implemented showSoftInputOnFocus for iOS (#28834)

Summary:
`showSoftInputOnFocus` was added in #25028, but it was only added for Android. There was a lot of discussion on the original issue being addressed (#14045), that there is a need for this on iOS as well. The issue with iOS was brought up again on #27243.

On a related note, when searching this repo's issues for `showSoftInputOnFocus`, it appears that there are several closed issues that claim that the Android implementation doesn't work (#25685, #25687, #26643). So perhaps the Android implementation needs to be looked at as well (I myself have not gotten around to confirming whether it works or not)

## Changelog

[iOS] [Added] - Add showSoftInputOnFocus to TextInput
Pull Request resolved: #28834

Test Plan:
You'd use this just like you would in the Android implementation:
```jsx
<TextInput showSoftInputOnFocus={false} />
```

## GIFs
### Before change
![May-04-2020 20-52-49](https://user-images.githubusercontent.com/4932784/81034028-9d89cf80-8e4a-11ea-906c-64f62504f80c.gif)

### After change
![May-04-2020 20-54-27](https://user-images.githubusercontent.com/4932784/81034035-a11d5680-8e4a-11ea-918e-119a1c9e2a19.gif)

Differential Revision: D21418763

Pulled By: shergin

fbshipit-source-id: 561e72fc2cf16b30446132f6b96b8aa2b4a92daf

Author: gurs1kh

Libraries/Components/TextInput/AndroidTextInputNativeComponent.js

@@ -183,7 +183,6 @@ export type NativeProps = $ReadOnly<{|
   /**
    * When `false`, it will prevent the soft keyboard from showing when the field is focused.
    * Defaults to `true`.
-   * @platform android
    */
   showSoftInputOnFocus?: ?boolean,
 

Libraries/Components/TextInput/TextInput.js

@@ -408,7 +408,6 @@ type AndroidProps = $ReadOnly<{|
   /**
    * When `false`, it will prevent the soft keyboard from showing when the field is focused.
    * Defaults to `true`.
-   * @platform android
    */
   showSoftInputOnFocus?: ?boolean,
 |}>;

Libraries/DeprecatedPropTypes/DeprecatedTextInputPropTypes.js

@@ -616,7 +616,6 @@ module.exports = {
   /**
    * When `false`, it will prevent the soft keyboard from showing when the field is focused.
    * Defaults to `true`.
-   * @platform android
    */
   showSoftInputOnFocus: PropTypes.bool,
 };

Libraries/Text/TextInput/RCTBackedTextInputViewProtocol.h

@@ -20,6 +20,7 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic, assign, readonly) BOOL textWasPasted;
 @property (nonatomic, assign) UIEdgeInsets textContainerInset;
 @property (nonatomic, strong, nullable) UIView *inputAccessoryView;
+@property (nonatomic, strong, nullable) UIView *inputView;
 @property (nonatomic, weak, nullable) id<RCTBackedTextInputDelegate> textInputDelegate;
 @property (nonatomic, readonly) CGSize contentSize;
 @property (nonatomic, strong, nullable) NSDictionary<NSAttributedStringKey,id> *defaultTextAttributes;

Libraries/Text/TextInput/RCTBaseTextInputView.h

@@ -51,6 +51,7 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic, copy, nullable) NSAttributedString *attributedText;
 @property (nonatomic, copy) NSString *inputAccessoryViewID;
 @property (nonatomic, assign) UIKeyboardType keyboardType;
+@property (nonatomic, assign) BOOL showSoftInputOnFocus;
 
 /**
  Sets selection intext input if both start and end are within range of the text input.

Libraries/Text/TextInput/RCTBaseTextInputView.m

@@ -302,6 +302,17 @@ - (void)setKeyboardType:(UIKeyboardType)keyboardType
   }
 }
 
+- (void)setShowSoftInputOnFocus:(BOOL)showSoftInputOnFocus
+{
+  if (showSoftInputOnFocus) {
+    // Resets to default keyboard.
+    self.backedTextInputView.inputView = nil;
+  } else {
+    // Hides keyboard, but keeps blinking cursor.
+    self.backedTextInputView.inputView = [[UIView alloc] init];
+  }
+}
+
 #pragma mark - RCTBackedTextInputDelegate
 
 - (BOOL)textInputShouldBeginEditing

Libraries/Text/TextInput/RCTBaseTextInputViewManager.m

@@ -52,6 +52,7 @@ @implementation RCTBaseTextInputViewManager
 RCT_EXPORT_VIEW_PROPERTY(blurOnSubmit, BOOL)
 RCT_EXPORT_VIEW_PROPERTY(clearTextOnFocus, BOOL)
 RCT_EXPORT_VIEW_PROPERTY(keyboardType, UIKeyboardType)
+RCT_EXPORT_VIEW_PROPERTY(showSoftInputOnFocus, BOOL)
 RCT_EXPORT_VIEW_PROPERTY(maxLength, NSNumber)
 RCT_EXPORT_VIEW_PROPERTY(selectTextOnFocus, BOOL)
 RCT_EXPORT_VIEW_PROPERTY(selection, RCTTextSelection)

RNTester/js/examples/TextInput/TextInputExample.ios.js

@@ -707,4 +707,16 @@ exports.examples = ([
       );
     },
   },
+  {
+    title: 'showSoftInputOnFocus',
+    render: function(): React.Node {
+      return (
+        <View>
+          <WithLabel label="showSoftInputOnFocus: false">
+            <TextInput showSoftInputOnFocus={false} style={[styles.default]} />
+          </WithLabel>
+        </View>
+      );
+    },
+  },
 ]: Array<RNTesterExampleModuleItem>);

ReactCommon/fabric/components/textinput/iostextinput/primitives.h

@@ -180,6 +180,12 @@ class TextInputTraits final {
    */
   KeyboardType keyboardType{KeyboardType::Default};
 
+  /*
+   * iOS & Android
+   * Default value: `true`.
+   */
+  bool showSoftInputOnFocus{true};
+
   /*
    * Some values iOS- or Android-only (inherently particular-OS-specific)
    * Default value: `Default`.

ReactCommon/fabric/components/textinput/iostextinput/propsConversions.h

@@ -88,6 +88,11 @@ static TextInputTraits convertRawProp(
       "keyboardType",
       sourceTraits.keyboardType,
       defaultTraits.keyboardType);
+  traits.showSoftInputOnFocus = convertRawProp(
+      rawProps,
+      "showSoftInputOnFocus",
+      sourceTraits.showSoftInputOnFocus,
+      defaultTraits.showSoftInputOnFocus);
   traits.returnKeyType = convertRawProp(
       rawProps,
       "returnKeyType",