Take a screenshot on Android

Question

I'm trying to build a custom launcher for android that needs to take a screenshot of the device right after the user presses the home button and consequently right before my app (the launcher) goes back to the foreground. Pretty much the idea is to take a screenshot of whatever the device was showing right before my launcher/activity/app took over the screen.

I am aware that such a thing requires root access, but that's not a problem. Can anyone show me how to take screenshots? Some sample code? A tutorial online? I have looked online but couldn't find anything useful. I'm trying to simply take screenshots just like a gazillion apps on the Android Market already do with root access. Thanks in advance :-)

score 4 · Accepted Answer · edited May 23 '17 at 11:49

4

This is a security breach. You should have a rooted device in order to do it.

You can use this code with your own app: (I got this code from this answer to another question: https://stackoverflow.com/a/5651242/237838 )

// image naming and path  to include sd card  appending name you choose for file
String mPath = Environment.getExternalStorageDirectory().toString() + "/" + ACCUWX.IMAGE_APPEND;   

// create bitmap screen capture
Bitmap bitmap;
View v1 = mCurrentUrlMask.getRootView();
v1.setDrawingCacheEnabled(true);
bitmap = Bitmap.createBitmap(v1.getDrawingCache());
v1.setDrawingCacheEnabled(false);

OutputStream fout = null;
imageFile = new File(mPath);

try {
   fout = new FileOutputStream(imageFile);
   bitmap.compress(Bitmap.CompressFormat.JPEG, 90, fout);
   fout.flush();
   fout.close();
} catch (FileNotFoundException e) {
   e.printStackTrace();
} catch (IOException e) {
   e.printStackTrace();
}

Try looking this code for additional help:

code.google.com/p/android-screenshot-library/wiki/DeveloperGuide

P.S. It's possible to take a screenshot from Android using DDMS, but this is another story.

P.P.S. If you want to draw your launcher transparently over the activity below it you need to set pixel format to RGBA (only dealt with OpenGL) and render accordingly. You don't need to take a screenshot of the underlaying activity to do that.

Rooted device: use this code on the rooted device:

process = Runtime.getRuntime().exec("su -c cat /dev/graphics/fb0");
InputStream is = process.getInputStream();

edited May 23 '17 at 11:49

Community

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answered Jun 02 '12 at 19:33

Sergey K.

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That takes a screenshot of my activity's view. Not really useful if I want to take screenshots when my app is in the background. – AxiomaticNexus Jun 02 '12 at 19:47
1

You mast be rooted to take shots of anything that is not yours. – Sergey K. Jun 02 '12 at 19:50
1

I know, that's why I said that root access was not a problem – AxiomaticNexus Jun 02 '12 at 19:53
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As I said in the answer, what you are trying to achieve is a security breach (imaging an app taking screenshot of your credit card IDs). – Sergey K. Jun 02 '12 at 19:55
1

I know, but how can I do it anyway? Lots of apps on the Android Market do it. – AxiomaticNexus Jun 02 '12 at 19:56
let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/12064/discussion-between-sergey-k-and-yasmani-llanes) – Sergey K. Jun 02 '12 at 19:59
So, Are you successful done this? If yes, Please share your solution for me. Thanks so much. – Nguyen Minh Binh Sep 04 '12 at 08:07
The code in this answer is a copy-and-paste of this answer to another question: http://stackoverflow.com/a/5651242/237838 – Andrew Barber Aug 06 '13 at 16:57

Take a screenshot on Android

1 Answers1