I did the factory reset, and my computer is newly installed. I enabled the USB debuging, and connect to the computer. It shows the drivers are installed successfully, and i can see so in the device manager. But the phone does not show the RSA dialog to comfirm the connection, and in the DDMS, it is offline... My nexus is official android 4.2.2 Has anyone met this issue? Please give advice! thanks!
/*****Update****/ I tried on my office computer. When connected to the office computer, the dialog, which shows the RSA key fingerprint, pops up. But as i tried this on my home computer, no dialog and merely the notifications on the bar.
Using terminal (cmd in windows), go into sdk/platform-tools folder.
Then launch adb devices command.
You should see "Starting daemon" and then the Fingerprint popup will appear on your device.
If does not, unplug usb cable, restart pc, plug the cable to phone and try again launching adb command.
For Linux adb kill-server or if adb is running in sudo sudo adb kill-server
On android device Settings > Developer options > Revoke USB debug authorizations USB Debug option is still Enabled
Connect the device to linux mach. sudo adb devices
check RSA Fingerprint popup is seen
Make sure you have the Android SDK Platform-tools updated to 16.0.1. I ran into this problem after update to 4.2.2 and updating adb and platform-tools solved the problem. The steps are neatly explained here -> http://www.thekirankumar.com/blog/2013/02/17/how-to-fix-adb-device-offline-issue-after-android-4-2-2-upgrade/
I just had the same issue on my mac book and solved it by quitting out of Parallels desktop.
The problem manifested for both a Motorola Atrix and brand new 11/14/2014 Galaxy S5.
The issue seemed to be that the sequence
- Connect USB Mac to Phone
- Get challenged to use this phone for USB debugging
- Confirm the RSA key
Was being interrupted at the device recognition level.
For me, the issue was Parallels Desktop stopping the handshake to ask if I wanted to connect this device to my Mac or Windows instance.
If you have android studio on your computer, you can see RSA dialog via android studio.
- Open Android Studio
- Run a project
- Select the device you want
then RSA diolog screen appears on your device.
You need to enable the Developer Option by going to Settings-->About Phone --> Tap 7 Times on Build Number Option.
Then open command prompt - Check the adb version by typing "adb version" if it shows 1.0.31 then you are good to go else update your adt version to 1.0.31 or higher.
After doing the above step-- type adb devices - It will show device offline and on you phone the RSA Key Dialog will open up . Mark always option and then you can see the device online.
来源：https://stackoverflow.com/questions/17218953/nexus-4-does-not-show-the-rsa-dialog-when-connecting-usb-in-debug-mode