3.- AndroidManifest.
We are going to modify the AndroidManifes.xml with the APK Editor Study program, @Anke explains how to modify the AndroidManifest in this topic:
Open .apk
AndroidManifest.xml
Change:
android:theme="@android:style/Theme"
by
android:theme="@android:style/Theme.Translucent.NoTitleBar">
Save.
Save .apk.
ooooooooooo000000ooooooooo
Install .apk.
Open. Close. Open app
You can set a semi-transparent color, example 22993355
Investigate res folder, maybe you can change some Style and Theme options in components.
I got this idea on the B4A forums:
https://www.b4x.com/android/forum/pages/results/?query=translucent.Notitlebar+screen+b4a
Here in Spanish:
http://kio4.com/appinventor/127F_fondo_transparente_2.htm
This method is easier, in App Inventor you don't need to add any files, just the text .Translucent.NoTitleBar
True...
at the time this guide was made, there was no theme support in AI2 and you had to make your own depending on what you wanted
It was more of show off that it has been done before..
Another example. Splash Screen.
Zoom an image when the app starts.
p127F_fondotransparente_Splash.aia (93.9 KB)
Do you have a demo/video so we can see it in action
Juan the metod to make background screen transparent works also for screen 2?
Thanks in adv 
If you change in .apk...
android:roundIcon="@mipmap/ic_launcher" android:theme="@android:style/Theme.Translucent.NoTitleBar">
... Screen1 and Screen2 get transparent background.
borrar_p127F_fondotransparente_2.aia (85.7 KB)
It is beautiful :). Is it possible to make 1 screen non-transparent and screen 2 transparent?
Try in Design Screen1 set colors in
Screen1.BackgroundColor: None
VerticalArrangement1.BackgroundColor: None
Etiqueta1.BackgroundColor: None
btn_close.BackgroundColor: None
I will have fun. We can get a real splash ekran.
This theme should be permanently selectable in appinventor. It would be a good complement.
There is a Extension to add Elements to manifest maybe this can be used instead of editing apk.
I don't know, whether it's possible or not, just posted so you could know this Extension 
Hi! I'm confused of how to open the app. I downloaded the apk file and have the app installed on my phone. But when I open the app, it opens the app with the background and when I press start the only thing that happens is that the seconds start counting. And when I press the button at the bottom where it says "Pulsa" it only exits the app but there are no buttons like the video you showed us. Can someone please help me to know how to open it the right way? Thanks for anyone who replies!
In these examples the applications are working in the foreground.
They are two different examples.
Do the first example.
You made amazing thing I never seen an transparent app
What do you mean by that? Sorry I'm kinda new at this.
like the video you showed us
Example without video:
p127F_fondotransparente.aia (5.8 KB) (is a simple counter)
Thanks for replying but I've already tried that one. Is it because of my phone?
