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  1. jni/
  2. src/
  3. Android.bp
  8. uinput


Two options to use the uinput command:

1. Interactive through stdin:

type uinput - into the terminal, then type/paste commands to send to the binary. Use Ctrl+D to signal end of stream to the binary (EOF).

This mode can be also used from an app to send uinput events. For an example, see the cts test case at:

When using another program to control uinput in interactive mode, registering a new input device (for example, a bluetooth joystick) should be the first step. After the device is added, you need to wait for the onInputDeviceAdded (see InputDeviceListener) notification before issuing commands to the device. Failure to do so will cause missed events and inconsistent behavior.

2. Using a file as an input:

type uinput <filename>, and the file will be used an an input to the binary. You must add a sufficient delay after a “register” command to ensure device is ready. The interactive mode is the recommended method of communicating with the uinput binary.

All of the input commands should be in pseudo-JSON format as documented below. See examples here.

The file can have multiple commands one after the other (which is not strictly legal JSON format, as this would imply multiple root elements).

Command description

  1. register Register a new uinput device
idintegerDevice id
commandstringMust be set to “register”
namestringDevice name
vid16-bit integerVendor id
pid16-bit integerProduct id
busstringBus that device should use
configurationint arrayuinput device configuration
ff_effects_maxintegerff_effects_max value
abs_infoarrayABS axes information

Device ID is used for matching the subsequent commands to a specific device to avoid ambiguity when multiple devices are registered.

Device bus is used to determine how the uinput device is connected to the host. The options are “usb” and “bluetooth”.

Device configuration is used to configure uinput device. “type” field provides the UI_SET_* control code, and data is a vector of control values to be sent to uinput device, depends on the control code.

typeintegerUI_SET_ control type
dataint arraycontrol values

Device ff_effects_max must be provided if FFBIT is set.

Device abs_info fields are provided to set the device axes information. It is an array of below objects: | Field | Type | Description | |:-------------:|:-------------:|:-------------------------- | | code | integer | Axis code | | info | object | ABS information object |

ABS information object is defined as below: | Field | Type | Description | |:-------------:|:-------------:|:-------------------------- | | value | integer | Latest reported value | | minimum | integer | Minimum value for the axis | | maximum | integer | Maximum value for the axis | | fuzz | integer | fuzz value for noise filter| | flat | integer | values to be discarded | | resolution | integer | resolution of axis |

See struct input_absinfo) definitions.


{ "id": 1, "command": "register", "name": "Keyboard (Test)", "vid": 0x18d2, "pid": 0x2c42, "bus": "usb", "configuration":[ {"type":100, "data":[1, 21]}, // UI_SET_EVBIT : EV_KEY and EV_FF {"type":101, "data":[11, 2, 3, 4]}, // UI_SET_KEYBIT : KEY_0 KEY_1 KEY_2 KEY_3 {"type":107, "data":[80]} // UI_SET_FFBIT : FF_RUMBLE ], "ff_effects_max" : 1, "abs_info": [ {"code":1, "info": {"value":20, "minimum":-255, "maximum":255, "fuzz":0, "flat":0, "resolution":1} }, {"code":8, "info": {"value":-50, "minimum":-255, "maximum":255, "fuzz":0, "flat":0, "resolution":1} } ] }
  1. delay Add a delay to command processing
idintegerDevice id
commandstringMust be set to “delay”
durationintegerDelay in milliseconds


  "id": 1,
  "command": "delay",
  "duration": 10
  1. inject Send an array of uinput event packets [type, code, value] to the uinput device
idintegerDevice id
commandstringMust be set to “inject”
eventsinteger arrayevents to inject

The “events” parameter is an array of integers, encapsulates evdev input_event type, code and value, see the example below.


  "id": 1,
  "command": "inject",
  "events": [0x01, 0xb,  0x1,   // EV_KEY, KEY_0, DOWN
             0x00, 0x00, 0x00,  // EV_SYN, SYN_REPORT, 0
             0x01, 0x0b, 0x00,  // EV_KEY, KEY_0, UP
             0x00, 0x00, 0x00,  // EV_SYN, SYN_REPORT, 0
             0x01, 0x2,  0x1,   // EV_KEY, KEY_1, DOWN
             0x00, 0x00, 0x01,  // EV_SYN, SYN_REPORT, 0
             0x01, 0x02, 0x00,  // EV_KEY, KEY_1, UP
             0x00, 0x00, 0x01   // EV_SYN, SYN_REPORT, 0


  1. As soon as EOF is reached (either in interactive mode, or in file mode), the device that was created will be unregistered. There is no explicit command for unregistering a device.
  2. The getevent utility can used to print out the key events for debugging purposes.