Flutter Html Editor – Enhanced

Flutter HTML Editor Enhanced is a text editor for Android, iOS, and Web to help write WYSIWYG HTML code with the Summernote JavaScript wrapper.

Note that the API shown in this README.md file shows only a part of the documentation and, also, conforms to the GitHub master branch only! So, here you could have methods, options, and events that aren’t published/released yet! If you need a specific version, please change the GitHub branch of this repository to your version or use the online API Reference (recommended).

Video Example	Light Mode andToolbarType.nativeGrid	Dark Mode andToolbarPosition.belowEditor

Flutter Web

Table of Contents:

• “Enhanced”? In what ways?
• Setup
• Usage
• API Reference
  • Parameters Table
  • Methods Table
  • Callbacks Table
  • Getters
  • Toolbar
  • Plugins
  • HtmlEditorOptions Parameters
    • autoAdjustHeight
    • adjustHeightForKeyboard
    • filePath
    • shouldEnsureVisible
    • webInitialScripts
  • HtmlToolbarOptions Parameters
    • customToolbarButtons and customToolbarButtonsInsertionIndices
    • linkInsertInterceptor, mediaLinkInsertInterceptor, otherFileLinkInsert, mediaUploadInterceptor, and onOtherFileUpload
    • onButtonPressed and onDropdownChanged
    • toolbarPosition: ToolbarPosition.custom
  • HtmlEditorController Parameters
    • processInputHtml, processOutputHtml, and processNewLineAsBr
• Examples
• Notes
• FAQ
• License
• Contribution Guide

In what ways is this package “enhanced”?

1. It has official support for Flutter Web, with nearly all mobile features supported. Keyboard shortcuts like Ctrl+B for bold work as well!
2. It has fully native Flutter-based widget controls
3. It uses a heavily optimized WebView to deliver the best possible experience when using the editor
4. It doesn’t use a local server to load the HTML code containing the editor. Instead, this package simply loads the HTML file, which improves performance and the editor’s startup time.
5. It uses a controller-based API. You don’t have to fiddle around with GlobalKeys to access methods, instead you can simply call <controller name>.<method name> anywhere you want.
6. It has support for many of Summernote’s methods
7. It has support for all of Summernote’s callbacks
8. It exposes the InAppWebViewController so you can customize the WebView however you like – you can even load your own HTML code and inject your own JavaScript for your use cases.
9. It has support for dark mode
10. It has support for extremely granular toolbar customization

More is on the way! File a feature request or contribute to the project if you’d like to see other features added.

Setup

Add html_editor_enhanced: ^2.2.0 as dependency to your pubspec.yaml.

Additional setup is required on iOS to allow the user to pick files from storage. See here for more details.

For images, the package uses FileType.image, for video FileType.video, for audio FileType.audio, and for any other file FileType.any. You can just complete setup for the specific buttons you plan to enable in the editor.

v2.0.0 Migration Guide:

Migration Guide

Basic Usage

import 'package:html_editor/html_editor.dart';

HtmlEditorController controller = HtmlEditorController();

@override Widget build(BuildContext context) {
    return HtmlEditor(
        controller: controller, //required
        htmlEditorOptions: HtmlEditorOptions(
          hint: "Your text here...",
          //initalText: "text content initial, if any",
        ),   
        otherOptions: OtherOptions(
          height: 400,
        ),
    );
}

Important note for Web:

At the moment, there is quite a bit of flickering and repainting when having many UI elements draw over IframeElements. See https://github.com/flutter/flutter/issues/71888 for more details.

The current workaround is to build and/or run your Web app with flutter run --web-renderer html and flutter build web --web-renderer html.

Follow https://github.com/flutter/flutter/issues/80524 for updates on a potential fix, in the meantime the above solution should resolve the majority of the flickering issues.

API Reference

For the full API reference, see here.

For a full example, see here.

Below, you will find brief descriptions of the parameters the HtmlEditor widget accepts and some code snippets to help you use this package.

Parameters – HtmlEditor

Parameters – HtmlEditorController

Parameters – HtmlEditorOptions

Parameters – HtmlToolbarOptions

Toolbar Options

Styling Options

Styling Options – applies to dropdowns only

Styling Options – applies to buttons only

Parameters – Other Options

Methods

Access these methods like this: <controller name>.<method name>

Callbacks

Every callback is defined as a Function(<parameters in some cases>). See the documentation for more specific details on each callback.

Getters

Currently, the package has one getter: <controller name>.editorController. This returns the InAppWebViewController, which manages the webview that displays the editor.

This is extremely powerful, as it allows you to create your own custom methods and implementations directly in your app. See flutter_inappwebview for documentation on the controller.

This getter should not be used in Flutter Web. If you are making a cross platform implementation, please use kIsWeb to check the current platform in your code.

Toolbar

This API allows you to customize the toolbar in a nice, readable format.

By default, the toolbar will have all buttons enabled except the “other file” button, because the plugin cannot handle those files out of the box.

Here’s what that a custom implementation could look like:

HtmlEditorController controller = HtmlEditorController();
Widget htmlEditor = HtmlEditor(
  controller: controller, //required
  //other options
  toolbarOptions: HtmlToolbarOptions(
    defaultToolbarButtons: [
        StyleButtons(),
        ParagraphButtons(lineHeight: false, caseConverter: false)
    ]
  )
);

If you leave the Toolbar constructor blank (like Style() above), then the package interprets that you want all the buttons for the Style group to be visible.

If you want to remove certain buttons from the group, you can set their button name to false, as shown in the example above.

Order matters! Whatever group you set first will be the first group of buttons to display.

If you don’t want to show an entire group of buttons, simply don’t include their constructor in the Toolbar list! This means that if you want to disable just one button, you still have to provide all other constructors.

You can also create your own toolbar buttons! See below for more details.

Plugins

This API allows you to add certain Summernote plugins from the Summernote Awesome library.

Currently the following plugins are supported:

1. Summernote Case Converter – Convert the selected text to all lowercase, all uppercase, sentence case, or title case. Supported via a dropdown in the toolbar in ParagraphButtons.
2. Summernote List Styles – Customize the ul and ol list style. Supported via a dropdown in the toolbar in ListButtons.
3. Summernote RTL – Switch the currently selected text between LTR and RTL format. Supported via two buttons in the toolbar in ParagraphButtons.
4. Summernote At Mention – Shows a dropdown of available mentions when the ‘@’ character is typed into the editor. The implementation requires that you pass a list of available mentions, and you can also provide a function to call when a mention is inserted into the editor.
5. Summernote File – Support picture files (jpg, png, gif, wvg, webp), audio files (mp3, ogg, oga), and video files (mp4, ogv, webm) in base64. Supported via the image/audio/video/other file buttons in the toolbar in InsertButtons.

This list is not final, more can be added. If there’s a specific plugin you’d like to see support for, please file a feature request!

No plugins are activated activated by default. They can be activated by modifying the toolbar items, see above for details.

To activate Summernote At Mention:

HtmlEditorController controller = HtmlEditorController();
Widget htmlEditor = HtmlEditor(
  controller: controller, //required
  //other options
  plugins: [
    SummernoteAtMention(
      //returns the dropdown items on mobile
      getSuggestionsMobile: (String value) {
        List<String> mentions = ['test1', 'test2', 'test3'];
        return mentions
            .where((element) => element.contains(value))
            .toList();
      },
      //returns the dropdown items on web
      mentionsWeb: ['test1', 'test2', 'test3'],
      onSelect: (String value) {
        print(value);
      }
    ),
  ]
);

HtmlEditorOptions parameters

This section contains longer descriptions for select parameters in HtmlEditorOptions. For parameters not mentioned here, see the parameters table above for a short description. If you have further questions, please file an issue.

autoAdjustHeight

Default value: true

This option parameter sets the height of the editor automatically by getting the value returned by the JS document.body.scrollHeight and the toolbar GlobalKey (toolbarKey.currentContext?.size?.height).

This is useful because the toolbar could have either 1 – 5 rows depending on the widget’s configuration, screen size, orientation, etc. There is no reliable way to tell how large the toolbar is going to be until after build() is executed, and thus simply hardcoding the height of the webview can induce either empty space at the bottom or a scrollable webview. By using the JS and a GlobalKey on the toolbar widget, the editor can get the exact height and update the widget to reflect that.

There is a drawback: The webview will visibly shift size after the page is loaded. Depending on how large the change is, it could be jarring. Sometimes, it takes a second for the webview to adjust to the new size and you might see the editor page jump down/up a second or two after the webview container adjusts itself.

If this does not help your use case feel free to disable it, but the recommended value is true.

adjustHeightForKeyboard

Default value: true, only considered on mobile

This option parameter changes the height of the editor if the keyboard is active and it overlaps with the editor.

This is useful because webviews do not shift their view when the keyboard is active on Flutter at the moment. This means that if your editor spans the height of the page, if the user types a long text they might not be able to see what they are typing because it is obscured by the keyboard.

When this parameter is enabled, the webview will shift to the perfect height to ensure all the typed content is visible, and as soon as the keyboard is hidden, the editor shifts back to its original height.

The webview does take a moment to shift itself back and forth after the keyboard pops up/keyboard disappears, but the delay isn’t too bad. It is highly recommended to have the webview in a Scrollable and shouldEnsureVisible enabled if there are other widgets on the page – if the editor is on the bottom half of the page it will be scrolled to the top and then the height will be set accordingly, rather than the plugin trying to set the height for a webview obscured completely by the keyboard.

See below for an example use case.

If this does not help your use case feel free to disable it, but the recommended value is true.

filePath

This option parameter allows you to fully customize what HTML is loaded into the webview, by providing a file path to a custom HTML file from assets.

There is a particular format that is required/recommended when providing a file path for web, because the web implementation will load the HTML as a String and make changes to it directly using replaceAll()., rather than using a method like evaluateJavascript() – because that does not exist on Web.

On Web, you should include the following:

1. <!--darkCSS--> inside <head> – this enables dark mode support
2. <!--headString--> inside <body> and below your summernote <div> – this allows the JS and CSS files for any enabled plugins to be loaded
3. <!--summernoteScripts--> inside <body> and below your summernote <div> – REQUIRED – this allows Dart and JS to communicate with each other. If you don’t include this, then methods/callbacks will do nothing.

Notes:

1. Do not initialize the Summernote editor in your custom HTML file! The package will take care of that.
2. Make sure to set the id for Summernote to summernote-2! – <div id="summernote-2"></div>.
3. Make sure to include jquery and the Summernote JS/CSS in your file! The package does not do this for you.
   
   You can use these files from the package to avoid adding more asset files:

<script src="assets/packages/html_editor_enhanced/assets/jquery.min.js"></script>
<link href="assets/packages/html_editor_enhanced/assets/summernote-lite.min.css" rel="stylesheet">
<script src="assets/packages/html_editor_enhanced/assets/summernote-lite.min.js"></script>

See the example HTML file below for an actual example.

shouldEnsureVisible

Default value: false

This option parameter will scroll the editor container into view whenever the webview is focused or text is typed into the editor.

You can only use this parameter if your HtmlEditor is inside a Scrollview, otherwise it does nothing.

This is useful in cases where the page is a SingleChildScrollView or something similar with multiple widgets (eg a form). When the user is going through the different fields, it will pop the webview into view, just like a TextField would scroll into in view if text is being typed inside it.

See below for an example with a good way to use this.

webInitialScripts

This parameter allows you to specify custom JavaScript for the editor on Web. These can be called at any point in time using controller.evaluateJavascriptWeb.

You must add these scripts using the WebScript class, which takes a name and a script argument. name must be a unique identifier, otherwise your desired script may not be executed. Pass your JavaScript code in the script argument.

The package supports returning values from JavaScript as well. You should run var result = await controller.evaluateJavascriptWeb(<name>, hasReturnValue: true);.

To get the return value, you must add the following at the end of your JavaScript:

window.parent.postMessage(JSON.stringify({"type": "toDart: <WebScript name goes here>", <add any other params you wish to return here>}), "*");

You can view a complete example below

HtmlToolbarOptions parameters

This section contains longer descriptions for select parameters in HtmlToolbarOptions. For parameters not mentioned here, see the parameters table above for a short description. If you have further questions, please file an issue.

customToolbarButtons and customToolbarButtonsInsertionIndices

These two parameters allow you to insert custom buttons and set where they are inserted into the toolbar widget list.

This would look something like this:

HtmlEditorController controller = HtmlEditorController();
Widget htmlEditor = HtmlEditor(
  controller: controller, //required
  //other options
  toolbarOptions: HtmlToolbarOptions(
    defaultToolbarButtons: [
      StyleButtons(),
      FontSettingButtons(),
      FontButtons(),
      ColorButtons(),
      ListButtons(),
      ParagraphButtons(),
      InsertButtons(),
      OtherButtons(),
    ],
    customToolbarButtons: [
      //your widgets here
      Button1(),
      Button2(),
    ],
    customToolbarInsertionIndices: [2, 5]
  )
);

In the above example, we have defined two buttons to be inserted at indices 2 and 5. These buttons will not be inserted before FontSettingButtons and before ListButtons, respectively! Each default button group may have a few different sub-groups:

If some of your buttons are deactivated, the number of subgroups could be reduced. The insertion index depends on these subgroups rather than the overall button group. An easy way to count the insertion index is to build the app and count the number of separator spaces between each button group/dropdown before the location you want to insert your button.

So with this in mind, Button1 will be inserted between the first two subgroups in FontSettingButtons, and Button2 will be inserted between the two subgroups in FontButtons.

When creating an onPressed/onTap/onChanged method for your widget, you can use controller.execCommand or any of the other methods on the controller to perform actions in the editor.

Notes:

1. using controller.editorController.<method> will do nothing on Web!
2. If you don’t provide customToolbarButtonsInsertionIndices, the plugin will insert your buttons at the end of the default toolbar list
3. If you provide customToolbarButtonsInsertionIndices, it must be the same length as your customToolbarButtons widget list.

linkInsertInterceptor, mediaLinkInsertInterceptor, otherFileLinkInsert, mediaUploadInterceptor, and onOtherFileUpload

These callbacks help you intercept any links or files being inserted into the editor.

For linkInsertInterceptor, mediaLinkInsertInterceptor, and mediaUploadInterceptor, you must return a bool to tell the plugin what it should do. When you return false, it assumes that you have handled the user request and taken action. When you return true, the plugin will use the default handlers to handle the user request.

onOtherFileLinkInsert and onOtherFileUpload are required when using the “other file” button. This button isn’t active by default, so if you make it active, you must provide these functions, otherwise nothing will happen when the user inserts a file other than image/audio/video.

See below for an example.

onButtonPressed and onDropdownChanged

These callbacks help you intercept any button presses or dropdown changes.

You must return a bool to tell the plugin what it should do. When you return false, it assumes that you have handled the user request and taken action. When you return true, the plugin will use the default handlers to handle the user request.

Some buttons and dropdowns, such as copy/paste and the case converter, don’t need to update their changed value, so functions to update the value after handling the user request will not be provided for those buttons.

See below for an example.

Custom toolbar position using ToolbarPosition.custom

You can use toolbarPosition: ToolbarPosition.custom and the ToolbarWidget() widget to fully customize exactly where you want to place the toolbar. THe possibilities are endless – you could place the toolbar in a sticky header using Slivers, you could decide to show/hide the toolbar whenever you please, or you could make the toolbar into a floating, draggable widget!

ToolbarWidget() requires the HtmlEditorController you created for the editor itself, along with the HtmlToolbarOptions you supplied to the Html constructor. These can be simply copy-pasted, no changed necessary.

A basic example where the toolbar is placed in a different location than normal:

HtmlEditorController controller = HtmlEditorController();
Widget column = Column(
  mainAxisAlignment: MainAxisAlignment.center,
  children: <Widget>[
    HtmlEditor(
      controller: controller,
      htmlEditorOptions: HtmlEditorOptions(
        hint: 'Your text here...',
        shouldEnsureVisible: true,
        //initialText: "<p>text content initial, if any</p>",
      ),
      htmlToolbarOptions: HtmlToolbarOptions(
        toolbarPosition: ToolbarPosition.custom, //required to place toolbar anywhere!
        //other options
      ),
      otherOptions: OtherOptions(height: 550),
    ),
    //other widgets here
    Widget1(),
    Widget2(),
    ToolbarWidget(
      controller: controller,
      htmlToolbarOptions: HtmlToolbarOptions(
        toolbarPosition: ToolbarPosition.custom, //required to place toolbar anywhere!
        //other options
      ),
    )
  ]
);

HtmlEditorController Parameters

processInputHtml, processOutputHtml, and processNewLineAsBr

Default values: true, true, false, respectively

processInputHtml replaces any occurrences of " with \\", ' with \\', and \r, \r\n, \n, and \n\n with empty strings. This is necessary to prevent syntax exceptions when inserting HTML into the editor as quotes and other special characters will not be escaped. If you have already sanitized and escaped all relevant characters from your HTML input, it is recommended to set this parameter false. You may also want to set this parameter false on Web, as in testing it seems these characters are handled correctly by default, but that may not be the case for your HTML.

processOutputHtml replaces the output HTML with "" if:

1. It is empty
2. It is <p></p>
3. It is <p><br></p>
4. It is <p><br/></p>

These may seem a little random, but they are the three possible default/initial HTML codes the Summernote editor will have. If you’d like to still receive these outputs, set the parameter false.

processNewLineAsBr will replace \n and \n\n with <br/>. This is only recommended when inserting plaintext as the initial value. In typical HTML any new-lines are ignored, and therefore this parameter defaults to false.

Examples

See the example app to see how the majority of methods & callbacks can be used. You can also play around with the parameters to see how they function.

This section will be updated later with more specialized and specific examples as this library grows and more features are implemented.

Example for linkInsertInterceptor, mediaLinkInsertInterceptor, otherFileLinkInsert, mediaUploadInterceptor, and onOtherFileUpload:

Example code

Example for onButtonPressed and onDropdownChanged

Example code

Example for adjustHeightForKeyboard:

Example code

Example for shouldEnsureVisible:

Example code

Example HTML for filePath:

Example HTML

Example for webInitialScripts:

View code

Notes

Due to this package depending on a webview for rendering the HTML editor, there will be some general weirdness in how the editor behaves. Unfortunately, these are not things I can fix, they are inherent problems with how webviews function on Flutter.

If you do find any issues, please report them in the Issues tab and I will see if a fix is possible, but if I close the issue it is likely due to the above fact.

1. When switching between dark and light mode, a reload is required for the HTML editor to switch to the correct color scheme. You can implement this programmatically in Flutter Mobile: <controller name>.editorController.reload(), or in Flutter Web: <controller name>.reloadWeb(). This will reset the editor! You can save the current text, reload, and then set the text if you’d like to maintain the state.
2. If you are making a cross platform implementation and are using either the editorController getter or the reloadWeb() method, use kIsWeb in your app to ensure you are calling these in the correct platform.

FAQ

• How can I display the final output of the editor? – Examples given for both raw HTML output and rendered HTML output – https://github.com/tneotia/html-editor-enhanced/issues/2
• How can I set the editor to “fullscreen” by default? – https://github.com/tneotia/html-editor-enhanced/issues/4
• The editor does not accept any key inputs when using the iOS Simulator. How can I fix this? – https://github.com/tneotia/html-editor-enhanced/issues/7
• Clicking on the editor makes the cursor appear on the second line relative with the hint. Is there a workaround? – https://github.com/tneotia/html-editor-enhanced/issues/24
• How can I give the editor box a custom background color on mobile? – https://github.com/tneotia/html-editor-enhanced/issues/27
• I see a file upload button in the top left of my application on Web. How can I remove it? – https://github.com/tneotia/html-editor-enhanced/issues/28
• I can’t tap drawer items above the text editor on Web. How can I fix this? – https://github.com/tneotia/html-editor-enhanced/issues/30
• How can I remove the “dragbar” at the bottom of the editor? – https://github.com/tneotia/html-editor-enhanced/issues/42
• How can I detect if an image has been deleted from the editor? – https://github.com/tneotia/html-editor-enhanced/issues/43
• How can I handle editor focus? – https://github.com/tneotia/html-editor-enhanced/issues/47
• How can I set the default text direction for the editor content? – https://github.com/tneotia/html-editor-enhanced/issues/49
• How can I handle relative URLs for images in my initial text? – https://github.com/tneotia/html-editor-enhanced/issues/50
• How can I give the editor box a custom background color on web? – https://github.com/tneotia/html-editor-enhanced/issues/57
• How can I create a toolbar dropdown for custom fonts? – https://github.com/tneotia/html-editor-enhanced/issues/59

Download Flutter WYSIWYG editor source code on GitHub

Check out the implementation guide on pub.dev

https://pub.dev/packages/html_editor_enhanced

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