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