How to use ScreenShotClient in my android application

Question

I am developing an application which helps user to capture android screen shot (Android 4.x) . I know that framebuffer is broken on android ICS. I hear that we can use ScreenShotClient to do this as below.

ScreenshotClient screenshotClient = new ScreenshotClient();
screenshotClient->update();

But, what library I have to import to use it? Is it available to use under jni code?

Isn't this duplicate of http://stackoverflow.com/questions/2661536/screenshot-android? — Alex Cohn, Sep 25 '12 at 13:43
OK, have you seen the answer in [**how-to-capture-the-android-device-screen-content**](http://stackoverflow.com/questions/3067586/how-to-capture-the-android-device-screen-content#7979151)? — Alex Cohn, Sep 27 '12 at 19:46
Yes, I did. I wrote a similar app which using ScreenShotClient to take screenshot, but I couldn't build it. The needed library was not found. — Nguyen Minh Binh, Sep 28 '12 at 02:29
Have you found the **surfaceflinger_client/SurfaceComposerClient.h** file? — Alex Cohn, Sep 28 '12 at 19:14
I downloaded that file (and many other needed files) from https://github.com/android then put them into /jni folder but I can't build it. My JNI folder was shared here: https://dl.dropbox.com/u/15261504/jni.zip — Nguyen Minh Binh, Oct 01 '12 at 03:30

Alex Cohn · Accepted Answer · 2012-10-02T11:06:46.063

7

The library you need is called libsurfaceflinger_client.so. You can pull it from any device running Gingerbread ~~or higher~~ version of Android, with command

adb pull /system/lib/libsurfaceflinger_client.so

On ICS or JB, class ScreenshotClient is part of libgui.so. The makefile for screencap which is the example of using ScreenshotClient, suggests that linker may need other libraries:

libcutils libutils libbinder libskia libui libgui

Also, the code of screencap.cpp goes as follows:

ScreenshotClient screenshot;
if (screenshot.update() == NO_ERROR) {
    base = screenshot.getPixels();
    w = screenshot.getWidth();
    h = screenshot.getHeight();
    f = screenshot.getFormat();
    size = screenshot.getSize();
} else {
    const char* fbpath = "/dev/graphics/fb0";
    int fb = open(fbpath, O_RDONLY);
    if (fb >= 0) {
        struct fb_var_screeninfo vinfo;
        if (ioctl(fb, FBIOGET_VSCREENINFO, &vinfo) == 0) {
...

This means that at least you must check that update() succeed. Unfortunately, unless teh device is rooted, the apps cannot be granted permission to read from /dev/graphics/fb0 and use the fallback of /system/bin/screencap or /system/bin/screenshot.

edited Oct 02 '12 at 11:06

answered Sep 28 '12 at 19:46

Alex Cohn

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Yeah. I can pull it from that folder to my Project. But I don't know how to use it to capture android screen. Could you give me some hints? – Nguyen Minh Binh Oct 01 '12 at 03:35
Wait a sec. You wrote elsewhere that you have the code in your project, but cannot build it because you don't know where to find the **.so** file – Alex Cohn Oct 01 '12 at 04:37
Hm. The adb command does not work for my device running Android 4.1.1.: **remote object '/system/lib/libsurfaceflinger_client.so' does not exist** – Claas Wilke Oct 02 '12 at 09:24
1

Well, on 4.0 and higher the library is called **libgui.so**. The makefile for `screencap` which is ***the*** example of using **ScreenshotClient**, suggests that linker may need other libraries: `libcutils libutils libbinder libskia libui libgui`. – Alex Cohn Oct 02 '12 at 10:49

How to use ScreenShotClient in my android application

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