Develop Reference

How to upload a file and read the contents of a file in android

I am working on an android application where I want users to upload a file and I want to read the contents of uploaded file and display it . I have been reading files from SD card but I now I need the user to upload a file . I searched a lot but I didn't get any solution for it.
My code for reading the file from SD card
File file = new File(dir, "/tounzip/b.txt");
FileInputStream fileInputStream = null;
try {
fileInputStream = new FileInputStream(file);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
DataInputStream input = new DataInputStream(fileInputStream);
Its reading the file contents successfully but Is there any way to make the user upload the file and read the contents from it ? Any help would be great !! Thanks !!

Android file chooser
You require a file picker/file chooser.
Logic is you read the stream and save the stream in your app sandbox (app's memory i.e. /data/package..) then do whatever you want from there.
If file size is small then even a in-memory implementation will help.

Copying resource file to external storage on android not working

I'm working on a mediaplayer application and am trying to have some default songs get put on the phone in case the user doesn't have any on their phone (I'm pulling the list of actual songs via mediastore).
So I have the songs put in the res/raw folder and fun the following code to copy them. It seems to be copying ok (since astro file browser and other apps see them fine) but the mediastore still can't find them.
I think it's something with the permissions on the file but I'm not sure what. Anybody know why?
InputStream song = getResources().openRawResource(R.raw.aquarel);
File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC), "aquarel.mp3");
Log.e(TAG, "File1: " + file.getPath());
OutputStream copySong = new FileOutputStream(file);
byte[] buffer = new byte[1024];
int readvalue = 0;
readvalue = song.read(buffer);
while (readvalue > 0) {
copySong.write(buffer, 0, readvalue);
readvalue = song.read(buffer);
}
copySong.close();

"When you add files to Android’s filesystem these files are not picked
up by the MedaScanner automatically.
...
If you want your files to be added to the media library, you can do so
either by using the MediaStore content provider, or by using the
MediaScanner."
You can add them by sending a broadcast:
Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
intent.setData(Uri.fromFile(file));
sendBroadcast(intent);
(Source)

File Not Found Error reading SD Card

I'm writing an airplane simulator program and want the user to be able create model files seperately using XML. Then, in the app they can select which model (XML file) to load. I have the XML files in a subdirectory on my SD card and can read it with my BLU phone but not my Motorola Photon II. With the Motorola I get a file not found when initializing the input stream. I have the following code...
In the Manifest I have set read external storage permission...
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
Here's the code to open the XML file...
File file = new File(Environment.getExternalStorageDirectory().getPath() + "/SimFiles/Vehicles/" + "myModel.xml");
InputStream in = new BufferedInputStream(new FileInputStream(file));
It's pretty straight forward. So, why on one and not the other? Is it a permissions thing- one more strict than the other? Thanks.

Try using this...
File file = new File(Environment.getExternalStorageDirectory() + "/SimFiles/Vehicles/" + "myModel.xml");
InputStream in = new BufferedInputStream(new FileInputStream(file));

how to create .json file and how to write json object into json file ...In android

I am using this code for creating the new file and write the json object in test.json file but I am unable to create file.Please find mistake and give the best result
One things I have also write the code for permission in manifest file..
Thanks,
String fileName = "test";
File file = new File("/data/data/packagename/test.json");
file.createNewFile();
DataOutputStream fos = new DataOutputStream(openFileOutput(fileName , Context.MODE_PRIVATE));
if(file.exists()){
fos.write(jsString.getBytes());
fos.close();
}

This will not land on C:/ anyway. At best at your SD card or some other folder, and since android is a unix based system. you should be careful on how you use "slashes"

where to store xml updates in packaged android app?

I guess I'm a little confused as to how files are stored on an actual machine (or emulator even).
While programming, I can save my xml file in the assets folder manually, but how to write an app that will have to connect to the network and download the file,save it somewhere and then manipulate it ? where will it store said file ?
I want to create a new file, but I read on another post that the assets folder as such is not available once packaged; So where are they created and stored ? How can they be transferred. Its just, I'm new to this platform and the file system is a little confusing.

If you want to use XML that is updated, you should think of copying the file(s) from assets to device storage. You can take a look at How to copy files from 'assets' folder to sdcard? to know how this can be done.
Another alternative is to use the database where you can store the parsed data from the XML. So that you need not parse the file whenever you need to access the contents.

You have two options: call getFilesDir() from your activity to obtain a path to the internal data folder that can only be read/write from your app.
Or, you can write/read your xml file to external storage (SD Card). Use the method Environment.getExternalStorageDirectory() to get the root path of the external storage, then create your own folder as you see fit.
Note that if you write to external storage, every app in the phone will have access to it.

Even I faced this issue. Now I have a xml file which is has application properties.This is packaged in the assets folder.Once packaged we cannot edit a file in assets folder.
Now on app load I just copy this file to path returned by
context.getFilesDir().getAbsolutePath();
And the application edit it from the same place. You can see if the file is modified in the FileExplorer panel of DDMS view. The file is stored in the folder named same as your application package name for eg: com.abhi.maps
Alternatively you can also copy it to SD card.However it is risky because, sd card may bot be available all the time.
You can use the following code to copy file from assets folder:
private static void copyFile(String filename, Context context) {
AssetManager assetManager = context.getAssets();
InputStream in = null;
OutputStream out = null;
try {
in = assetManager.open(filename);
String newFileName = context.getFilesDir() + "/" + filename;
out = new FileOutputStream(newFileName);
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1) {
out.write(buffer, 0, read);
}
in.close();
in = null;
out.flush();
out.close();
out = null;
} catch (Exception e) {
Log.e("tag", e.getMessage());
}
}
Hope it helps! :)