目录环境能力接口（ohos.file.environment）提供获取公共目录路径的能力，支持三方应用在公共文件用户目录下进行文件访问操作。
约束限制
使用此方式，需确认设备具有以下系统能力：SystemCapability.FileManagement.File.Environment.FolderObtain，当前支持2in1设备。
从API版本26.0.0开始，支持tablet设备。
if (!canIUse('SystemCapability.FileManagement.File.Environment.FolderObtain')) {
console.error('this api is not supported on this device');
return;
} 获取公共目录路径。
import { BusinessError } from '@kit.BasicServicesKit';
import { Environment } from '@kit.CoreFileKit'; function getUserDirExample() {
try {
const downloadPath = Environment.getUserDownloadDir();
console.info(`Succeeded in getting user download dir: ${downloadPath}`);
const documentsPath = Environment.getUserDocumentDir();
console.info(`Succeeded in getting user document dir: ${documentsPath}`);
} catch (error) {
const err: BusinessError = error as BusinessError;
console.error(`Failed to get user dir. Code: ${err.code}, message: ${err.message}`);
}
} 以Download目录为例，访问Download目录下的文件。
import { BusinessError } from '@kit.BasicServicesKit';
import { Environment } from '@kit.CoreFileKit';
import { fileIo } from '@kit.CoreFileKit';
import { common } from '@kit.AbilityKit';
// 请在组件内获取context，确保this.getUIContext().getHostContext()返回结果为UIAbilityContext
let context = this.getUIContext().getHostContext() as common.UIAbilityContext; function readUserDownloadDirExample(context: common.UIAbilityContext) {
try {
// 获取 Download 目录
const downloadPath = Environment.getUserDownloadDir();
console.info(`Succeeded in getting user download dir: ${downloadPath}`);
const dirPath = context.filesDir;
// 查看 Download 目录下的文件并拷贝到沙箱目录中
let fileList: string[] = fileIo.listFileSync(downloadPath);
fileList.forEach((file, index) => {
console.info(`${downloadPath} ${index}: ${file}`);
if (fileIo.statSync(`${downloadPath}/${file}`).isFile()) {
fileIo.copyFileSync(`${downloadPath}/${file}`, `${dirPath}/${file}`);
}
});
// 查看沙箱目录下对应的文件
fileList = fileIo.listFileSync(dirPath);
fileList.forEach((file, index) => {
console.info(`Succeeded in listing file, ${dirPath} ${index}: ${file}`);
});
} catch (error) {
const err: BusinessError = error as BusinessError;
console.error(`Failed to read user download dir. Code: ${err.code}, message: ${err.message}`);
}
} 以Download目录为例，保存文件到Download目录。
import { BusinessError } from '@kit.BasicServicesKit';
import { Environment } from '@kit.CoreFileKit';
import { fileIo } from '@kit.CoreFileKit'; function writeUserDownloadDirExample() {
// 检查是否具有 READ_WRITE_DOWNLOAD_DIRECTORY 权限，无权限则需要向用户申请授予权限。
try {
// 获取 Download 目录
const downloadPath = Environment.getUserDownloadDir();
console.info(`Succeeded in getting user download dir: ${downloadPath}`);
// 保存 temp.txt 到 Download 目录下
const file = fileIo.openSync(`${downloadPath}/temp.txt`, fileIo.OpenMode.CREATE | fileIo.OpenMode.READ_WRITE);
fileIo.writeSync(file.fd, 'write a message');
fileIo.closeSync(file);
} catch (error) {
const err: BusinessError = error as BusinessError;
console.error(`Failed to write user download dir. Code: ${err.code}, message: ${err.message}`);
}
} 除了通过ArkTS访问公共目录的方式，也可通过C/C++接口进行目录访问，具体可以参考 oh_environment.h。
约束限制
接口的详细说明，请参考oh_environment.h。
| 接口名称 | 描述 |
|---|---|
| FileManagement_ErrCode OH_Environment_GetUserDownloadDir (char **result) | 获取用户Download目录沙箱路径。支持2in1设备。 从API版本26.0.0开始，支持tablet设备 |
| FileManagement_ErrCode OH_Environment_GetUserDesktopDir (char **result) | 获取用户Desktop目录沙箱路径。支持2in1设备。 从API版本26.0.0开始，支持tablet设备 |
| FileManagement_ErrCode OH_Environment_GetUserDocumentDir (char **result) | 获取用户Document目录沙箱路径。支持2in1设备。 从API版本26.0.0开始，支持tablet设备 |
在CMake脚本中链接动态库
CMakeLists.txt中添加以下lib。
target_link_libraries(sample PUBLIC libohenvironment.so libhilog_ndk.z.so)
添加头文件
#include <filemanagement/environment/oh_environment.h> #include <filemanagement/fileio/oh_fileio.h> #include <hilog/log.h>
调用OH_Environment_GetUserDownloadDir接口获取用户Download目录沙箱路径，在接口中使用malloc申请的内存需要在使用完后释放因此需要free对应的内存。示例代码如下所示：
#include <cstdlib>
void GetUserDownloadDirExample()
{
char *downloadPath = nullptr;
FileManagement_ErrCode ret = OH_Environment_GetUserDownloadDir(&downloadPath);
if (ret == 0) {
OH_LOG_INFO(LOG_APP, "Succeeded in getting user download directory, download path=%{public}s", downloadPath);
} else {
OH_LOG_ERROR(LOG_APP, "Failed to get download path, error code is %{public}d", ret);
}
free(downloadPath);
} 调用OH_Environment_GetUserDownloadDir接口获取用户Download目录沙箱路径，并查看Download目录下的文件。示例代码如下所示：
#include <cstdlib> #include <dirent.h>
void ScanUserDownloadDirPathExample()
{
// 获取 download 路径
char *downloadPath = nullptr;
FileManagement_ErrCode ret = OH_Environment_GetUserDownloadDir(&downloadPath);
if (ret == 0) {
OH_LOG_INFO(LOG_APP, "Succeeded in scanning user download directory, path=%{public}s", downloadPath);
} else {
OH_LOG_ERROR(LOG_APP, "Failed to get download path, error code is %{public}d", ret);
return;
}
// 查看文件夹下的文件
struct dirent **namelist = nullptr;
int num = scandir(downloadPath, &namelist, nullptr, nullptr);
if (num < 0) {
free(downloadPath);
OH_LOG_ERROR(LOG_APP, "Failed to scan directory");
return;
}
for (int i = 0; i < num; i++) {
OH_LOG_INFO(LOG_APP, "Succeeded in scanning directory, file name is %{public}s", namelist[i]->d_name);
}
free(downloadPath);
for (int i = 0; i < num; i++) {
free(namelist[i]);
}
free(namelist);
} 调用OH_Environment_GetUserDownloadDir接口获取用户Download目录沙箱路径，并保存temp.txt到Download目录下。示例代码如下所示：
#include <fstream>
void WriteUserDownloadDirPathExample()
{
// 获取 download 路径
char *downloadPath = nullptr;
FileManagement_ErrCode ret = OH_Environment_GetUserDownloadDir(&downloadPath);
if (ret == 0) {
OH_LOG_INFO(LOG_APP, "Succeeded in getting user download directory, path=%{public}s", downloadPath);
} else {
OH_LOG_ERROR(LOG_APP, "Failed to get download path, error code is %{public}d", ret);
return;
}
// 保存文件到 download 目录下
std::string filePath = std::string(downloadPath) + "/temp.txt";
free(downloadPath);
std::ofstream outfile;
outfile.open(filePath.c_str());
if (!outfile) {
OH_LOG_ERROR(LOG_APP, "Failed to open file");
return;
}
std::string msg = "Write a message";
outfile.write(msg.c_str(), msg.size());
outfile.close();
}