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CoronaViewer (for Corona SDK/Enterprise)

CoronaViewer lets you edit your Corona project on your Mac/Win desktop and preview those code changes in real-time on your device.

NOTE: CoronaCards developers should go here.

Getting Started

Dropbox Setup

CoronaViewer requires a Dropbox account. You'll also want to install Dropbox on your desktop computer so that you can sync edits from your desktop to the device.

In terms of where your project files should go, we'll get to that in a second. There will be a special folder that's automatically created after you launch the app and then login to Dropbox from your device.

Running on device

Build the Corona project in this repo and install it on your device. (Corona Enterprise users, see below for additional info.)

First time launch

If this is the first time you launch the app, you'll be prompted with Dropbox's standard login interface:

Dropbox Login UI iOS

Once you've successfully logged in with Dropbox, a special folder will automatically be created on your Mac or Win computer:


This is where you should copy your Corona project files, e.g. ${DROPBOX_FOLDER}/Apps/CoronaViewer/main.lua.

NOTE: Do not create this folder manually or remove the hidden files created by Dropbox. Only files in this location will be synchronized with your device. The rest of your Dropbox folder is not visible to CoronaViewer.

Automatic File Updates

The CoronaViewer app will automatically update files based on modification date (iOS) or by revision number (Android). When that happens, it will also relaunch your project.

The file update operates by synchronizing files between the device and the special Dropbox folder on your desktop computer. During synchronization, CoronaViewer caches the files locally on the device. Files on the device are only updated based on whether the modification date of the incoming file is newer than the version of the file sitting locally on the device. Make sure that the date and time are set identically on your desktop computer and device (automatic setting is best).

CoronaViewer Actions

CoronaViewer has built-in actions that can be triggered by tapping the screen with 4 fingers (i.e. 4 simultaneous touches) on iOS and by pressing the back button on Android:

CoronaViewer actions

Relaunch Project

The "Relaunch" action allows you to relaunch your app in CoronaViewer similar to how you relaunch it in the Corona Simulator.

Reset Project (Switching Projects)

The "Reset Project" action is useful when you are switching projects, i.e. copying in files from another project into the special Dropbox folder.

One problem that can occur when switching projects from the previous to the next, there are files which overlap in name (e.g. main.lua). Your next project may contain files that have an older modification date than the previous files.(iOS)

In this case, CoronaViewer may appear to continue to use the files from your previous project instead of the files from your next project, i.e. the files you've just copied into the Dropbox folder on your desktop computer.

If this happens, you can inform CoronaViewer to reset the project, thereby bypassing the modification date mechanism described above in 'Automatic File Updates'.

This is normally not needed on Android.

Orientation and Content Scaling

CoronaViewer uses the config.lua and build.settings files in this project, not the ones in the project you are viewing (i.e. ${DROPBOX_FOLDER}/Apps/CoronaViewer). Therefore, you will need to modify the CoronaViewer's version of config.lua and build.settings if your settings differ. These include:

  • content width
  • content height
  • content scale
  • frame rate
  • orientation (default and supported)

You'll then need to rebuild your modified CoronaViewer project so your changes take effect.

Xcode Simulator

CoronaViewer also works in the Xcode Simulator. You simply build CoronaViewer for Xcode Simulator instead of for your device.

Corona Enterprise

If you are using Enterprise, you will need to add libplugin_viewer.a (iOS) or the jar files (Android). This plugin is available from the Enterprise daily builds page (click on the "Enterprise" tab).

This library should appear in the "Link Binary with Libraries" build phase of your app's Xcode project.



On Enterprise, you'll have to add the following permissions:

<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

You will also have to add the following activities/services:

        <data android:scheme="db-l1q0pln8qsi8qyp" />
        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.BROWSABLE"/>
        <category android:name="android.intent.category.DEFAULT" />
<service android:name="plugin.viewer.LauncherService" />



On Enterprise, if you have overridden the CFBundleURLTypes array in your Info.plist, then you need to make sure that a CFBundleURLSchemes entry exists. It should correspond to the one in build.settings.

To do this, Open Info.plist in an external text editor and add the following where appropriate:



Custom fonts will need to be added to the build and not to the dropbox folder.

config.lua and build.settings

CoronaViewer does not use the config.lua or build.settings in your Dropbox folder. See 'Orientation and Content Scaling' above to learn more about how to control this.

File updates

Files are updated based on modification time and file size. To get the device to update the file, you must make sure the modification time is newer and the file size if different (iOS).

If this becomes an issue, you should use CoronaViewer's reset action, as described in 'Reset Project' above.

Lua errors

If there are Lua runtime errors in your project (e.g. in main.lua), CoronaViewer will display a black screen. You should check your device console for error messages.

One project at a time

Only one project can reside in the CoronaViewer folder. You need to switch out all the files (except for the hidden Dropbox files) in the folder when changing projects.


Supported Platforms

  • iOS
  • Android

Product Tiers

CoronaViewer is available to the following subscriptions/tiers:

  • Corona SDK
  • Corona Enterprise
  • CoronaCards uses a slightly different workflow. Learn more