Develop Reference

Drag & drop the class files from one package to another is not happening in android studio

I am using the Android studio version:
Android Studio 3.2.1
Build #AI-181.5540.7.32.5056338, built on October 9, 2018
JRE: 1.8.0_152-release-1136-b06 x86_64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
macOS 10.12.6
In earlier versions of android studio, I was able to drag & drop the
class files from one package to another and refractor would happen
automatically.
Its not happening, Now class files appears to have locked.
How to resolve this

try to copy paste the folder or class rather than using drag and drop. I hope it will work for you.

Android SDK cannot be found after every gradle sync

I have been facing this issue for 2 days that Android SDK cannot be found after I sync the gradle files, I have to close project and remove from the recent projects and re-open it, I don't remember what I updated or what I changed recently.
And yes, I have already tried invalidate caches and restart, clearing gradle cache etc.
System Specs:
Android Studio 3.1.3
Build #AI-173.4819257, built on June 4, 2018
JRE: 1.8.0_152-release-1024-b01 x86_64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Mac OS X 10.13.5
Thanks in advance.

First rebuild the app. might this has a good result
And remember don't use many countries IP like Iran because Android Studio Boycott this country. And thus connect to Vpn and Then Clean And Build project.
this ways might help you

Android plugin for Eclipse (ADT) disappears after SDK 20 upgrading

I've just upgraded to the Android SDK rev 20 and since then no way to install the ADT plugin in Eclipse 3.7.2. Although the package (Android DDMS, Android Development Tools) is referenced in the Eclipse installed software, I don't have shown-up any Android project or perspective, at the point that I can't set the SDK path in Windows/Preferences ...
I've also tried to re-install, nada. Accessory: Linux Ubuntu 12.04
Thanks for help!

SDK r20 works only with ADT r20 so you have to update your ADT too.
To update your ADT do the following procedure :
In eclipse go : Help -> Install New Software...
Now in Work with field type this link https://dl-ssl.google.com/android/eclipse/
Now press enter. You will see some items in list view below. Select all and press next.
Now accept the agreement an click next.
This will update your ADT. an you should be able to see it in eclipse
For more information see : Android Developer Site

I was having the same problems on Ubuntu 12.10.
I found that this was due to the fact I was using Java 1.5. After upgrading to Java 1.7, the problem disappeared

What JVM is your default on Ubuntu? ADT requires a JVM that can handle keystores correctly. Using Sun Java 6 is fine.
Besides that, ADT has optional dependencies to some of the Web Service Tools (WST) for the XML editing related features. Maybe you can check whether that is correctly installed?
And if nothing else helps: Eclipse 3.8 and 4.2 have been released 6 days ago, so just using a fresh installation of Eclipse 4.2 together with ADT 20 might be the best choice in the long run.

We had a similar problem.
Solved it by going to Help -> Check For Updates.
Deselect everything except the items that specify version 20. Can't remember the exact list by heart.
Then click next and follow instructions.
Should sort out the problem.
Edit:
The most important one is the "Android Development Tools" itself from that list.
The other 3 Android are also important.

Setting the "-vm" option in eclipse.ini with a JDK 1.6 solved the problem for me.
Trying to uninstall/install did not help.

While in android layout edtior, Properties view does not get updated when i click any view

HI I have this weird issue.
I have the latest version of ADT (11) in eclipse 3.6 R2.
When i open any layout xml in graphical view and if i click on any component, the properties window does not get updated/refreshed.
Does any one have face this before? Any solutions?
Note: i Have this issue in some previous verion of ADT as well. Also i use google plugin installed.
I have a seperate copy of eclipse + ADT which works well. (ADT version 10).

This is an issue with Eclipse 3.6.2 (see https://bugs.eclipse.org/bugs/show_bug.cgi?id=162079 ) - if you use an earlier version (e.g. 3.5.2) or a 3.7 milestone it should work.
However, we've fixed this for ADT 12 such that it should work on all Eclipse versions (see http://code.google.com/p/android/issues/detail?id=17384 ).
-- Tor

Eclipse crashes on Android SDK and AVD Manager

I tried to install Android SDK plugin on my existing Eclipse Classic 3.6.0 (Helios). I managed to do everything else, but when I try to add components using Android SDK and AVD Manager in Eclipse, whole Eclipse just crashes.
Anyone have any idea what's going on?
Eclipse Crash Log on pastebin.com

NOTE: there is NO date shown on this page( Currently 2010 Nov )
This page states,
http://developer.android.com/sdk/requirements.html
System Requirements
Supported Development Environments
Eclipse IDE
Eclipse 3.4 (Ganymede) or 3.5 (Galileo)
Caution: There are known issues with the ADT plugin running with Eclipse 3.6. Please stay on 3.5 until further notice.
ALSO NOTE
looking at your pastebin.com post
you PATH variable is corrupt

As of Feb 2013, using Android Dev Tools (Android SDK and Eclipse), build v21.0.1 - the AVD Manager crashed repeatedly using JDK v7x. Using JDK v6x resolved the issue, able to setup virtual devices now.