he 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
.
================================sno测试:
130|root@android:/ # screencap --help
unknown option -- -usage: screencap [-hp] [-d display-id] [FILENAME]
-h: this message
-p: save the file as a png.
-d: specify the display id to capture, default 0.
If FILENAME ends with .png it will be saved as a png.
If FILENAME is not given, the results will be printed to stdout.
1|root@android:/ # screencap -p testcap.png ///《----------------------------------这里可以截图。