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
<uses-permission android:name="android.permission.READ_FRAME_BUFFER" />
贴出JNI代码，或资源下载地址:http://download.****.net/detail/zmyde2010/3835127
jni/com_android_ScreenCap_ScreenCapNative.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.
*/
#define LOG_TAG "ScreenCapNative-JNI"
//#define LOG_NDEBUG 0
#include "JNIHelp.h"
#include "jni.h"
#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>
namespace android {
static void android_ScreenCap_ScreenCapNative_nativeCaptureScreen(JNIEnv* env,
jobject obj, jstring file)
{
const char *file_path = env->GetStringUTFChars(file, NULL);
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) {
LOGE("screen capture failed: %s\n", strerror(-err));
exit(0);
}
LOGD("screen capture success: w=%u, h=%u, pixels=%p\n",
w, h, heap->getBase());
LOGD("saving file as PNG in %s ...\n", file_path);
SkBitmap b;
b.setConfig(SkBitmap::kARGB_8888_Config, w, h);
b.setPixels(heap->getBase());
SkImageEncoder::EncodeFile(file_path, b,
SkImageEncoder::kPNG_Type, SkImageEncoder::kDefaultQuality);
}
static JNINativeMethod gScreenCapNativeMethods[] = {
/* name, signature, funcPtr */
{ "nativeCaptureScreen", "(Ljava/lang/String;)V",
(void*) android_ScreenCap_ScreenCapNative_nativeCaptureScreen },
};
int register_android_ScreenCap_ScreenCapNative(JNIEnv* env) {
int res = jniRegisterNativeMethods(env, "com/android/ScreenCap/ScreenCapNative",
gScreenCapNativeMethods, NELEM(gScreenCapNativeMethods));
LOG_FATAL_IF(res < 0, "Unable to register native methods.");
return 0;
}
extern "C" jint JNI_OnLoad(JavaVM* vm, void* reserved)
{
JNIEnv* env = NULL;
jint result = -1;
if (vm->GetEnv((void**) &env, JNI_VERSION_1_4) != JNI_OK) {
LOGE("GetEnv failed!");
return result;
}
LOG_ASSERT(env, "Could not retrieve the env!");
register_android_ScreenCap_ScreenCapNative(env);
return JNI_VERSION_1_4;
}
} /* namespace android */
jni/Android.mk
LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)
LOCAL_SRC_FILES := com_android_ScreenCap_ScreenCapNative.cpp
LOCAL_C_INCLUDES += \
$(JNI_H_INCLUDE)
LOCAL_SHARED_LIBRARIES := \
libnativehelper \
libcutils \
libutils \
libbinder \
libskia \
libui \
libsurfaceflinger_client
LOCAL_C_INCLUDES += \
external/skia/include/core \
external/skia/include/effects \
external/skia/include/images \
external/skia/src/ports \
external/skia/include/utils
LOCAL_MODULE:= libscreencapjni
LOCAL_MODULE_TAGS := optional
LOCAL_PRELINK_MODULE := false
include $(BUILD_SHARED_LIBRARY)
看到有人问Java怎么调用JNI，贴出例子:
src/com/android/ScreenCap/ScreenCapNative.java
/*
[email protected] */
package com.android.ScreenCap;
import java.io.File;
import android.os.Environment;
public class ScreenCapNative {
static {
System.loadLibrary("screencapjni");
};
private native static void nativeCaptureScreen(String file);
public static String startCaptureScreen() {
String file_name = getUniqueFileName();
if (file_name != null) {
nativeCaptureScreen(file_name);
}
return file_name;
}
private static String getUniqueFileName() {
File file = null;
if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
file = createUniqueFile(Environment.getExternalStorageDirectory(),
"ScreenCap.PNG");
} else if (Environment.getInternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
file = createUniqueFile(Environment.getInternalStorageDirectory(),
"ScreenCap.PNG");
}
return (file != null) ? file.getAbsolutePath() : null;
}
private static File createUniqueFile(File directory, String filename) {
File file = new File(directory, filename);
if (!file.exists()) {
return file;
}
// Get the extension of the file, if any.
int index = filename.lastIndexOf('.');
String format;
if (index != -1) {
String name = filename.substring(0, index);
String extension = filename.substring(index);
format = name + "-%d" + extension;
}
else {
format = filename + "-%d.PNG";
}
for (int i = 2; i < Integer.MAX_VALUE; i++) {
file = new File(directory, String.format(format, i));
if (!file.exists()) {
return file;
}
}
return null;
}
}
可以在你的Acitvity或Service里面调用ScreenCapNative.startCaptureScreen();来截屏
4.0源码已经公布了，大家不要花时间研究2.3的截屏了
当然最好是系统级实现，响应某个组合键来截屏，像Android4.0
发两张截图:
我上传了全部源码，包括编译后的APK,so，稍后请到我的资源里面下载:
http://download.****.net/detail/zmyde2010/3911916
例子中截屏作为一个开机启动的后台service，在需要截屏的任何地方(系统servic或其他APK)，发送
Intent "com.android.CAPTURE_SCREEN" 即可
我的测试版本是2.3.4，其它不保证能用
