看到有一个网站分享代码片段，想起自己以前就曾经有过这样的收集代码片段的设想，到用的时候随时复制粘贴^_^。就在这里收集吧
C++文件操作
#include <stdio.h>
#include <error.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#include <stdint.h>
int main()
{
const char *filename = "test/testfile";
FILE *fp = fopen(filename, "wb");
if (!fp){
printf("Open file %s fail, error code %d, error message: %s\n",
filename, errno, strerror(errno));
return -1;
}
fwrite("hello world", 10, 1, fp);
fclose(fp);
return 0;
}
常用code
#include <stdio.h>
perror("message");
fflush(stdout);
printf("%ld\n", ftell(fp));
fseek(fp, 2, SEEK_SET);
#include <unstd.h>
int main(int argc, char *argv[])
{
int ch;
while((ch = getopt(argc,argv,"s:pj:"))!= -1)
{
//putchar(ch);
//printf("\n");
//fflush(stdout);
switch(ch)
{
case 's':
printf("option s:'%s'\n",optarg);
/*handle code*/
break;
case 'p':
/*handle code*/
break;
case 'j':
printf("option s:'%s'\n",optarg);
/*handle code*/
break;
default:
printf("other option: %c\n", ch);
}
}
}
String8 tpath;
tpath = tpath.format("/data/");
camera memory monitor
#!/system/bin/sh
i=0
times=150
echo "camera memory usage" >/tmp/tmp.txt
while [ $i -le $times ]
do
echo "#"$i
adb shell cat /proc/meminfo |grep -w "MemFree\|Cached\|IonInUse" |tee -a /tmp/tmp.txt
adb shell dumpsys meminfo com.android.camera2 |grep -w "Pss\|TOTAL\|MEMINFO\|Applications" |tee -a /tmp/tmp.txt
adb shell dumpsys meminfo cameraserver |grep -w "Pss\|TOTAL\|MEMINFO\|Applications" |tee -a /tmp/tmp.txt
sleep 10s
let "i++"
done
capture script
#!/system/bin/sh
filename=`date +%Y%m%d-%H%M%S`
filename=capture_${filename}
date>/data/${filename}
i=0
while true
do
i=$((i+1))
input keyevent 27
echo "capture $i" >> /data/${filename}
sleep 6
done
Android Mutex
#include <utils/Mutex.h>
Mutex mTest;
void func()
{
Mutex::Autolock l(mTest);
}
void another_func()
{
status_t ret = mTest.tryLock();
if(ret != OK){//func is still running
ret = mTest.timedLock(2000000000/*2s*/);
}//wait for 2s
...
if(ret == OK){
mTest.unlock()
}
...
}
Android property
#include <cutils/log.h>
#include <cutils/properties.h>
char path[PROPERTY_VALUE_MAX];
property_get("test.cam.device", path, "/data/test");
char value[PROPERTY_VALUE_MAX];
property_get("xxxx.media.camera", value, "0");
if (atoi(value)) {
ALOGD("The value is %d", value);
}
if (property_get_bool("debug.test.cam", 0))
ALOGE("Is true");
ALOGI("cdb: %d %s %s", __LINE__, __func__, __FILE__);
ALOGE("cdb: %d %s %s", __LINE__, __func__, __FILE__);
ALOGW("cdb: %d %s %s", __LINE__, __func__, __FILE__);
Android.mk
include $(call all-subdir-makefiles)
######
LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)
LOCAL_SRC_FILES:= cameratest.cpp
LOCAL_SHARED_LIBRARIES := \
libcutils \
libutils \
libbinder \
libui \
libcamera_client \
libcamera_metadata \
libgui
LOCAL_C_INCLUDES += \
$(TOP)/system/media/camera/include \
LOCAL_MODULE:= cameratest
include $(BUILD_EXECUTABLE)
######
$(warning Message_to_show $(YY))
######
include $(BUILD_SHARED_LIBRARY)