android - 如何在SD卡上自动创建目录

我正在尝试将文件保存到以下位置

directory and sub-directory但是我得到了例外java.io.FileNotFoundException

但是，当我把路径作为"/sdcard/"时，它的工作原理。

现在我假设我无法以这种方式自动创建目录。

有人可以建议如何使用代码创建directory and sub-directory吗？

15个解决方案

433 votes

如果您创建一个包装顶级目录的File对象，您可以调用它的mkdirs()方法来构建所有需要的目录。 就像是：

// create a File object for the parent directory

File wallpaperDirectory = new File("/sdcard/Wallpaper/");

// have the object build the directory structure, if needed.

wallpaperDirectory.mkdirs();

// create a File object for the output file

File outputFile = new File(wallpaperDirectory, filename);

// now attach the OutputStream to the file object, instead of a String representation

FileOutputStream fos = new FileOutputStream(outputFile);

注意：使用Environment.getExternalStorageDirectory()来获取“SD卡”目录可能是明智之举，因为如果手机出现了除SD卡以外的其他东西(例如内置闪存，则可能会更改) 苹果手机)。 无论哪种方式，您都应该记住，您需要检查以确保它实际存在，因为可能会移除SD卡。

更新：自API级别4(1.6)起，您还必须请求许可。 这样的事情(在清单中)应该有效：

Jeremy Logan answered 2019-04-03T13:02:01Z

57 votes

有同样的问题，只想添加AndroidManifest.xml也需要此权限：

Daniel answered 2019-04-03T13:02:34Z

39 votes

这对我有用。

uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"

在你的清单和下面的代码中

public static boolean createDirIfNotExists(String path) {

boolean ret = true;

File file = new File(Environment.getExternalStorageDirectory(), path);

if (!file.exists()) {

if (!file.mkdirs()) {

Log.e("TravellerLog :: ", "Problem creating Image folder");

ret = false;

}

}

return ret;

}

Vijay Kumar A B answered 2019-04-03T13:03:14Z

22 votes

实际上我使用了部分@fiXedd的答案，它对我有用：

//Create Folder

File folder = new File(Environment.getExternalStorageDirectory().toString()+"/Aqeel/Images");

folder.mkdirs();

//Save the path as a string value

String extStorageDirectory = folder.toString();

//Create New file and name it Image2.PNG

File file = new File(extStorageDirectory, "Image2.PNG");

确保使用mkdirs()而不是mkdir()来创建完整路径

Amt87 answered 2019-04-03T13:03:55Z

12 votes

使用API 8及更高版本，SD卡的位置已更改。 @ fiXedd的答案很好，但是为了更安全的代码，你应该使用Environment.getExternalStorageState()来检查媒体是否可用。 然后，您可以使用getExternalFilesDir()导航到所需的目录(假设您使用的是API 8或更高版本)。

您可以在SDK文档中内容。

Nick Ruiz answered 2019-04-03T13:04:34Z

8 votes

确保存在外部存储：[http://developer.android.com/guide/topics/data/data-storage.html#filesExternal]

private boolean isExternalStoragePresent() {

boolean mExternalStorageAvailable = false;

boolean mExternalStorageWriteable = false;

String state = Environment.getExternalStorageState();

if (Environment.MEDIA_MOUNTED.equals(state)) {

// We can read and write the media

mExternalStorageAvailable = mExternalStorageWriteable = true;

} else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {

// We can only read the media

mExternalStorageAvailable = true;

mExternalStorageWriteable = false;

} else {

// Something else is wrong. It may be one of many other states, but

// all we need

// to know is we can neither read nor write

mExternalStorageAvailable = mExternalStorageWriteable = false;

}

if (!((mExternalStorageAvailable) && (mExternalStorageWriteable))) {

Toast.makeText(context, "SD card not present", Toast.LENGTH_LONG)

.show();

}

return (mExternalStorageAvailable) && (mExternalStorageWriteable);

}

Parth mehta answered 2019-04-03T13:05:02Z

6 votes

我遇到了同样的问题。 Android中有两种类型的权限：

危险(访问联系人，写入外部存储...)

正常(Android会自动批准普通权限，而Android用户需要批准危险权限。)

以下是在Android 6.0中获取危险权限的策略

检查您是否已获得许可

如果您的应用已获得许可，请继续正常运行。

如果您的应用尚未获得许可，请要求用户批准

在onRequestPermissionsResult中收听用户批准

这是我的情况：我需要写入外部存储。

首先，我检查一下我是否有权限：

...

private static final int REQUEST_WRITE_STORAGE = 112;

...

boolean hasPermission = (ContextCompat.checkSelfPermission(activity,

Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED);

if (!hasPermission) {

ActivityCompat.requestPermissions(parentActivity,

new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},

REQUEST_WRITE_STORAGE);

}

然后检查用户的批准：

@Override

public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {

super.onRequestPermissionsResult(requestCode, permissions, grantResults);

switch (requestCode)

{

case REQUEST_WRITE_STORAGE: {

if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)

{

//reload my activity with permission granted or use the features what required the permission

} else

{

Toast.makeText(parentActivity, "The app was not allowed to write to your storage. Hence, it cannot function properly. Please consider granting it this permission", Toast.LENGTH_LONG).show();

}

}

}

}

Syed Abdul Basit answered 2019-04-03T13:06:51Z

5 votes

我遇到了同样的问题，无法在Galaxy S上创建目录，但能够在Nexus和Samsung Droid上成功创建目录。 我如何修复它是通过添加以下代码行：

File dir = new File(Environment.getExternalStorageDirectory().getPath()+"/"+getPackageName()+"/");

dir.mkdirs();

Garima Srivastava answered 2019-04-03T13:07:18Z

5 votes

不要忘记确保文件/文件夹名称中没有特殊字符。 当我使用变量设置文件夹名称时，用“：”发生在我身上

不允许文件/文件夹名称中的字符

“* /：＆lt;＆gt;？\ |

你可能会发现这个代码在这种情况下很有帮助。

下面的代码删除所有“：”并用“ - ”替换它们

//actualFileName = "qwerty:asdfg:zxcvb" say...

String[] tempFileNames;

String tempFileName ="";

String delimiter = ":";

tempFileNames = actualFileName.split(delimiter);

tempFileName = tempFileNames[0];

for (int j = 1; j < tempFileNames.length; j++){

tempFileName = tempFileName+" - "+tempFileNames[j];

}

File file = new File(Environment.getExternalStorageDirectory(), "/MyApp/"+ tempFileName+ "/");

if (!file.exists()) {

if (!file.mkdirs()) {

Log.e("TravellerLog :: ", "Problem creating Image folder");

}

}

Praveen answered 2019-04-03T13:08:18Z

5 votes

File sdcard = Environment.getExternalStorageDirectory();

File f=new File(sdcard+"/dor");

f.mkdir();

这将在你的SD卡中创建一个名为dor的文件夹。然后获取eg- filename.json的文件，手动插入dor文件夹。 喜欢：

File file1 = new File(sdcard,"/dor/fitness.json");

.......

.....

＆LT; uses-permission android：name =“android.permission.WRITE_EXTERNAL_STORAGE”/＆gt;

并且不要忘记在清单中添加代码

jayant singh answered 2019-04-03T13:09:03Z

4 votes

//Create File object for Parent Directory

File wallpaperDir = new File(Environment.getExternalStorageDirectory().getAbsoluteFile() +File.separator + "wallpaper");

if (!wallpaperDir.exists()) {

wallpaperDir.mkdir();

}

File out = new File(wallpaperDir, wallpaperfile);

FileOutputStream outputStream = new FileOutputStream(out);

vikseln answered 2019-04-03T13:09:22Z

3 votes

刚刚完成Vijay的帖子......

表现

uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"

功能

public static boolean createDirIfNotExists(String path) {

boolean ret = true;

File file = new File(Environment.getExternalStorageDirectory(), path);

if (!file.exists()) {

if (!file.mkdirs()) {

Log.e("TravellerLog :: ", "Problem creating Image folder");

ret = false;

}

}

return ret;

}

用法

createDirIfNotExists("mydir/"); //Create a directory sdcard/mydir

createDirIfNotExists("mydir/myfile") //Create a directory and a file in sdcard/mydir/myfile.txt

你可以检查错误

if(createDirIfNotExists("mydir/")){

//Directory Created Success

}

else{

//Error

}

Ismael Di Vita answered 2019-04-03T13:10:05Z

3 votes

这将使sdcard中的文件夹具有您提供的文件夹名称。

File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/Folder name");

if (!file.exists()) {

file.mkdirs();

}

Shweta Chauhan answered 2019-04-03T13:10:34Z

1 votes

您可以使用/ sdcard /而不是Environment.getExternalStorageDirectory()

private static String DB_PATH = "/sdcard/Android/data/com.myawesomeapp.app/";

File dbdir = new File(DB_PATH);

dbdir.mkdirs();

Peter Drinnan answered 2019-04-03T13:11:05Z

1 votes

ivmage.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

Intent i = new Intent(

Intent.ACTION_PICK,

android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

startActivityForResult(i, RESULT_LOAD_IMAGE_ADD);

}

});`

Vishnu Namboodiri answered 2019-04-03T13:11:27Z