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