Develop Reference

Create CSV or TXT file in app and save it to 'download' folder - Android

I searched and tried a lot before asking this.
But all the code that I'm trying is not working.
I want the file to be stored in the download folder and be accessible from the user also if he uninstalls the app.
I also tried using opencsv library. Could you provide a tested way to create a csv or txt file and store to download folder?

Save to to publicDir(Downloads folder) you first need permission.WRITE_EXTERNAL_STORAGE
check docs
Note this won't work without permmissions
private void saveData(){
String csv_data = "";/// your csv data as string;
File root = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
//if you want to create a sub-dir
root = new File(root, "SubDir");
root.mkdir();
// select the name for your file
root = new File(root , "my_csv.csv");
try {
FileOutputStream fout = new FileOutputStream(root);
fout.write(csv_data.getBytes());
fout.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
boolean bool = false;
try {
// try to create the file
bool = root.createNewFile();
} catch (IOException ex) {
ex.printStackTrace();
}
if (bool){
// call the method again
saveData()
}else {
throw new IllegalStateException("Failed to create image file");
}
} catch (IOException e) {
e.printStackTrace();
}
}

How to delete a file from internal memory before replacing it

I would like to delete an internal file at runtime. When I download from an external server, the old version of the file (with the same name) is replaced, however I am unable to read it. I think that I need to delete the previous file before downloading the new version. Here is an example of what I have tried so far:
try {
FileOutputStream fos = getApplicationContext().openFileOutput("mytext.txt", Context.MODE_PRIVATE);
fos.write(getStringFromFile(pictosFile.getAbsolutePath()).getBytes());
Log.e("mytextfile",""+getStringFromFile(pictosFile.getAbsolutePath()));
progressDialog.cancel();
fos.close();
}
catch (IOException e) {
e.printStackTrace();
}
catch (Exception e) {
e.printStackTrace();
}
This allows me to save the file into internal memory, but I am unsure about how to delete the previous file before writing the new version.

If you need to ensure that the file is overwritten, i.e. delete an old copy before saving a new version, you can use the exists() method for a file object. Here is an example showing how to delete an old version of an image file before writing a new file with the same name in a nested directory:
// Here TARGET_BASE_PATH is the path to the base folder
// where the file is to be stored
// 1 - Check that the file exists and delete if it does
File myDir = new File(TARGET_BASE_PATH);
// Create the nested directory structure if it does not exist (first write)
if(!myDir.exists())
myDir.mkdirs();
String fname = "my_new_image.jpg";
File file = new File(myDir,fname);
// Delete the previous versions of the file if it exists
if(file.exists())
file.delete();
String filename = file.toString();
BufferedOutputStream bos = null;
// 2 - Write the new version of the file to the same location
try{
bos = new BufferedOutputStream(new FileOutputStream(filename));
Bitmap bmp = Bitmap.createBitmap(width,height,Bitmap.Config.ARGB_8888);
bmp.copyPixelsFromBuffer(buf);
bmp.compress(Bitmap.CompressFormat.PNG,90,bos);
bmp.recycle();
}
catch(FileNotFoundException e){
e.printStackTrace();
}
finally{
try{
if(bos != null)
bos.close();
}
catch(IOException e){
e.printStackTrace();
}
}
You must also ensure that you have read / write access to memory, make sure that you ask the user for these permissions at run time and have the following in your manifest:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

Unable to write to external SD Card in Android

I am trying to write files in the external SD card folder. Even after having set the required permission in the manifest file, I am unable to write on the external SD card.
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
Code:
String path = "/mnt/extsd/nit.txt";
File myFile = new File(path);
if (!myFile.exists()) {
try {
myFile.createNewFile();
} catch(Exception e)
{
txtText.setText("Failed-" + e.getMessage());
e.printStackTrace();
}
}
try {
FileOutputStream fostream = new FileOutputStream(myFile);
OutputStreamWriter oswriter = new OutputStreamWriter(fostream);
BufferedWriter bwriter = new BufferedWriter(oswriter);
bwriter.write("Hi welcome ");
bwriter.newLine();
bwriter.close();
oswriter.close();
fostream.close();
txtText.setText("success");
} catch(Exception e)
{
txtText.setText("Failed-" + e.getMessage());
e.printStackTrace();
}
On the other hand when I use ES File Explorer and try to create a file, it creates it without any issues.

Don't use the absolute path String path = "/mnt/extsd/nit.txt"; because you never know about android device being used by users. Rather you can get the external storage directory path by using Environment.getExternalStorageDirectory().toString().

You should be able to call Environment.getExternalStorageDirectory() to get the root path to the SD card and use that to create a FileOutputStream. From there, just use the standard java.io routines.
File log = new File(Environment.getExternalStorageDirectory(), "your_file_name.txt");
try {
out = new BufferedWriter(new FileWriter(log.getAbsolutePath(), false));
out.write("any data");
} catch (Exception e) {
}
And don't forget to close the streams.

First check sd-card is available or not.
String state = Environment.getExternalStorageState();
String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
if (Environment.MEDIA_MOUNTED.equals(state))
{
File folder = folder = new File(extStorageDirectory, "FolderName");
if(!folder.exists())
{
folder.mkdir();//making folder
}
File file = new File(folder,"Filename");//making file
}
Please try this code, it work in my application.

Android: problems creating a file

I'm writing an Android application in which I want to create text files in a particular folder and afterwards I want to read the files from my device.
I'm doing this way:
File sd = Environment.getExternalStorageDirectory();
File f;
FileWriter fw = null;
String path = sd.getAbsolutePath() + "/Samples/";
f = new File(path+File.separator+"filename.txt");
if (!f.exists())
{
f.mkdirs();//Creates the directory named by this file, creating missing parent directories if necessary
try
{
f.createNewFile();
//fw = new FileWriter(f, true);
}
catch (IOException e)
{
Log.e("ERROR","Exception while creating file:"+e.toString());
}
The problem is that in this way I create another folder instead of a text file. What can I do? Thanks

Instead of:
f.mkdirs();
do:
path.mkdirs();

I found the solution and I want to share it with you:
File sd = Environment.getExternalStorageDirectory();
File folder;
String path = sd.getAbsolutePath() ;
folder = new File(path, dirName);
if (!folder.exists()){
folder.mkdirs();}
try{
File file = new File(folder, fileName+".txt");
file.createNewFile();
} catch (IOException e) {
Log.e("ERROR", "Exception while creating file:" + e.toString());
}
I hope this could help other people having the same problem. Good luck

File upload picture android

I develop application with imageview, my problem is when I clicked button load picture, then will be shown gallery, then I want to copy selected image to res/drawable android, is it possible? if yes, can give me source code ?
Regards,

You cannot write to res/drawable. You can download image which can be stored in sdcard but you can't add images dynamically to drawable folder.

i am afraid res/ is read-only while running. Instead they give us the option or create files and our personal data in our application space
=====
File root = android.os.Environment.getExternalStorageDirectory();
File dir = new File (root.getAbsolutePath() + "/app_name");
dir.mkdirs();
File file = new File(dir, "myAppData.jpg");
try {
FileOutputStream f = new FileOutputStream(file);
PrintWriter pw = new PrintWriter(f);
pw.println(bytes);// bytes would be data from the source file
pw.flush();
pw.close();
f.close();
} catch (FileNotFoundException e) {
//..
} catch (IOException e) {
//...
}