I'm relatively new to Android. I'm transferring a file from an Android Wear device to a phone, which I did through PutDataRequest. On the phone side I get a DataItemAsset which can provide me a file descriptor using Wearable.DataApi.getFdForAsset(). My question is how do I save this file to external storage?
Thank you!
Here's how I managed to upload a text file from an Android Wear watch to it's paired mobile phone. There may be a simpler way, but this is what worked for me.
(1) On the watch side, create a text file, and read it into an Asset which you can put through the DataApi:
public void SendTextFile()
{
// Get folder for output
File sdcard = Environment.getExternalStorageDirectory();
File dir = new File(sdcard.getAbsolutePath()+ "/MyAppFolder/");
if (!dir.exists()) {dir.mkdirs();} // Create folder if needed
final File file = new File(dir, "test.txt");
if (file.exists()) file.delete();
// Write a text file to external storage on the watch
try {
Date now = new Date();
long nTime = now.getTime();
FileOutputStream fOut = new FileOutputStream(file);
PrintStream ps = new PrintStream(fOut);
ps.println("Time = "+Long.toString(nTime)); // A value that changes each time
ps.close();
} catch (Exception e) {
}
// Read the text file into a byte array
FileInputStream fileInputStream = null;
byte[] bFile = new byte[(int) file.length()];
try {
fileInputStream = new FileInputStream(file);
fileInputStream.read(bFile);
fileInputStream.close();
} catch (Exception e) {
}
// Create an Asset from the byte array, and send it via the DataApi
Asset asset = Asset.createFromBytes(bFile);
PutDataMapRequest dataMap = PutDataMapRequest.create("/txt");
dataMap.getDataMap().putAsset("com.example.company.key.TXT", asset);
PutDataRequest request = dataMap.asPutDataRequest();
PendingResult<DataApi.DataItemResult> pendingResult = Wearable.DataApi
.putDataItem(mGoogleApiClient, request);
}
(2) On the mobile side, receive the asset and write it back out to a file:
public void onDataChanged(DataEventBuffer dataEvents) {
for (DataEvent event : dataEvents) {
if (event.getType() == DataEvent.TYPE_CHANGED &&
event.getDataItem().getUri().getPath().equals("/txt"))
{
// Get the Asset object
DataMapItem dataMapItem = DataMapItem.fromDataItem(event.getDataItem());
Asset asset = dataMapItem.getDataMap().getAsset("com.example.company.key.TXT");
ConnectionResult result =
mGoogleApiClient.blockingConnect(10000, TimeUnit.MILLISECONDS);
if (!result.isSuccess()) {return;}
// Convert asset into a file descriptor and block until it's ready
InputStream assetInputStream = Wearable.DataApi.getFdForAsset(
mGoogleApiClient, asset).await().getInputStream();
mGoogleApiClient.disconnect();
if (assetInputStream == null) { return; }
// Get folder for output
File sdcard = Environment.getExternalStorageDirectory();
File dir = new File(sdcard.getAbsolutePath() + "/MyAppFolder/");
if (!dir.exists()) { dir.mkdirs(); } // Create folder if needed
// Read data from the Asset and write it to a file on external storage
final File file = new File(dir, "test.txt");
try {
FileOutputStream fOut = new FileOutputStream(file);
int nRead;
byte[] data = new byte[16384];
while ((nRead = assetInputStream.read(data, 0, data.length)) != -1) {
fOut.write(data, 0, nRead);
}
fOut.flush();
fOut.close();
}
catch (Exception e)
{
}
// Rescan folder to make it appear
try {
String[] paths = new String[1];
paths[0] = file.getAbsolutePath();
MediaScannerConnection.scanFile(this, paths, null, null);
} catch (Exception e) {
}
}
}
}
You will also need to add the following permission to your manifests at both ends to write to external storage: android.permission.WRITE_EXTERNAL_STORAGE
Note: the most frustrating thing to watch out for is this: if the data does not change, no transfer will occur. So, when you're testing if you write the same data file contents twice, it will only come across the first time - even if you deleted the file from the first run. I lost quite a few hours to this insidious feature of the DataApi ! That's why my code above is writing the current time into the text file.
Also, of course make sure that you set up the GoogleApiClient object to connect, add listeners, etc as described here:
http://developer.android.com/training/wearables/data-layer/index.html
Related
I've got a question that probably borders on opinion, but I've not any related questions or documentation that answers, so I feel like it's a fair one to ask.
I'm trying to build an android app which modifies music files, and what I'd like to do is have a shared folder so that the files and the results can be accessible and shared. I'd like it if it was among the other folders like Music, Downloads, Movies, etc, or even under Music since it's music related. However this seems like it's a security no no in Android, as after I've made something and put it in there I have to use an intent to access it again, where as I'd rather just be able to open the files and not have a permissions based fiasco. Maybe some type of symbolic link like in Linux that pointed to my apps internal folder could be used, but of this I'm still uncertain.
In any case, is there a way I should go about this? If so, are there some resources I could be pointed to?
Thank you in advance to anyone who takes this up!
Edit for CommonsWare:
I used the following to create the folder:
File mediaStorageDir = new File(Environment.getExternalStorageDirectory(), APP_NAME);
And this to copy files from elsewhere to there:
public void copyFileToHomeDirectory(Uri uri)
{
try
{
ContentResolver contentResolver = getApplicationContext().getContentResolver();
String fileName = queryName(contentResolver, uri);
//Get file extension
String fileType = fileName.substring(fileName.length() - 4, fileName.length());
if(fileType.equalsIgnoreCase(MP3_EXTENSION))
{
String path = Environment.getExternalStorageDirectory() + APP_FOLDER;
InputStream in = contentResolver.openInputStream(uri);
File outputFile = new File(path + File.separator + fileName);
outputFile.createNewFile();
OutputStream out = new FileOutputStream(outputFile);
//First we crack open the file to copy it's contents:
byte[] buffer = new byte[KB_SIZE];
int read;
while ((read = in.read(buffer)) != -1)
{
out.write(buffer, 0, read);
}
in.close();
in = null;
// write the output file (You have now copied the file)
out.flush();
out.close();
out = null;
}
}
catch(FileNotFoundException fnfe)
{
Log.e(TAG, "FileNotFoundException");
Log.e(TAG, Log.getStackTraceString(fnfe));
}
catch(IOException ioe)
{
Log.e(TAG, "IOException");
Log.e(TAG, Log.getStackTraceString(ioe));
}
catch(Exception e)
{
Log.e(TAG, "General Exception");
Log.e(TAG, Log.getStackTraceString(e));
}
}
I've tried other methods that I've overwritten in the process, but accessing the files to be used again I need something like this:
public void openDirectory(View view)
{
// Choose a directory using the system's file picker.
Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
// Provide read access to files and sub-directories in the user-selected
// directory.
//intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
//intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
//intent.addCategory(Intent.CATEGORY_OPENABLE);
// Optionally, specify a URI for the directory that should be opened in
// the system file picker when it loads.
//intent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, uriToLoad);
intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
intent.addCategory(Intent.CATEGORY_OPENABLE);
intent.setType("*/*"); //use image/* for photos, etc.
//The result of this code will be calling the onActivityResult function below
startActivityForResult(intent, REQUEST_MUSIC_DIR);
}
Edit2:
I've reorganized the folders to what I think I should be doing so that I can work with the files freely, however, even in my internal cache storage (getCacheDir() + folder_name) either isn't letting me create the files (outputFile.createNewFile doesn't throw an error) or it isn't letting me open them when I go to get a directory listing.
Here's my code for creating the file:
String path = getCacheDir() + MY_SUB_FOLDER;
//uri is obtained through ACTION_OPEN_DOCUMENT intent
InputStream in = contentResolver.openInputStream(uri);
File outputFile = new File(path + "/" + fileName);
outputFile.createNewFile();
Log.i(TAG, "The new file's directory/path is: " + outputFile.getAbsolutePath());
//NOTE: This is returning /data/user/0/com.example.myapplication/cache/MY_SUB_FOLDER/file_name.mp3
OutputStream out = new FileOutputStream(outputFile);
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;
This is my code for attempting to open and read these newly created files
File directory = new File(getCacheDir(), MY_SUB_FOLDER);
Log.i(TAG, "This is the directory we're trying to get the files from: " + directory.getAbsolutePath());
//NOTE: This returns /data/user/0/com.example.myapplication/cache/MY_SUB_FOLDER
File[] files = directory.listFiles();
if(files != null)
{
for(int i = 0; i < files.length; i++)
{
Log.d(TAG, "Files found: " + files[i].getAbsolutePath());
}
}
The files variable isn't null but it's length is 0 and no files are found.
Edit3:
I am catching the exceptions and logging any stack traces, which currently returns nothing.
catch(FileNotFoundException fnfe)
{
Log.i(TAG, "FileNotFoundException");
Log.i(TAG, Log.getStackTraceString(fnfe));
}
catch(IOException ioe)
{
Log.i(TAG, "IOException");
Log.i(TAG, Log.getStackTraceString(ioe));
}
catch(Exception e)
{
Log.i(TAG, "General Exception");
Log.i(TAG, Log.getStackTraceString(e));
}
I am working in a project that have to upload multiple audio files (.amr) to google drive to a specific folder. Now I am going through "startIntentSender" method to show a picker to choose a folder in drive. For a single file it is working fine, But I need to send multiple files at a time without any picker and I have to send that to a specific folder that I need to specify in program. I have searched a lot but I am getting confused. Now Google Drive Api is deprecated. Is there any method for multiple uploading ?
Drive.DriveApi.newDriveContents(mGoogleApiClient)
.setResultCallback(new ResultCallback<DriveApi.DriveContentsResult>() {
#Override
public void onResult(DriveApi.DriveContentsResult result) {
if (!result.getStatus().isSuccess()) {
Log.i(TAG, "Failed to create new contents.");
return;
}
OutputStream outputStream = result.getDriveContents().getOutputStream();
try {
FileInputStream fileInputStream = new FileInputStream(mAllCallRecordFiles.get(i).getFilePath());
byte[] buffer = new byte[1024];
int bytesRead;
while ((bytesRead = fileInputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
}
} catch (IOException e1) {
Log.i(TAG, "U AR A MORON! Unable to write file contents.");
}
MetadataChangeSet metadataChangeSet = new MetadataChangeSet.Builder()
.setMimeType("audio/*")
.build();
IntentSender intentSender = Drive.DriveApi
.newCreateFileActivityBuilder()
.setInitialMetadata(metadataChangeSet)
.setInitialDriveContents(result.getDriveContents())
.build(mGoogleApiClient);
try {
startIntentSender(intentSender, null, 0, 0, 0);
} catch (IntentSender.SendIntentException e) {
Log.i(TAG, "Failed to launch file chooser.");
}
}
})
I suggest you yo use the REST part of google drive's api to do that: https://developers.google.com/drive/api/v2/about-sdk
It looks like there is no way to send more than one file in a single request, but you can just make a loop and send multiple requests each one with a single file, then you will be uploading them at the same time anyway.
This can help you with that: https://developers.google.com/drive/api/v2/manage-uploads
This way you can choose the folder you want setting the proper id in the parent property of the file, as stated in the api documentation:
String folderId = "0BwwA4oUTeiV1TGRPeTVjaWRDY1E";
File fileMetadata = new File();
fileMetadata.setTitle("photo.jpg");
fileMetadata.setParents(Collections.singletonList(
new ParentReference().setId(folderId)));
java.io.File filePath = new java.io.File("files/photo.jpg");
FileContent mediaContent = new FileContent("image/jpeg", filePath);
File file = driveService.files().insert(fileMetadata, mediaContent)
.setFields("id, parents")
.execute();
System.out.println("File ID: " + file.getId());
This is the full documentation on how to manage folders https://developers.google.com/drive/api/v2/folder
I hope this helps you.
I'm doing a simple app in Android and in a certain part of the app I would like to create an Excel file and write in it. I've already prepared everything to use jexcel library to edit an excel using Java, but the thing is I can't find the Excel file I created. I've tried to find it in my own device executing the app, but I couldn't.
String fileName = "hours.xls";
File file = new File(getApplicationContext().getFilesDir() + fileName);
Can anybody help me please?
Thanks in advance :)
On Android KitKat, it returns /data/data/{your package name}/files, however I imagine this could change depending on your platform version. Thus if you're just trying to dig through your filesystem and see a file, it's safe to use this path, but if you're using this path for some functionality across multiple platform versions, you should only reference it using getFilesDir().
What are you planning on using this file for? Do you want it usable by other apps too? Using getApplicationContext().getFilesDir() will give you /data/data/com.package/files but if you want a file that's easily accessible by yourself and other apps, you're better off using something like getExternalFilesDir()
If you want to access your file via your PC (with an usb cable) or via a file manager on your device, prefer:
new File(getExternalFilesDir(null), fileName);
This folder is created in .../Android/data/ ... com.yoursociety.yourapp/files ...
null means that you do not want to store files in predefined folders like Movies, Pictures and so on.
(See documentation for more info)
This worked:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
context = getApplicationContext();
b = (Brain)load("brain.txt");
if (b == null) {
b = new Brain();
}
vocabulary = (ArrayList <String>) load("vocabulary.txt");
if (vocabulary == null) {
vocabulary = new ArrayList <String> ();
vocabulary.add("I love you.");
vocabulary.add("Hi!");
}
b.setRunning(true);
}
public Object load(String fileName) {
File file = new File("/storage/emulated/0/Android/data/com.cobalttechnology.myfirstapplication/files/" + fileName);
if (!file.exists()) {
return null;
}
try {
Object o;
FileInputStream fis = new FileInputStream(file);
ObjectInputStream ois = new ObjectInputStream(fis);
o = ois.readObject();
if (o == null) {
System.out.println(fileName + " = null");
}
ois.close();
fis.close();
System.out.println("Loaded: " + fileName);
return o;
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException cnfe) {
cnfe.printStackTrace();
}
return null;
}
public void save(Object o, String fileName) {
File file = new File("/storage/emulated/0/Android/data/com.cobalttechnology.myfirstapplication/files/" + fileName);
try {
if (!file.exists()) {
file.createNewFile();
}
FileOutputStream fos = new FileOutputStream(file);
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(o);
oos.close();
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
Read the documentation, this method reads the files stored in the internal storage that were created with
with openFileOutput():
getFilesDir()
Returns the absolute path to the directory on the filesystem where
files created with openFileOutput(String, int) are stored.
I have a layout where I have an Edit Text field where I enter my data.
I have 2 buttons.Save and Plot.
When I press save I want to save the data (in xls format) from edittext field and the current date in sd card.
When I press the plot ,I want to plot them.
To save data:
case R.id.savebtn:
savefunc();
break;
...
public void savefunc(){
//saving
File sdCard = Environment.getExternalStorageDirectory();
File directory = new File (sdCard, "MyFiles");
directory.mkdirs();
File file = new File(directory, filename);
try {
FileOutputStream fOut = new FileOutputStream(file);
DataOutputStream os = new DataOutputStream(fOut);
os.writeUTF(thedata);
os.writeUTF(mydate);
os.close();
} catch (FileNotFoundException e) {
// handle exception
} catch (IOException e) {
// handle exception
}
}
For reading:
public void readfunc(){
File sdCard = Environment.getExternalStorageDirectory();
File directory = new File (sdCard, "MyFiles");
File file = new File(directory, filename);
try{
FileInputStream fIn = new FileInputStream(file);
DataInputStream is = new DataInputStream(fIn);
String name = is.readUTF();
String content = is.readUTF();
is.close();
} catch (FileNotFoundException e) {
// handle exception
} catch (IOException e) {
// handle exception
}
}
and :
case R.id.savebtn:
savefunc();
break;
case R.id.graphicsbtn:
readfunc();
...
But the xls file asks me format , I choose UTF8 and it is empty.
If I leave it shows chinese characters.
I am not sure about the "reading" part of the code.
Read this documentation here have more information about save data to external storage and read it is:
Saving and Reading file from External storage
Ok, I found this and works fine!
I tried to create a RandomAccessFile object from a raw resource file in android resource directory without success.
I'm only able to get a inputstream object from raw resource file.
getResources().openRawResource(R.raw.file);
Is it possible to create a RandomAccessFile object from raw asset file or Do I need to stick with inputstream?
It's simply not possible to seek forward and back in an input stream without buffering everything in between into memory. That can be extremely costly, and isn't a scalable solution for reading a (binary) file of some arbitrary size.
You're right: ideally, one would use a RandomAccessFile, but reading from the resources provides an input stream instead. The suggestion mentioned in the comments above is to use the input stream to write the file to the SD card, and randomly access the file from there. You could consider writing the file to a temporary directory, reading it, and deleting it after use:
String file = "your_binary_file.bin";
AssetFileDescriptor afd = null;
FileInputStream fis = null;
File tmpFile = null;
RandomAccessFile raf = null;
try {
afd = context.getAssets().openFd(file);
long len = afd.getLength();
fis = afd.createInputStream();
// We'll create a file in the application's cache directory
File dir = context.getCacheDir();
dir.mkdirs();
tmpFile = new File(dir, file);
if (tmpFile.exists()) {
// Delete the temporary file if it already exists
tmpFile.delete();
}
FileOutputStream fos = null;
try {
// Write the asset file to the temporary location
fos = new FileOutputStream(tmpFile);
byte[] buffer = new byte[1024];
int bufferLen;
while ((bufferLen = fis.read(buffer)) != -1) {
fos.write(buffer, 0, bufferLen);
}
} finally {
if (fos != null) {
try {
fos.close();
} catch (IOException e) {}
}
}
// Read the newly created file
raf = new RandomAccessFile(tmpFile, "r");
// Read your file here
} catch (IOException e) {
Log.e(TAG, "Failed reading asset", e);
} finally {
if (raf != null) {
try {
raf.close();
} catch (IOException e) {}
}
if (fis != null) {
try {
fis.close();
} catch (IOException e) {}
}
if (afd != null) {
try {
afd.close();
} catch (IOException e) {}
}
// Clean up
if (tmpFile != null) {
tmpFile.delete();
}
}
Why not get a new AssetFileDescriptor each time you need a seek? It seems not to be a cpu cycles intensive task (or is it?)
//seek to your first start position
InputStream ins = getAssets().openFd("your_file_name").createInputStream();
isChunk.skip(start);
//read some bytes
ins.read(toThisBuffer, 0, length);
//later on
//seek to a different position, need to openFd again!
//because createInputStream can be called on asset file descriptor only once.
//This resets the new stream to file offset 0,
//so need to seek (skip()) to a new position relative to file beginning.
ins = getAssets().openFd("your_file_name").createInputStream();
ins.skip(start2);
//read some bytes
ins.read(toThatBuffer, 0, length);
I've used this method in my app that needs random access to a 20Mb resource file hundreds of times per second.