Flutter macOS Embedder
FlutterTextInputPlugin Class Reference

#import <FlutterTextInputPlugin.h>

Inheritance diagram for FlutterTextInputPlugin:

Instance Methods

(instancetype) - initWithViewController:
 
(BOOL) - isFirstResponder
 
(BOOL) - handleKeyEvent:
 
(void) - handleMethodCall:result:
 
(NSRect) - firstRectForCharacterRange:actualRange:
 
(NSDictionary *) - editingState
 

Properties

FlutterTextFieldclient
 
NSTextInputContext * textInputContext
 
NSString * customRunLoopMode
 

Detailed Description

A plugin to handle text input.

Responsible for bridging the native macOS text input system with the Flutter framework text editing classes, via system channels.

This is not an FlutterPlugin since it needs access to FlutterViewController internals, so needs to be managed differently.

When accessibility is on, accessibility bridge creates a NSTextField, i.e. FlutterTextField, for every text field in the Flutter. This plugin acts as a field editor for those NSTextField[s].

Definition at line 24 of file FlutterTextInputPlugin.h.

Method Documentation

◆ editingState

◆ firstRectForCharacterRange:actualRange:

- (NSRect) firstRectForCharacterRange: (NSRange)  range
actualRange: (NSRangePointer)  actualRange 

Provided by category FlutterTextInputPlugin(TestMethods).

◆ handleKeyEvent:

- (BOOL) handleKeyEvent: (NSEvent*)  event

Handles key down events received from the view controller, responding YES if the event was handled.

Note, the Apple docs suggest that clients should override essentially all the mouse and keyboard event-handling methods of NSResponder. However, experimentation indicates that only key events are processed by the native layer; Flutter processes mouse events. Additionally, processing both keyUp and keyDown results in duplicate processing of the same keys.

Definition at line 605 of file FlutterTextInputPlugin.mm.

605  :(NSEvent*)event {
606  if (event.type == NSEventTypeKeyUp ||
607  (event.type == NSEventTypeFlagsChanged && event.modifierFlags < _previouslyPressedFlags)) {
608  return NO;
609  }
610  _previouslyPressedFlags = event.modifierFlags;
611  if (!_shown) {
612  return NO;
613  }
614 
615  _eventProducedOutput = NO;
616  BOOL res = [_textInputContext handleEvent:event];
617  // NSTextInputContext#handleEvent returns YES if the context handles the event. One of the reasons
618  // the event is handled is because it's a key equivalent. But a key equivalent might produce a
619  // text command (indicated by calling doCommandBySelector) or might not (for example, Cmd+Q). In
620  // the latter case, this command somehow has not been executed yet and Flutter must dispatch it to
621  // the next responder. See https://github.com/flutter/flutter/issues/106354 .
622  // The event is also not redispatched if there is IME composition active, because it might be
623  // handled by the IME. See https://github.com/flutter/flutter/issues/134699
624 
625  // both NSEventModifierFlagNumericPad and NSEventModifierFlagFunction are set for arrow keys.
626  bool is_navigation = event.modifierFlags & NSEventModifierFlagFunction &&
627  event.modifierFlags & NSEventModifierFlagNumericPad;
628  bool is_navigation_in_ime = is_navigation && self.hasMarkedText;
629 
630  if (event.isKeyEquivalent && !is_navigation_in_ime && !_eventProducedOutput) {
631  return NO;
632  }
633  return res;
634 }

◆ handleMethodCall:result:

◆ initWithViewController:

- (instancetype) initWithViewController: (FlutterViewController*)  viewController

Initializes a text input plugin that coordinates key event handling with |viewController|.

Definition at line 342 of file FlutterTextInputPlugin.mm.

342  :(FlutterViewController*)viewController {
343  // The view needs an empty frame otherwise it is visible on dark background.
344  // https://github.com/flutter/flutter/issues/118504
345  self = [super initWithFrame:NSZeroRect];
346  self.clipsToBounds = YES;
347  if (self != nil) {
348  _flutterViewController = viewController;
349  _channel = [FlutterMethodChannel methodChannelWithName:kTextInputChannel
350  binaryMessenger:viewController.engine.binaryMessenger
351  codec:[FlutterJSONMethodCodec sharedInstance]];
352  _shown = FALSE;
353  // NSTextView does not support _weak reference, so this class has to
354  // use __unsafe_unretained and manage the reference by itself.
355  //
356  // Since the dealloc removes the handler, the pointer should
357  // be valid if the handler is ever called.
358  __unsafe_unretained FlutterTextInputPlugin* unsafeSelf = self;
359  [_channel setMethodCallHandler:^(FlutterMethodCall* call, FlutterResult result) {
360  [unsafeSelf handleMethodCall:call result:result];
361  }];
362  _textInputContext = [[NSTextInputContext alloc] initWithClient:unsafeSelf];
363  _previouslyPressedFlags = 0;
364 
365  // Initialize with the zero matrix which is not
366  // an affine transform.
367  _editableTransform = CATransform3D();
368  _caretRect = CGRectNull;
369  }
370  return self;
371 }

References _caretRect, _editableTransform, and FlutterMethodChannel::methodChannelWithName:binaryMessenger:codec:.

◆ isFirstResponder

- (BOOL) isFirstResponder

Whether this plugin is the first responder of this NSWindow.

When accessibility is on, this plugin is set as the first responder to act as the field editor for FlutterTextFields.

Returns false if accessibility is off.

Definition at line 373 of file FlutterTextInputPlugin.mm.

373  {
374  if (!self.flutterViewController.viewLoaded) {
375  return false;
376  }
377  return [self.flutterViewController.view.window firstResponder] == self;
378 }

Property Documentation

◆ client

- (FlutterTextField*) client
readwritenonatomicweak

The NSTextField that currently has this plugin as its field editor.

Must be nil if accessibility is off.

Definition at line 31 of file FlutterTextInputPlugin.h.

Referenced by FlutterTextField::startEditing, and FlutterTextField::updateString:withSelection:.

◆ customRunLoopMode

- (NSString*) customRunLoopMode
readwritenonatomicassign

Provided by category FlutterTextInputPlugin(TestMethods).

Definition at line 68 of file FlutterTextInputPlugin.h.

◆ textInputContext

- (NSTextInputContext*) textInputContext
readwritenonatomicassign

Provided by category FlutterTextInputPlugin(TestMethods).

Definition at line 67 of file FlutterTextInputPlugin.h.


The documentation for this class was generated from the following files:
FlutterViewController
Definition: FlutterViewController.h:62
FlutterMethodChannel
Definition: FlutterChannels.h:220
FlutterTextInputPlugin
Definition: FlutterTextInputPlugin.h:24
+[FlutterMethodChannel methodChannelWithName:binaryMessenger:codec:]
instancetype methodChannelWithName:binaryMessenger:codec:(NSString *name,[binaryMessenger] NSObject< FlutterBinaryMessenger > *messenger,[codec] NSObject< FlutterMethodCodec > *codec)
FlutterJSONMethodCodec
Definition: FlutterCodecs.h:455
_editableTransform
CATransform3D _editableTransform
Definition: FlutterTextInputPlugin.mm:325
_caretRect
CGRect _caretRect
Definition: FlutterTextInputPlugin.mm:339