Scene:
An Android project in Eclipse was deleted, but the delete project contents from disk (cannot be undone) was not checked. After the deletion, the next time you want to open the Android project, File->import->, Next is a bug, such as: can only select "General under the existing Projects into Workspace", can not be selected under the Android "Existing Android ...".
If the latter is selected, it will not be imported:
Another way is to cut the items in the workspace to a different place before re-importing the workspace.
Finally, remember that you cannot choose Copy Projects into Workspace when you import Workspace into the Workspace project again. Otherwise, some files in the project will be overwritten during the copy process. And because the copied source and destination addresses are in the same location, replication is confusing and some files are corrupted.
ADT Imports items that already exist in workspace