Cannot send combination key with sendevent command in my android device via ADB

Question

I am struggling on sending combination key like "ctrl" + "a" on my samsung J7 with android 8.1.0.

After finding resources in the Internet, I found some commands that help sending text via ADB such as:

adb shell input keyevent 29 => a
adb shell input text "a" => a

However, when I used sendevent to send text "a", it didn't work (The same as "ctrl" + "a"). My command is below:

adb shell sendevent /dev/input/event6 1 30 1 => Key down.
adb shell sendevent /dev/input/event6 0 0 0 -> End report.
adb shell sendevent /dev/input/event6 1 30 0 => Key up.
adb shell sendevent /dev/input/event6 0 0 0 => End report.

Then I checked keycode followed by link, I executed the command:

adb shell getevent -p

The output is:

add device 1: /dev/input/event2
  name:     "accelerometer_sensor"
  events:
    REL (0002): 0000  0001  0002  0007  0009
  input props:
    <none>
add device 2: /dev/input/event3
  name:     "proximity_sensor"
  events:
    ABS (0003): 0019  : value 1, min 0, max 1, fuzz 0, flat 0, resolution 0
  input props:
    <none>
add device 3: /dev/input/event6
  name:     "sec_touchscreen"
  events:
    KEY (0001): 0145* 014a
    ABS (0003): 0000  : value 0, min 0, max 1079, fuzz 0, flat 0, resolution 0
                0001  : value 0, min 0, max 1919, fuzz 0, flat 0, resolution 0
                002f  : value 0, min 0, max 9, fuzz 0, flat 0, resolution 0
                0030  : value 0, min 0, max 255, fuzz 0, flat 0, resolution 0
                0031  : value 0, min 0, max 255, fuzz 0, flat 0, resolution 0
                0035  : value 0, min 0, max 1079, fuzz 0, flat 0, resolution 0
                0036  : value 0, min 0, max 1919, fuzz 0, flat 0, resolution 0
                0039  : value 0, min 0, max 65535, fuzz 0, flat 0, resolution 0
                003e  : value 0, min 0, max 1, fuzz 0, flat 0, resolution 0
  input props:
    INPUT_PROP_DIRECT
add device 4: /dev/input/event4
  name:     "Codec3026 Headset Events"
  events:
    KEY (0001): 0072  0073  00e2  0246
  input props:
    <none>
add device 5: /dev/input/event0
  name:     "meta_event"
  events:
    REL (0002): 0006  0007
  input props:
    <none>
could not get driver version for /dev/input/mice, Not a typewriter
add device 6: /dev/input/event1
  name:     "sec_touchkey"
  events:
    KEY (0001): 009e  00fe
    LED (0011): 0008
  input props:
    <none>
add device 7: /dev/input/event5
  name:     "gpio_keys"
  events:
    KEY (0001): 0072  0073  0074  00ac
  input props:
    <none>

The output means the device /dev/input/event6 does not have keyevent for inputting texts.

So my question is: How can I implement combination key with keydown and keyup separately?

Thanks so much for helping.

Answer 1

After doing a lot of research, I figured out the root cause is from meta key code.

I tried to use a third party application, but the origin version couldn't send meta key codes correctly on Android 8+.

Therefore, I made some changes and then requested a pull ticket as issue. During waiting for merging, I publish the modified version in my repo in case anyone needs it. You can download only ADBKeyboard.apk on this repo since it is updated though.

Now I can send Ctrl + A as below: (4096 is META_CONTROL_ON, 29 is KEYCODE_A)

adb shell am broadcast -a ADB_INPUT_TEXT --es mcode '4096,29'