Develop Reference

Storing images in the Android filesystem

An Android novice here.
I'm trying to complete a task which involves creating a simple app containing buttons on a single page. Each button, when clicked, should display the corresponding image.
One thing I don't understand in the instructions is that "the images should be stored on the phone filesystem rather than compiled into the application under
resources". What exactly does this mean? Do I need to load the images into the phone manually every time I try running the application? Any guidance would be appreciated.

private void saveImage(Bitmap finalBitmap, int i ) {
File file = new File (path+name.jpg);
if (file.exists ()) file.delete ();
try {
FileOutputStream out = new FileOutputStream(file);
finalBitmap.compress(Bitmap.CompressFormat.JPEG, 50, out);
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
This method will save bitmap as a jpeg file on your phone.
P.S.
path - path of place where you want to save
name - name of image

Apps can include images in their resources/drawable folder that get added into the actual app .apk file. That makes them retrievable using R.drawable.image_name. Sounds like the instructions you are following does not want you do this. They want you to store them on the phone in the data/data/package file structure. If this is the case you can find plenty of examples on how to do this. The answer by Arsen Sench here does this.

How can I export Layout or Views as images to visible gallery folder in Android?

After searching about "How to save Layout views as images", I've found some solution to save in Internal and External Storage. But It seems the image file created is going to save in some data/data/... folder that is not visible normally. Actually I want the image visible in gallery for the user. I've found some code like below, but I even can't check if the image is created or not:
View content = findViewById(R.id.relativeLayout);
String yourimagename = "MyImageFile";
content.setDrawingCacheEnabled(true);
Bitmap bitmap = content.getDrawingCache();
File file = new File("/" + yourimagename + ".png");
try {
if (!file.exists()) {
file.createNewFile();
}
FileOutputStream ostream = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.PNG, 10, ostream);
ostream.close();
content.invalidate();
} catch (Exception e) {
e.printStackTrace();
} finally {
content.setDrawingCacheEnabled(false);
}

But It seems the image file created is going to save in some data/data/... folder that is not visible normally.
The file will be saved where the programmer elects to save it.
Actually I want the image visible in gallery for the user. I've found some code like below, but I even can't check if the image is created or not
That code will not work on any version of Android, as new File("/" + yourimagename + ".png") is not going to give you a usable File, as it points to a place that you can neither read nor write.
You are welcome to save the image to internal storage or external storage. Since you want this image to be picked up by "gallery"-type apps, you are best off choosing external storage, then using MediaScannerConnection and its scanFile() method to get the file indexed by the MediaStore, since gallery apps will tend to use the MediaStore as their source of images.
On the whole, I worry that getDrawingCache() will be unreliable. You may be better served telling your root View to draw to your own Bitmap-backed Canvas instead.

Android app generate

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.

Class Recognition; R.drawable.balloons

Okay, I seem to be having a small issue with R.drawable.balloons. I'm trying to use a template for building a private external storage file that I found on Android Developer, but balloons keeps giving an error (cannot be resolved or is not a field). I was wondering if I could get some help fixing it.
Here's the code section it sits in:
void createExternalStoragePrivateFile() {
// Create a path where we will place our private file on external
// storage.
File file = new File(getExternalFilesDir(null), "DemoFile.jpg");
try {
/*
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.
*/
// Creates file to stream picture
OutputStream os = new FileOutputStream(file);
// Allows app to accept the picture
InputStream is = getResources().openRawResource(R.drawable.balloons);
byte[] data = new byte[is.available()];
is.read(data);
os.write(data);
is.close();
os.close();
} catch (IOException e) {
// Unable to create file, likely because external storage is
// not currently mounted.
Log.w("ExternalStorage", "Error writing " + file, e);
}
}
A heads up, in case I get called out for being a copy/paster, this is only supposed to be a template, but I would like to test that it works before I make changes. Sorry.

You need an image named balloons in the res\drawable folder of your project (or any of its variants, such as drawable-hdpi, &c). The R class is autogenerated.
See How do I add R drawable android?

How do i create folders in sdcard containing images while installing application on device?

I am using gridview example with image adapter to render images with difference that these images are retrieved from a particular folder in sdcard for e.g. /sdcard/images.
I am testing this application on emulator.For this i have firstly configured sdcard on emulator and then pushed the images on this particular folder through DDMS under eclipse.
What i want to know is that is it possible to create images folder containing images in sdcard when a user installs the application on the real device and if possible what is the way to do it?

I'm not aware of a way to do it (which is not to say that it cant be done).
One thing that you definitely can do is create the folder when the user first runs the application, and fill it with the images.

You should read the Android Documentation covering the External Storage section.

I think it is possible . you can put all images in a asset folder and when you application will start you can copy it to a particular folder in SD Card. Here is the link for copy the database form asset folder to application . You can try it for copy the images form asset folder to SDCard.
http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/

You can copy images from assets to SDcard
This method copies images from assets folder to your Sdcard .here Jaydeep's Folder is the name of my folder on sdcard.You can use your folder name in that place.
public void copyImagesInSdcard()
{
assetManager = mycontext.getAssets();
assetManager1 = mycontext.getAssets();
System.out.println("In copyImagesInSdcard");
try
{
str1=assetManager.list("");
ss=assetManager1.list(str1[1]);
InputStream is;
//System.out.println(ss[0]);
File file=new File(Environment.getExternalStorageDirectory().getPath() + "/Jaydeep's Folder");
if(file.exists()!=true)
{
file.mkdir();
}
else
{
if(file.length()==0)
{
file.mkdir();
}
System.out.println("Length:"+file.length());
}
for(int i=0;i<ss.length;i++)
{
is=assetManager1.open(str1[1] + "/" + ss[i]);
file=new File(Environment.getExternalStorageDirectory().getPath() + "/Jaydeep's Folder/" + ss[i] );
FileOutputStream out=new FileOutputStream(file);
//Bitmap bi = BitmapDrawable.createFromStream(is,ss[0]);
byte b[] =new byte[4096];
while (is.read(b) != -1) {
out.write(b);
}
out.close();
}
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}

This can be done by creating zip of all resources and put them in assets folder and then unzip these folder into sdcard using following reference: http://www.jondev.net/articles/Unzipping_Files_with_Android_%28Programmatically%29