Open sourced the onSelectionChange event

Summary: public

Open-sourced the onSelectionChange event for RCTTextView, and also added onSelectionChange support for RCTTextField.

Reviewed By: javache

Differential Revision: D2647541

fb-gh-sync-id: ab0ab37f5f087e708a199461ffc33231a47d2133

Libraries/Components/TextInput/TextInput.js

@@ -31,7 +31,6 @@ var invariant = require('invariant');
 var requireNativeComponent = require('requireNativeComponent');
 
 var onlyMultiline = {
-  onSelectionChange: true, // not supported in Open Source yet
   onTextInput: true, // not supported in Open Source yet
   children: true,
 };
@@ -413,6 +412,17 @@ var TextInput = React.createClass({
   _renderIOS: function() {
     var textContainer;
 
+    var onSelectionChange;
+    if (this.props.selectionState || this.props.onSelectionChange) {
+      onSelectionChange = function(event: Event) {
+        if (this.props.selectionState) {
+          var selection = event.nativeEvent.selection;
+          this.props.selectionState.update(selection.start, selection.end);
+        }
+        this.props.onSelectionChange && this.props.onSelectionChange(event);
+      };
+    }
+
     var props = Object.assign({}, this.props);
     props.style = [styles.input, this.props.style];
     if (!props.multiline) {
@@ -430,7 +440,8 @@ var TextInput = React.createClass({
           onFocus={this._onFocus}
           onBlur={this._onBlur}
           onChange={this._onChange}
-          onSelectionChangeShouldSetResponder={() => true}
+          onSelectionChange={onSelectionChange}
+          onSelectionChangeShouldSetResponder={emptyFunction.thatReturnsTrue}
           text={this._getText()}
           mostRecentEventCount={this.state.mostRecentEventCount}
         />;
@@ -465,7 +476,7 @@ var TextInput = React.createClass({
           onFocus={this._onFocus}
           onBlur={this._onBlur}
           onChange={this._onChange}
-          onSelectionChange={this._onSelectionChange}
+          onSelectionChange={onSelectionChange}
           onTextInput={this._onTextInput}
           onSelectionChangeShouldSetResponder={emptyFunction.thatReturnsTrue}
           text={this._getText()}
@@ -581,14 +592,6 @@ var TextInput = React.createClass({
     }
   },
 
-  _onSelectionChange: function(event: Event) {
-    if (this.props.selectionState) {
-      var selection = event.nativeEvent.selection;
-      this.props.selectionState.update(selection.start, selection.end);
-    }
-    this.props.onSelectionChange && this.props.onSelectionChange(event);
-  },
-
   _onTextInput: function(event: Event) {
     this.props.onTextInput && this.props.onTextInput(event);
   },

Libraries/Text/RCTTextField.h

@@ -9,6 +9,8 @@
 
 #import <UIKit/UIKit.h>
 
+#import "RCTComponent.h"
+
 @class RCTEventDispatcher;
 
 @interface RCTTextField : UITextField
@@ -23,6 +25,8 @@
 @property (nonatomic, strong) NSNumber *maxLength;
 @property (nonatomic, assign) BOOL textWasPasted;
 
+@property (nonatomic, copy) RCTDirectEventBlock onSelectionChange;
+
 - (instancetype)initWithEventDispatcher:(RCTEventDispatcher *)eventDispatcher NS_DESIGNATED_INITIALIZER;
 
 - (void)textFieldDidChange;

Libraries/Text/RCTTextField.m

@@ -21,6 +21,7 @@
   BOOL _jsRequestingFirstResponder;
   NSInteger _nativeEventCount;
   BOOL _submitted;
+  UITextRange *_previousSelectionRange;
 }
 
 - (instancetype)initWithEventDispatcher:(RCTEventDispatcher *)eventDispatcher
@@ -28,15 +29,22 @@
   if ((self = [super initWithFrame:CGRectZero])) {
     RCTAssert(eventDispatcher, @"eventDispatcher is a required parameter");
     _eventDispatcher = eventDispatcher;
+    _previousSelectionRange = self.selectedTextRange;
     [self addTarget:self action:@selector(textFieldDidChange) forControlEvents:UIControlEventEditingChanged];
     [self addTarget:self action:@selector(textFieldBeginEditing) forControlEvents:UIControlEventEditingDidBegin];
     [self addTarget:self action:@selector(textFieldEndEditing) forControlEvents:UIControlEventEditingDidEnd];
     [self addTarget:self action:@selector(textFieldSubmitEditing) forControlEvents:UIControlEventEditingDidEndOnExit];
+    [self addObserver:self forKeyPath:@"selectedTextRange" options:0 context:nil];
     _reactSubviews = [NSMutableArray new];
   }
   return self;
 }
 
+- (void)dealloc
+{
+  [self removeObserver:self forKeyPath:@"selectedTextRange"];
+}
+
 RCT_NOT_IMPLEMENTED(- (instancetype)initWithFrame:(CGRect)frame)
 RCT_NOT_IMPLEMENTED(- (instancetype)initWithCoder:(NSCoder *)aDecoder)
 
@@ -154,6 +162,10 @@ static void RCTUpdatePlaceholder(RCTTextField *self)
                                      text:self.text
                                       key:nil
                                eventCount:_nativeEventCount];
+
+  // selectedTextRange observer isn't triggered when you type even though the
+  // cursor position moves, so we send event again here.
+  [self sendSelectionEvent];
 }
 
 - (void)textFieldEndEditing
@@ -197,6 +209,36 @@ static void RCTUpdatePlaceholder(RCTTextField *self)
   return YES;
 }
 
+- (void)observeValueForKeyPath:(NSString *)keyPath
+                      ofObject:(RCTTextField *)textField
+                        change:(NSDictionary *)change
+                       context:(void *)context
+{
+  if ([keyPath isEqualToString:@"selectedTextRange"]) {
+    [self sendSelectionEvent];
+  }
+}
+
+- (void)sendSelectionEvent
+{
+  if (_onSelectionChange &&
+      self.selectedTextRange != _previousSelectionRange &&
+      ![self.selectedTextRange isEqual:_previousSelectionRange]) {
+
+    _previousSelectionRange = self.selectedTextRange;
+
+    UITextRange *selection = self.selectedTextRange;
+    NSInteger start = [self offsetFromPosition:[self beginningOfDocument] toPosition:selection.start];
+    NSInteger end = [self offsetFromPosition:[self beginningOfDocument] toPosition:selection.end];
+    _onSelectionChange(@{
+      @"selection": @{
+        @"start": @(start),
+        @"end": @(end),
+      },
+    });
+  }
+}
+
 - (BOOL)becomeFirstResponder
 {
   _jsRequestingFirstResponder = YES;

Libraries/Text/RCTTextFieldManager.m

@@ -87,6 +87,7 @@ RCT_EXPORT_VIEW_PROPERTY(selectTextOnFocus, BOOL)
 RCT_EXPORT_VIEW_PROPERTY(blurOnSubmit, BOOL)
 RCT_EXPORT_VIEW_PROPERTY(keyboardType, UIKeyboardType)
 RCT_EXPORT_VIEW_PROPERTY(keyboardAppearance, UIKeyboardAppearance)
+RCT_EXPORT_VIEW_PROPERTY(onSelectionChange, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(returnKeyType, UIReturnKeyType)
 RCT_EXPORT_VIEW_PROPERTY(enablesReturnKeyAutomatically, BOOL)
 RCT_EXPORT_VIEW_PROPERTY(secureTextEntry, BOOL)

Libraries/Text/RCTTextView.h

@@ -28,6 +28,8 @@
 @property (nonatomic, assign) NSInteger mostRecentEventCount;
 @property (nonatomic, strong) NSNumber *maxLength;
 
+@property (nonatomic, copy) RCTDirectEventBlock onSelectionChange;
+
 - (instancetype)initWithEventDispatcher:(RCTEventDispatcher *)eventDispatcher NS_DESIGNATED_INITIALIZER;
 
 - (void)performTextUpdate;

Libraries/Text/RCTTextView.m

@@ -43,6 +43,7 @@
   NSAttributedString *_pendingAttributedText;
   NSMutableArray<UIView<RCTComponent> *> *_subviews;
   BOOL _blockTextShouldChange;
+  UITextRange *_previousSelectionRange;
 }
 
 - (instancetype)initWithEventDispatcher:(RCTEventDispatcher *)eventDispatcher
@@ -59,6 +60,8 @@
     _textView.scrollsToTop = NO;
     _textView.delegate = self;
 
+    _previousSelectionRange = _textView.selectedTextRange;
+
     _subviews = [NSMutableArray new];
     [self addSubview:_textView];
   }
@@ -284,6 +287,30 @@ RCT_NOT_IMPLEMENTED(- (instancetype)initWithCoder:(NSCoder *)aDecoder)
   }
 }
 
+- (void)textViewDidChangeSelection:(RCTUITextView *)textView
+{
+  if (_onSelectionChange &&
+      textView.selectedTextRange != _previousSelectionRange &&
+      ![textView.selectedTextRange isEqual:_previousSelectionRange]) {
+
+    _previousSelectionRange = textView.selectedTextRange;
+
+    UITextRange *selection = textView.selectedTextRange;
+    NSInteger start = [textView offsetFromPosition:[textView beginningOfDocument] toPosition:selection.start];
+    NSInteger end = [textView offsetFromPosition:[textView beginningOfDocument] toPosition:selection.end];
+    _onSelectionChange(@{
+      @"selection": @{
+        @"start": @(start),
+        @"end": @(end),
+      },
+    });
+  }
+
+  if (textView.editable && [textView isFirstResponder]) {
+    [textView scrollRangeToVisible:textView.selectedRange];
+  }
+}
+
 - (void)setText:(NSString *)text
 {
   NSInteger eventLag = _nativeEventCount - _mostRecentEventCount;

Libraries/Text/RCTTextViewManager.m

@@ -34,6 +34,7 @@ RCT_EXPORT_VIEW_PROPERTY(clearTextOnFocus, BOOL)
 RCT_EXPORT_VIEW_PROPERTY(selectTextOnFocus, BOOL)
 RCT_REMAP_VIEW_PROPERTY(keyboardType, textView.keyboardType, UIKeyboardType)
 RCT_REMAP_VIEW_PROPERTY(keyboardAppearance, textView.keyboardAppearance, UIKeyboardAppearance)
+RCT_EXPORT_VIEW_PROPERTY(onSelectionChange, RCTDirectEventBlock)
 RCT_REMAP_VIEW_PROPERTY(returnKeyType, textView.returnKeyType, UIReturnKeyType)
 RCT_REMAP_VIEW_PROPERTY(enablesReturnKeyAutomatically, textView.enablesReturnKeyAutomatically, BOOL)
 RCT_REMAP_VIEW_PROPERTY(color, textColor, UIColor)