i have a problem with my code that is supposed to write some data string to my sdcard. i use a class to do this:
public class CVS {
private String path;
private String filename;
private File dir;
private File file;
private FileWriter fw;
public CVS() {
path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/traffic/";
filename = "data.cvs";
file = new File(path, filename);
createDir();
}
private void createDir() {
dir = new File(path);
if(!dir.exists()) {
if(file.mkdirs() == false) {
Log.d(Config.LOGTAG, "UHOH!!!!!!!!!!!!!!!!!!!!!!!!");
}
}
else Log.d(Config.LOGTAG, "dir exists");
}
public void writeToFile(String data) {
try {
fw = new FileWriter(file);
fw.append(data); Log.d(Config.LOGTAG, "data saved to file...");
}
catch(Exception e) {
Log.d(Config.LOGTAG, "file: " + e.getMessage());
}
}
}
this results ALWAYS in an exeption being caught in writeToFile(), saying "permission denied". actually, i set permissions to WRITE_EXTERNAL_STORAGE in the manifest. so - what am i doing wrong!?
additional info: real device with sd card mounted. no emulator. android 2.2. if i create the dir myself, the problem wont go away :(
Either:
Your manifest is wrong, or
Your external storage is mounted on your development machine, or
Your manual concatenation of your directory is wrong
Your code is ok but still you can add a check for whether sdcard is inserted or not, if you run this code and sdcard is not inserted then it will throw an exception, good practice is that you should always catch the exeptions.
you can check sdcard by following code...
if (android.os.Environment.getExternalStorageState().equals
(android.os.Environment.MEDIA_MOUNTED))
{
//code or logic if sd card is inserted....
}
else
{
Log.e("Exception","SD Card not found!");
}
All of the answers are needed, but if it's a Samsung device, then you need to append "/external_sd/" to the path - because they decided they needed to dork with our minds and break the API:
"http://developer.samsung.com/forum/board/thread/view.do?boardName=GeneralB&messageId=162934&messageNumber=1381&startId=zzzzz~&searchType=TITLE&searchText=sdcard
Related
I've developed an app which
- download some data ( .png and .wav files )
- insert the path where each files is downloaded into a database (SQLite)
So far so good, everything works.
Some users asked me if there was a way to move the the downloaded data in the sd card in order to save some internal space.
By now i create the directory with this line of code
File directory = getApplicationContext().getDir("folderName", Context.MODE_PRIVATE);
Then the app will fill it with all the stuff I downloaded.
I tried using this piece of code:
try {
File newFolder = new File(Environment.getExternalStorageDirectory(), "TestFolder");
if (!newFolder.exists()) {
newFolder.mkdir();
}
try {
File file = new File(newFolder, "MyTest" + ".txt");
file.createNewFile();
System.out.println("Path: " + file.getPath());
} catch (Exception ex) {
System.out.println("ex: " + ex);
}
} catch (Exception e) {
System.out.println("e: " + e);
}
And this create a folder and a text file into: /storage/emulated/0/TestFolder/MyTest.txt
Which is not my sdcard directory, it should be:
/storage/sdcard1/TestFolder/MyTest.txt
So my question is:
- where and how I saved my app's private data (.png and .wav files) in the SD card?
The getExternalFilesDir, getExternalStorageDirectory or relatives, does not always return a folder on a SD card. On my Samsung for example, it returns an emulated, internal SD card.
You can get all external storage devices (also the removable) using ContextCompat.getExternalFilesDirs.
My next step, is to use the folder on the device with the largest free space. To get that, I enumerate the getExternalFilesDirs, and call getUsableSpace on every folder.
I use this code to store (cache) bitmaps in a folder named "bmp" on the device.
#SuppressWarnings("ResultOfMethodCallIgnored")
private static File[] allCacheFolders(Context context) {
File local = context.getCacheDir();
File[] extern = ContextCompat.getExternalCacheDirs(context);
List<File> result = new ArrayList<>(extern.length + 1);
File localFile = new File(local, "bmp");
localFile.mkdirs();
result.add(localFile);
for (File anExtern : extern) {
if (anExtern == null) {
continue;
}
try {
File externFile = new File(anExtern, "bmp");
externFile.mkdirs();
result.add(externFile);
} catch (Exception e) {
e.printStackTrace();
// Probably read-only device, not good for cache -> ignore
}
}
return result.toArray(new File[result.size()]);
}
private static File _cachedCacheFolderWithMaxFreeSpace;
private static File getCacheFolderWithMaxFreeSpace(Context context) {
if (_cachedCacheFolderWithMaxFreeSpace != null) {
return _cachedCacheFolderWithMaxFreeSpace;
}
File result = null;
long free = 0;
for (File folder : allCacheFolders(context)) {
if (!folder.canWrite()) {
continue;
}
long currentFree = folder.getUsableSpace();
if (currentFree < free) {
continue;
}
free = currentFree;
result = folder;
}
_cachedCacheFolderWithMaxFreeSpace = result;
return result;
}
try this
File sdCard = Environment.getExternalStorageDirectory();
File dir = new File (sdCard.getAbsolutePath() + "/newfolder");
dir.mkdirs();
add permission in Manifest file
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
I have a directory structure of files in external storage. They don't show up in the Android File Transfer app, so I think it's a media scanner problem.
I'm creating them with a FileOutputStream in a directory based on Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS).
I have the following method, called from an activity, so context is an activity (forget that this blocks the main thread for now!):
public void scan(Context context, File base) {
File[] files = base.listFiles();
if (files == null) {
return;
} else {
for (File file : files) {
if (file.isFile()) {
String path = file.getAbsolutePath();
MediaScannerConnection.scanFile(context, new String[]{path}, null, null);
Log.e("Langstroth", path);
} else if (file.isDirectory()) {
this.scan(context, file);
}
}
}
}
public void scan(Context context) {
this.scan(context, this.baseDir);
}
}
The output of the log is as expected:
E/MyApp﹕ /storage/emulated/0/Documents/Langstroth/sample/5000/1430576404874.wav
E/MyApp﹕ /storage/emulated/0/Documents/Langstroth/sample/5000/1430577209491.wav
And then lots of:
E/MyApp﹕ Scan completed path /storage/emulated/0/Documents/Langstroth/sample/5000/1430576404874.wav uri content://media/external/audio/media/7836
E/MyApp﹕ Scan completed path /storage/emulated/0/Documents/Langstroth/sample/5000/1430577209491.wav uri content://media/external/audio/media/7838
This proves that the files exist. They don't show up in the Android File Transfer though.
Here's the strange thing. Another method:
public void otherDemo(Context context, File baseDir) {
String newPath = baseDir.getAbsolutePath() + "/some/random/dirs";
Log.e("Langstroth", "New path " + newPath);
File dir = new File(newPath);
dir.mkdirs();
Log.e("Langstroth", dir.exists() ? "Dir exists": "Dir does not exist");
File f = new File(dir, "myfile.txt");
try {
new BufferedOutputStream(new FileOutputStream(f)).close();
} catch (IOException e) {
e.printStackTrace();
}
Log.e("Langstroth", f.exists() ? "File exists": "File does not exist");
MediaScannerConnection.scanFile(context, new String[]{f.getAbsolutePath()}, null, null);
}
and the log output:
E/MyApp﹕ New path /storage/emulated/0/Documents/Langstroth/some/random/other/dirs
E/MyApp﹕ Dir exists
E/MyApp﹕ File exists
E/MyApp﹕ File: /storage/emulated/0/Documents/Langstroth/some/random/other/dirs/myfile.txt
E/MyApp﹕ Other scan completed path /storage/emulated/0/Documents/Langstroth/some/random/other/dirs/myfile.txt uri content://media/external/file/7842
One test file shows up, the others don't
Proof:
Where are the other files?
Generally speaking, before you let another process work with a file, you want to ensure all bytes are flushed to disk, via getFD().sync(). In particular, this seems to help with the whole media scanning thing.
the files shows up in a .listFiles(), and .exist(), and the callback for the MediaScanner says that it completed correctly. Surely an extant (if empty) file should show up?
The ways of the media scanner are mysterious. :-) IOW, beats me.
Bear in mind that there are multiple moving parts here: your app, the media scanner, the MTP daemon on Android, and your MTP client. The breakdown could be at any stage. If you unplug and re-plug in the device, and now the files show up in your MTP client, my guess would be that the MTP client is working off of a slightly stale cache.
Both files are present on the sdcard, but for whatever reason exists() returns false the the png file.
//String path = "/mnt/sdcard/Android/data/com.gemoro.toffer/cache/1551619351/0/foto/-921042926.png";
String path = "/mnt/sdcard/Android/data/com.gemoro.toffer/cache/1551619351/0/foto/-1200240592.pdf";
File file2 = new File(path);
if (null != file2)
{
if(file2.exists())
{
LOG.x("file exist");
}
else
{
LOG.x("file does not exist");
}
}
Now, I've look at what's under the hood, what the method file.exists() does actually and this is what it does:
public boolean exists()
{
return doAccess(F_OK);
}
private boolean doAccess(int mode)
{
try
{
return Libcore.os.access(path, mode);
}
catch (ErrnoException errnoException)
{
return false;
}
}
May it be that the method finishes by throwing the exception and returning false?
If so,
how can I make this work
what other options to check if a file exists on the sdcard are available for use?
Thanks.
1 You need get the permission of device
Add this to AndroidManifest.xml
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
2 Get the external storage directory
File sdDir = Environment.getExternalStorageDirectory();
3 At last, check the file
File file = new File(sdDir + filename /* what you want to load in SD card */);
if (!file.canRead()) {
return false;
}
return true;
Note: filename is the path in the sdcard, not in root.
For example: you want find
/mnt/sdcard/Android/data/com.gemoro.toffer/cache/1551619351/0/foto/-921042926.png
then filename is
./Android/data/com.gemoro.toffer/cache/1551619351/0/foto/-921042926.png
.
Please try this code. Hope it should helpful for you. I am using this code only. Its working fine for me to find the file is exists or not. Please try and let me know.
File file = new File(path);
if (!file.isFile()) {
Log.e("uploadFile", "Source File not exist :" + filePath);
}else{
Log.e("uploadFile","file exist");
}
Check that USB Storage is not connected to the PC. Since Android device is connected to the PC as storage the files are not available for the application and you get FALSE to File.Exists().
Check file exist in internal storage
Example : /storage/emulated/0/FOLDER_NAME/FILE_NAME.EXTENTION
check permission (write storage)
and check file exist or not
public static boolean isFilePresent(String fileName) {
return getFilePath(fileName).isFile();
}
get File from the file name
public static File getFilePath(String fileName){
String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
File folder = new File(extStorageDirectory, "FOLDER_NAME");
File filePath = new File(folder + "/" + fileName);
return filePath;
}
///edited
I try to run the program on the main thread and it can read and save.
I think is problem of the asynctask!!
///
First I already add the user permission to the android manifest
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
I try to read a raw image data from mnt/sdcard/Bluetooth and process it and then write to the internal sdcard and the write path is mnt/sdcard/Bluetooth.
The program can run in my android emulator and save File.
However,when run it real phone, it seems that the phone can only read my file,but not save file.
public class MainActivity extends Activity {
String filenameIn ="ardrone.raw";
File file = new File(Environment.getExternalStorageDirectory()+"/Bluetooth/", filenameIn);
String filename ="convertA.jpg";
File outputfile = new File(Environment.getExternalStorageDirectory() +"/Bluetooth/",filename);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myImageView = (ImageView)findViewById(R.id.imageView);
Toast.makeText(this, "search raw file", Toast.LENGTH_LONG).show();
new imageProcess().execute();
sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED,Uri.parse("file://" + Environment.getExternalStorageDirectory())));
Bitmap myBitmap = BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()
.getAbsolutePath()+"/Bluetooth/convertA.jpg");
myImageView.setImageBitmap(myBitmap);
if (file.exists()){
Toast.makeText(this, "InFile:)", Toast.LENGTH_LONG).show();
}
else{
Toast.makeText(this, "InFile:(((((", Toast.LENGTH_LONG).show();
}
if (outputfile.exists()){
Toast.makeText(this, "outputfile:)", Toast.LENGTH_LONG).show();
}
else{
Toast.makeText(this, "outputfile:(((((", Toast.LENGTH_LONG).show();
}
}
public class imageProcess extends AsyncTask<String, Integer, Boolean>{
Boolean check_point= false;
#Override
protected Boolean doInBackground(String... arg0) {
try {
receiveVideoRawData();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
}
public void receiveVideoRawData() throws IOException{
byte[] buf_rcv = new byte[153600];
ByteArrayOutputStream ous = new ByteArrayOutputStream();
InputStream ios = new FileInputStream(file);
int read = 0;
while ( (read = ios.read(buf_rcv)) != -1 ) {
ous.write(buf_rcv, 0, read);
}
ous.close();
ios.close();
ReadRawFileImage readMyRawData=new ReadRawFileImage();
image = readMyRawData.readUINT_RGBImage(buf_rcv);
//transfer data
OutputStream _outStream = new FileOutputStream(outputfile);
Bitmap pBitmap = image ;
pBitmap.compress(Bitmap.CompressFormat.JPEG, 90, _outStream);
_outStream.flush();
_outStream.close();
}
}
The first thing is to check if your path exists; on different phones the sd card may be mounted at different locations. On my Linux,
$ ~/android-sdk-linux/platform-tools/adb shell ls -l /mnt/sdcard/
The 2nd thing is to check permissions on the file and the containing directory.
Then, you might examine the logs (they may already contain an error message); then, add debug output to your code and examine the logs with that debug output.
try making your new file writable using file.writable(true). It could also be that your new file doesnt really exist.
Apparently you only need to set the external read permission if you don't have the write permission, this might be overwriting your write privileges?
http://developer.android.com/reference/android/Manifest.permission.html#READ_EXTERNAL_STORAGE
First you should confirm that the real device has SDCARD storage(Some device have not "SDCARD" storage).
Please see below reference to get all storage list
How to list additional external storage folders (mount points)?
I want to create a directory on sd card keeping it as a separate activity in one of my application. I wrote the following code in the onCreate() of the application. It is not creating the directory though this code works fine if I try to implement it as an independent application.
Please suggest a solution for this problem.
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
try{
String dirName = "/sdcard/TEST";
File newFile = new File(dirName);
newFile.mkdirs();
Log.d("CaptureTest.java","Directory created");
if(newFile.exists()){
Log.d("capturetest.java","directory exists");
if(newFile.isDirectory()){
Log.d("capturetest.java","isDirectory = true");
}
else Log.d("capturetest.java","isDirectory = false");
} else
{
Log.d("capturetest.java","directory doesn't exist");
}
} catch(Exception e){
Log.d("capturetest.java","Exception creating folder " + e);
}
........................................
..........................................
}
The SD card might be mounted at /mnt/sdcard instead of /sdcard.
But the safest technique to get the external storage directory is like in the following code
File myDirectory = new File(Environment.getExternalStorageDirectory(), "my directory");
if(!myDirectory.exists()) {
myDirectory.mkdirs();
}
There could be a number of things causing this:
Check that external storage is available and writeable before trying to write to it.
Don't use String dirName = "/sdcard/TEST"; use Environment.getExternalStorageDirectory() or Context.getExternalFilesDir() instead.
This page has some really useful tips for correctly accessing the SD card.