Can't read file from external storage on emulator - android

I'm trying to load a file from Environment.getExternalStorageDirectory() into a SoundPool. The file exists, but still I get
E/SoundPool: error loading /storage/emulated/0/dialpad/sounds/mamacita_us/one.mp3
when I try to load it. On a real device it works perfectly, from the exact same path.
This is the code I'm using to load the file:
if( isExternalStorageReadable() ){
String externalStorageAbsolutePath = Environment.getExternalStorageDirectory().getAbsolutePath();
String soundFilesPath = (new File(externalStorageAbsolutePath, "dialpad/sounds/mamacita_us")).getPath();
Log.d("DEBUG", (new File(soundFilesPath, "one.mp3")).getAbsolutePath() );
Log.d("DEBUG", (new File(soundFilesPath, "one.mp3")).exists() ? "EXISTS" : "DOES NOT EXSIST");
sounds.put("1", soundPool.load((new File(soundFilesPath, "one.mp3")).getAbsolutePath(), 1));
sounds.put("2", soundPool.load( (new File(soundFilesPath, "two.mp3")).getPath(), 1 ));
}
isExternalStorageReadable() is a helper method:
public boolean isExternalStorageReadable() {
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state) ||
Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
return true;
}
return false;
}
The LogCat outputs say
D/DEBUG: /storage/emulated/0/dialpad/sounds/mamacita_us/one.mp3
D/DEBUG: EXISTS
I had an idea that perhaps it was a file permission issue, but I don't know... ls -l in adb shell gives me
-rw-rw---- root sdcard_rw 18288 2009-07-06 13:42 one.mp3
-rw-rw---- root sdcard_rw 21422 2009-07-06 13:44 two.mp3
Have tried changing the permissions using chmod but they never change. I've used adb push to push the files to the emulator.
Anyone have any idea how to solve this? As I said it's working perfectly on a real device for the same path, so it seems to be an issue with the Genymotion emulator and/or file system. The emulator is running Android 6.0 (API23).
Oh, and yes I'm declaring
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
in my manifest.

READ_EXTERNAL_STORAGE is considered a"dangerous permission" under the new runtime permissions model introduced in Android 6.0.
You will need to request permission to access the external storage.
Your device is probably running an Android version <6.0 so it will work on that without requesting permission.
http://developer.android.com/guide/topics/security/permissions.html#normal-dangerous

Related

Android : Create a file in /data/local/tmp from an automated test

Goal:
Taking a screenshot during an automated test on a device. Pull the screenshot file using adb once the test is done.
Context:
I'm currently trying to write automated tests to take snapshots of the device screen. Using UiDevice to navigate, I would like to take a screenshot in the middle of a test. UiDevice has a method takeScreenshot that I call when I would like to take a snapshot.
After some investigation, I realised that the class responsible to write the image into file UiAutomatorBridge catches an Exception :
java.io.FileNotFoundException:
/data/local/tmp/screenshots/screen2.png: open failed: EACCES
(Permission denied)
Using adb, I created the file and set all permissions to all users.
adb shell touch /data/local/tmp/screenshots/screen1.png
adb shell chmod 777 /data/local/tmp/screenshots
Once done, I can take a screenshot with :
#Test
public void takeSnapShot() {
String filename = "/data/local/tmp/screenshots/screen1.png";
File file = new File(filename);
assertEquals(true, mDevice.takeScreenshot(file));
}
Problem :
I would like to be able to create a file directly while the test is executing, without the need of using adb.
I tried to create a file directly from Java using createNewFile.
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
But I get an IOException
java.io.IOException: open failed: EACCES (Permission denied)
Has anyone an idea of what is going on ? I'm quite new to Linux, so don't hesitate to suggest something even if it seems obvious to you ;)
Should I post this on superuser instead ?
EDIT
The directory /data has these permissions
drwxrwx--x system system 2016-01-14 14:03 data
I can't list the content of /data, which makes me believe the user "shell" doesn't belong to the group "system". I can't list the content of /data/local neither.
However, the /data/local/tmp is owned by "shell".
drwxrwx--x shell shell 2016-01-14 12:20 . (tmp)
/data/local/tmp gives +x permission to all users.
Finally, the directory "screenshots" belongs to shell with permissions 777.
drwxrwxrwx shell shell 2016-01-14 11:46 screenshots
To my understanding, any user should be able to access /data/local/tmp/screenshots
Instead of saving under /data/local/tmp/, use Environment.getExternalStorageDirectory().
You need a read/write permission to do that. You have to add these two lines into the Manifest of the application ! (I tried to add those lines into the /androidTest/Manifest.xml file, but it has no effects).
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
While it solves the problem of finding a common directory to save/read screenshots, it brings a new one as well.
Having to add these 2 permissions isn't a big deal if you already had them. But if you don't want to ask the user for those permissions, you have to add/remove these lines every time you test/sign your application, which is far from ideal.
EDIT :
In this post, someone proposed to make use of the build differentials (debug, release) to have two different Manifests.
In the end, I have 3 Manifests :
Release Manifest (without external read/write permissions)
Debug Manifest (with external read/write permissions)
AndroidTest Manifest for
tools:overrideLibrary="android.support.test.uiautomator.v18"

Why there are two sdcards location in my emulator?

My Android version is 4.4, and i created a emulator with the 50 MB Size
After start the emulator and i run the adb shell command.
Found ther is a sdcard dir below the /whic permission is lrwxrwxrwx
But there is another sdcard dir below the /storage/ which permission is drwxrwx--x, are those two dirs are the same one?If so, why those two dirs have different permission?
whic sdcard path will be return when i run the below sentence?I wish it will return the /sdcard, but actually the value is /storage/sdcard.
SDPATH = Environment.getExternalStorageDirectory() + "/";
It is easy to find whether those two directories are actually point to the same space. Right?
Assume they are, then it is very possible to see different permissions, because symbolic link does not inherit permission. It is normally 777 as modified by the umask setting.

vold.fstab file in Android 4.3

I want to get the external and internal storage in my app. I'm using this code
Scanner scanner = new Scanner(new File("/etc/vold.fstab"));
while (scanner.hasNext()) {
String line = scanner.nextLine();
if (line.toLowerCase().contains("dev_mount")) {
if (line.toLowerCase().contains("nonremovable")) {
VoldMounts.put(line.split(" ")[2],true);
}else {
VoldMounts.put(line.split(" ")[2],false);
}
}
}
It's working fine on Android 4.2.2 and below, but on Android 4.3 the file is changed to /fstab.<device> and this file needs root access. How can I read the fstab without the need of root access? I don't want to use /proc/mount.
Thanks.
Here is some official information that confirms that "for Android releases 4.3 and later, the various fstab files used by init, vold and recovery were unified in the /fstab. file". As that file has -rw-r----- root root permissions there is no way to read it from an app on a non-rooted device.

Nexus 4 not showing files via MTP

I'm trying to simply write a simple XML file to the SD card and I noticed that my Nexus 4 does write the file, but it is not viewable via the MTP protocol using Windows 7.
code:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
CustomerQueryRqType customerQueryRequest = new CustomerQueryRqType();
Serializer serializer = new Persister();
File myFile = new File(Environment.getExternalStorageDirectory() + "/customerQueryRequest.xml");
try {
boolean created = myFile.createNewFile();
serializer.write(customerQueryRequest, myFile);
} catch (Exception e) {
e.printStackTrace();
}
}
I can see the file on the phone itself with Astro File Manager:
but Windows doesn't see it...:
adb shell on the directory shows:
ls -l
drwxrwxr-x root sdcard_rw 1970-01-16 20:51 Alarms
drwxrwxr-x root sdcard_rw 1970-01-16 20:51 Android
drwxrwxr-x root sdcard_rw 2012-11-21 19:30 DCIM
drwxrwxr-x root sdcard_rw 1970-01-16 20:51 Download
drwxrwxr-x root sdcard_rw 1970-01-16 20:51 Movies
drwxrwxr-x root sdcard_rw 1970-01-16 20:51 Music
drwxrwxr-x root sdcard_rw 1970-01-16 20:51 Notifications
drwxrwxr-x root sdcard_rw 2012-11-19 12:06 Pictures
drwxrwxr-x root sdcard_rw 1970-01-16 20:51 Podcasts
drwxrwxr-x root sdcard_rw 2012-11-19 13:22 Ringtones
drwxrwxr-x root sdcard_rw 2012-11-19 14:33 bluetooth
-rw-rw-r-- root sdcard_rw 79 2012-12-05 22:26 customerQueryRequest.xml
drwxrwxr-x root sdcard_rw 2012-11-20 02:50 data
-rw-rw-r-- root sdcard_rw 11394 2012-11-19 13:54 eightpen_custom_gestures
drwxrwxr-x root sdcard_rw 2012-11-19 13:17 media
What's going on with my Nexus 4? Why is it hiding my things from Windows?
Seems to be a known issue affecting Android USB file access over MTP. The MTP cache gets out of date until a reboot of the phone.
A workaround is:
Clear the "Media Storage" app's data
Use the SDrescan or the SD Scanner (also works on Android 4.4/5, available on F-Droid) app to force an update
Or just avoid using USB at all. The issue does not affect other methods of accessing the files. For example, try AirDroid to transfer files.
Note: This doesn't work for Android 5.0.2: After clearing "Media Storage" and using an SD Rescanner, the folders appears in Windows 7 as unopenable 4K files. The only solution at that point is to clear once again Media Storage and restart the device
You can use the following code after file close
MediaScannerConnection.scanFile(this, new String[] { file.getAbsolutePath() }, null, null);
Source:
https://code.google.com/p/android/issues/detail?id=38282
After spending hours on this issue I solved like this:
private void rescanFolder(String dest) {
// Scan files only (not folders);
File[] files = new File(dest).listFiles(new FileFilter() {
#Override
public boolean accept(File pathname) {
return pathname.isFile();
}
});
String[] paths = new String[files.length];
for (int co=0; co< files.length; co++)
paths[co] = files[co].getAbsolutePath();
MediaScannerConnection.scanFile(activity, paths, null, null);
// and now recursively scan subfolders
files = new File(dest).listFiles(new FileFilter() {
#Override
public boolean accept(File pathname) {
return pathname.isDirectory();
}
});
for (int co=0; co<files.length; co++)
rescanFolder(files[co].getAbsolutePath());
}
The thing is that you have to scan files only (not folders) and then repeat recursively for each fubfolder
EDIT
In addition, if you don't want pictures to be added to your photo album (but just your contents to appear over mtp protocol), remember to place an empty .nomedia file in your folder before rescanning it, like this:
new File(myFolder + File.separator + ".nomedia").createNewFile();
rescanFolder(myFolder);
The best workaround I found to the bug mentioned in the accepted answer is to copy data from Android OS to a another machine/server (Linux, MacOS, windows) using SSH.
Make sure that the device (Android) and the machine (where you want to copy the data) are reachable per IP or host name, for example by connecting them to the same wifi network.
Optional and recommended
Connect the android device using USB tethering. This ensures fast speed because of the wired connection and guarantees that both IP addresses are visible to each other because both are in the same network.
In the Android device
Install an SSH server. SSHelper worked like a charm
Run the SSHelper and go to the configuration tab to get the IP address, port, and password. In the example below, they are 192.168.1.5, 2222 and 'admin'.
The default password is admin but if you decide to change it hit the button "Restart server with new values" after changing it
In the machine
Install rsync. If happen to use Ubuntu it is already installed by default.
Open a shell and type the following command. Change the IP address and port to your values
rsync -avzhP --inplace --info=progress2 -e 'ssh -p 2222' 192.168.1.5:/storage/emulated/0/DCIM/Camera/ /home/username/path/to/pics/
you will get the following prompt, enter your password
SSHelper Version 8.5 Copyright 2014, P. Lutus
Default password is "admin" (recommend: change it)
username#192.168.1.5's password: admin
receiving incremental file list
The other suggestions did not work for me:
Using USB storage mode instead of MTP is not supported by the device (as many other newer devices).
There was no option in my OS (Android 6.0.1) to clear the "Media Storage" app data.
Other methods of sharing files over the network had their draw backs. FTP does not ensure the files integrity. If the connection is dropped it either overwrites or skips all files, so one of the files might be incomplete. Other protocols might be hard to install and other apps might use proprietary protocols.
On Xperia Z below code worked just fine:
String screenShotFile = "....";
activity.sendBroadcast(new Intent(
Intent.ACTION_MEDIA_MOUNTED, Uri
.fromFile(screenShotFile)));
for 4.4+ use:
activity.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE,
Uri.fromFile(screenShotFile)));
(unfortunalelly I dont remember if I have tested it well enough)
http://commonsware.com/blog/2013/11/06/android-4p4-permission-regressions.html
notice /storage/emulated. Android 4.2 has some funky emulated per-app/user access stuff going on, for example a separate /sdcard/ for each user. Try moving the file to /sdcard/ instead of the emulated sdcard that is shown.
The simple code proposed to question How can I refresh MediaStore on Android? does the necessary update of MediaStore, if called after I put a file on external storage. Content on my Nexus 4 is refreshed instantly in Window 7 file explorer.
I needed to create a directory and copy some sample files for my app. After a lot of experiments and research the following procedure worked flawlessly for me:
1) Created directory using File.mkdir().
2) Copied files in directory and run MediaScanner on each file.
MediaScannerConnection.scanFile(context, new String[]{file.getAbsolutePath()}, null, null);
3) Run MediaScanner on directory.
MediaScannerConnection.scanFile(context, new String[]{directory.getAbsolutePath()}, null, null);
Result: The files and directory appear instantaneously on PC over MTP.
Had a similar issue with my OneplusOne:
After software update (to 6.0.1) i was not able to see my camera pictures when connecting to the computer (PTP and MTP). Both app's SDRescan and SDscanner had no effect.
My solution was to copy all pictures from DCIM to another folder using terminal or any file Explorer app on the Phone. When connecting to computer i was able to see the copied files.. i moved them to my computer and cleared my camera folder. No permanent solution but it fixed the problem for me at least until i do the next backup. =D
The above answers are fine for creating the file. If you later delete the file and want that change to be reflected as well, you can do one of the following; let's first cover two solutions that seem like they work, but will cause problems on some devices. The first one is to scan the deleted file:
context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(file)));
This works on many devices for deleted files, but on some devices it'll actually cause a new 0-byte file to be created, which probably isn't what you want. In that case, if you're running on < 4.4 KitKat, you can do this:
context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri.fromFile(folder)));
Where folder is equal to file.getParentFile(). Unfortunately, on KitKat 4.4 and above, this will cause a SecurityException to get thrown, so for those devices, you can try deleting directly from the Media Store:
final Uri externalFilesUri = Files.getContentUri("external");
context.getContentResolver().delete(externalFilesUri, Files.FileColumns.DATA + "=?", new String[] {file.getAbsolutePath()});
I've tested this one as a workaround for ACTION_MEDIA_MOUNTED not working on KitKat, and it works in my testing on the Nexus 5.
Recently I faced with the same problem but some additional research helped find hidden files. It seems that Google has made some changes in storage structure. All these files were moved to another folder This Computer\HTC One\Internal Storage\storage\emulated\0. But it's strange that not all files were moved.
Android 4.4.2
From the documentation here, you need to call MediaScannerConnection.scanFile :
// Tell the media scanner about the new file so that it is
// immediately available to the user.
MediaScannerConnection.scanFile(this,
new String[] { file.toString() }, null,
new MediaScannerConnection.OnScanCompletedListener() {
public void onScanCompleted(String path, Uri uri) {
Log.i("ExternalStorage", "Scanned " + path + ":");
Log.i("ExternalStorage", "-> uri=" + uri);
}
});

Change file permission in application

I try to change file permission in application. Code is below:
Runtime.getRuntime().exec("chmod 777 /sdcard/test.txt");
This code NOT works in my application, but no error log.
I also checked the shell tools under /system/bin, find chmod is under /system/bin, but some other info shown that chmod > toolbox. I am not clear about this. My application has used android:sharedUserId="android.uid.system".
How to run this code or how to change permission of file? Thanks a lot.
Runtime rt = Runtime.getRuntime();
Process proc;
try {
proc = rt.exec(new String[] { "su", "-c", "chmod 777 " + Constants.filename });
proc.waitFor();
} catch (Exception e){ //DOSTUFFS }
This should do the trick
You've used the path /sdcard/ in your test -- is your SD Card formatted with a filesystem that supports standard Unix permissions? (FAT does not.)
You did not give an explicit path to chmod(1) in your string -- are you certain that chmod(1) is:
available on your device
available with your current PATH environment variable setting?
You can only change the permissions on files you own; are you certain that whatever your application's effective userid is owns the file on the SD card?
Lastly, Android may have additional security restrictions on changing file permissions. I don't know Android well, but perhaps changing file permission bits requires entries in the manifest declaring the operations, perhaps changing file permissions can only be done through provided APIs.

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