churn (previously D4924639)
I don't think the velocity based leadFactor is helping and might actually be hurting because
it causes a lot of churn in the items we render.
Instead, this diff introduces fillPreference which biases the window expansion in the direction of scroll,
but doesn't actually affect the final bounds of the window at all, so items that are already rendered are
more likely to stay rendered.
**Test Plan: **
Played around in debug mode and watched the overlay - seems better. Also tests all pass.
T16621861
== [Lists] Add initialScrollIndex prop
Makes it easy to load a VirtualizedList at a location in the middle of the content without
wasting time rendering initial rows that aren't relevant, for example when opening an infinite calendar
view to "today".
**Test Plan: **
With debug overlay, set `initialScrollIndex={52}` prop in `FlatListExample` and
and see it immediately render a full screen of items with item 52 aligned at the top of the screen. Note
no initial items are mounted per debug overlay. Scroll around a bunch and everything else seems to work
as normal.
No SectionList impl since `getItemLayout` isn't easy to use there.
T17091314
Reviewed By: bvaughn
Differential Revision: D4907958
fbshipit-source-id: 8b9f1f542f9b240f1e317f3fd7e31c9376e8670e
Summary:
**Bug Description**
The FlatList component receives content items via the data prop, and renders an initial number of items on the app's view. When a user scrolls to the end of the list, the component will append and render more available items at the end of the list. There was a bug where when the content was filtered, there were more available items but the component did not append/render them. This is due to the current appending/rendering logic in VirtualizedList, which does not account for data changes as a condition for updating/rendering. VirtualizedList is a dependency of FlatList, so this issue affects FlatList as well.
**Approach to Fixing Bug**
(i) Reproduce bug on iOS view of FlatList.
(ii) For VirtualizedList component:
# Isolate onEndReached function that appends more data to component UI.
# Isolate _onContentSizeChange function that is called when list content changes.
# Write snapshot tests using jest, based off existing test for FlatList.
# Refactor logic to append more data to list into _maybeCallOnEndReached function.
# Call _maybeCallOnEndReached in both _onContentSizeChange and _onScroll.
(iii) Run snapshot tests and observe jest output.
(iv) Bring up iOS view of FlatList and check that component now renders more items when content is filtered.
Many thanks to sahrens for guidance in developing this code!
Reviewed By: sahrens
Differential Revision: D4877388
fbshipit-source-id: c10c9eef1912f491450a62b81a9bc41f7f784203
Summary:
It's just causing problems (e.g. when combined with transform animations like those used
in some navigators) and hopefully it's not necessary with JS-side windowing. If people need the
perf, they can turn it on themselves.
Should fix https://github.com/facebook/react-native/issues/13316 and related issues.
Reviewed By: achen1
Differential Revision: D4884147
fbshipit-source-id: 95c82448581076c0d0b2c80b1cd80cc294898174
Summary:
A nice bit of polish for apps is to update the separators between list items
when press actives the highlight (things get especially noticeable/ugly when
the separators are not full width and don't adjust). This can be difficult to
coordinate and update efficiently, so we bake the functionality into
`VirtualizedList`.
The approach taken here is a little different from `ListView`. We pass a new
`separators` object with `renderItem` that has easy-to-use callbacks for toggling
the 'highlighted' prop on both adjacent separators - they can be wired up
directly to the `onShow/HideUnderlay` props of `TouchableHighlight` (pit of
success and all that - we want those RN apps to be polished!), but we also
provide a more generic `separators.updateProps` method to set any custom
props. This also passes in `leadingItem` so more custom wiring can be done on
initial render (e.g. linking the highlight state with `Animated`).
This also moves the separator rendering into the `CellRenderer`. I think this might
also fix some subtle measurement bugs with the `onLayout` not capturing the
height of the separator, so that's nice too, but the main reason is to have
an easy place to store the state so we don't have to re-render the entire list
like `ListView` does. Instead we track references to the cells and call update
only on the two we care about so the feedback is instantaneous even with big,
heavy lists.
This diff also messes with a bunch of flow and updates the example to be more
like a standard list.
`SectionList` support is coming in a stacked diff.
**TestPlan**
Video demo:
https://youtu.be/uFE7qGA0mg4
Pretty sure this is backwards compatible....
Reviewed By: thechefchen
Differential Revision: D4833557
fbshipit-source-id: 685af46243ba13246bf280dae8a4223381ce8cea
Summary: It can be much more convenient instead of binding and setting `extraData` or what-not.
Reviewed By: blairvanderhoof
Differential Revision: D4829165
fbshipit-source-id: bb781fedc831059e7b5065ea4357955aed79beda
Summary:
If tracking is enabled and the sampling check passes on a scroll or layout event,
we compare the scroll offset to the layout of the rendered items. If the items don't cover
the visible area of the list, we fire an `onFillRateExceeded` call with relevant stats for
logging the event through an analytics pipeline.
The measurement methodology is a little jank because everything is async, but it seems directionally
useful for getting ballpark numbers, catching regressions, and tracking improvements.
Benchmark testing shows a ~2014 MotoX starts hitting the fill rate limit at about 2500 px / sec,
which is pretty fast scrolling.
This also reworks our frame rate stuff so we can use a shared `SceneTracking` thing and track blankness
globally.
Reviewed By: bvaughn
Differential Revision: D4806867
fbshipit-source-id: 119bf177463c8c3aa51fa13d1a9d03b1a96042aa
Summary:
Basic functionality that takes `itemIndex` and `sectionIndex`
**TestPlan**
Added this to onChangeText:
this._listRef.getNode().scrollToLocation({itemIndex: 6, sectionIndex: 3, viewOffset: 25});
and saw it scroll to the correct position right under the sticky header.
Reviewed By: bvaughn
Differential Revision: D4821714
fbshipit-source-id: 261e373f9c4af384db5a363df5b0fd9274b1bdfe
Summary:
so users can call `setNativeProps` and do more compositing.
**Test Plan:**
Added this to `onPress` of `SectionListExample` and `FlatListExample`:
this._listRef.getNode().getScrollResponder().setNativeProps({scrollEnabled: false});
and saw scroll get disabled. Note the call to `getNode` because we are using the `Animated.createComponent` wrapper.
Reviewed By: achen1, bvaughn
Differential Revision: D4821711
fbshipit-source-id: 8d1f3dd7ccc646524f154721c5c7036620d57132
Summary:
Should key separators with their cells.
**Test Plan**
before/after in this video: https://youtu.be/vid1w5x8-58
Reviewed By: achen1
Differential Revision: D4821708
fbshipit-source-id: 261f1bac34dfa9001297a24a44f11128f338e62b
Summary: it's possible to update data and not have the content length change, which could prevent onEndReached from ever firing again, so fix that.
Reviewed By: bvaughn, yungsters
Differential Revision: D4783818
fbshipit-source-id: ec4640f4b8cf820165b045eaafee6fb41c0b0499
Oleg Lokhvitsky
Maarten Schumacher
Christopher Chedeau
Mike Lambert
zongwan
Janic Duplessis
Rene Weber
Spencer Ahrens
Kexi Long
Jean Regisser
Jakob Kerkhove
ashoat
Xinbo Wang
Louis Lagrange
Jeff Case
Tony Tan
Gabe Levi
Eric Vicenti
