Develop Reference

error: more than one device/emulator - cant remove unity emulator

Im trying to get debug info through logcat when developing for android. Logcat does not show any info but only an error
error: more than one device/emulator
When i run command
adb devices
i get
List of devices attached
R3CT20DP74P device
emulator-5562 offline
I guess the emulator is preventing my phone from connecting with adb? Im also guessing thats what causing catlog from logging from my phone. Do i remove the emulator -5562 somehow? Ive tried adb kill-server but the emulator reapears.
Ive also tried
adb -s emulator-5562 emu kill
returns:
error: could not connect to TCP port 5562: cannot connect to 127.0.0.1:5562: No connection could be made because the target machine actively refused it. (10061)
Ive tried:
adb.exe -s R3CT20DP74P forward tcp:7201 tcp:7201
which returns
7201
but does nothing else. Emulator is still there.

First of all, there are 2 separate errors that you're getting, and they actually have nothing to do with each other. You'll need to deal with both of them:
error: more than one device/emulator:
you need to run adb kill-server to clear the connected devices, and then restart ADB. It'll auto-connect any devices that are physically connected via USB, but it won't connect any emulators or devices that are connected via wireless debugging
error: could not connect to TCP port: it looks like you're trying to connect via wireless debugging, and it's a bit finicky. It times out after a while, and the device starts rejecting your connection requests. To fix it, you have to physically connect your device to the PC using a USB cable, and as soon as you do that, it should give you a confirmation prompt on the device to allow the USB debugging connection. After you approve that request, you'll need to turn off wireless debugging, and then turn it right back on. It'll generate a new TCP port for you to use, and you will now be able to connect to wireless debugging using that new port

Unpluging usb cable also disconnects wireless adb connection [duplicate]

I develop on my tablet using android studio.
The tablet is connected to the computer by wifi using
adb connect <ip_andress>:5555
My application contains listeners for USB devices attached/detached.
But unfourtunately, when I connect/disconnect usb device to/from the tablet, the adb connection is getting killed, and I can no longer see the device under "adb devices".

It is not a adb-connection-by-wifi what gets killed. It is just that USB enumerations affect the sys.usb.* system properties which on many devices is causing restart of adbd regardless whether it's being used over USB or tcpip.
Do grep "stop adbd" /init*rc to see what I mean.
You could either comment out those stop adbd lines or just disconnect the USB cable before running your adb connect command.

I was never able to connect my cellphone with my computar through wi-fi.
I had already given up. I followed all the instructions and tips, and nothing worked.
Finally, I did what no one said to do.
I've connected the phone to the WiFi network provided by the cable modem itself and not to some (not all) additional networks that are included in the router.
At home I use one of these networks, because I use a Deco Tp-Link router, which propagates the signal to my entire house, but this network is NOT compatible with ADB. It does not identify it as belonging to the same network.
After this, I use the normal procedure described here.
a) Connect cellphone with a USB cable
b) Find the IP_Phone depends on system in the cell phone. Here I use Settings, About Phone, Status and IP address.
c) Run the following adb commands in Command Prompt (Windows) or Terminal (Linux), where IP_Phone is the IP above mentioned. Normally adb.exe is an executable stored in computer path. adb is already included in Android Studio package.
adb tcpip 5555
adb connect IP_Phone
d) Now disconnect USB cable and it's ready. The cellphone model continues to appear in the status line in the top of Android Studio.
-/-
The best wifi is that defined in Cable Modem. It, unlike an any account defined in my router, answers to a ping command.
ping IP_Phone

Disconnect the usb cable just before running adb connect <*ip_address_of_your_phone*>

No Consistent Way to Connect ADB over TCP

I am debugging an Android app that usually crashes when I plug into an Arduino it is supposed to be communicating with. Consequently, I need to get a wireless connection to the device's logcat, which is what brought me to ADB over TPC as seen on the Android developers webpage.
The recommended process is:
C:\Users\User> cd AppData\Local\Android\sdk\platform-tools
C:\Users\User\AppData\Local\Android\sdk\platform-tools> adb kill-server
C:\Users\User\AppData\Local\Android\sdk\platform-tools> adb start-server
* daemon not running; starting now at tcp:5037
* daemon started successfully
C:\Users\User\AppData\Local\Android\sdk\platform-tools> adb tcpip 5555
restarting in TCP mode port: 5555
C:\Users\User\AppData\Local\Android\sdk\platform-tools> adb connect 10.20.5.160:5555
However, the typical response is:
unable to connect to 10.20.5.160:5555: cannot connect to 10.20.5.160:5555: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. (10060)
I could not consistently get a connection between a PC and mobile device. Over the course of three weeks using several networks and devices, I could only connect two times out of an agonizing many attempts.
I have dug deep into the posted questions on stackoverflow and tried literally every recommended alteration to getting an adb connection, from using an Android Studio plugin to forwarding ports to trying several other ports to toggling my device's internet. I still could not get a connection more than a fraction of a percent of the time.
When I look at the network state of my device after adb tpip <port>, I find no evidence of the device trying to look for a connection:
C:\Users\User\AppData\Local\Android\sdk\platform-tools> adb shell
j3ltevzw:/ $ netstat -n
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 ::ffff:10.20.5.160:4214 ::ffff:173.194.196.188: ESTABLISHED
udp 4288 0 adb shell ip -f inet addr show wlan0:68 10.20.5.1:67 ESTABLISHED
Active UNIX domain sockets (w/o servers)
Proto RefCnt Flags Type State I-Node Path
... ... ... ... ... ...
... ... ... ... ... ...
Also, when I try to ping my device, I usually get:
C:\Users\Benjamin\AppData\Local\Android\sdk\platform-tools> ping 10.20.5.160
Pinging 10.20.5.160 with 32 bytes of data:
Reply from 10.20.5.232: Destination host unreachable.
Reply from 10.20.5.232: Destination host unreachable.
Reply from 10.20.5.232: Destination host unreachable.
Reply from 10.20.5.232: Destination host unreachable.
Ping statistics for 10.20.5.160:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss)
What I am looking for is a process or file that can be run and consistently open a tcp adb connection, or at least explain what about my setup is invalid. Ideas?
Update 1:
I have started a bounty on this question. I feel like the problem with the ADB software used to make connection for debugging is two fold:
adb tcpip <port> does not always invoke the mobile device to listen on the specified port
adb connect <ip>:<port>, I am assuming, is not given permission by the network to connect; I am not a networking expert, but the fact that pinging a device returns "destination host unreachable" seems a little off
I will award the first person to find a successful solution. Seeing that having an ADB USB connection gives a user access to both the mobile device's and host's terminal, there really is no excuse for a connection not to be able to be made between the two.
Update 2:
I have recently had more success in connecting to the ADB as well as receiving successful pings at my school network. Note at this network connects are insecure and the host and mobile devices where on separate subnetworks. Any idea why these conditions would work over my secure network at home that uses only one subnet?

Try starting from scratch and setup ADB-over-tcp following steps below:
Turn off USB debugging on your device and turn it on again (just to reset).
Kill the ADB server on your PC using adb kill-server
Connect your device to the PC using the USB cable and type adb devices. This will automatically restart the ABD server again.
Enter adb tcpip 5555 on your PC terminal. This will switch the adbd daemon on your device to tcp-ip mode.
Disconnect your device from USB. Now connect your device to the same wireless network as your PC, either the same wi-fi or use your phone as a hotspot.
Determine your phone's ip. You can do this in the wi-fi settings on your phone. If you are using your phone as hotspot, then generally your ip should be 192.168.43.1 (not required but most of the time it's the same).
Connect to ADB via tcp using adb connect <IP>
This should hopefully connect your device to your pc via tcp-ip.

I found a solution that works for me, but I feel it shouldn't necessary and it may not applicable for everybody else with these issues, so its still not quite what I was aiming for.
Anyways, after seeing riyaz-ali suggest what an IP address I should be for using a mobile hotstop through a phone, I realized any network complications would be solved if I was the network, so I connected my mobile device to the mobile hotspot on my laptop.
Instant ping responses and immediate ADB connection with the popularly suggested commands.

Just found myself in the same situation. Had no problem yesterday but today couldn't connect.
Solution was simple, I realized that today I'm connected to VPN which obviously makes me belonging to a different network.
So, disconnecting and connection to the same Wi-Fi solved the trouble.

adb wifi often go offline, how to keep adb online?

I'm using Android tablet communicating with a USB device through USB port, the tablet only has one usb port, so I use adb wifi as my debug tool. However, when I connect adb through WIFI, the connection won't keep long(only a few minutes us usually), how to keep the adb wifi connection online all the time?
Another question, is it possible to use USB HUB to connect the tablet with both USB flash-drive and my computer, and keep adb running?
Many thanks!!!

After lots of unsuccessful attempts,I have noticed that turning Allow ADB debugging in charge only mode specification on , solved the problem . It makes the device online and accessable over wifi to ADB.
You can find it under Developer options section.

Here is what I found out from researching everywhere and developing on my own for more than a week.
Q1. adb service often crashes if it is not doing any executions for a long long time.
A1. calling adb commands time to time keeps adb server online.
Q2. wifi connected device sometimes disconnect.
A2. Before you check your wifi on the connected device, check the wifi that your ADB server is running on. Ping to google and if it is well connected, ping to the device.
Wireless can disconnect on its own and even wired connection is sometimes disconnected. so calling "adb connect ..." when the device is not already connected is necessary. You could do this easily by saving "adb devices > device.txt" and query out whether your expected wifi is on the list. If not, connect again..(do this in another thread).
Q3. wifi connected device is sometimes offline.
A3. This is because by TCP/IP connection your ADB server is now on Time_Wait stance. The last connection was interrupted that the next connection is now offline because the last connection is not completely shut down. You can either manually disconnect/connect your device's wifi or restart TCPIP connection by ex) "adb tcpip 5555"
If you want to do this automatically, you are going to have to disconnect/connect your device's wifi programmatically.
Leave any other questions and I can answer on the comments.

When connection is lost and adb devices shows device is offline, like this:
prompt> adb devices
List of devices attached
192.168.1.1:5555 offline
then adb disconnect IP followed by adb connect IP will often work:
prompt> adb disconnect 192.168.1.1
disconnected 192.168.1.1
prompt> adb devices
List of devices attached
prompt> adb connect 192.168.1.1
connected to 192.168.1.1
prompt> adb devices
List of devices attached
192.168.1.1:5555 device

Use adb over wi-fi without any third-party apps. Follow the steps.
Connect device via USB
Open your terminal and check your device is listed with adb devices command
Type adb tcpip 5555 and enter (or use another port instead of 5555)
Plug out your USB cable. You don't need it anymore.
Take your Android phone and go Settings/About/Status
Check the IP address part. Let's say your IP address is 192.168.x.y
In your terminal, write the command adb connect 192.168.x.y
Now, you have connected your device via wi-fi.
You can see your device in adb devices
Enjoy it! :)

This seems like an issue with your wifi. As a precaution, just keep the terminal open and whenever you need to test just press the 'UP arrow' key to get to previously ran adb connect "<ip>" command.

I tried many ways but this one worked out for me:
force the display on and of in a loop would keep the device online
adb shell input keyevent 224
timeout 2
adb shell input keyevent 26
timeout 58
this turns the display on every minute for 2 seconds

So, I'm using Scrcpy and Adb to wirelessly connect to my Phone(for developing Flutter Apps) and since the screen wasn't staying awake even by Scrcpy --stay-awake command.
I had to change Lock Settings=>Lock Screen => Sleep, and settings to Never Sleep.

ADB over ethernet

I have an android device which I want to connect to using ADB. For reasons that don't matter here I need it to have an ethernet connection, not wifi. The device itself refuses to have both ethernet and wifi connections at the same time.
I have been using a third party app called ADB WiFi to connect to it with ADB when it is in WiFi mode, and I have found that I can connect to it in wifi, then switch the device into ethernet, and then reconnect to the new IP, and it works.
I would dearly like to be able to connect to my device (which is often remote and hard to reach) without first switching it into wifi and back, to which end I have written my own little app which uses SU and does:
setprop service.adb.tcp.port 5555
stop adbd
start adbd
It says that it is working when I run it and produces no error messages, but I can't connect afterwards. It doesn't work in wifi mode either. After setting up a connection once using the 3rd party app, I can then use stop adbd to prevent adb working, and I can use my application above to enable it again, without wifi or 3rd party intervention, which suggests that it is doing what it thinks it is doing, but missing a one off step.
Does anyone know if there is another thing that must be set / enabled / poked in order for adbd to work? Does anyone know what I'm missing?
Thanks

Have you tried this:
adb tcpip 5555
adb connect 192.168.1.1:5555
replacing the 192.168.1.1 with your phones IP Address?

I was able to get both ADB (through USB) and Ethernet, but it was device specific. I used the Asus Transformer Pad TF701T with the keyboard dock. The dock allowed me to connect the ADB cable and provided a full size USB port. I connected a compatible USB to Ethernet adapter to get Ethernet.