Develop Reference

Storage in android studio

I am trying to pull multiple images from gallery and place in grid view , Unfortunately I am not able to do so, Can you help me with that. And also I made a folder in sd card and I m trying to store audio as well as photographs in the same folder. Can you help me with that as well?
I am using android 2.3.
So I have included this code inside the button click but on click of button it has created the folder but its not storing the file inside the folder. On click of the button every other thing is working, its opening the gallery and its calculating numpic. I am not sure why its not storing the file in CN Video folder.
public void onClick(View v) {
Intent pass_data = new Intent(MainRecord.this, OpenGallery.class);
pass_data.putExtra("numpic",numpic);
startActivity(pass_data);
// Saving Audio recorded file to directory
File f = new File(Environment.getExternalStorageDirectory() + "/CNvideo");
if(f.isDirectory()) {
//Write code for the folder exist condition
}else {
// create a File object for the parent directory
File CNvideoDirectory = new File("/sdcard/CNVideo/");
// have the object build the directory structure, if needed.
CNvideoDirectory.mkdirs();
// create a File object for the output file
String filename = getfilename();
File outputFile = new File(CNvideoDirectory, filename);
// now attach the OutputStream to the file object, instead of a String representation
try {
FileOutputStream fos = new FileOutputStream(outputFile);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}};

Where should I have users save the images that they made on my app

My users make custom images on my app and I am unsure what directory I should use when they save. Should I use MediaStore.Images.Media.EXTERNAL_CONTENT_URI?

Basically MediaStore.Images.Media.EXTERNAL_CONTENT_URI is part of Content Resolver which allow you to read and write resource from your user device. You need to ask yourself wether it is good to save their image into device. You could save your image in private or public which still decided by you. There is internal and external storage, wether you need all image to be deleted when your app is deleted or you don't want other app access the photo you user created use internal storage otherwise use external storage.Take a look on this link which take you step by step to understand why, which,how to save file into your app.

You can make a directory of your own app in the internal storage of the device and store all the pictures made from your app there.
You can make the directory using
File directory = new File(Environment.getExternalStorageDirectory() + File.separator + "<app name>");
if(!directory.exists){
directory.mkdirs;
}
And then store the pictures in this path
Random generator = new Random();
int n = 10000;
n = generator.nextInt(n);
String name = "<image name>"+n+".jpg";
File pictureFile = new File(directory, name);
pictureFile.createNewFile();
try {
FileOutputStream out = new FileOutputStream(pictureFile);
finalBitmap.compress(Bitmap.CompressFormat.JPEG, 90, out);
out.close();
} catch (Exception e) {
e.printStackTrace();
}

Copy database when phone hasn't got external memory

I have got a problem with backup database in my app. I am working on Android 2.2.3 and this has sd card installed. Making copy of the database works fine. The problem occures when I'am testing my app on the phone with internal memory enought big like sd cards (Nexus 32gb). In this scenario my method doesn't work extracting file to sd card because it doesn't (sd card) exist. How to make copy of database to internal independed location? I've tried:
File outPut = new File(Environment.getRootDirectory().toString() + "/myfolder/");
but got permission denied and can not create folder with data. Can anyone show correct way?
EDITED:
I don't get it. I'd like to make new folder with dataBackup. I've defined correct location for that but it says that can not find file. SDCard is present. Why it can not create that folder - "/storeUGif/databaseName.db".?
Here is absolute path for destination folder:
public static final String OUTPUT_BACKUP_DATABASE = Environment.getExternalStorageDirectory().getAbsolutePath() + "/storeUGif/" + SqliteHelper.DATABASE_NAME;
if(isSdPresent())
{
//File outPut = new File(Environment.getExternalStorageDirectory().getAbsolutePath().toString()+"/StoreUGif/"+SqliteHelper.DATABASE_NAME);
File outPut = new File(Tools.OUTPUT_BACKUP_DATABASE);
File storeUGif = new File(Environment.getExternalStorageDirectory().getAbsolutePath().toString());
storeUGif.mkdir();
File currentDB = getApplicationContext().getDatabasePath(SqliteHelper.DATABASE_NAME);
FileInputStream is = new FileInputStream(currentDB);
OutputStream os = new FileOutputStream(outPut);
byte[] buffer = new byte[1024];
while (is.read(buffer) > 0) {
os.write(buffer);
}
os.flush();
os.close();
is.close();
}
else
{
Toast.makeText(this, "SDCard is unvailable", Toast.LENGTH_SHORT).show();
}

Use Environment.getExternalStorageDirectory() to get a valid path.
Despite its name, it will return the default storage, either the external or (if missiing) the internal one.
For reference: http://developer.android.com/reference/android/os/Environment.html#getExternalStorageDirectory()

android-where to store lots of images and how to move them while installing

I'm writing an android app that contains about 500 images .
there are somethings that make me worry, I don't want to use internet.
1-the application size will be very big , is there anyway to moving images to sd card while installing? some devices may don't have this amount of space on the phone .
2-should I make 3 images for hdpi , ldpi and mdpi ?

You can put you image in asset folder. If you want to transfer image from assets to SD Card then you can't do like this.
But you can do by one way. You put your image on server and at 1st time when you will open app you can download it and save it in SD Card and then access from there.

Yes, it will be big. No, you can't remove them from your package.
No, you can make only hdpi images. Android will scale them automatically (which may slow down a bit the app).
Suggestion - use internet. Since the user has internet to download your app, he can wait to download the resources on first start. Also it give you the ability to add/remove files via online configuration. Just imagine if you have to add 1 image and upload new version - this means that the user will have to download the same huge package again.

I had a similar requirement - include a bunch of images in the app, but in my case, the image had to be accessible by any user or app, not just the app that unpacked them. I stored them in the res/raw folder and copied them to user space on start up:
private void loadCopyResources() {
// copy resources to space any activity can use
String sourceName;
String resourceName;
String fileName;
int resource;
String typeName = sourceSink.Types.photo.toString();
for (sourceSink.Sources source: sourceSink.Sources.values() ){
for (int i = 0; i< photoFileCount; i++) {
sourceName = source.toString();
resourceName = sourceName + "_" + typeName + (i+1); // i.e. dropbox_photo2
fileName = resourceName + ".jpg"; // files requires extension
resource = getResources().getIdentifier(resourceName, "raw", "com.example.myapp");
createExternalStoragePublicFile(typeName,fileName, resource); // copy it over
}
}
}
void createExternalStoragePublicFile(String fType, String fname, int res ) {
// Create a path where we will place our picture in the user's
// public pictures directory. Note that you should be careful about
// what you place here, since the user often manages these files. For
// pictures and other media owned by the application, consider
// Context.getExternalMediaDir().
File path = null;
if (((fType.equals(sourceSink.Types.photo.toString())) || (fType.equals(sourceSink.Types.file.toString())) ) ){
path = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES);
}
if (fType.equals(sourceSink.Types.music.toString())) {
path = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_MUSIC);
}
if (fType.equals(sourceSink.Types.video.toString())) {
path = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_MOVIES);
}
File file = new File(path, "/" + fname);
try {
// Make sure the Pictures directory exists.
path.mkdirs();
// Very simple code to copy a picture from the application's
// resource into the external file. Note that this code does
// no error checking, and assumes the picture is small (does not
// try to copy it in chunks). Note that if external storage is
// not currently mounted this will silently fail.
InputStream is = getResources().openRawResource(res);
OutputStream os = new FileOutputStream(file);
byte[] data = new byte[is.available()];
is.read(data);
os.write(data);
is.close();
os.close();
scanMedia(file);
} catch (IOException e) {
// Unable to create file, likely because external storage is
// not currently mounted.
Log.w("ExternalStorage", "Error writing " + file, e);
}
}
sourceSink, which I didn't include, is just a list of file names and file types I needed copied.

access android media directory?

ey up. ive built a simple music app that reads wav files from the sdcard and plays them.
how do i access the default media directory?
this is how i get the sdcard
public void LoadSounds() throws IOException
{
String extState = Environment.getExternalStorageState();
if(!extState.equals(Environment.MEDIA_MOUNTED)) {
//handle error here
}
else {
File sd = new File(Environment.getExternalStorageDirectory ()); //this needs to be a folder the user can access, like media
as usual the docs dont give an actual example of usage but it says this - If you're using API Level 8 or greater, use getExternalFilesDir() to open a File that represents the external storage directory where you should save your files. This method takes a type parameter that specifies the type of subdirectory you want, such as DIRECTORY_MUSIC...
how do i use it?
thank you
edit:
this makes it crash if i try to fill a spinner array with file path Strings.
File path = getExternalFilesDir(Environment.DIRECTORY_MUSIC);
File sd = new File(path, "/myFolder");
File[] sdDirList = sd.listFiles(new WavFilter());
if (sdDirList != null)
{
//sort the spinner
amountofiles = sdDirList.length;
array_spinner=new String[amountofiles];
......
final Spinner s = (Spinner) findViewById(R.id.spinner1); //crashes here
ArrayAdapter<?> adapter = new ArrayAdapter<Object>(this,
android.R.layout.select_dialog_item, array_spinner);
EDIT2:
ok so ive done this test that is supposed to write a txt file to the music directory.
i run the app, no txt file is written anywhere on the device i can find.
// Path to write files to
String path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC).getAbsolutePath();
String fname = "mytest.txt";
// Current state of the external media
String extState = Environment.getExternalStorageState();
// External media can be written onto
if (extState.equals(Environment.MEDIA_MOUNTED))
{
try {
// Make sure the path exists
boolean exists = (new File(path)).exists();
if (!exists){ new File(path).mkdirs(); }
// Open output stream
FileOutputStream fOut = new FileOutputStream(path + fname);
fOut.write("Test".getBytes());
// Close output stream
fOut.flush();
fOut.close();
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
another edit: i will get this working!!
so if i use this line it creates a folder on the sdcard called 'Musictest'. dont understand??
String path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC + "test").getAbsolutePath();
////////////////////////////////////////////////////////////////////
Final Edit:
right so this will look for a folder called test in the devices music directory.
if it doesnt exist, it will be created.
(some fixing to be done here, error if empty) it then lists the files in the directory and adds them to an array.
public void LoadSounds() throws IOException
{
String extState = Environment.getExternalStorageState();
// Path to write files to
String path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC + "/test").getAbsolutePath();
if(!extState.equals(Environment.MEDIA_MOUNTED)) {
//handle error here
}
else {
//do your file work here
// Make sure the path exists
boolean exists = (new File(path)).exists();
//if not create it
if (!exists){ new File(path).mkdirs(); }
File sd = new File(path);
//This will return an array with all the Files (directories and files)
//in the external storage folder
File[] sdDirList = sd.listFiles();
if (sdDirList != null)
{
//add the files to the spinner array
array_spinnerLoad=new String[sdDirList.length];
files = new String[sdDirList.length];
for(int i=0;i<sdDirList.length;i++){
array_spinnerLoad[i] = sdDirList[i].getName();
files[i] = sdDirList[i].getAbsolutePath();
}
}
}
}

as mentioned in the docs, getExternalFilesDir() return File. And File object can represent either file or directory.
Therefore:
File musicDirectory = new File( getExternalFilesDir(Environment.DIRECTORY_MUSIC));
Will give you the object to play with.