Develop Reference

Nothing Happening when trying to write to file on SD card android

I am using the following code to write to an SD card:
File dir =new File(android.os.Environment.getExternalStorageDirectory(),"MyFolder");
if(!dir.exists())
{
dir.mkdirs();
}
String filename= "MyDoople.txt";
try
{
File f = new File(dir+File.separator+filename);
FileOutputStream fOut = new FileOutputStream(f);
OutputStreamWriter myOutWriter = new OutputStreamWriter(
fOut);
myOutWriter.append("Mytest");
myOutWriter.close();
fOut.close();
Toast.makeText(getBaseContext(),
"Text Updated",
Toast.LENGTH_SHORT).show();
}
catch(Exception e)
{
e.printStackTrace();
}
However when I run my app, and then go check in the SD card, there is nothing there. Why am I not seeing the file that I created? I am using android jellybean 4.1 and have added the write permissions in the manifest file.

From your code, you're writing to the folder "MyFolder" under primary external storage.
What is the device you are using? Does it have interal storage in additional to sd card? If yes, then your file is written to the internal storage, but not the sd card.
Edit:
To access SD Card, you simply replace android.os.Environment.getExternalStorageDirectory() with the sd card path.
It is not an easy task to find the path of SD card.
One method is to use ContextCompat.getExternalFilesDirs(context, null), the first element of the returned value would be the same android.os.Environment.getExternalStorageDirectory(), the second element would be somewhere of the sdcard.
However, could be depending on your android version, the directory returned could be a sub-directory on the sd card, i.e. your application specific directory instead of the root of SD card. You have to check and manually change it if you want to find the root directory.
http://developer.android.com/reference/android/support/v4/content/ContextCompat.html#getExternalFilesDirs%28android.content.Context,%20java.lang.String%29

I can't write to the external SD card(extSdCard) in Android Studio

I have created an android app that needs to create a folder and write text files on my external SD card(extSdCard). I am using the Galaxy S4 device and have written the following codes for that. I already know the path of /mnt/.. file and have created a string for it. The android manifest.xml file uses the permission.i have checked the codes in "adb logcat" in Cmd prompt and it does not give any error but doesn't create any folder. The device has also been checked unconnected with the PC. Would appreciate if you help me. Here is the code.
String externalFilePath="/mnt/extSdCard/tmp";
Log.d(TAG, "externalFilePath is: "+externalFilePath);
File myfile = new File(externalFilePath, "Hello");

First of all make sure that you have this line inside your manifest,xml, somewhere outside application tag.
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
Then you can write a File doing this :
File sdcard = Environment.getExternalStorageDirectory();
File dir = new File(sdcard.getAbsolutePath() + "/tmp/");
// creates if doesn't exists
dir.mkdir();
// create a File
File file = new File(dir, "Example.txt");
FileOutputStream os = outStream = new FileOutputStream(file);
//this is the text that will be inside of the Example.txt
String data = "Hello world";
os.write(data.getBytes());
os.close();
Hope it helps :)

try this code to generate files under your application package
File path = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
// Replace DIRECTORY_PICTURES with your needs
File file = new File(path, "Hello");
Also make sure you have added the permissions

Outputting a txt file to a folder in internal memory in android

I am in need to create a text file where the input is taken from the user.
I am trying to save the txt file in a folder(folder should be created even if it is not there)
My code is as follows,
FileOutputStream fileos = null;
if (FreeMemory() != 0) {
FileOutputStream fos=null;
try {
File path=new File(getFilesDir(),"sri");
if(!path.exists()){
path.mkdir();
}
File mypath=new File(path,"myfile.txt");
if (!mypath.exists()) {
fos = new FileOutputStream( mypath);
String text="Write Hii";
fos.write(text.getBytes());
fos.close();
}
}catch(Exception e){
}
}
The "path" variable gives this path: "/data/data/com.example.gm/files/sri"
I navigated to this path in my device: Android-->Data-->com.example.gm-->files-->
but the folder "sri" is not created and even the file also. Am I navigating to th ecorrect path ? I am not able to find out the file in the device.
I searched for the folder by installing "Astro File Manager" app too. But, couldn't find it. I am not getting any Exception when writing to the folder. The code must be correct. But where is the folder and file? Please anyone help me in solving this.
I want to save the txt file in internal memory of my device.
Whats wrong with my code? Please suggest me the solution.
I have gone through many trails and finally approached stackoverflow.
Thanks for any help!!

The data in the internal storage is not accessible out side the application owning it, so any third party application like file browser or Astro File Manager will not be able to see the files. The application with root access will only be able to access the files in the internal memory. I believe you should programmatically verify if the file is created. getFilesDir() will give the internal memory location allocated to that app.

Have you give the permission in manifiest file
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

Android creating text file

I want to create/write new files on the device.
I am able to create file on sd card of the android device.
But in case if device is not having sd card then where should i create file which can be accessible from the ddms.
I tried to create it in /data/data/com.abc.app/files/ directory, But i don't have permissions to access this directory from the ddms to save the file on pc.
Which is the best location create new file on the device which can be access from ddms and application.

Try use cache dir local and external.
Here is a part of my code
File dir = context.getExternalCacheDir() != null ?
context.getExternalCacheDir() : context.getCacheDir();
File file = new File(dir, ".cachefile");//hidden
if (file.exists())
file.delete();
FileOutputStream out = new FileOutputStream(file);
//..
out.flush();
out.close();
Don't forget to have permissions read/write;
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

you have the permission to write/read in/from that folder through your applicatin. You have to use the pair openFileInput/openFileOutput
here the doc per openFileInput/openFileOutput

File creation in SD card not working

I am trying to create a file and store it in SD Card to be used as an input for some processing for an apps.
After searching for a while, I got this code which can create a file in SD card.But after running this,I couldn't see any file created in my SD card. Can anyone please help me what I am missing here.
BufferedWriter out = new BufferedWriter(new FileWriter(FileDescriptor.err));
try {
File root = Environment.getExternalStorageDirectory();
if (root.canWrite()) {
File perffile = new File(root, "samplefile.txt");
FileWriter perfwriter = new FileWriter(perffile, true);
out = new BufferedWriter(perfwriter);
}
} catch (IOException e) {
Log.e(TAG, "-Could not write file " + e.getMessage());
return;
}

If you want to add a file or folder or move application into your SD Card just do the following:
steps:
1) Open your Android application's source code file with a text or programming editor.
2) Browse to the location in the source code where you wish to call the function that writes a file to the device's external storage.
3) Insert this single line of code to check for the SD card:
File sdCard = Environment.getExternalStorageDirectory();
4) Insert these lines of code to set the directory and file name:
File dir = new File (sdcard.getAbsolutePath() + "/folder1/folder2");
dir.mkdirs();
File file = new File(dir, "example_file");
// The mkdirs funtion will create the directory folder for you, use it only you want to create a new one.
5) Replace "/folder1/folder2" in the above code with the actual path where you intend to save the file. This should be a location in which you normally save your application files. Also, change the "example_file" value to the actual file name you wish to use.
6) Insert the following line of code to output the file to the SD card:
FileOutputStream f = new FileOutputStream(file);
Finally step 7:
Save the file, then compile it and test the application using the Android emulator software or the device.
This will works!!! ;-)