Let ScrollView Know About Keyboard Opened Before Mount

Summary:
ScrollView has special behavior when the keyboard is open, but starts listening to keyboard events on mount. This means a ScrollView mounted after the keyboard is already up (e.g. for a typeahead) is not initialized to the keyboard being up.

This change adds `Keyboard.isVisible()` and `Keyboard.metrics()` APIs to allow seeding initial keyboard metrics.

Changelog:
[General][Fixed] - Inform ScrollView of Keyboard Events Before Mount

Reviewed By: JoshuaGross, yungsters

Differential Revision: D38701976

fbshipit-source-id: 42b354718fbf5001ca4b90de0442eeab0be91e7a

Libraries/Components/Keyboard/Keyboard.js

@@ -24,7 +24,7 @@ export type KeyboardEventEasing =
   | 'linear'
   | 'keyboard';
 
-export type KeyboardEventCoordinates = $ReadOnly<{|
+export type KeyboardMetrics = $ReadOnly<{|
   screenX: number,
   screenY: number,
   width: number,
@@ -36,7 +36,7 @@ export type KeyboardEvent = AndroidKeyboardEvent | IOSKeyboardEvent;
 type BaseKeyboardEvent = {|
   duration: number,
   easing: KeyboardEventEasing,
-  endCoordinates: KeyboardEventCoordinates,
+  endCoordinates: KeyboardMetrics,
 |};
 
 export type AndroidKeyboardEvent = $ReadOnly<{|
@@ -47,7 +47,7 @@ export type AndroidKeyboardEvent = $ReadOnly<{|
 
 export type IOSKeyboardEvent = $ReadOnly<{|
   ...BaseKeyboardEvent,
-  startCoordinates: KeyboardEventCoordinates,
+  startCoordinates: KeyboardMetrics,
   isEventFromThisApp: boolean,
 |}>;
 
@@ -103,6 +103,8 @@ type KeyboardEventDefinitions = {
  */
 
 class Keyboard {
+  _currentlyShowing: ?KeyboardEvent;
+
   _emitter: NativeEventEmitter<KeyboardEventDefinitions> =
     new NativeEventEmitter(
       // T88715063: NativeEventEmitter only used this parameter on iOS. Now it uses it on all platforms, so this code was modified automatically to preserve its behavior
@@ -110,6 +112,15 @@ class Keyboard {
       Platform.OS !== 'ios' ? null : NativeKeyboardObserver,
     );
 
+  constructor() {
+    this.addListener('keyboardDidShow', ev => {
+      this._currentlyShowing = ev;
+    });
+    this.addListener('keyboardDidHide', _ev => {
+      this._currentlyShowing = null;
+    });
+  }
+
   /**
    * The `addListener` function connects a JavaScript function to an identified native
    * keyboard notification event.
@@ -158,6 +169,20 @@ class Keyboard {
     dismissKeyboard();
   }
 
+  /**
+   * Whether the keyboard is last known to be visible.
+   */
+  isVisible(): boolean {
+    return !!this._currentlyShowing;
+  }
+
+  /**
+   * Return the metrics of the soft-keyboard if visible.
+   */
+  metrics(): ?KeyboardMetrics {
+    return this._currentlyShowing?.endCoordinates;
+  }
+
   /**
    * Useful for syncing TextInput (or other keyboard accessory view) size of
    * position changes with keyboard movements.

Libraries/Components/Keyboard/KeyboardAvoidingView.js

@@ -22,7 +22,7 @@ import type {
   ViewLayout,
   ViewLayoutEvent,
 } from '../View/ViewPropTypes';
-import type {KeyboardEvent, KeyboardEventCoordinates} from './Keyboard';
+import type {KeyboardEvent, KeyboardMetrics} from './Keyboard';
 
 type Props = $ReadOnly<{|
   ...ViewProps,
@@ -71,7 +71,7 @@ class KeyboardAvoidingView extends React.Component<Props, State> {
     this.viewRef = React.createRef();
   }
 
-  _relativeKeyboardHeight(keyboardFrame: KeyboardEventCoordinates): number {
+  _relativeKeyboardHeight(keyboardFrame: KeyboardMetrics): number {
     const frame = this._frame;
     if (!frame || !keyboardFrame) {
       return 0;

Libraries/Components/ScrollView/ScrollView.js

@@ -42,7 +42,7 @@ import type {HostComponent} from '../../Renderer/shims/ReactNativeTypes';
 import type {ViewProps} from '../View/ViewPropTypes';
 import ScrollViewContext, {HORIZONTAL, VERTICAL} from './ScrollViewContext';
 import type {Props as ScrollViewStickyHeaderProps} from './ScrollViewStickyHeader';
-import type {KeyboardEvent} from '../Keyboard/Keyboard';
+import type {KeyboardEvent, KeyboardMetrics} from '../Keyboard/Keyboard';
 import type {EventSubscription} from '../../vendor/emitter/EventEmitter';
 
 import Commands from './ScrollViewCommands';
@@ -731,7 +731,7 @@ class ScrollView extends React.Component<Props, State> {
     new Map();
   _headerLayoutYs: Map<string, number> = new Map();
 
-  _keyboardWillOpenTo: ?KeyboardEvent = null;
+  _keyboardMetrics: ?KeyboardMetrics = null;
   _additionalScrollOffset: number = 0;
   _isTouching: boolean = false;
   _lastMomentumScrollBeginTime: number = 0;
@@ -769,7 +769,7 @@ class ScrollView extends React.Component<Props, State> {
       );
     }
 
-    this._keyboardWillOpenTo = null;
+    this._keyboardMetrics = Keyboard.metrics();
     this._additionalScrollOffset = 0;
 
     this._subscriptionKeyboardWillShow = Keyboard.addListener(
@@ -1075,8 +1075,8 @@ class ScrollView extends React.Component<Props, State> {
     let keyboardScreenY = Dimensions.get('window').height;
 
     const scrollTextInputIntoVisibleRect = () => {
-      if (this._keyboardWillOpenTo != null) {
-        keyboardScreenY = this._keyboardWillOpenTo.endCoordinates.screenY;
+      if (this._keyboardMetrics != null) {
+        keyboardScreenY = this._keyboardMetrics.screenY;
       }
       let scrollOffsetY =
         top - keyboardScreenY + height + this._additionalScrollOffset;
@@ -1094,8 +1094,8 @@ class ScrollView extends React.Component<Props, State> {
       this._preventNegativeScrollOffset = false;
     };
 
-    if (this._keyboardWillOpenTo == null) {
-      // `_keyboardWillOpenTo` is set inside `scrollResponderKeyboardWillShow` which
+    if (this._keyboardMetrics == null) {
+      // `_keyboardMetrics` is set inside `scrollResponderKeyboardWillShow` which
       // is not guaranteed to be called before `_inputMeasureAndScrollToKeyboard` but native has already scheduled it.
       // In case it was not called before `_inputMeasureAndScrollToKeyboard`, we postpone scrolling to
       // text input.
@@ -1243,32 +1243,28 @@ class ScrollView extends React.Component<Props, State> {
   scrollResponderKeyboardWillShow: (e: KeyboardEvent) => void = (
     e: KeyboardEvent,
   ) => {
-    this._keyboardWillOpenTo = e;
+    this._keyboardMetrics = e.endCoordinates;
     this.props.onKeyboardWillShow && this.props.onKeyboardWillShow(e);
   };
 
   scrollResponderKeyboardWillHide: (e: KeyboardEvent) => void = (
     e: KeyboardEvent,
   ) => {
-    this._keyboardWillOpenTo = null;
+    this._keyboardMetrics = null;
     this.props.onKeyboardWillHide && this.props.onKeyboardWillHide(e);
   };
 
   scrollResponderKeyboardDidShow: (e: KeyboardEvent) => void = (
     e: KeyboardEvent,
   ) => {
-    // TODO(7693961): The event for DidShow is not available on iOS yet.
-    // Use the one from WillShow and do not assign.
-    if (e) {
-      this._keyboardWillOpenTo = e;
-    }
+    this._keyboardMetrics = e.endCoordinates;
     this.props.onKeyboardDidShow && this.props.onKeyboardDidShow(e);
   };
 
   scrollResponderKeyboardDidHide: (e: KeyboardEvent) => void = (
     e: KeyboardEvent,
   ) => {
-    this._keyboardWillOpenTo = null;
+    this._keyboardMetrics = null;
     this.props.onKeyboardDidHide && this.props.onKeyboardDidHide(e);
   };
 
@@ -1547,7 +1543,7 @@ class ScrollView extends React.Component<Props, State> {
     // keyboard, except on Android where setting windowSoftInputMode to
     // adjustNone leads to missing keyboard events.
     const softKeyboardMayBeOpen =
-      this._keyboardWillOpenTo != null || Platform.OS === 'android';
+      this._keyboardMetrics != null || Platform.OS === 'android';
 
     return hasFocusedTextInput && softKeyboardMayBeOpen;
   };