I have gone through multiple threads about SDcard file writing problems, but could not see a answer that would help me.
I have used
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
in my manifest for node.
2. Following code creates a file but doesn't write to it. Writer never throws an exception either. When I go back to SDCard and see the file created is of 0 kb. ( which is due to createnew function)
3. SDCard shows the file created with these permissions ----rwxr-x ( write not being there for others )
4. The behaviour is same on emulator or devices liek ASUS pad or Acer Iconia devices.
What is the regular way applications create files with content on SDCard from an Android application ?
if(isExternalStorageWritable()) {
File testFile = new File(Environment.getExternalStorageDirectory().getAbsolutePath(),Filename);
try {
if (testFile.createNewFile()) {
Log.i(TAG + ": createSdcardFile","Empty file on external storage created");
BufferedWriter out = new BufferedWriter(new OutputStreamWriter(
openFileOutput(Filename, MODE_APPEND)));
out.write(Content);
out.close();
Log.i(TAG + ": createSdcardFile","Content to new file created");
created = true;
}
} catch(IOException e) {
Log.e(TAG,"Unable to create/write to new file on external storage. Terminating testCDMReadPositive");
Log.e(TAG,e.getMessage());
}
}
4.Using mode MODE_WORLD_WRITABLE gives same result i.e. a 0kb file on SDCard
5. Anyone with experience in writing files on externalstorage ( /mnt/sdcard ) would know how to do this. Any help or direction, highly appreciated. Thank you
Maybe a stupid suggestion, but did you delete the old testfile before the new run? Because your if clause will prevent writing to the file if it already existed.
Related
I have written a method which creates a file and writes data to the file and stores in the internal storage. When I get the absolute path or path of the file [I have added log messages to experiment with the operations on the File], it shows me that the file is getting created under the root directory and its under the /data/data/mypackagename/files/filename.txt. Nevertheless, I could find these folders on the DDMS where I could find the file which has been created by the method which I have written. But I am unable to open that file too as I don't have permissions.
When I look at my Android device, I can't find these directories. I looked up on stack overflow and some have answered that the /data/data folders in the internal storage are hidden and to access them I have to root the device which I don't want to do.
Next approach: There is a folder called as MyFiles on the android device [I am using Galaxy Tab 4 running Android 4.4 for testing]. Under this folder there is Device Storage directory which has various folders like Documents, Pictures, Music, Ringtones, Android, etc, etc.. So, the apps like camera, spread sheet apps, are able to write or save pictures into the pictures folder or txt files in the documents folder. Similarly, how could I write the file which I am creating in the function to the Documents folder or any other folder which could be accessible over the device. Please help me how could I do it, any help is appreciated.
The following is the code which I have written:
public void addLog(String power_level){
// creates a logFile in the root directory of the internal storage of the application.
// If the file does not exists, then it is created.
Log.d("AppendPower", "In addLog method");
//File logFile = new File(((Context)this).getFilesDir(), "logFile.txt");
File logFile = new File(getFilesDir(), "logFile.txt");
Log.d("FilesDir Path", getFilesDir().getAbsolutePath());
Log.d("FilesDir Name", getFilesDir().getName());
Log.d("Path on Android", logFile.getPath());
Log.d("Absolute Path on Android", logFile.getAbsolutePath());
Log.d("Parent", logFile.getParent());
if(!logFile.exists()){
try{
logFile.createNewFile();
}catch(IOException io){
io.printStackTrace();
}
}
try{
BufferedWriter writer = new BufferedWriter(new FileWriter(logFile, true));
writer.write("Battery level reading");
writer.append(power_level);
Log.d("Power_Level in try", power_level);
writer.newLine();
writer.close();
}catch(IOException e){
e.printStackTrace();
}
}
As you have figured out writing to root directories in Android is impossible unless you root the device. Thats why even some apps in Play-store asking for root permissions before installing the app. Rooting will void your warranty so i don't recommend it if you don't have serious requirement.
Other than root directories you can access any folder which are visible in your Android file manager.
Below is how you can write into sd with some data - Taken from : https://stackoverflow.com/a/8152217/830719
Use these code you can write a text file in SDCard along with you need to set permission in android manifest
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
this is the code :
public void generateNoteOnSD(String sFileName, String sBody){
try
{
File root = new File(Environment.getExternalStorageDirectory(), "Notes");
if (!root.exists()) {
root.mkdirs();
}
File gpxfile = new File(root, sFileName);
FileWriter writer = new FileWriter(gpxfile);
writer.append(sBody);
writer.flush();
writer.close();
Toast.makeText(this, "Saved", Toast.LENGTH_SHORT).show();
}
catch(IOException e)
{
e.printStackTrace();
importError = e.getMessage();
iError();
}
}
.
1) If your purpose is debugging, you may just write to the /sdcard/. It always works.
2) Again, if your purpose is debugging, you may try to set read permissions on your app's directories. A while ago it worked for me on some Android devices (but did not work on at least one device).
Add this permission in your AndroidManifest.xml file:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
Then use this shortest recipe:
try
{
FileOutputStream fos =
openFileOutput("myfile.txt", getApplicationContext().MODE_PRIVATE);
fos.write("my text".getBytes());
fos.close();
}
catch (Exception exception)
{
// Do something, not just logging
}
It will be saved in "/data/data/my.package.name/files/" path.
I'm having a little problem with my android app.
My app generates a .html file when a "export button" is pressed.
But I can't see the file in my pc or in the Android's Download app. I can only see it in Astro file manager.
That's how I generate and saved my file .
String string = "Hello World"
String filename = "/sdcard/Download/teste.html";
FileOutputStream outputStream;
try {
File file = new File(filename);
boolean newFile = file.createNewFile();
if(!newFile){ //if the file exists I delete it and generate a new file
file.delete();
newFile=file.createNewFile();
}
Context context=getActivity();
FileOutputStream fOut = new FileOutputStream(file,true);
// Write the string to the file
fOut.write(string.getBytes());
/* ensure that everything is
* really written out and close */
fOut.flush();
fOut.close();
}
catch (Exception e) {
e.printStackTrace();
}
I suppose there is a way to visualize this file without the Astro app but I can't find how do this, if someone can help I'll be grateful.
Thanks
First, never hardcode paths. Your path will be wrong on some Android devices. Please use the proper methods on Environment (e.g., getExternalStoragePublicDirectory()) or Context (e.g., getExternalFilesDir()) to get the roots under which you can safely place files.
Beyond that, files that you write to external storage will not be visible to PCs until that file is indexed by MediaScannerConnection, and even then it might require the user to perform some sort of "reload" or "refresh" operation in their file browser to see it.
I have another blog post with more about external storage which may be of use to you.
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"/>
I saw this problem has been met many times, but strangely I was not able to find a solution.
I am trying to write a binary file to the SDcard. This is the source code:
private void saveDataLongs() {
try
{
ObjectOutputStream oos = new ObjectOutputStream(ctx.openFileOutput(Environment.getExternalStorageDirectory().getAbsolutePath()+"/longs.bin", ctx.MODE_WORLD_WRITEABLE));
for (int w=0; w<longCount; w++)
oos.writeLong(longs[w]);
oos.close();
}
catch(IOException e)
{ e.printStackTrace(); }
}
The Manifest contains
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
and I receive this error:
01-21 22:19:57.323: E/AndroidRuntime(13713): java.lang.RuntimeException: Unable to start activity ComponentInfo{it.ccc.ccc/it.ccc.ccc.Ccc}: java.lang.IllegalArgumentException: File /sdcard/longs.bin contains a path separator
From other posts I could understand that some functions are meant to write only in the private storage of the app, so they don't expect to manage directories and paths.
Is some one able to help me? Whall I use a different method to write the data to the sd, or just make some other action before doing it? I'm trying to write to the sdcard a simple binary file (btw it's a precalculated sequence of number, and I need to pass it to my PC and then move it back to the assets, so, if there is a different way to obtain this goal, it's ok anyway).
Thank you very much.
You say that you are trying to write to external storage, but you are calling openFileOutput(), which is for internal storage.
Change:
new ObjectOutputStream(ctx.openFileOutput(Environment.getExternalStorageDirectory().getAbsolutePath()+"/longs.bin", ctx.MODE_WORLD_WRITEABLE));
to:
new ObjectOutputStream(new FileOutputStream(new File(Environment.getExternalStorageDirectory(), "longs.bin")));
or, better yet, to:
new ObjectOutputStream(new FileOutputStream(new File(ctx.getExternalFilesDir(null), "longs.bin")));
I like CommonsWare's answer. I would simply like to add that if you ever DO want to go down a path, don't use /. Use File.separator. I don't think I've ever had any errors come up when simply using / but still.
So if you made a sub-folder called "To-dos" in the sdcard's directory, you would do something like the following:
new ObjectOutputStream(new File(Environment.getExternalStorageDirectory() + File.separator + "To-dos", "longs.bin"));
I would like to save a file on external SdCard.I have implemented an application for save a file on external sdcard.But my Android MotorolaARTIX2 device contains internal sdcard.When i am trying to save file on external sdcard it always saving to internal sdcard in my device.
I have implemented my application as follows:
try {
File root = Environment.getExternalStorageDirectory();
if (root.canWrite()){
File file = new File(root, "myfile.txt");
FileWriter gpxwriter = new FileWriter(file);
BufferedWriter out = new BufferedWriter(gpxwriter);
out.write("Hello world");
out.close();
}
} catch (IOException e) {
Log.e("Exception", "Could not write file " + e.getMessage());
}
From the above code my application always saving myfile.txt file on internal sdcard but not external sdcard-ext.And my application is support all devices with same code.
How can i save myfile.txt on sdcard-ext(external) not on sdcard(internal) in my device?
please any body help me....
Motorola has an API for this. Look here: http://developer.motorola.com/docs/motorola-external-storage-api/ But that's not a good generic solution. You probably need to scan the filesystem for a more generic solution that will work on all devices.
Take a look at the answer from this question, especially the one from Baron