I am using creative sdk of adobe's demo on android platform
Operation: MainActivity then launch Image Editor. then home key. then launch app. Image Editor activity disappear.
I don't know how to config to make Image Editor don't disappear. Does everyone know?
The Image Editor Activity disappears because Android destroys it as part of the Activity Lifecycle.
If you want to recreate the previous state of the app on relaunch, have a look at the Android docs on Recreating an Activity. The two sections about "Save your Activity state" and "Restore your Activity state" are likely what you want.
Note that your user will still lose any edits they made, but you can still restore the Image Editor Activity with the image they were editing.