I have a doubt, how I can delete a folder on Android 11 (or 10)?
Have much answers here on Stack how to do it, but nothing of worked.
This code worked for me on Android 5:
public static boolean deleteDir(File dir) {
if (dir.isDirectory()) {
String[] children = dir.list();
for (int i=0; i<children.length; i++) {
boolean success = deleteDir(new File(dir, children[i]));
if (!success) {
return false;
}
}
}
// The directory is now empty so delete it
return dir.delete();
}
On newest versions of Android it not work. I noticed that there are applications that can to do this, so I imagine it is possible. Any answer about it?
Android has done much to change its permission models around file access since Android 10 and 11. The preferred approach is to use Scoped Storage APIs.
Many of the old file read/write permissions are on life support and will no longer work. If they do continue to work, then must justify to Google why you need them, and then go through a security approval by Google. You will only be granted approval if you app is classified as a file browser application, or the like.
Basically, the new model is to use Android's file browsers to gain access to read/write/update a particular file that the user selects, and defer the rest of the file management to Google's first-party applications. The access you get is based on what the user selected in the first-party file browser. You are then handed a URI back to your application with the proper permissions to perform the intended action, such as read/write/etc...
You may find this video useful:
https://www.youtube.com/watch?v=RjyYCUW-9tY
Have you tried Context.deleteFile() ?
getApplicationContext().deleteFile(filename);
since Enviroment.getExternalStorageDirectory() is deprecated I have a little Problem. I have 2 applications (a lite and a pro version of an app). These apps have a database which I could export and import. When switching from lite to pro app, the user could import the "old" database into the new app. The database was stored under a folder inside his "sdcard". But now on Android 12 devices we no longer have access to that External Storage.
So how could I solve the problem?
Cause I think, context.getExternalFilesDir((Environment.DIRECTORY_DOCUMENTS)
doesn't work cause the namespace of both apps are different. And I guess it will not work to open a file which is not located under the namespace of the app the file is requested.
Yes, sharing the app's shared memory with another one is not possible.
Other options are using a external server / Firbase to create profile for users and store there data in it.
The easiest way is not to have two apps. Make the single app work for both modes, and gate features at runtime based on the type of license. You can even make the upgrade an in app purchase.
I found a solution by myself, but if someone else is looking for a solution it might be helpful.
I ask the user to specify a file location via
Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
intent.addCategory(Intent.CATEGORY_OPENABLE);
intent.setType("application/db");
intent.putExtra(Intent.EXTRA_TITLE, "xyz.db");
mCreateNewDatabaseFile.launch(intent);
then in the mCreateNewDatabaseFile
private final ActivityResultLauncher<Intent> mCreateNewDatabaseFile = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), result -> {
if (result.getResultCode() == RESULT_OK) {
if (result.getData() != null && result.getData().getData() != null) {
Uri path = result.getData().getData();
getContentResolver().takePersistableUriPermission(path, Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
getContentResolver().takePersistableUriPermission(path, Intent.FLAG_GRANT_READ_URI_PERMISSION);
mPreferences.edit().putString(PREF_KEY_DATABASE_EXPORT_PATH, path.toString()).apply();
}
}
});
So even with another process I can read and write the file.
So in the lite Version I can create the db file and in the pro version I can let the user choose this file for import.
I hope it will help others with similar questions.
You can (should) use a ContentProvider to have other apps query your database using accessible methods of your ContentProvider :
you can configure a content provider to allow other applications to
securely access and modify your app data
(this will enforce Single-responsibility principle)
Android 11,
I'm trying to create a publicly accessible folder I can store my media files within, which will contain 1 folder and 1 text file per game type (there could be many), I do not want any other application to have access to the root folder for the exception of file explorers, as the user 'could' have content inside the folder that is R18 restricted or might not, I'm not in control of what content goes in there, it would be nice if I could provide that so that a child doesn't in mistakenly bump into the content while looking for pictures on the device for barnie.
I found some code on GitHub that did just the above on Android 10 and works flawlessly for Android 10, but cannot find anything but blue pills about it when it comes to Android 11, help in the form of example code would be great, yes I know targeting only Android 11 limits me but I'd rather live with the limit than play with many different versions of code.
val intent = Intent(Intent.ACTION_OPEN_DOCUMENT_TREE).apply {
flags = Intent.FLAG_GRANT_READ_URI_PERMISSION or
Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION
}
startActivityForResult(intent, OPEN_FOLDER_REQUEST_CODE)
EDIT 2
After some hacking around, because 'startActivityForResult(Intent!, Int): Unit' is deprecated. Deprecated in Java, I end up with this, results is a URI, can I now use this to pass files to other API calls now?
pref = getSharedPreferences("myPref", Context.MODE_PRIVATE)
var userFolderData: String? = pref.getString("userFolderData", "")
if (userFolderData=="") {
val getUserFolderData =
registerForActivityResult(ActivityResultContracts.OpenDocumentTree()) {
mytools.debug(it.toString())
pref.edit().putString("userFolderData",it.toString()).apply()
userFolderData = it.toString()
}
getUserFolderData.launch("".toUri())
}
mytools.debug("userFolderData = ${userFolderData}")
EDIT 3
So I ran a test on the URI returned; always the same story not matter what I do, yes that's pretty ugly hack but it's the easiest way I can find to test it.
ivtitleimage.setImageURI("content://com.android.externalstorage.documents/document/primary%3ATest%2FMelsDeck%2Fbendover01.jpg".toUri())
31833-31833/com.example.cardgamexxx E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.cardgamexxx, PID: 31833
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.cardgamexxx/com.example.cardgamexxx.MainActivity}: java.lang.SecurityException: Permission Denial: opening provider com.android.externalstorage.ExternalStorageProvider from ProcessRecord{5a390cf 31833:com.example.cardgamexxx/u0a741} (pid=31833, uid=10741) requires that you obtain access using ACTION_OPEN_DOCUMENT or related APIs
EDIT 4
Right, so user selects folder/creates one with registerForActivityResult code above, I place files in it with Cx File Explorer and automagically drum roll! ...
I do not have read access to the file placed there, anyway thought I'd comment here as I don't want people stumbling on the post and thinking this works, because it doesn't.
On an Android 11 device your app can only create folders on root of external storage in the classic way if it has requested 'all files acces'.
Or it can use Storage Access Framework and for instance ACTION_OPEN_DOCUMENT_TREE to let the user create a folder in root of external storage and then select it.
In my application, I need to store lots of images in the device storage. Such files tend to fulfill the device storage, and I want to allow users to be able to choose external SD card as the destination folder.
I read everywhere that Android doesn't allow users to write to external SD card, by SD card I mean the external and mountable SD card and not the external storage, but file manager applications manage to write to External SD on all Android versions.
What is the better way to grant read/write access to external SD card on different API levels (Pre-KitKat, KitKat, Lollipop+)?
Update 1
I tried Method 1 from Doomknight's answer, with no avail:
As you can see I'm checking for permissions at runtime before attempting to write on SD:
HashSet<String> extDirs = getStorageDirectories();
for(String dir: extDirs) {
Log.e("SD",dir);
File f = new File(new File(dir),"TEST.TXT");
try {
if(ActivityCompat.checkSelfPermission(this,Manifest.permission.WRITE_EXTERNAL_STORAGE)==PackageManager.PERMISSION_GRANTED) {
f.createNewFile();
}
} catch (IOException e) {
e.printStackTrace();
}
}
But I get an access error, tried on two different devices: HTC10 and Shield K1.
10-22 14:52:57.329 30280-30280/? E/SD: /mnt/media_rw/F38E-14F8
10-22 14:52:57.329 30280-30280/? W/System.err: java.io.IOException: open failed: EACCES (Permission denied)
10-22 14:52:57.329 30280-30280/? W/System.err: at java.io.File.createNewFile(File.java:939)
10-22 14:52:57.329 30280-30280/? W/System.err: at com.myapp.activities.TestActivity.onResume(TestActivity.java:167)
10-22 14:52:57.329 30280-30280/? W/System.err: at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1326)
10-22 14:52:57.330 30280-30280/? W/System.err: at android.app.Activity.performResume(Activity.java:6338)
10-22 14:52:57.330 30280-30280/? W/System.err: at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3336)
10-22 14:52:57.330 30280-30280/? W/System.err: at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3384)
10-22 14:52:57.330 30280-30280/? W/System.err: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2574)
10-22 14:52:57.330 30280-30280/? W/System.err: at android.app.ActivityThread.access$900(ActivityThread.java:150)
10-22 14:52:57.330 30280-30280/? W/System.err: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1399)
10-22 14:52:57.330 30280-30280/? W/System.err: at android.os.Handler.dispatchMessage(Handler.java:102)
10-22 14:52:57.330 30280-30280/? W/System.err: at android.os.Looper.loop(Looper.java:168)
10-22 14:52:57.330 30280-30280/? W/System.err: at android.app.ActivityThread.main(ActivityThread.java:5885)
10-22 14:52:57.330 30280-30280/? W/System.err: at java.lang.reflect.Method.invoke(Native Method)
10-22 14:52:57.330 30280-30280/? W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:819)
10-22 14:52:57.330 30280-30280/? W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:709)
10-22 14:52:57.330 30280-30280/? W/System.err: Caused by: android.system.ErrnoException: open failed: EACCES (Permission denied)
10-22 14:52:57.330 30280-30280/? W/System.err: at libcore.io.Posix.open(Native Method)
10-22 14:52:57.330 30280-30280/? W/System.err: at libcore.io.BlockGuardOs.open(BlockGuardOs.java:186)
10-22 14:52:57.330 30280-30280/? W/System.err: at java.io.File.createNewFile(File.java:932)
10-22 14:52:57.330 30280-30280/? W/System.err: ... 14 more
Summary
You can grant read/write access to external SD card on the different api levels (API23+ at run time).
Since KitKat, permissions are not necessary if you use app-specific directories, required otherwise.
Universal way:
The history says that there is no universal way to write to external SD card but continues...
This fact is demonstrated by these examples of external storage configurations for devices.
API-based way:
Prior to KitKat try to use Doomsknight method 1, method 2 otherwise.
Request permissions in manifest (Api < 23) and at run time (Api >= 23).
Recommended way:
ContextCompat.getExternalFilesDirs solves the access error when you don't need to share files.
The secure way of sharing it is to use a content provider or the new Storage Access Framework.
Privacy-aware way:
As of Android Q Beta 4, apps that target Android 9 (API level 28) or lower see no change, by default.
Apps targeting Android Q by default (or opting into it) are given a filtered view into external storage.
Initial answer.
Universal way to write to external SD card on Android
There is no universal way to write to external SD card on Android due to continuous changes:
Pre-KitKat: official Android platform has not supported SD cards at all except for exceptions.
KitKat: introduced APIs that let apps access files in app-specific directories on SD cards.
Lollipop: added APIs to allow apps to request access to folders owned by other providers.
Nougat: provided a simplified API to access common external storage directories.
... Android Q privacy change: App-scoped and media-scoped storage
What is the better way to grant read/write access to external SD card
on different API levels
Based on Doomsknight's answer and mine, and Dave Smith and Mark Murphy blog posts: 1, 2, 3:
Ideally, use the Storage Access
Framework
and
DocumentFile
as Jared Rummler pointed. Or:
Use your app specific path/storage/extSdCard/Android/data/com.myapp.example/files.
Add read/write permission to manifest for pre-KitKat, no permission required later for this path.
Try to use your App path and Doomsknight's methods considering KitKat and Samsung case.
Filter and use getStorageDirectories, your App path and read/write permissions prior to KitKat.
ContextCompat.getExternalFilesDirs since KitKat. Considering devices that return internal first.
Updated answer.
Update 1. I tried Method 1 from Doomknight's answer, with no avail:
As you can see I'm checking for permissions at runtime before
attempting to write on SD...
I would use application-specific directories to avoid the issue of your updated question and ContextCompat.getExternalFilesDirs() using getExternalFilesDir documentation as reference.
Improve the heuristics to determine what represents removable media based on the different api levels like android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT
... But I get an access error, tried on two different devices: HTC10
and Shield K1.
Remember that Android 6.0 supports portable storage devices and third-party apps must go through the Storage Access Framework. Your devices HTC10 and Shield K1 are probably API 23.
Your log shows a permission denied exception accessing /mnt/media_rw, like this fix for API 19+:
<permission name="android.permission.WRITE_EXTERNAL_STORAGE" >
<group gid="sdcard_r" />
<group gid="sdcard_rw" />
<group gid="media_rw" /> // this line is added via root in the link to fix it.
</permission>
I never tried it so I can not share code but I would avoid the for trying to write on all the returned directories and look for the best available storage directory to write into based on remaining space.
Perhaps Gizm0's alternative to your getStorageDirectories() method it's a good starting point.
ContextCompat.getExternalFilesDirs solves the issue if you don't need access to other folders.
Android 1.0 .. Pre-KitKat.
Prior to KitKat try to use Doomsknight method 1 or read this response by Gnathonic.
public static HashSet<String> getExternalMounts() {
final HashSet<String> out = new HashSet<String>();
String reg = "(?i).*vold.*(vfat|ntfs|exfat|fat32|ext3|ext4).*rw.*";
String s = "";
try {
final Process process = new ProcessBuilder().command("mount")
.redirectErrorStream(true).start();
process.waitFor();
final InputStream is = process.getInputStream();
final byte[] buffer = new byte[1024];
while (is.read(buffer) != -1) {
s = s + new String(buffer);
}
is.close();
} catch (final Exception e) {
e.printStackTrace();
}
// parse output
final String[] lines = s.split("\n");
for (String line : lines) {
if (!line.toLowerCase(Locale.US).contains("asec")) {
if (line.matches(reg)) {
String[] parts = line.split(" ");
for (String part : parts) {
if (part.startsWith("/"))
if (!part.toLowerCase(Locale.US).contains("vold"))
out.add(part);
}
}
}
}
return out;
}
Add the next code to your AndroidManifest.xml and read Getting access to external storage
Access to external storage is protected by various Android
permissions.
Starting in Android 1.0, write access is protected with
the WRITE_EXTERNAL_STORAGE permission.
Starting in Android 4.1, read
access is protected with the READ_EXTERNAL_STORAGE permission.
In order to ... write files on the external storage, your app must
acquire ... system
permissions:
<manifest ...>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
</manifest>
If you need to both..., you need to request
only the WRITE_EXTERNAL_STORAGE permission.
Read Mark Murphy's explanation and recommended Dianne Hackborn and Dave Smith posts
Until Android 4.4, there was no official support for removable media in Android, Starting in KitKat, the concept of “primary” and “secondary” external storage emerges in the FMW API.
Prior apps are just relying on MediaStore indexing, ship with the hardware or examine mount points and apply some heuristics to determine what represents removable media.
Android 4.4 KitKat introduces the Storage Access Framework (SAF).
Ignore the next note due to bugs, but try to use ContextCompat.getExternalFilesDirs():
Since Android 4.2, there has been a request from Google for device manufacturers to lock down removable media for security (multi-user support) and new tests were added in 4.4.
Since KitKat getExternalFilesDirs() and other methods were added to return a usable path on all available storage volumes (The first
item returned is the primary volume).
The table below indicates what a developer might try to do and how KitKat will respond:
Note: Beginning with Android 4.4, these permissions are not required
if you're reading or writing only files that are private to your app.
For more info..., see saving files that
are app-private.
<manifest ...>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"
android:maxSdkVersion="18" />
</manifest>
Also read Paolo Rovelli's explanation and try to use Jeff Sharkey's solution since KitKat:
In KitKat there's now a public API for interacting with
these secondary shared storage devices.
The new Context.getExternalFilesDirs() and
Context.getExternalCacheDirs() methods can return multiple paths,
including both primary and secondary devices.
You can then iterate
over them and check Environment.getStorageState() and
File.getFreeSpace() to determine the best place to store your files.
These methods are also available on ContextCompat in the support-v4 library.
Starting in Android 4.4, the owner, group and modes of files on
external storage devices are now synthesized based on directory
structure. This enables apps to manage their package-specific
directories on external storage without requiring they hold the broad
WRITE_EXTERNAL_STORAGE permission. For example, the app with package
name com.example.foo can now freely access
Android/data/com.example.foo/ on external storage devices with no
permissions. These synthesized permissions are accomplished by
wrapping raw storage devices in a FUSE daemon.
With KitKat your chances for a "complete solution" without rooting are
pretty much zero:
The Android project has definitely screwed up here.
No apps get full access to external SD cards:
file managers: you cannot use them to manage your external SD card. In
most areas, they can only read but not write.
media apps: you cannot
retag/re-organize your media collection any longer, as those apps
cannot write to it.
office apps: pretty much the same
The only place 3rd party apps are allowed to write on your
external card are "their own directories" (i.e.
/sdcard/Android/data/<package_name_of_the_app>).
The only ways to
really fix that require either the manufacturer (some of them fixed
it, e.g. Huawei with their Kitkat update for the P6) – or root... (Izzy's explanation continues here)
Android 5.0 introduced changes and the DocumentFile helper class.
getStorageState Added in API 19, deprecated in API 21,
use getExternalStorageState(File)
Here's a great tutorial for interacting with the Storage Access
Framework in KitKat.
Interacting with the new APIs in Lollipop is very similar (Jeff Sharkey's explanation).
Android 6.0 Marshmallow introduces a new runtime permissions model.
Request permissions at runtime if API level 23+ and read Requesting Permissions at Run Time
Beginning in Android 6.0 (API level 23), users grant permissions to
apps while the app is running, not when they install the app ... or update the app ... user can revoke the permissions.
// Assume thisActivity is the current activity
int permissionCheck = ContextCompat.checkSelfPermission(thisActivity,
Manifest.permission.WRITE_EXTERNAL_STORAGE);
Android 6.0 introduces a new runtime permissions model where apps
request capabilities when needed at runtime. Because the new model
includes the READ/WRITE_EXTERNAL_STORAGE permissions, the platform
needs to dynamically grant storage access without killing or
restarting already-running apps. It does this by maintaining three
distinct views of all mounted storage devices:
/mnt/runtime/default is shown to apps with no special storage
permissions...
/mnt/runtime/read is shown to apps with
READ_EXTERNAL_STORAGE
/mnt/runtime/write is shown to apps with
WRITE_EXTERNAL_STORAGE
Android 7.0 provides a simplified API to access external storage dirs.
Scoped Directory Access
In Android 7.0, apps can use new APIs to request access to specific
external storage directories, including directories on removable media
such as SD cards...
For more information, see the Scoped Directory Access training.
Read Mark Murphy posts: Be Careful with Scoped Directory Access. It was deprecated in Android Q:
Note that the scoped directory access added in 7.0 is deprecated in
Android Q.
Specifically, the createAccessIntent() method on StorageVolume is
deprecated.
They added a createOpenDocumentTreeIntent() that can be used as an
alternative.
Android 8.0 Oreo .. Android Q Beta changes.
Starting in Android
O, the
Storage Access Framework allows custom documents
providers
to create seekable file descriptors for files residing in a remote
data source...
Permissions,
prior to Android O, if an app requested a permission at runtime and the permission was granted, the system also incorrectly granted
the app the rest of the permissions that belonged to the same
permission group, and that were registered in the manifest.
For apps targeting Android O, this behavior has been corrected. The app is granted only the permissions it has explicitly requested.
However, once the user grants a permission to the app, all subsequent
requests for permissions in that permission group are automatically
granted.
For example, READ_EXTERNAL_STORAGE and WRITE_EXTERNAL_STORAGE...
Update: An Android Q earlier beta release temporarily replaced the READ_EXTERNAL_STORAGE and WRITE_EXTERNAL_STORAGE permissions with more fine-grained, media-specific permissions.
Note: Google introduced roles on Beta 1 and removed them from the documentation before Beta 2...
Note: The permissions specific to media collections that were introduced in earlier beta releases—READ_MEDIA_IMAGES, READ_MEDIA_AUDIO, and READ_MEDIA_VIDEO—are now obsolete. More info:
Q Beta 4 (final APIs) review by Mark Murphy: The Death of External Storage: The End of the Saga(?)
"Death is more universal than life. Everyone dies, but not everyone
lives." ― Andrew Sachs
Related questions and recommended answers.
How can I get external SD card path for Android 4.0+?
mkdir() works while inside internal flash storage, but not SD card?
Diff between getExternalFilesDir and getExternalStorageDirectory()
Why getExternalFilesDirs() doesn't work on some devices?
How to use the new SD card access API presented for Android 5.0 (Lollipop)
Writing to external SD card in Android 5.0 and above
Android SD Card Write Permission using SAF (Storage Access Framework)
SAFFAQ: The Storage Access Framework FAQ
Related bugs and issues.
Bug: On Android 6, when using getExternalFilesDirs, it won't let you create new files in its results
Writing to directory returned by getExternalCacheDir() on Lollipop fails without write permission
I believe there are two methods to achieve this:
METHOD 1: (does NOT work on 6.0 and above, due to permission changes)
I have been using this method for years on many device version with no issue. Credit is due to the original source, as it was not me who wrote it.
It will return all mounted media (including Real SD Cards) in a list of strings directory locations. With the list you can then ask the user where to save, etc.
You can call it with the following:
HashSet<String> extDirs = getStorageDirectories();
Method:
/**
* Returns all the possible SDCard directories
*/
public static HashSet<String> getStorageDirectories() {
final HashSet<String> out = new HashSet<String>();
String reg = "(?i).*vold.*(vfat|ntfs|exfat|fat32|ext3|ext4).*rw.*";
String s = "";
try {
final Process process = new ProcessBuilder().command("mount")
.redirectErrorStream(true).start();
process.waitFor();
final InputStream is = process.getInputStream();
final byte[] buffer = new byte[1024];
while (is.read(buffer) != -1) {
s = s + new String(buffer);
}
is.close();
} catch (final Exception e) {
e.printStackTrace();
}
// parse output
final String[] lines = s.split("\n");
for (String line : lines) {
if (!line.toLowerCase().contains("asec")) {
if (line.matches(reg)) {
String[] parts = line.split(" ");
for (String part : parts) {
if (part.startsWith("/"))
if (!part.toLowerCase().contains("vold"))
out.add(part);
}
}
}
}
return out;
}
METHOD 2:
Use the v4 support library
import android.support.v4.content.ContextCompat;
Just call the following to get a list of File locations of storage.
File[] list = ContextCompat.getExternalFilesDirs(myContext, null);
The locations differ in usage however though.
Returns absolute paths to application-specific directories on all
external storage devices where the application can place persistent files
it owns. These files are internal to the application, and not typically
visible to the user as media.
External storage devices returned here are considered a permanent part of
the device, including both emulated external storage and physical media
slots, such as SD cards in a battery compartment. The returned paths do
not include transient devices, such as USB flash drives.
An application may store data on any or all of the returned devices. For
example, an app may choose to store large files on the device with the
most available space
More Info on ContextCompat
They are like app specific files. Hidden from other apps.
Just another answer. This answer only shows 5.0+ because I believe Doomknight's answer posted here is the best way to do for Android 4.4 and below.
This is originally posted here (Is there a way to get SD Card size in Android?) by me to get the external SD Card's size on Android 5.0+
To get the External SD card as a File:
public File getExternalSdCard() {
File externalStorage = null;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
File storage = new File("/storage");
if(storage.exists()) {
File[] files = storage.listFiles();
for (File file : files) {
if (file.exists()) {
try {
if (Environment.isExternalStorageRemovable(file)) {
externalStorage = file;
break;
}
} catch (Exception e) {
Log.e("TAG", e.toString());
}
}
}
}
} else {
// do one of many old methods
// I believe Doomsknight's method is the best option here
}
return externalStorage;
}
Note: I only get the "first" external sd card however you can modify it and return ArrayList<File> instead of File and let the loop continue instead of calling break after the first one is found.
In addition to all other nice answers, I could add a bit more to this question so it can give wider coverage for readers. In my answer here, I would use 2 countable resources to present External Storage.
The first resource is from Android Programming, The Big Nerd Ranch Guide 2nd edition, chapter 16, page 294.
The book describes the basic and external file and directory methods. I will try to make a resume of what could be relevant to your question.
The following part from the book:
External Storage
Your photo needs more than a place on the screen. Full-size pictures are too large to stick inside a
SQLite database, much less an Intent. They will need a place to live on your device’s filesystem.
Normally, you would put them in your private storage. Recall that you used your private storage
to save your SQLite database. With methods like Context.getFileStreamPath(String) and
Context.getFilesDir(), you can do the same thing with regular files, too (which will live in a
subfolder adjacent to the databases subfolder your SQLite database lives in)
Basic file and directory methods in Context
| Method |
|---------------------------------------------------------------------------------------|
|File getFilesDir() |
| - Returns a handle to the directory for private application files. |
| |
|FileInputStream openFileInput(String name) |
| - Opens an existing file for input (relative to the files directory). |
| |
|FileOutputStream openFileOutput(String name, int mode) |
| - Opens a file for output, possibly creating it (relative to the files directory). |
| |
|File getDir(String name, int mode) |
| - Gets (and possibly creates) a subdirectory within the files directory. |
| |
|String[] fileList() |
| - Gets a list of file names in the main files directory, such as for use with |
| openFileInput(String). |
| |
|File getCacheDir() |
| - Returns a handle to a directory you can use specifically for storing cache files. |
| You should take care to keep this directory tidy and use as little space as possible|
If you are storing files that only your current application needs to use, these methods are exactly what
you need.
On the other hand, if you need another application to write to those files, you are out of luck: while
there is a Context.MODE_WORLD_READABLE flag you can pass in to openFileOutput(String, int), it is
deprecated, and not completely reliable in its effects on newer devices. If you are storing files to share
with other apps or receiving files from other apps (files like stored pictures), you need to store them on
external storage instead.
There are two kinds of external storage: primary, and everything else. All Android devices have at
least one location for external storage: the primary location, which is located in the folder returned by
Environment.getExternalStorageDirectory(). This may be an SD card, but nowadays it is more
commonly integrated into the device itself. Some devices may have additional external storage. That
would fall under “everything else.”
Context provides quite a few methods for getting at external storage, too. These methods provide easy
ways to get at your primary external storage, and kinda-sorta-easy ways to get at everything else. All of
these methods store files in publicly available places, too, so be careful with them.
External file and directory methods in Context
| Method |
| --------------------------------------------------------------------------------------|
|File getExternalCacheDir() |
| - Returns a handle to a cache folder in primary external storage. Treat it like you do|
| getCacheDir(), except a little more carefully. Android is even less likely to clean |
| up this folder than the private storage one. |
| |
|File[] getExternalCacheDirs() |
| - Returns cache folders for multiple external storage locations. |
| |
|File getExternalFilesDir(String) |
| - Returns a handle to a folder on primary external storage in which to store regular |
| files. If you pass in a type String, you can access a specific subfolder dedicated |
| to a particular type of content. Type constants are defined in Environment, where |
| they are prefixed with DIRECTORY_. |
| For example, pictures go in Environment.DIRECTORY_PICTURES. |
| |
|File[] getExternalFilesDirs(String) |
| - Same as getExternalFilesDir(String), but returns all possible file folders for the |
| given type. |
| |
|File[] getExternalMediaDirs() |
| - Returns handles to all the external folders Android makes available for storing |
| media – pictures, movies, and music. What makes this different from calling |
| getExternalFilesDir(Environment.DIRECTORY_PICTURES) is that the media scanner |
| automatically scans this folder. The media scanner makes files available to |
| applications that play music, or browse movies and photos, so anything that you |
| put in a folder returned by getExternalMediaDirs() will automatically appear in |
| those apps. |
Technically, the external folders provided above may not be available, since some devices use a removable SD card for external storage. In practice this is rarely an issue, because almost all modern devices have nonremovable internal storage for their “external” storage. So it is not worth going to extreme lengths to account for it. But we do recommended including simple code to guard against the possibility, which you will do in a moment.
External storage permission
In general, you need a permission to write or read from external storage. Permissions are well-known string values you put in your manifest using the <uses-permission> tag. They tell Android that you want to do something that Android wants you to ask permission for.
Here, Android expects you to ask permission because it wants to enforce some accountability. You tell Android that you need to access external storage, and Android will then tell the user that this is one of the things your application does when they try to install it. That way, nobody is surprised when you start saving things to their SD card.
In Android 4.4, KitKat, they loosened this restriction. Since Context.getExternalFilesDir(String) returns a folder that is specific to your app, it makes sense that you would want to be able to read and write files that live there. So on Android 4.4 (API 19) and up, you do not need this permission for this folder. (But you still need it for other kinds of external storage.)
Add a line to your manifest that requests the permission to read external storage, but only up to API Listing 16.5 Requesting external storage permission (AndroidManifest.xml)
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.bignerdranch.android.criminalintent" >
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"
android:maxSdkVersion="18" />
The maxSdkVersion attribute makes it so that your app only asks for this permission on versions of Android that are older than API 19, Android KitKat.
Note that you are only asking to read external storage. There is also a WRITE_EXTERNAL_STORAGE permission, but you do not need it. You will not be writing anything to external storage: The camera app will do that for you
The second resource is this link read all of it, but you can also jump to Using the External Storage section.
Reference:
Android Storage Options: https://developer.android.com/guide/topics/data/data-storage.html
Book site: https://www.bignerdranch.com/we-write/android-programming
More reading stuff:
https://developer.android.com/reference/android/os/Environment.html#getExternalStoragePublicDirectory%28java.lang.String%29
https://developer.android.com/reference/android/os/Environment.html#DIRECTORY_PICTURES
https://developer.android.com/reference/android/os/Environment.html#DIRECTORY_MOVIES
How can I get external SD card path for Android 4.0+?
Disclaimer: This information was taken from Android Programming: The Big Nerd Ranch Guide with permission from the authors. For more information on this book or to purchase a copy, please visit bignerdranch.com.
This topic is a bit old but I was looking for a solution and after some research I came with the code below to retrieve a list of available "external" mount points that, according to my knowledge, works on many different devices.
Basically, it reads available mount points, filters out invalid ones, tests the rest if they are accessible and adds them if all the conditions are satisfied.
Of course, required permissions must be granted before the code is invoked.
// Notice: FileSystemDevice is just my own wrapper class. Feel free to replace it with your own.
private List<FileSystemDevice> getDevices() {
List<FileSystemDevice> devices = new ArrayList<>();
// Add default external storage if available.
File sdCardFromSystem = null;
switch(Environment.getExternalStorageState()) {
case Environment.MEDIA_MOUNTED:
case Environment.MEDIA_MOUNTED_READ_ONLY:
case Environment.MEDIA_SHARED:
sdCardFromSystem = Environment.getExternalStorageDirectory();
break;
}
if (sdCardFromSystem != null) {
devices.add(new FileSystemDevice(sdCardFromSystem));
}
// Read /proc/mounts and add all mount points that are available
// and are not "special". Also, check if the default external storage
// is not contained inside the mount point.
try {
FileInputStream fs = new FileInputStream("/proc/mounts");
String mounts = IOUtils.toString(fs, "UTF-8");
for(String line : mounts.split("\n")) {
String[] parts = line.split(" ");
// parts[0] - mount type
// parts[1] - mount point
if (parts.length > 1) {
try {
// Skip "special" mount points and mount points that can be accessed
// directly by Android's functions.
if (parts[0].equals("proc")) { continue; }
if (parts[0].equals("rootfs")) { continue; }
if (parts[0].equals("devpts")) { continue; }
if (parts[0].equals("none")) { continue; }
if (parts[0].equals("sysfs")) { continue; }
if (parts[0].equals("selinuxfs")) { continue; }
if (parts[0].equals("debugfs")) { continue; }
if (parts[0].equals("tmpfs")) { continue; }
if (parts[1].equals(Environment.getRootDirectory().getAbsolutePath())) { continue; }
if (parts[1].equals(Environment.getDataDirectory().getAbsolutePath())) { continue; }
if (parts[1].equals(Environment.getExternalStorageDirectory().getAbsolutePath())) { continue; }
// Verify that the mount point is accessible by listing its content.
File file = new File(parts[1]);
if (file.listFiles() != null) {
try {
// Get canonical path for case it's just symlink to another mount point.
String devPath = file.getCanonicalPath();
for(FileSystemDevice device : devices) {
if (!devices.contains(devPath)) {
devices.add(new FileSystemDevice(new File(devPath)));
}
}
} catch (Exception e) {
// Silently skip the exception as it can only occur if the mount point is not valid.
e.printStackTrace();
}
}
} catch (Exception e) {
// Silently skip the exception as it can only occur if the mount point is not valid.
e.printStackTrace();
}
}
}
fs.close();
} catch (FileNotFoundException e) {
// Silently skip the exception as it can only occur if the /proc/mounts file is unavailable.
// Possibly, another detection method can be called here.
e.printStackTrace();
} catch (IOException e) {
// Silently skip the exception as it can only occur if the /proc/mounts file is unavailable.
// Possibly, another detection method can be called here.
e.printStackTrace();
}
return devices;
}
Here is a way of creating a new file in the External Storage (SDCard if present in the device or device External Storage if not). Just replace "foldername" with the name of your desired destination folder and "filename" with the name of the file you are saving. Of course here you can see how to save a generic File, now you can search for how to save images maybe here or whatever in a file.
try {
File dir = new File(Environment.getExternalStorageDirectory() + "/foldername/");
if (!dir.exists()){
dir.mkdirs();
}
File sdCardFile = new File(Environment.getExternalStorageDirectory() + "/foldername/" + fileName );
int num = 1;
String fileNameAux = fileName;
while (sdCardFile.exists()){
fileNameAux = fileName+"_"+num;
sdCardFile = new File(Environment.getExternalStorageDirectory() + "/foldername/" + fileNameAux);
num++;
}
This also controls that file exists and adds a number in the end of the name of the new file to save it.
Hope it helps!
EDIT: Sorry, i forgot you have to ask for <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> in your manifest
(or programatically if you prefer from Marshmallow)
For versions below Marshmallow you can directly give the permissions in the manifest.
But for devices with Marshmallow and above you need to grant the permissions on run time.
By using
Environment.getExternalStorageDirectory();
you can directly access the External SD card (Mounted one)
Hope this helps.
I'm trying get some licensing code from AndroidPit.com working, but I get "Unable to start service Intent". Basically my code looks like this:
Intent licenseIntent = new Intent("de.androidpit.app.services.ILicenseService");
if (mContext.bindService(licenseIntent, this, Context.BIND_AUTO_CREATE))
{
// success
}
else
{
// failure (I get this all the time(
}
I tried passing ILicenseService class explicitly:
Intent licenseIntent = new Intent(mContext, de.androidpit.app.services.ILicenseService.class);
but I still get the same problem.
I managed to get Android Market LVL library working which uses identical code, so I don't really understand why it fails to find "de.androidpit.app.services.ILicenseService", but manages to find "com.android.vending.licensing.ILicensingService".
Most of the answers I found here say that you need to append stuff to your AndroidManifest.xml, but you don't anything for "com.android.vending.licensing.ILicensingService" to work, so I guess I shouldn't need anything "de.androidpit.app.services.ILicenseService" (they both derive from android.os.IInterface).
Thanks in advance.
Most of the answers I found here say that you need to append stuff to your AndroidManifest.xml
Those answers are correct.
but you don't anything for "com.android.vending.licensing.ILicensingService" to work
That is because com.android.vending.licensing.ILicensingService is a remote service, one that is not in your project, but rather in the firmware of the device.
so I guess I shouldn't need anything "de.androidpit.app.services.ILicenseService" (they both derive from android.os.IInterface).
That is flawed reasoning. By your argument, java.util.HashMap does not go in the manifest, and both java.util.HashMap and any implementation of Activity all derive from Object, so therefore you do not need to put your activities in the manifest. If you try this, you will quickly discover that your activities no longer work.
If it is a component (activity, service, content provider, or some implementations of BroadcastReceiver), and the implementation of the component is in your project (directly, via a JAR, via a library project, etc.), you must have an entry in the manifest for it.
Wherever you got the service from should provide you with instructions for adding the service to your manifest, and they should also supply you with instructions for creating the Intent used to bind to it. If they do not provide this documentation, perhaps you should reconsider your use of this product.
The solution in my case was to start a server part on my phone (AppCenter from AndroidPit.com in this case). No entries in AndroidManifest are necessary for the client application.