Use dolphin (or other browser) like yakuake - kde-plasma

Question

I often want to open a file browser to open a file and then close the browser.
Is there a way (a plasmoid, a dolphin plugin, another browser...) which could allow me to have a file browser "in the style of" yakuake? (i.e. unfolding with a shortcut, and re-folding when I chose the file I want)

Answer 1

Took me some time, but finally managed to get what you want (and eventually, what I also want :) with xdotool (on Ubuntu sudo apt-get install xdotool).
With this script, you can have any application behave like you asked:
#!/bin/bash
SEARCHED_WINDOW=$1
COMMAND=${2:-$SEARCHED_WINDOW}
SEARCHED_WINDOW_CLASSNAME=toggleApp$SEARCHED_WINDOW
WINDOW_ID=$(xdotool search --classname $SEARCHED_WINDOW_CLASSNAME)
VISIBLE_WINDOW_ID=$(xdotool search --onlyvisible --classname $SEARCHED_WINDOW_CLASSNAME 2>/dev/null)
if [ -z "$WINDOW_ID" ]; then
$COMMAND 2>/dev/null &
pid=$!
NEW_WINDOW_ID=$(xdotool search --onlyvisible --sync --pid $pid 2>/dev/null)
xdotool set_window --classname $SEARCHED_WINDOW_CLASSNAME $NEW_WINDOW_ID
xdotool windowfocus $NEW_WINDOW_ID
elif [ -z "$VISIBLE_WINDOW_ID" ]; then
xdotool windowmap $WINDOW_ID
xdotool windowfocus $WINDOW_ID
else
xdotool windowunmap $VISIBLE_WINDOW_ID
fi
(Inspired from here)
You call it like this:
./toggle.sh dolphin
If the command to launch the program is different, you can add a second parameter:
./toggle.sh appName commandToLaunchApp
What this script does is the following:
If the app is not running: launch it, give window a specific class, and give window focus
If the app is running but with no visible window: make window visible and give it focus
Else, i.e. app is running and visible: hide it.
All you have left to do is map a shortcut to the above-mentionned command to launch the script. In KDE : System settings > Shortcuts and gestures > Custom shortcuts. Then Edit > New > Global shortcut > Command.
Plus, this script works with any app, should work with any EWMH compliant window manager, and allows you to have other instances of the same app (this is why I added the class trick).

Answer 2

The closest solution to what you want is the Widget Layer Compiz plugin.
This plugin enables you to make appear a layer on top of your workspace. You can configure this layer to hold windows of your choice, in your case that would be the file manager. It has a hide/show feature which you can bind to a hotkey.
It uses Window Matching rules to define the windows to hold.
More information on http://wiki.compiz.org/Plugins/Widget
However, this would imply that you use the Compiz compositing manager.