android截屏代码：C++实现

示例代码在:

frameworks\base\services\surfaceflinger\tests\screencap\screencap.cpp



/*

* Copyright (C) 2010 The Android Open Source Project

*

* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

*

* http://www.apache.org/licenses/LICENSE-2.0

*

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

*/



#include <utils/Log.h>



#include <binder/IPCThreadState.h>

#include <binder/ProcessState.h>

#include <binder/IServiceManager.h>



#include <binder/IMemory.h>

#include <surfaceflinger/ISurfaceComposer.h>



#include <SkImageEncoder.h>

#include <SkBitmap.h>



using namespace android;



int main(int argc, char** argv)

{

if (argc != 2) {

printf("usage: %s path\n", argv[0]);

exit(0);

}



const String16 name("SurfaceFlinger");

sp<ISurfaceComposer> composer;

getService(name, &composer);



sp<IMemoryHeap> heap;

uint32_t w, h;

PixelFormat f;

status_t err = composer->captureScreen(0, &heap, &w, &h, &f, 0, 0);

if (err != NO_ERROR) {

fprintf(stderr, "screen capture failed: %s\n", strerror(-err));

exit(0);

}



printf("screen capture success: w=%u, h=%u, pixels=%p\n",

w, h, heap->getBase());



printf("saving file as PNG in %s ...\n", argv[1]);



SkBitmap b;

b.setConfig(SkBitmap::kARGB_8888_Config, w, h);

b.setPixels(heap->getBase());

SkImageEncoder::EncodeFile(argv[1], b,

SkImageEncoder::kPNG_Type, SkImageEncoder::kDefaultQuality);



return 0;

}

编译后生成/system/bin/test-screencap

测试时终端输入test-screencap /mnt/sdcard/scapxx.png

可以看到SD卡生成截屏文件scapxx.png，默认大小为屏幕分辨率



如果想把这个功能写到自己的应用里

写个JNI，参考上面代码即可，但记得权限声明



<span style="font-size:24px;"><uses-permission android:name="android.permission.READ_FRAME_BUFFER" /></span>



当然最好是系统级实现，响应某个组合键来截屏，像Android4.0



作者 zmyde2010

http://www.2cto.com/kf/201111/109924.html