Android: how to capture screen in gingerbread (screenshot in 2.3)

The sample code is as follows:

Frameworks \ base \ Services \ surfaceflinger \ tests \ 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;}

Compile and generate/system/bin/test-screencap

Enter test-screencap/mnt/sdcard/scapxx.png

You can see scapxx.png. The default size is the screen resolution.

If you want to write this function to your own application

Write a JNI file. Refer to the code above, but remember the permission statement.

<uses-permission android:name="android.permission.READ_FRAME_BUFFER" />

Post the JNI code, or resource: http://download.csdn.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.cppLOCAL_C_INCLUDES += \$(JNI_H_INCLUDE)LOCAL_SHARED_LIBRARIES := \libnativehelper \libcutils \libutils \libbinder \libskia \    libui \    libsurfaceflinger_clientLOCAL_C_INCLUDES += \external/skia/include/core \external/skia/include/effects \external/skia/include/images \external/skia/src/ports \external/skia/include/utilsLOCAL_MODULE:= libscreencapjniLOCAL_MODULE_TAGS := optionalLOCAL_PRELINK_MODULE := falseinclude $(BUILD_SHARED_LIBRARY)    

Someone asked Java how to call JNI and posted an example:

Src/COM/Android/screencap/screencapnative. Java

/* zmyde2010@csdn */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;    }  }

You can call screencapnative. startcapturescreen (); In Your acitaskor service to take screenshots.

The 4.0 source code has been published, so don't take the time to study the 2.3 screenshots.

Of course, it is best to implement it at the system level and respond to a combination of keys for screenshots, such as android4.0.

Send two images:

I uploaded all the source code, including the compiled APK and so. Please download it from my resources later:

Http://download.csdn.net/detail/zmyde2010/3911916

In this example, the screenshot is used as a background service for startup. It is sent wherever the screenshot is needed (system servic or other APK ).
Intent "com. Android. capture_screen"

My test version is 2.3.4. Other versions cannot be used.