Develop Reference

Create a file folder for app

The below code doesn't create a folder in my device.
String intStorageDirectory = context.getFilesDir().toString();
File folder = new File(intStorageDirectory, "test");
folder.createNewFile();;
I need a folder created for my app to store media, when user installs it. That folder should be visible on file explorer. How can i do it?

With the current snippet you created a file, you can also create folder by creating file but your current directory is the base folder, getFilesDir() points internal storage for your app which not visible nor accessible unless explicitly declared. You can create a folder and file by creating with new File().createNewFile() or create only folder using mkdirs() but you won't be able to display it using a file explorer app and that folder and files inside it will be deleted when/if user uninstalls your app.
To save files externally(This doesn't mean saving to SD Card) you can create directory and file with
File mediaStorageDir = new File(Environment.getExternalStorageDirectory(), folderName);
if (!mediaStorageDir.exists()) {
mediaStorageDir.mkdirs()
}
File mediaFile = new File(mediaStorageDir.getAbsolutePath() + File.separator + fileName);
And you need some kind of OutputStream to write data to that file.
Make sure that you ask <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> inside your AndroidManifest.xml file and ask write permission on runtime if your android:targetSdkVersion="23" or above

new File(context.getFielsDir(), "test").mkdirs();
createNewFile creates a file, not a folder. Using mkdirs instead of mkdir ensures that all parents exist. There's also no reason to go through a string when you already have a File.

Adding folder.mkdirs(); should work in place of folder.createNewFile(); And don't forget to add the permissions.
This will create a folder in you data directory.
And just a suggestion , if you want to store media in a SD card folder maybe Environment.getExternalStorageDirectory() is good.

create visible folder sdcard, Android

I'm developping an application where I need to create new folders/files in the sdcard. The thing is I can see them using a root explorer but not with the default one which comes with Android.
I've taken a look at several similar questions here but don't seem to work for me.
For sure, I'm using in my manifest this:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
and I'm writing all the Files using:
String path = Environment.getExternalStorageDirectory() + "/FolderName/FileName.format"
but as I said, these new folders/files remained hidden and can only be seen using a root explorer. Neither the folder nor file name starts with "."
Thanks in advance.

Try using mkDirs()
File dir = new File(fullPath);
if (!dir.exists()) {
dir.mkdirs();
}

creating folder in android emulator

I am developing an android application. I need to create a folder in the internal memory, but when I try to create the folder I get the error below. I am running in an emulator.
mkdir failed for /mnt/New Folder , read only file system
I have tried many paths, but still the error persists. The only folder that I am able to create is called "cache", but I cannot browse it by my file chooser activity.
Any idea where is the suitable place to create folders without any permissions?

You can achieve it by this from a Context object (like Activity).
File files_folder = getFilesDir();
File files_child = new File(files_folder, "files_child");
files_child.mkdirs();
File created_folder = getDir("custom", MODE_PRIVATE);
File f1_child = new File(created_folder, "custom_child");
f1_child.mkdirs();
The function
getFilesDir()
will get the folder data/data/yourpackagename/files in internal memory. And the function
getDir("custom", MODE_PRIVATE)
will create a folder name app_custom in your app internal folder.
Answered by Minhtdh

I guess what you call internal memory is atualy the external memory (which can be open by
file chooser activity, the real internal memory only can be open if you have rooted)
If that true, you should chek those belows:
- first, you will need the write storeage permission in Manisfest
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
- then you should use `
String path =
Environment.getExternalStorageDirectory().getAbsolutePath() +
"/yourfoldername"
`
than
mnt/yourfoldername
at last you should use mkdirs to create folder than mkdir

how to hide images from android gallery

One part of my current project is downloading images from URL then saving to SDCard. But the problem is all of saved images in sdcard is displayed in android gallery page. What I want is "I don't want all of my saved images in android gallery."

Add ".nomedia" file. Did not work? Try the second option.
Save your files to a folder that starts with ".", e.g., /sdcard/.myimages/

You can create .nomedia file using this code:
String NOMEDIA=".nomedia";
File Folder = new File(Environment.getExternalStorageDirectory() + "/mydir");
if(Folder.mkdir()) {
nomediaFile = new File(Environment.getExternalStorageDirectory() + "/mydir/"+ NOMEDIA);
if(!nomediaFile.exists()){
nomediaFile.createNewFile();
}
}

I found a simple way(I think so).
Create a folder in 'Android' folder(where data & obb folders are present) and put your media(pics,videos, etc.,) in the folder you've created.
Gallery app ignores that 'Android' folder. Simple :-)

its so late and i know other answers are complete but i think putting .nomedia file makes all pictures in that particular folder hidden :
just change extension of image file programmatically and this way gallery cant detect it as an image . eg if your image is "pic1.jpg" rename it to "pic1.aaa";
and when you want show it again rename it again

Make picture available only for my Android application

I have an application which has loads of pictures. The total picture is saved in an SD card due to large number of picture. The main problem is that the pictures are available in gallery. I want a way to hide the picture from the gallery but must be available for my application.
I did put " . " in front of the file name to make it hidden
but the images were not displayed in may application also!
Anyone.. help.. please
thanks..

Gallery handles all media files it knows about, so if you want it to stay away of your assets you got two solutions. First, add .nomedia file to the folder with your images, and Gallery should skip it (most image viewers would honor .nomedia, yet there's no guarantee). Other solution is to use some own, proprietary file format, so Gallery or other tools won't be able to process it. I'd recomment .nomedia if that's sufficient solution.

Add .nomedia file into the image folder. The important thing is that, the folder should be empty, when you add .nomedia file. If the folder contains some images before adding '.nomedia' file, the gallery will not hide those images, and it will hide the images added after '.nomedia' file. So The first file added to the image folder should be '.nomedia'.
Hope dis will help you
Thankx,

This line of code can add the .nomedia file in your directory and makes your images hidden from the gallery
String NOMEDIA=" .nomedia";
File Folder = new File(Environment.getExternalStorageDirectory() + "/mydir");
if(Folder.mkdir()) {
nomediaFile = new File(Environment.getExternalStorageDirectory() + "/mydir/"+ NOMEDIA);
if(!nomediaFile.exists()){
nomediaFile.createNewFile();
}
}

i think the place where you save the images matter, try to save them into application cache directory, or files directory.
you can get access to cache directory using : getCacheDir() in your activity.
and your files directory: getFilesDir()
these two directories must not be visible or accessible to any other applications expect your application,

I used assets to accomplish this in my app.