Develop Reference

Android mkdirs() doesn't work

I'm trying to generate a folder with my android application in my phone storage (not on the sdcard) but my mkdirs() is not working.
I have set the android.permission.WRITE_EXTERNAL_STORAGE in my manifest and use this basic code :
File mediaStorageDir = new File(Environment.getExternalStorageDirectory(), "/MyDirName");
if (!mediaStorageDir.exists()) {
if (!mediaStorageDir.mkdirs()) {
Log.d("App", "failed to create directory");
}
}
but it doesn't work ... The mkdirs is always at false and the folder is not created.
I have tried everything and looked at all the topics about it but nothing is working and I don't know why.

if you target and compile sdk is higher then lolipop then please refer this link
or
File sourcePath = Environment.getExternalStorageDirectory();
File path = new File(sourcePath + "/" + Constants.DIR_NAME + "/");
path.mkdir();

If you you the emulator and the Device File Explorer of Android Studio, be sure that you right-click over a folder of the emulator and then click on 'synchronize' to update the files displayed. The Device File Explorer doesn't update by itself in real time.

when writing code for android API 29 and above use the following permission in your application manifest (AndroidManifest.xml)
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> <uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE"/>
Then in your java file add the following lines of code
`ActivityCompat.requestPermissions(this, new String[]
{
Manifest.permission.READ_EXTERNAL_STORAGE,
Manifest.permission.WRITE_EXTERNAL_STORAGE
},
PackageManager.PERMISSION_GRANTED);
StrictMode.VmPolicy.Builder builder = new StrictMode.VmPolicy.Builder();
StrictMode.setVmPolicy(builder.build());
file = new File(Environment.getExternalStorageDirectory().getPath(), "MyDirName/");
if (!file.exists()) {
try {
file.mkdirs();
} catch (Exception e) {
e.printStackTrace();
}
}
`

android mkdirs not working

i need to save an image from camera on android.
i used the write external storage permission in manifest and i am using this code
File dir = new File(Environment.getExternalStorageDirectory(), "Test");
if (!dir.exists() || !dir.isDirectory())
dir.mkdirs();
String path = dir.getAbsolutePath();
Log.d(TAG, path); //log show the path
File file = new File(dir.getAbsolutePath() + "/Pic.jpg");
Log.d(TAG, file.getAbsolutePath()); //again path is shown here
outStream = new FileOutputStream(file);
outStream.write(bytes);
outStream.close();
Log.d(TAG, "onPictureTaken - wrote bytes: " + bytes.length); //fail here
} catch (FileNotFoundException e) {
Log.d(TAG, "not done"); //error is here (this exception is thrown)
} catch (IOException e) {
Log.d(TAG, "not");
} finally { }
i also tried mkdir() instead of mkdirs() same result.
any idea what went wrong in the code?
thanks

For those not as experienced like me. I fought this issue, lost hair for some time. I am targeting api 21 (for compatibility sake) and it worked on lollipop but on marshmallow it would not create the directory. I did have the "uses" permission in the manifest but it still would not work. Apparently in Marshmallow when you install with Android studio it never asks you if you should give it permission it just quietly fails, like you denied it. You must go into Settings, apps, select your application and flip the permission switch on.

Some one like me who was trying in Android10. Please use below API in manifest:
<application android:requestLegacyExternalStorage="true" ... >
...
</application>
Latest Update From Google:
After you update your app to target Android 11, the system ignores the requestLegacyExternalStorage flag.

Did you put
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
in your AndroidManifest? If you are using android M you must request user permission to write on sd, look here an example

IDIOT ME! i have used the Manifest Permission but when installed the app on phone i didnt grant permission for storage!... i understand a negative on this question... but i hope if someone else face the same..check your phone permission. sorry all for inconvenience.

you have created directory, not file. Create new file with following code
File file = new File(dir.getAbsolutePath() + "/Pic.jpg");
file.createNewFile()

if you are testing on android M, you should probably check Settings > App > Permission to see if permission to access storage is granted. This saved me.

if you already allowed R/W permission(Runtime Permission too) and still doesn't work add this below mentioned line in your AndroidManifest.xml
<application
........
........
android:requestLegacyExternalStorage="true">
Note: this must required if you'r targeting Android 10+

Starting from API 30 you can only write in your app-specific files
File dir = new File(context.getFilesDir(), "YOUR_DIR");
dir.mkdirs();
or in the external storage of your app Android/data
File dir = new File(myContext.getExternalFilesDir("FolderName"),"YOUR_DIR");
UPDATE
this answer provided another solution https://stackoverflow.com/a/65744517/8195076
UPDATE
another way is to grant this permission in manifest
<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" />
like this answer https://stackoverflow.com/a/66968986/8195076

Try this. Provide runtime permission for marshmallow it is perfectly work in my Application code :
private String getFilename(String strFileName) {
String filepath = Environment.getExternalStorageDirectory().getPath();
File fileBase = new File(filepath, "Test");
if (!fileBase.exists()) {
fileBase.mkdirs();
}
return (file.getAbsolutePath() + "/" + strFileName + file_exts[currentFormat]);
}
new File(getFilename(edt.getText().toString().trim()))

outputFile = new File(apkStorage + "/" + downloadFileName );
//Create Output file in Main File
//Create New File if not present
if (!outputFile.exists()) {
isExternalStorageWritable();
outputFile.getParentFile().mkdirs();
outputFile.createNewFile();
Log.e(TAG, "File Created");
OutputStream fos = new FileOutputStream(outputFile);//Get OutputStream for NewFile Location
InputStream fis = c.getInputStream();//Get InputStream for connection
byte[] buffer = new byte[1024];//Set buffer type
int len1 = 0;//init length
while ((len1 = fis.read(buffer)) >0) {
fos.write(buffer, 0, len1);//Write new file
}
//Close all connection after doing task
fos.close();
fis.close();
I wrote this code for creating a file, but it is not working in android 11

when writing code for android API 29 and above use the following permission in your application manifest (AndroidManifest.xml)
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE"/>
Adjust your code to read like the following
ActivityCompat.requestPermissions(this, new String[]
{
Manifest.permission.READ_EXTERNAL_STORAGE,
Manifest.permission.WRITE_EXTERNAL_STORAGE
},
PackageManager.PERMISSION_GRANTED);
StrictMode.VmPolicy.Builder builder = new StrictMode.VmPolicy.Builder();
StrictMode.setVmPolicy(builder.build());
file = new File(Environment.getExternalStorageDirectory().getPath(), "TestDirectory/Document/");
if (!file.exists()) {
try {
file.mkdirs();
} catch (Exception e) {
e.printStackTrace();
}
}

Unable to write image to Android SD Card (Permission Denied) [duplicate]

The following code which consists of downloading a file from a server and save it in the storage works fine when the device has an internal storage.
But when I tried it with a device with no internal storage, only with external storage I get the following exception.
java.io.filenotfoundexception open failed eacces (permission denied)
public void downloadFile(String dlUrl, String dlName) {
int count;
HttpURLConnection con = null;
InputStream is = null;
FileOutputStream fos = null;
try {
URL url = new URL( dlUrl );
con = (HttpURLConnection) url.openConnection();
con.setDoInput(true);
con.connect();
is = url.openStream();
String dir = Environment.getExternalStorageDirectory() + Util.DL_DIRECTORY;
File file = new File( dir );
if( !file.exists() ){
file.mkdir();
}
Util.LOG_W(TAG, "Downloading: " + dlName + " ...");
fos = new FileOutputStream(file + "/" + dlName);
byte data[] = new byte[1024];
while( (count = is.read(data)) != -1 ){
fos.write(data, 0, count);
}
Util.LOG_D(TAG, dlName + " Download Complete!");
} catch (Exception e) {
Util.LOG_E(TAG, "DOWNLOAD ERROR = " + e.toString() );
bServiceDownloading = false;
}
finally{
try {
if( is != null)
is.close();
if( fos != null)
fos.close();
if( con != null)
con.disconnect();
} catch (Exception e) {
Util.LOG_E(TAG, "CLOSE ERROR = " + e.toString() );
}
}
}
And in manifest file I has the following:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
Any suggestions what maybe the cause?
By the way Environment.getExternalStorageDirectory() returns /mnt/sdcard/ and file.mkdir() return false.

This attribute is "false" by default on apps targeting
Android 10 or higher.
<application android:requestLegacyExternalStorage="true" ... >
...
</application>

This problem seems to be caused by several factors.
Check#1
First add this permission in your manifest file and check if it is working:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<application>
...
</application>
　　.....
Check#2:
If you are running on an emulator, check the properties to see if it has an SD card.
Check#3:
Disable file transfer from device to computer. If Enabled, the app wont be able to access the SD card.
Check#4:
If still not working, try the following:
String dir = Environment.getExternalStorageDirectory().getAbsolutePath()
For me the following worked:
The problem is that getExternalStorageDirectory returns /mnt/sdcard whereas I need the actual path of external storage which is /mnt/sdcard-ext and there is no API in android that can get me the absolute path of removable sdcard.
My solution was to hard code the directory as follows:
String dir = "/mnt/sdcard-ext" ;
Since the application is intended to work only on one device, the above did the job.
If you encounter the same problem, use an file explorer application to find out the name of the external directory and hard code it.

Use READ_EXTERNAL_STORAGE permission to read data from the device.

Did you try it on emulator? Check the properties if it has an SD card. I had the same problem, and it was because the emulator did not have an SD card. Check if yours has or not.

I had the same problem, and i solved it by disabling file transfer from device to computer.
Because if u enable file transfer, sd card is not accessible to debugging application.

try
Environment.getExternalStorageDirectory().getAbsolutePath()
and don't forget to add
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Try using mkdirs instead of mkdir. If you are creating a directory path and parent doesn't exist then you should use mkdirs.

I suspect you are running Android 6.0 Marshmallow (API 23) or later. If this is the case, you must implement runtime permissions before you try to read/write external storage.
https://developer.android.com/training/permissions/requesting.html

i have done very silly mistake.
I have already put in AndroidManifest.xml
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
and also add permission in java file,as get permission pragmatically.
But there is mistake of Manifest.permission.READ_EXTERNAL_STORAGE.
Please use Manifest.permission.WRITE_EXTERNAL_STORAGE.
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, requestCode);

I had the same problem. I used the write and read permission in the manifest correctly , yet it didn't work! The solution was very silly: unplug your phone from the PC before running the application. It seems when your phone is connected as "Mass storage" to the PC, the application cannot access the external storage.

First in your manifest file declare permissions :
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" />
now in header of application tag of manifest file :
android:requestLegacyExternalStorage="true"
now defines provider for your app in between tag of manifest file. as :
<provider
android:name="androidx.core.content.FileProvider"
android:authorities="${applicationId}.provider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="#xml/provider_path" />
</provider>
now create a folder xml in res folder like this :
now create a xml file provider_path.xml and copy below code in it :
<?xml version="1.0" encoding="utf-8"?>
<path>
<external-path
name="external_files"
path="." />
now in your activity :
String filename = null ;
URL url = null;
try {
url = new URL("http://websitename.com/sample.pdf");
filename = url.getPath();
filename = filename.substring(filename.lastIndexOf('/')+1);
} catch (MalformedURLException e) {
e.printStackTrace();
}
File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)+"/"+filename);
if(file.exists()){
Uri uri = FileProvider.getUriForFile(context, "com.example.www"+".provider",file);
Intent i = new Intent(Intent.ACTION_VIEW);
i.setDataAndType(uri, "application/pdf");
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|Intent.FLAG_GRANT_READ_URI_PERMISSION);
context.startActivity(i);
}
else {
//download file here
new AlertDialog.Builder(context)
.setTitle("Information")
.setMessage("Do you want to download this file ?")
.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
})
.setPositiveButton("Continue", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url+""));
request.setTitle(filename);
request.setMimeType("application/pdf");
request.allowScanningByMediaScanner();
request.setAllowedOverMetered(true);
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, filename);
DownloadManager downloadManager = (DownloadManager)context.getSystemService(DOWNLOAD_SERVICE);
downloadManager.enqueue(request);
}
}).show();
}

Android - WRITE_EXTERNAL_STORAGE permission and writing app's log

All I want is to be able to write a log/exception report for my app inside a very specific folder (related to my app) in order to understand failures and exceptions, so this is the code I'm using:
File logFile = new File(Environment.getExternalStorageDirectory() + File.separator + "/appname/log.txt");
if (!logFile.exists()) {
try {
if (logFile.getParentFile().mkdir()) {
if (!logFile.createNewFile())
showPopup(context.getString(R.string.app_name), "error creating log file");
}
} catch (IOException e) {
e.printStackTrace();
}
}
try {
BufferedWriter buf = new BufferedWriter(new FileWriter(logFile, true));
buf.append(text);
buf.newLine();
buf.flush();
buf.close();
} catch (IOException e) {
e.printStackTrace();
}
For the above to work, I have to add the following permissions: android.permission.WRITE_EXTERNAL_STORAGE but when the user reads it, it says both reading and writing the external storage and understandably, this is scaring away the user. Is there a better way to log my app's behavior and use a less scary permission for that?

First, switch from:
File logFile = new File(Environment.getExternalStorageDirectory() + File.separator + "/appname/log.txt");
to:
File logFile = new File(context.getExternalFilesDir(), "log.txt");
Not only does this avoid manual string concatenation when creating your path, and not only does this stop cluttering up the user's external storage with random app-specific directories, but it now means that you can have:
<uses-permission
android:name="android.permission.WRITE_EXTERNAL_STORAGE"
android:maxSdkVersion="18" />
to eliminate WRITE_EXTERNAL_STORAGE on API Level 19+.
Beyond that, try raising your targetSdkVersion to 4 or higher. Quoting the docs for READ_EXTERNAL_STORAGE:
Note: If both your minSdkVersion and targetSdkVersion values are set to 3 or lower, the system implicitly grants your app this permission. If you don't need this permission, be sure your targetSdkVersion is 4 or higher.

Try this:
File storageDir = new File(Environment.getExternalStorageDirectory(), "your folder name");
storageDir.mkdir();
Put this code to your manifest file:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Permission denied when writing into sdCard

I'm trying write a file into SDCard, but I am getting error in logcat:
01-24 09:03:33.647: W/System.err(3353): java.io.FileNotFoundException: /mnt/sdcard/fun/itisfun.txt: open failed: EACCES (Permission denied)
01-24 08:24:28.007: W/System.err(3353): Caused by: libcore.io.ErrnoException: open failed: EACCES (Permission denied)
01-24 09:03:33.756: W/System.err(3353):at libcore.io.Posix.open(Native Method)
And here my code to write into SDCard:
File root = null;
try {
// check for SDcard
root = Environment.getExternalStorageDirectory();
Log.i(TAG,"path.." +root.getAbsolutePath());
//check sdcard permission
if (root.canWrite()){
File fileDir = new File(root.getAbsolutePath()+"/fun/");
fileDir.mkdirs();
File file = new File(fileDir, "itisfun.txt");
FileWriter filewriter = new FileWriter(file);
BufferedWriter out = new BufferedWriter(filewriter);
out.write("I m enjoying......dude");
out.close();
}
} catch(...) {
...
}
Manifest:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<permission android:name="android.permission.INTERNET"></permission>

For writing to the Sdcard you need to give the permission in your manifest file
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

You need to make sure you have the permission #Ram mentions, and the SD Card is mounted. You can check if it is mounted by:-
if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState()))
You should handle an unmounted card gracefully, but a common gotcha is if your phone is plugged in via the USB cable you may have it mounted via your desktop OS, which means it's not mounted by Android.
Thanks,
Ryan

Here's a bit of code I use,
public void yourMethod(){
File root = getDir(getApplicationContext());
try {
File fileDir = new File(root.getAbsolutePath()+"/fun/");
fileDir.mkdirs();
File file = new File(fileDir, "itisfun.txt");
FileWriter filewriter = new FileWriter(file);
BufferedWriter out = new BufferedWriter(filewriter);
out.write("I m enjoying......dude");
out.close();
} catch(...) {
...
}
}
public File getDir(Context context) {
if (android.os.Environment.getExternalStorageState().equals(
android.os.Environment.MEDIA_MOUNTED))
cacheDir = new File(
android.os.Environment.getExternalStorageDirectory(),
DIRECTORY_NAME);
else
cacheDir = context.getCacheDir();
return cacheDir;
}
If there is no external storage, it basically uses the phones internal cache (not good for large files)
Read this

If you're on 4.4, read here: http://www.androidcentral.com/kitkat-sdcard-changes Basically you can no longer read and write anywhere on the drive. You can only write to your private directory and directories you've become the owner of.

Check that your directory fun and the file itisfun.txt exists on the SDcard, if you want to make them by program, you have to add the permission:
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
This permission allows the application to create file or directory, the permission:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> only allows the application to read and write the file that is already exist.
Make sure that your permission is outside of the <application> tag, usually before it.