Summary: Some OEMs have changed out the default scroller implementation in their ScrollView. We now check for that case and handle it gracefully instead of crashing.
Reviewed By: foghina
Differential Revision: D3876492
fbshipit-source-id: 4d03b88c4972e939c8352eeb9f30275e3ecf76e2
Summary:
This adds support for `Animated.event` driven natively. This is WIP and would like feedback on how this is implemented.
At the moment, it works by providing a mapping between a view tag, an event name, an event path and an animated value when a view has a prop with a `AnimatedEvent` object. Then we can hook into `EventDispatcher`, check for events that target our view + event name and update the animated value using the event path.
For now it works with the onScroll event but it should be generic enough to work with anything.
Closes https://github.com/facebook/react-native/pull/9253
Differential Revision: D3759844
Pulled By: foghina
fbshipit-source-id: 86989c705847955bd65e6cf5a7d572ec7ccd3eb4
Summary:
The issue here is that on some devices (ie. Nexus 5X), under certain
circumstances, the text gets trimmed. A simple example is P56651885, where the
text is at the end of the line and some padding is set. Digging further with
P56659346, I found that only the paddings that have integer pixel values work
correctly: these are the values P56656483, and this is the screenshot of that
test: {F63510378}.
It turns out that when we set the padding directly on the TextView, we have to
convert from float to int, and use `ceil` in the process. We lose some precision
here, since the csslayout will use the float values to compute the layout of the
views. The ideal solution would be to just set the float values on the TextView,
but since we can't do that, we should avoid using `ceil` instead of `floor`
since it can have bad side-effects in some scenarios.
Going way back to D1881202 and D1710471, we started using `ceil` because that
is how android handles non-integer
density ratios: "This figure is the factor by which you should multiply the dp
units on order to get the actual pixel count for the current screen. (Then add
0.5f to round the figure up to the nearest whole number, when converting to an
integer.)", see https://developer.android.com/guide/practices/screens_support.html.
Reviewed By: emilsjolander
Differential Revision: D3876310
fbshipit-source-id: 701c05a8b1a045d4e06fc89ffe79162c1eecb62c
Summary:
With our previous fix to resize the Modal on orientation change, we broke the
computation of its size. The existing computation in `ModalHostShadowNode` was
in fact correct, and we were overriding it from `onSizeChanged`. By computing the
size of the Modal in `onSizeChanged` directly (and correctly), we fix this, and
simplify code by removing the `ModalHostShadowNode`.
Reviewed By: foghina
Differential Revision: D3863054
fbshipit-source-id: aaf4a8881798df4d2ab1dab882a9d9dfdc0a9342
Summary:
The original method getNativeProps in ViewManagerPropertyUpdater.java create more HashMaps and putAll method need to re-hash the key again to avoid conflicts. This pull request pass the map as params to avoid the problem and update ReactPropertyProcessor.java to adapt the change.
Closes https://github.com/facebook/react-native/pull/9916
Differential Revision: D3873152
fbshipit-source-id: 089840e5272265662cdbf58d88580f9203153b69
Summary:
This adds support for sticky headers on Android. The implementation if based primarily on the iOS one (https://github.com/facebook/react-native/blob/master/React/Views/RCTScrollView.m#L272) and adds some stuff that was missing to be able to handle z-index, view clipping, view hierarchy optimization and touch handling properly.
Some notable changes:
- Add `ChildDrawingOrderDelegate` interface to allow changing the `ViewGroup` drawing order using `ViewGroup#getChildDrawingOrder`. This is used to change the content view drawing order to make sure headers are drawn over the other cells. Right now I'm only reversing the drawing order as drawing only the header views last added a lot of complexity especially because of view clipping and I don't think it should cause issues.
- Add `collapsableChildren` prop that works like `collapsable` but applies to every child of the view. This is needed to be able to reference sticky headers by their indices otherwise some subviews can get optimized out and break indexes.
Closes https://github.com/facebook/react-native/pull/9456
Differential Revision: D3827366
Pulled By: fred2028
fbshipit-source-id: d346068734c5b987518794ab23e13914ed13b5c4
Summary:
This adds support for sticky headers on Android. The implementation if based primarily on the iOS one (https://github.com/facebook/react-native/blob/master/React/Views/RCTScrollView.m#L272) and adds some stuff that was missing to be able to handle z-index, view clipping, view hierarchy optimization and touch handling properly.
Some notable changes:
- Add `ChildDrawingOrderDelegate` interface to allow changing the `ViewGroup` drawing order using `ViewGroup#getChildDrawingOrder`. This is used to change the content view drawing order to make sure headers are drawn over the other cells. Right now I'm only reversing the drawing order as drawing only the header views last added a lot of complexity especially because of view clipping and I don't think it should cause issues.
- Add `collapsableChildren` prop that works like `collapsable` but applies to every child of the view. This is needed to be able to reference sticky headers by their indices otherwise some subviews can get optimized out and break indexes.
Closes https://github.com/facebook/react-native/pull/9456
Differential Revision: D3827366
fbshipit-source-id: cab044cfdbe2ccb98e1ecd3e02ed3ceaa253eb78
Summary: Introduce `overflow:scroll` so that scrolling can be implemented without the current overflow:visible hackiness. Currently we use AT_MOST to measure in the cross axis but not in the main axis. This was done to enable scrolling containers where children are not constraint in the main axis by their parent. This caused problems for non-scrolling containers though as it meant that their children cannot be measured correctly in the main axis. Introducing `overflow:scroll` fixes this.
Reviewed By: astreet
Differential Revision: D3855801
fbshipit-source-id: 3c365f9e6ef612fd9d9caaaa8c650e9702176e77
Summary: Introduce `overflow:scroll` so that scrolling can be implemented without the current overflow:visible hackiness. Currently we use AT_MOST to measure in the cross axis but not in the main axis. This was done to enable scrolling containers where children are not constraint in the main axis by their parent. This caused problems for non-scrolling containers though as it meant that their children cannot be measured correctly in the main axis. Introducing `overflow:scroll` fixes this.
Reviewed By: astreet
Differential Revision: D3855801
fbshipit-source-id: 6077b0bcb68fe5ddd4aa22926acab40ff4d83949
Summary: This is to be able to depend on ReactClippingViewGroup from BaseViewManager. Devs using ReactClippingViewGroup may need to update their imports when updating past this commit.
Reviewed By: lexs
Differential Revision: D3835328
fbshipit-source-id: 290c08b130d837e553b68a90377bd9a30b7ec6dc
Summary:
This automatically changes the size of the modal by listening to dialog size changes and propagating
those changes through UIManager.
In detail: I've looked into three ways of doing this:
1. Send `onSizeChanged` events/info from the View to the CSSNode directly. This is kinda hacky because you would need to hold a reference to the CSSNode somewhere, either in the View or in the ViewManager. But then you'll have to take care of the lifecycle of the CSSNode, so that you don't update it after it has been dismissed. Not great.
2. The version we went for, is to just update the size of the corresponding CSSNode in the same way we do it for root nodes: we inform the UIManager that the size of the root node has changed, and it will propagate that change, triggering a `dispatchViewUpdates` if none is underway, so that the layout is updated.
3. The other solution we thought of is to treat the Modal as a root view. This would mean rendering an application with the tag of the Modal as the root of the application. That tag would be received by calling some method into UIManager and ReactModalHostManager to create a new RootView, create a Dialog and plop the root view in it. The idea was to maintain the JS API that we now have, but make the implementation more correct (ie. since both RootView and the Modal must deal with touch handling), and could have other benefits (ie. no hacks necessary for making the inspector work on top of modals). However, the change is not trivial and I don't know just how much code would have to be changed to make this work correctly. We might revisit this at a later stage, after we've done more work on having several root views at the same time in the app.
Reviewed By: foghina
Differential Revision: D3841379
fbshipit-source-id: f5e363e27041b785cf44eb59da04bc789306ddb9
Summary:
Setting the line height with the help of Android-provided StaticLayout is incorrect. A
simple example app will display the following when `setLineSpacing(50.f, 0.f)`
is set: {F62987699}. You'll notice that the height of the first line is a few
pixels shorter than the other lines.
So we use a custom LineHeightSpan instead, which needs to be applied to the text
itself, and no height-related attributes need to be set on the TextView itself.
Reviewed By: lexs
Differential Revision: D3841658
fbshipit-source-id: 7257df4f1b2ce037554c7a7a5ca8f547a2056939
Summary:
This is just D3835023 again since it got reverted, plus the fix from D3841918 baked in. Here's the old summary:
We never actually closed the websocket connection. Furthermore, upon calling `closeQuietly()`, `onClose()` is called, which does `reconnect()`. This results in ReactInstanceManager leaking after calling `destroy()` and nullifying all references to it.
To fix this I made sure `closeQuietly()` actually closes the connection for good, and made sure we actually call it when destroying an instance.
Reviewed By: AaaChiuuu
Differential Revision: D3849353
fbshipit-source-id: e1ce5e2d5840bfbd42a13043c3cc8c617e9fa64a
Summary:
Here's a little background. Resizing is inferior to scaling. See http://frescolib.org/docs/resizing-rotating.html#_
Currently, React Native has a heuristic to use resize when the image is likely to be from the device's camera. However, there may be other cases where a developer wants to use resize. For example, when the developer knows they'll be downloading a large image from a service but the image will be rendered at a small size on the device.
This change adds a `resizeMethod` prop to the `Image` component so developers can choose how Fresco resizes the image. The options are 'auto', 'resize', or 'scale'. When 'auto' is specified, a heuristic is used to choose between 'resize' and 'scale'. The default value is 'auto'.
**Test plan (required)**
In a small test app, verified that the `resizeMethod` prop properly influences the mechanism that is used to resize the image (e.g. resize or scale).
Adam Comella
Microsoft Corp.
Closes https://github.com/facebook/react-native/pull/9652
Differential Revision: D3841322
Pulled By: foghina
fbshipit-source-id: 6c78b5c75ea73053aa10386afd4cbff45f5b8ffe
Summary:
Ugh. We never actually closed the websocket connection. Furthermore, upon calling `closeQuietly()`, `onClose()` is called, which does `reconnect()`. Beautiful. This results in `ReactInstanceManager` leaking after calling `destroy()` and nullifying all references to it.
To fix this I made sure `closeQuietly()` actually closes the connection for good, **and** made sure we actually call it when destroying an instance.
Reviewed By: AaaChiuuu
Differential Revision: D3835023
fbshipit-source-id: 31811805dd97b725ea5887cffed9bed49addda83
Summary: Get rid of the old behaviour of JSON encoding in `nativeRequireModuleConfig` and consistently use the same names for function types "async/promise/sync"
Reviewed By: lexs
Differential Revision: D3819348
fbshipit-source-id: fc798a5abcaf6a3ef9d95bd8654afa7825c83967
Summary:
Currently, `<Text>` and `<TextInput>` components on Android do not support borders.
This change adds support for the borderRadius, borderColor, and
borderWidth props on the `<Text>` and `<TextInput>` components on Android.
ReactViewGroup already implements this functionality so
we copied its implementation over into the ReactTextView
and ReactEditText classes.
**Test plan (required)**
Verified that the various border props work on Text and TextInput components in a test app.
Adam Comella
Microsoft Corp.
Closes https://github.com/facebook/react-native/pull/9658
Differential Revision: D3819993
Pulled By: lexs
fbshipit-source-id: 183b0aa95369dd781f03b5a1f0f409ab47284e39
Summary: It's called `timestamp` on iOS, making it consistent.
Reviewed By: foghina
Differential Revision: D3820937
fbshipit-source-id: 2805f1fc10d6445d8b31676e0e3dca348510ffe7
Summary: Casting to long too early here and dropping some precision, resulting in skipped (not dropped) frames.
Reviewed By: sahrens
Differential Revision: D3819153
fbshipit-source-id: 83676cf4c9129638348890c74d563db121049e4a
Summary:
Add native support on iOS and Android for `Animated.diffClamp` that was added in #9419.
**Test plan**
Tested that it works properly using the native animations UIExplorer example.
Closes https://github.com/facebook/react-native/pull/9691
Differential Revision: D3813440
fbshipit-source-id: 48a3ecddf3708fa44b408954d3d8133ec8537f21
Summary:
Adds support for the `extrapolate` parameter on the native interpolation node. This is pretty much a 1 to 1 port of the JS implementation.
**Test plan**
Tested by adding the `extrapolate` parameter in the native animated UIExplorer example.
Closes https://github.com/facebook/react-native/pull/9366
Differential Revision: D3824154
fbshipit-source-id: 2ef593af827a8bd3d7b8ab2d53abbdc9516c6022
Summary:
ReactRootView currently intercepts and swallows all
`requestDisallowInterceptTouchEvent` calls, which made sense when the
ReactNativeView was the root of all views. In the context of react native views
embedded in other views though, we want to propagate the call to all parents
views, but not set it on the ReactRootView itself (because we still need the
`onInterceptTouchEvent` calls to dispatch the touch events to JS).
Reviewed By: foghina
Differential Revision: D3819255
fbshipit-source-id: 21f2dd173c76e98342193de384292fef2b407250
Summary:
This diff changes the textinput component to only scroll (and interrupt parent
views from scrolling), when it is possible for the text inside the component to
be scrolled. Before (D3735237), we would intercept all touch events on the
textinput if it's focused. But this makes it: a.) impossible to scroll a scrollview from within
a textinput that cannot be scrolled; b.) different from iOS behavior.
What the component now does is intercept move touches, and check if it can
scroll in any direction. If it does, it will intercept the touches and stop the parent
component from scrolling; otherwise, it will give the control back to the parent
component.
Note: this might change in the future to also detect the direction of the scroll, and
only block the scroll if the component can scroll in that direction. This is however not
trivial, since the scroll needs to be above some threshold of pixels. Blocking the
parent view from scrolling until that threshold is passed might cause incorrect behavior
in the parent component.
Reviewed By: astreet
Differential Revision: D3764267
fbshipit-source-id: 47e7b5e03855b3c85789e04fc31a8317afbafa84
Summary:
This adds the `didUpdateDimensions` event that already exists on iOS, and
updates the internal native dimensions data that needs repopulation after
orientation change.
Reviewed By: foghina
Differential Revision: D3819364
fbshipit-source-id: fc2b3b4d1991d101e5de4439ccef2189bc65fd58
Summary:
Landing D3528215 again, now that D3593884 has landed and makes that easier.
Copy-paste summary from previous diff:
So PanReponder.onPanResponderRelease/onPanResponderTerminate receive a
gestureState object containing a onPanResponderTerminate.vx/vy property. On
Android and iOS, they appear to be orders of magnitude different, which appear
to be due to the different scale of timestamps that are used when generating
touch events.
This pull request fixes the timestamps to be milliseconds on both platforms
(since I assume iOS is the more authoritative one, and is the one that
react-native-viewpager's vx thresholds written written to compare against.)
As far as I can tell, the RN code doesn't use the vx/vy properties, so they
should be okay. And looks like the RN code only cares about relative values of
startTimestamp/currentTimestamp/previousTimestamp though, so should be fine too.
it's quite possible there will be downstream android breakage with this change,
particularly for those who are already compensating for the RN discrepancy.
Reviewed By: foghina
Differential Revision: D3819761
fbshipit-source-id: fd2d85748ae6a9cde6af715aabb620f340c2220c
Summary:
Similar to iOS, send device orientation changes events. This does not have the
`getCurrentOrientation` method, because it's not used. If necessary, we'll
add it separately.
This also adds a simple example for testing.
We listen to orientation changes in `onGlobalLayout`, and check if the rotation of the device has changed. If it has, we emit the event.
But:
- `onGlobalLayout` (and `onConfigurationChanged` - which is the method usually used for checking for device orientation changes) is *not* called when the device goes from landscape
to reverse landscape (same with portrait), as that is not a relayout / configuration change. We could detect if this happens with the help of an `OrientationEventListener`. However, this listener notifies you if the degree
of the phone changes by a single degree, which means that you need to know by how many degrees the phone needs to change in order for the orientation to change. I haven't looked into how accurate this could be, but I suspect that in practice it would cause a lot of bugs. A simple `abgs` and google search reveals that everybody uses a different margin for detecting a rotation change (from 30 to 45 degrees), so I suspect that this won't work
as expected in practice. Therefore, we're not using this here, and we're sticking to what android provides via `onConfigurationChanged`. If we find that we have issues because users need to know when the user goes
from landscape to reverse landscape, then we'll have to revisit this.
Reviewed By: foghina
Differential Revision: D3797521
fbshipit-source-id: 62508efd342a9a4b41b42b6138c73553cfdefebc
Summary:
This fixes some inaccuracies in our reporting of textinput's contentsize.
First, we were not using the correct padding info. Then, we are converting the
contentSize width and height to ints right before sending
them over to JS. This adds some inaccuracy with the textinput behaviour,
especially in the case of auto expending text inputs, since those same sizes are
then sent right back.
Reviewed By: astreet
Differential Revision: D3806008
fbshipit-source-id: 7e32f91fde50099fd8a122833fd0042683e68df1
Summary:
Android PR for TextInput selection, based on the iOS implementation in #8958.
** Test plan **
Tested using the text selection example in UIExplorer.
Closes https://github.com/facebook/react-native/pull/8962
Differential Revision: D3819285
Pulled By: andreicoman11
fbshipit-source-id: 9a2408af2a8b694258c88ab5c46322830c71452a
Summary:
There are a couple of buggy behaviors in the current implementation of the `ellipsizeMode` prop on Android:
- Setting the `numberOfLines` prop stomps on whatever value you provided for `ellipsizeMode` earlier.
- The value you've provided for `ellipsizeMode` is used even if you've configured your view to have an unlimited size (i.e. `numberOfLines` is 0 or unspecified).
This change fixes these issues which makes Android's `ellipsizeMode` prop more consistent with iOS's. Additionally, it renames LineBreakMode to EllipsizeMode in a couple of places.
**Test plan (required)**
Verified that the `numberOfLines` and `ellipsizeMode` props work correctly in an Android test app.
Adam Comella
Microsoft Corp.
Closes https://github.com/facebook/react-native/pull/9594
Differential Revision: D3810166
Pulled By: foghina
fbshipit-source-id: 229c9bfc3ef10670a1090311ea9d095cb2c1121a
Summary:
This is similar to the iOS feature that was implemented by 84f68c338a.
**Test plan (required)**
Verified that the image dimensions are included in the `onLoad` callback in a test app. Also, this change is used in my team's app.
Adam Comella
Microsoft Corp.
Closes https://github.com/facebook/react-native/pull/9608
Differential Revision: D3797659
Pulled By: foghina
fbshipit-source-id: ea83a907bf6b0b61d9bc1e90fc7c64b7132db81f
Summary:
Fresco should only be initialized once. Re-initializing causes a few problems (https://github.com/facebook/react-native/issues/8677) and we don't need to do it.
If a Fresco configuration needs to change, you can just restart the application or add delegates for parts that can change and manually update them instead.
Reviewed By: astreet
Differential Revision: D3790908
fbshipit-source-id: 9df4c3be15ca49433120abd7ba1a4f5ae2a3f1c1
Summary:
When an absolutely positioned node appeared inside an overflow:hidden
parent, we were limiting its height. This is inconsistent with how
layout behaves on the web.
Closes https://github.com/facebook/css-layout/pull/218
Reviewed By: lucasr
Differential Revision: D3797285
Pulled By: emilsjolander
fbshipit-source-id: 98f98e77aa26edce86b9882c1cac284799b69a27
Summary:
One of the impacts of this bug is that Java is firing timer
completion events into JavaScript for timers that should have
been deleted. JavaScript filters these out so it doesn't impact
the app developer. However, Java is completing more timers
than necessary.
When cleaning up a timer, we were accidentally deleting the
whole set of timers for that context. Instead, we should
just delete that timer from its context.
Adam Comella
Microsoft Corp.
Closes https://github.com/facebook/react-native/pull/9361
Differential Revision: D3797573
fbshipit-source-id: c30ed600af741601f2babdfc61da9aac549cbadb
Summary: Add a static `Image.queryCache` function that can query multiple URLs at once. The result is a map where each URL that is in cache is mapped to the cache type (memory/disk). URLs that are not cached do not appear in the result.
Reviewed By: lexs
Differential Revision: D3791333
fbshipit-source-id: b183015d97423f0c095bf891f035dac2e23d8d11
Summary: I noticed we're doing too much manual work here, when Fresco has a nice handy shortcut for clearing all caches.
Reviewed By: kirwan
Differential Revision: D3791356
fbshipit-source-id: 4a55d0280e9483267741ae75383b50ca0b74c5c6
Summary:
`mRCTEventEmitter` is used by 2 different threads. It's assigned on the UI thread and it's accessed on the JavaScript thread. Currently, it can be the case that the UI thread assigns `mRCTEventEmitter` and later the JS thread accesses it but still sees null.
This change fixes the issue by marking the `mRCTEventEmitter` variable as `volatile` to ensure that both threads see the same value for `mRCTEventEmitter`.
**Test plan (required)**
This change is currently used in my team's app. We're no longer seeing a crash in `EventDispatcher`.
Adam Comella
Microsoft Corp.
Closes https://github.com/facebook/react-native/pull/9655
Differential Revision: D3790888
Pulled By: andreicoman11
fbshipit-source-id: 68cdbc74faffb36dc2bca8ad3d4a78929badbe9c
Summary: Added support for WebViews to take in an onContentSizeChange prop, which will return a native event that contains the width and height of the html content in the WebView. Also moved the ContentSizeChangeEvent from the recyclerview dir to the uimanager/events dir
Reviewed By: andreicoman11
Differential Revision: D3775399
fbshipit-source-id: 19a0579f8345e5853cc7311b80f1f1393c77ab58
Summary: added API to in UIManager to find the rootTag/View of any reactTag based on its layout (shadow views) hierarchy (not to be used by JS)
Reviewed By: javache
Differential Revision: D3750410
fbshipit-source-id: 68611e39930d53ece478f25245ddc7f7838daaa6
Summary:
Running the command `./gradlew clean` resulted in the following error:
```
./node_modules/react-native/ReactAndroid/src/main/jni//xreact/jni/Android.mk:42: *** Android NDK: Aborting. . Stop.
Android NDK: ./node_modules/react-native/ReactAndroid/src/main/jni//xreact/jni/Android.mk: Cannot find module with tag 'cxxreact' in import path
Android NDK: Are you sure your NDK_MODULE_PATH variable is properly defined ?
Android NDK: The following directories were searched:
```
The problem was that `REACT_COMMON_DIR` wasn't defined.
**Test plan (required)**
Running `./gradlew clean` now works.
Adam Comella
Microsoft Corp.
Closes https://github.com/facebook/react-native/pull/9607
Differential Revision: D3780364
fbshipit-source-id: 2b45d538413f7ee2cf0b36a1fa33287f0b1bf23f
Summary:
Setting the line height with the help of Android-provided StaticLayout is incorrect. A
simple example app will display the following when `setLineSpacing(50.f, 0.f)`
is set: {F62987699}. You'll notice that the height of the first line is a few
pixels shorter than the other lines.
So we use a custom LineHeightSpan instead, which needs to be applied to the text
itself, and no height-related attributes need to be set on the TextView itself.
Reviewed By: lexs
Differential Revision: D3751097
fbshipit-source-id: 6c5a8d01a6dca4ff6eef9c3aadd1b550054432d2
Summary:
Setting the line height with the help of Android-provided StaticLayout is incorrect. A
simple example app will display the following when `setLineSpacing(50.f, 0.f)`
is set: {F62987699}. You'll notice that the height of the first line is a few
pixels shorter than the other lines.
So we use a custom LineHeightSpan instead, which needs to be applied to the text
itself, and no height-related attributes need to be set on the TextView itself.
Reviewed By: lexs
Differential Revision: D3751097
fbshipit-source-id: c3574a1080efec26436a5c61afbff89afa8679e7
Summary: Runtime annotation processing uses reflection which is slow. We'll use build time annotation processing instead and create at build time static ModuleInfo classes which have "name", "canOverrideExistingModule", "supportsWebWorkers", "needsEagerInit".
Reviewed By: lexs
Differential Revision: D3752243
fbshipit-source-id: 3518c6f38087d8799a61410864007041389c0e15
Summary: Add support for `useNativeDriver: true` to `Animated.decay`. Add example in Native Animated Example UIExplorer app.
Reviewed By: ritzau
Differential Revision: D3690127
fbshipit-source-id: eaa5e61293ed174191cec72255ea2677dbaa1757
Summary: Border colors broke with recent change to default values in csslayout Spacing. This is a quick fix until we move react-native borders away from using Spacing.java which is a hack in the first place.
Reviewed By: lexs
Differential Revision: D3735435
fbshipit-source-id: 747c85798cb02e1a5139de038eb26b64ac4c5bf3
Summary: Sometimes the main component name is not known at activity construction time and depends on e.g. reading shared preferences. To support this use case, make `(Fragment)ReactActivity#getMainComponentName()` nullable and return `null` by default. In this case, the app will not be loaded in `onCreate` by default and the user has to call `loadApp` manually once the component name is known.
Reviewed By: andreicoman11
Differential Revision: D3722517
fbshipit-source-id: 062eed158798606e4160f1c142b23fd98ca618c8
Brad Daily
Pieter De Baets
Andy Street
Janic Duplessis
Andrei Coman
ransj
Fred Liu
Chris Hopman
leeight
Emil Sjolander
Andrew Y. Chen
Aaron Chiu
Felix Oghina
William Liu
Adam Comella
Andrei Coman
Konstantin Raev
Michał Gregorczyk
Kevin Gozali
Alexander Oprisnik
Scott Buckfelder
Lucas Rocha
king6cong
Alexander Blom
Michal Lowicki
Jennifer Wang
Don Yu
Lukas Piatkowski
Connor McEwen
Sriram Ramasubramanian
