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Flutter support for (Neo)vim

2019-10-07 23-31-40 2019-10-08 00_04_07


  • LSP features is power by analysis_server
    • autocomplete
    • diagnostics
    • format
    • rename
    • hover document
    • signature help
    • go to definition
    • go to implementation
    • go to references
    • document highlight
    • document symbol
    • code actions
    • more detail

      need flutter sdk and add to PATH environment

  • Automatically finds SDKs from PATH
  • Automatic hot reloads on save
  • Automatically run flutter pub get when pubspec.yaml change
  • Support flutter dev server
  • Snippet enhance flutter.provider.enableSnippet
  • Sdk switching
  • Devices List
  • Emulators List


:CocInstall coc-flutter

NOTE: install dart-vim-plugin plugin if your (neo)vim detect filetype incorrect

Most likely the extension will find your sdk automatically as long as the flutter command maps to an sdk location on your system.

If you are using a version manager like asdf that maps the flutter command to another binary instead of an sdk location or this extension cannot find your sdk for another reason you'll have to provide the extension with how to find your sdk. To do this there are a few options:

  1. If your version manager supports a which command like then you can set the flutter.sdk.flutter-lookup config option. Eg. "flutter.sdk.flutter-lookup": "asdf which flutter".
  2. You can add the path where to find the sdk to the flutter.sdk.searchPaths config option. Either specify the exact folder the sdk is installed in or a folder that contains other folders which directly have an sdk in them. Note that not all of these folders need to have an sdk, if they don't contain one they will simply be ignored
  3. Set the flutter.sdk.path config option to the exact path you want to use for your sdk. If you have also set the flutter.sdk.searchPaths then you can use the FlutterSDKs list (see below) to see what versions you have installed and set the config option for you. Note that this means that the flutter.sdk.path option will be overriden by this list

Running the app

When the extension starts and has found an sdk it will request from flutter the available devices. The device it will run the app on will be shown in the statusbar and can be changed using the FlutterDevices list. If you call with an explicit -d deviceId argument then the selected device will be ignored.

After making sure that the correct device is selected you can run the app by calling the


If you want to give arguments to the flutter run command you can simply append them:

:CocCommand -t lib/main.dart --flavor myflavor

coc-list sources

  • FlutterSDKs

    :CocList FlutterSDKs

    Shows all the sdks that can be found by using the searchPaths config and the flutter-lookup config options and allows you to switch between them, either only for your current workspace or globally. Besides those two ways to find sdks it also checks if you are using fvm and if so uses those directories to find your sdk. You can disable this using the flutter.fvm.enabled config option.

    You can also use this list to see what your current sdk is since it will have (current) behind it clearly.

  • FlutterDevices

    :CocList FlutterDevices

    Shows a list of available devices that can be selected to use as run destination. When selecting a device it will by default be stored in the workspaceState such that a device can be selected on a per project basis. If no device is stored yet in the workspaceState it will fall back to the globalState and otherwise simply use the first device reported by flutter. It also has the run action which only runs the app once on that device without changing the selected device.

    You can configure the default action that us used using the flutter.devicesDefaultAction config option as described below.

  • FlutterEmulators

    :CocList FlutterEmulators

    Shows emulators available to start.


  • flutter.trace.server default: off

    Trace level of log

  • flutter.enabled default: true

    Enable coc-flutter extension

  • flutter.lsp.debug default: false

    Enable debug for language server

  • flutter.lsp.initialization.onlyAnalyzeProjectsWithOpenFiles: default: true

    When set to true, analysis will only be performed for projects that have open files rather than the root workspace folder.

  • flutter.lsp.initialization.suggestFromUnimportedLibraries: default: true

    When set to false, completion will not include synbols that are not already imported into the current file

  • [flutter.lsp.initialization.closingLabels](#closing-labels): default: true

    When set to true, will display closing labels at end of closing, only neovim support.

  • flutter.sdk.searchPaths default: []

    the paths to search for flutter sdks, either directories where flutter is installed or directories which contain directories where flutter versions have been installed eg. /path/to/flutter (command at /path/to/flutter/bin/flutter) or ~/flutter_versions (command at ~/flutter_versions/version/bin/flutter).

  • flutter.sdk.dart-command default: ''

    dart command, leave empty should just work

  • flutter.sdk.dart-lookup default: ''

    (only use this if you don't have a flutter installation but only dart) command to find dart executable location, used to infer dart-sdk location

  • flutter.sdk.flutter-lookup default: ''

    command to find flutter executable location, used to infer location of dart-sdk in flutter cache

  • default: true

    Enable hot reload after save. Only when there are no errors for the save file

  • flutter.provider.enableSnippet Enable completion item snippet, default: true

    • import ''; => import '${1}';${0}
    • someName(…) => someName(${1})${0}
    • setState(() {}); => setState(() {\n\t${1}\n});${0}
  • flutter.openDevLogSplitCommand default: ''

    Vim command to open dev log window, like: botright 10split

  • flutter.workspaceFolder.ignore default: []

    Path start within the list will not treat as workspaceFolder. Also flutter sdk will not treat as workspaceFolder, more detail issues 50

  • flutter.runDevToolsAtStartup default: false

    Automatically open devtools debugger web page when a project is run

  • flutter.autoOpenDevLog default: false

    Automatically open the dev log after calling flutter run

  • flutter.autoHideDevLog default: false

    Automatically hide the dev log when the app stops running

  • flutter.selectedDeviceId default: null

    The id of the device that was last selected using the FlutterDevices list (only if the device is selected using one of the config actions).

  • flutter.devicesDefaultAction default: workspaceState

    The default action to use when pressing enter in the FlutterDevices list. The state options will store the selected device in coc's memos.json file. The config options will store the selected device in the coc-settings.json file.

  • dart.analysisExcludedFolders default: []

    An array of paths (absolute or relative to each workspace folder) that should be excluded from analysis.

  • dart.enableSdkFormatter default: true

    When set to false, prevents registration (or unregisters) the SDK formatter. When set to true or not supplied, will register/reregister the SDK formatter.

  • dart.lineLength default: 80

    The number of characters the formatter should wrap code at. If unspecified, code will be wrapped at 80 characters.

  • dart.completeFunctionCalls default: true

    Completes functions/methods with their required parameters.

  • dart.showTodos default: true

    Whether to generate diagnostics for TODO comments. If unspecified, diagnostics will not be generated.

Enable format on save:

"coc.preferences.formatOnSaveFiletypes": [

Code Actions

Add below config mapping

this config should be in the coc.nvim README

xmap <leader>a  <Plug>(coc-codeaction-selected)
nmap <leader>a  <Plug>(coc-codeaction-selected)

Applying codeAction to the selected region.

Example: <leader>aap for current paragraph, <leader>aw for the current word

Then you will see action list:

  • Wrap with Widget
  • Wrap with Center
  • etc


Open flutter only commands list: CocList --input=flutter commands

Global Commands:

  • Run flutter dev server
  • flutter.attach Attach running application
  • flutter.create Create flutter project using: flutter create
  • Run: flutter doctor
  • flutter.upgrade Run: flutter upgrade
  • Run: flutter pub get
  • flutter.devices open devices list
  • flutter.emulators open emulators list

LSP Commands

  • flutter.gotoSuper jump to the location of the super definition of the class or method

Dev Server Commands:

available when dev server running

  • Quit server
  • Detach server
  • Hot reload
  • Hot restart
  • To save a screenshot to flutter.png
  • Open flutter dev server log
  • Clear the flutter dev server log
  • Open observatory debugger and profiler web page
  • Copy the url of observatory debugger and profiler web page to the system clipboard (register +)
  • Open devtools debugger web page
  • You can dump the widget hierarchy of the app (debugDumpApp)
  • To toggle the elevation checker
  • For layers (debugDumpLayerTree)
  • To dump the rendering tree of the app (debugDumpRenderTree)
  • To toggle the display of construction lines (debugPaintSizeEnabled)
  • To simulate different operating systems, (defaultTargetPlatform)
  • To display the performance overlay (WidgetsApp.showPerformanceOverlay)
  • To enable timeline events for all widget build methods, (debugProfileWidgetBuilds)
  • To toggle the widget inspector (WidgetsApp.showWidgetInspectorOverride)
  • Accessibility (debugDumpSemantics) for inverse hit test order
  • Accessibility (debugDumpSemantics) for traversal order

Closing Labels

when flutter.lsp.initialization.closingLabels is true, the closing labels will be display at end of closing.

this feature only support neovim since vim do not support virtual text

disabled enabled

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