# Using DroidVNC-NG

(These instructions are based off the project readme found here)

Some Bass builds will come with droidVNC-NG as a VNC remote management solution that can work across the internet.

# How to use

  1. Launch the droidVNC-NG Admin Panel app.
  2. Set a good password and consider turning the Start on Boot off.
  3. Connect to your local Wi-Fi. For accepting a connection your device should be connected to some Local Area Network that you can control, normally it is a router. Connections via data networks (i.e. your mobile provider) are not supported.
  4. Click Start
  5. Set any permissions if requested
  6. Connect to your device from a remote machine

# Keyboard Shortcuts From a VNC Viewer

  • Ctrl-Shift-Esc triggers 'Recent Apps' overview
  • Home/Pos1 acts as Home button
  • End acts as Power button
  • Escape acts as Back button

# For accepting connections from outside

  1. You should allow Port Forwarding in your router's Firewall settings. Login to your router's settings (usually open 192.168.1.1 in your browser, some routers have password written on them).

  2. Find Port Forwarding, usually it's somewhere in Network - Firewall - Port Forwards.

  3. Create a new rule, this is an example from OpenWRT firmware.

    Name: VNC forwarding

    Protocol: TCP

    Source zone: wan may be "internet", "modem", something that suggests the external source.

    External port: 5900 by default or whatever you specified in the app.

    Destination zone: lan something that suggests local network.

    Internal IP address: your device's local IP address, leaving any is less secure. The device's address may change over time! You can look it up in your routers' connected clients info.

    Internal port: same as external port.

  4. Apply the settings, sometimes it requires rebooting a router.

  5. Figure out your public address i.e. https://www.hashemian.com/whoami/.

  6. Use this address and port from above to connect to your device.

# How to Pre-seed Preferences

DroidVNC-NG can read a JSON file with default settings that apply if settings were not changed by the user. A file named defaults.json needs to created under <external files directory>/Android/data/net.christianbeier.droidvnc_ng/files/ where depending on your device, <external files directory> is something like /storage/emulated/0 if the device shows two external storages or simply /sdcard if the device has one external storage.

An example defaults.json with completely new defaults (not all entries need to be provided) is:

{
    "port": 5901,
    "portReverse": 5555,
    "portRepeater": 5556,
    "scaling": 0.7,
    "viewOnly": false,
    "showPointers": true,
    "fileTransfer": true,
    "password": "supersecure",
    "accessKey": "evenmoresecure",
    "startOnBoot": true,
    "startOnBootDelay": 0
}

# Remote Control via the Intent Interface

droidVNC-NG features a remote control interface by means of Intents. This allows starting the VNC server from other apps or on certain events. It is designed to be working with automation apps like MacroDroid, Automate or Tasker as well as to be called from code.

You basically send an explicit Intent to net.christianbeier.droidvnc_ng.MainService with one of the following Actions and associated Extras set:

  • net.christianbeier.droidvnc_ng.ACTION_START: Starts the server.

    • net.christianbeier.droidvnc_ng.EXTRA_ACCESS_KEY: Required String Extra containing the remote control interface's access key. You can get/set this from the Admin Panel.
    • net.christianbeier.droidvnc_ng.EXTRA_REQUEST_ID: Optional String Extra containing a unique id for this request. Used to identify the answer from the service.
    • net.christianbeier.droidvnc_ng.EXTRA_PORT: Optional Integer Extra setting the listening port. Set to -1 to disable listening.
    • net.christianbeier.droidvnc_ng.EXTRA_PASSWORD: Optional String Extra containing VNC password.
    • net.christianbeier.droidvnc_ng.EXTRA_SCALING: Optional Float Extra between 0.0 and 1.0 describing the server-side framebuffer scaling.
    • net.christianbeier.droidvnc_ng.EXTRA_VIEW_ONLY: Optional Boolean Extra toggling view-only mode.
    • net.christianbeier.droidvnc_ng.EXTRA_SHOW_POINTERS: Optional Boolean Extra toggling per-client mouse pointers.
    • net.christianbeier.droidvnc_ng.EXTRA_FILE_TRANSFER: Optional Boolean Extra toggling the file transfer feature.
    • net.christianbeier.droidvnc_ng.EXTRA_FALLBACK_SCREEN_CAPTURE: Optional Boolean Extra indicating whether to start with fallback screen capture that does not need a user interaction to start but is slow and needs view-only to be off. Only applicable to Android 10 and newer.
  • net.christianbeier.droidvnc_ng.ACTION_CONNECT_REVERSE: Make an outbound connection to a listening viewer.

    • net.christianbeier.droidvnc_ng.EXTRA_ACCESS_KEY: Required String Extra containing the remote control interface's access key. You can get/set this from the Admin Panel.
    • net.christianbeier.droidvnc_ng.EXTRA_REQUEST_ID: Optional String Extra containing a unique id for this request. Used to identify the answer from the service.
    • net.christianbeier.droidvnc_ng.EXTRA_HOST: Required String Extra setting the host to connect to.
    • net.christianbeier.droidvnc_ng.EXTRA_PORT: Optional Integer Extra setting the remote port.
    • net.christianbeier.droidvnc_ng.EXTRA_RECONNECT_TRIES: Optional Integer Extra setting the number of tries reconnecting a once established connection. Needs request id to be set.
  • net.christianbeier.droidvnc_ng.ACTION_CONNECT_REPEATER Make an outbound connection to a repeater.

    • net.christianbeier.droidvnc_ng.EXTRA_ACCESS_KEY: Required String Extra containing the remote control interface's access key. You can get/set this from the Admin Panel.
    • net.christianbeier.droidvnc_ng.EXTRA_REQUEST_ID: Optional String Extra containing a unique id for this request. Used to identify the answer from the service.
    • net.christianbeier.droidvnc_ng.EXTRA_HOST: Required String Extra setting the host to connect to.
    • net.christianbeier.droidvnc_ng.EXTRA_PORT: Optional Integer Extra setting the remote port.
    • net.christianbeier.droidvnc_ng.EXTRA_REPEATER_ID: Required String Extra setting the ID on the repeater.
    • net.christianbeier.droidvnc_ng.EXTRA_RECONNECT_TRIES: Optional Integer Extra setting the number of tries reconnecting a once established connection. Needs request id to be set.
  • net.christianbeier.droidvnc_ng.ACTION_STOP: Stops the server.

    • net.christianbeier.droidvnc_ng.EXTRA_ACCESS_KEY: Required String Extra containing the remote control interface's access key. You can get/set this from the Admin Panel.
    • net.christianbeier.droidvnc_ng.EXTRA_REQUEST_ID: Optional String Extra containing a unique id for this request. Used to identify the answer from the service.

The service answers with a Broadcast Intent with its Action mirroring your request:

  • Action: one of the above Actions you requested
    • net.christianbeier.droidvnc_ng.EXTRA_REQUEST_ID: The request id this answer is for.
    • net.christianbeier.droidvnc_ng.EXTRA_REQUEST_SUCCESS: Boolean Extra describing the outcome of the request.

There is one special case where the service sends a Broadcast Intent with action net.christianbeier.droidvnc_ng.ACTION_STOP without any extras: that is when it is stopped by the system.

# Examples

# Start a password-protected view-only server on port 5901

Using adb shell am syntax:

adb shell am start-foreground-service \
 -n net.christianbeier.droidvnc_ng/.MainService \
 -a net.christianbeier.droidvnc_ng.ACTION_START \
 --es net.christianbeier.droidvnc_ng.EXTRA_ACCESS_KEY de32550a6efb43f8a5d145e6c07b2cde \
 --es net.christianbeier.droidvnc_ng.EXTRA_REQUEST_ID abc123 \
 --ei net.christianbeier.droidvnc_ng.EXTRA_PORT 5901 \
 --es net.christianbeier.droidvnc_ng.EXTRA_PASSWORD supersecure \
 --ez net.christianbeier.droidvnc_ng.EXTRA_VIEW_ONLY true
# Start a server with defaults from Tasker
  • Tasker action-category in menu is System -> Send Intent
  • In there:
    • Action net.christianbeier.droidvnc_ng.ACTION_START
    • Extra net.christianbeier.droidvnc_ng.EXTRA_ACCESS_KEY:<your api key from DroidVNC-NG start screen>
    • Package net.christianbeier.droidvnc_ng
    • Class net.christianbeier.droidvnc_ng.MainService
    • Target: Service
# Start a server with defaults from a Kotlin app
  • For apps targeting API level 30+, you'll need to specify that your app is able to see/use droidVNC-NG. You do this by adding the following snippet to your AndroidManifest.xml, right under the <manifest> namepace:
<queries>
    <package android:name="net.christianbeier.droidvnc_ng" />
</queries>
  • In your Kotlin code, it's then:
val intent = Intent()
intent.setComponent(ComponentName("net.christianbeier.droidvnc_ng", "net.christianbeier.droidvnc_ng.MainService"))
intent.setAction("net.christianbeier.droidvnc_ng.ACTION_START")
intent.putExtra("net.christianbeier.droidvnc_ng.EXTRA_ACCESS_KEY", "<your api key from DroidVNC-NG start screen>")
startForegroundService(intent)
# Make an outbound connection to a listening viewer from the running server

For example from Java code:

See MainActivity.java.

# Stop the server again

Using adb shell am syntax again:

adb shell am start-foreground-service \
 -n net.christianbeier.droidvnc_ng/.MainService \
 -a net.christianbeier.droidvnc_ng.ACTION_STOP \
 --es net.christianbeier.droidvnc_ng.EXTRA_ACCESS_KEY de32550a6efb43f8a5d145e6c07b2cde \
 --es net.christianbeier.droidvnc_ng.EXTRA_REQUEST_ID def456