Develop Reference

Extract exif information of image in android

Im new to android development and trying to get metadata of image using ExifInterface. I stored the image under drawable and trying to get the metadata but getting null values for all fields(date, imagelength, imagewidth). I tried to access image path as this :
String path = "drawable://" + R.drawable.testimage;
and provided this path to ExifInterface.
ExifInterface exif = new ExifInterface(path);
I dont know if storing image under drawable is correct or not because when I run the app in emulator I get something like this :
E/JHEAD﹕ can't open 'drawable://2130837561'
So if this is wrong then please tell me where should I store the image and how to provide image path to ExifInterface.
Thank you in advance.

To get a drawable, you can you this snippet:
Drawable drawable = getResources().getDrawable(android.R.drawable.your_drawable);
I'm not sure if your way is correct, as I've never seen it like that. Do you really need the path to your image to use it on that ExifInterface class?
Ok, I did some digging and found this question, which led me to this one. As it seems, you can not get an absolute path from a resource inside your apk. A good solution would be for you to save it as a file on the external memory, and then you can get the path you want.
First of all, add this to your AndroidManifest.xml, so your app can write to the cellphone memory:
<uses-permission
android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
Ok, to save it you can try this, first create a bitmap from your drawable resource:
Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.your_drawable);
After that get the path you want to save your images, and put it on a String. More info on that here.
The Android docs have a good example on how to get the path. You can see it here.
To keep it simple, I'll copy and paste the snippet from the docs.
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.
InputStream is = getResources().openRawResource(R.drawable.balloons);
OutputStream os = new FileOutputStream(file);
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);
}
}
void deleteExternalStoragePrivateFile() {
// Get path for the file on external storage. If external
// storage is not currently mounted this will fail.
File file = new File(getExternalFilesDir(null), "DemoFile.jpg");
if (file != null) {
file.delete();
}
}
boolean hasExternalStoragePrivateFile() {
// Get path for the file on external storage. If external
// storage is not currently mounted this will fail.
File file = new File(getExternalFilesDir(null), "DemoFile.jpg");
if (file != null) {
return file.exists();
}
return false;
}
After that, get the path of the file you saved on the external memory, and do as you wish.
I'll keep the old example as well. You can use the method getExternalStorageDirectory() to get the path, or getExternalCacheDir(). After that, you can use File method called getAbsolutePath() to get your String.
String path = (...) // (you can choose where to save here.)
File file = new File(path, "your_drawable.png");
FileOutputStream out = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.PNG, 100, out); // You can change the quality from 0 to 100 here, and the format of the file. It can be PNG, JPEG or WEBP.
out.flush();
out.close();
For more info on the Bitmap class, check the docs.
If you need more info, let me know and I'll try to show more samples.
EDIT: I saw your link, and there was this snippet there:
//change with the filename & location of your photo file
String filename = "/sdcard/DSC_3509.JPG";
try {
ExifInterface exif = new ExifInterface(filename);
ShowExif(exif);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(this, "Error!",
Toast.LENGTH_LONG).show();
}
As you can see, if you really want to see the exif data of a internal image resource, you'll have to save it somewhere else, and then you can try to get the absolute path for that File, then, call the method to show the exif.

How to get path of any file from my my application data folder

My application files are bellow, I want to get sharethis.png file in java code , What is syntax ?
I used this ...
Bitmap bMap = BitmapFactory.decodeFile("file:///android_asset/www/sharethis.png");
but not working

Try:
Bitmap shareThis = BitmapFactory.decodeResource(context.getResources(),
R.drawable.shareThis);

If you want to reference it from a JavaScript or html file in your assets folder, use file:///android_asset/www/sharethis.jpg.
Otherwise, according to this answer, this will list all the files in the assets folder:
AssetManager assetManager = getAssets();
String[] files = assetManager.list("");
This to open a certain file:
InputStream input = assetManager.open(assetName);

Try this:
try {
// get input stream
InputStream ims = getAssets().open("sharethis.png");
// load image as Drawable
Drawable d = Drawable.createFromStream(ims, null);
// set image to ImageView
mImage.setImageDrawable(d);
}
catch(IOException ex) {
Log.e("I/O ERROR","Failed")
}

Instead of using the assets dir, put the file into /res/raw , and you can then access it using the following URI: android.resource://com.your.packagename/" + R.raw.sharethis

AssetManager and InputStream for ImageView

This is the part of my function that assigns an image to my ImageView. I can not get it to show an image. I have my files listed under assets/signs/"image names." This code came straight from my textbook with some minor tweaks to fit my code. I appreciate the help.
String nextImage = signNames.remove(0);
AssetManager assets = getAssets();
InputStream stream;
try{
stream = assets.open("signs/"+nextImage + ".gif");
Drawable sign = Drawable.createFromStream(stream,nextImage +".gif" );
signImageView.setImageDrawable(sign);
}
catch(IOException e){
Log.e(TAG, "Error loading " +nextImage, e);
}

I think there is a much simpler idiom for what you are trying to do. No need to stream the image the want to display. Simply put the image in res/drawable (or res/drawable-hdpi, etc). Then simply:
signImageView.setImageResource(R.drawable.myImage)
Of if you need to get the resource from a dynamic string:
int id = getResources().getIdentifier("yourpackagename:drawable/" + nextImage, null, null);
signImageView.setImageResource(R.drawable.myImage)
see here
This assumes your signImageView is indeed an ImageView.

Get R.drawable ID's dynamically in android

I have a folder with a few images, these images are added by user dynamically. So i need to get the R.drawable ID's of these images in android.... ???

Where are you saving these images too? When images are being added dynamically at runtime usually you need to store them on the phones storage. If you want the images to be stored in the external storage (SDCard) then you can use the following code to retrieve them and add them to your view (Which I assume your doing). This code assumes the images are being stored to your devices SDCard, which is where they will be pulled from.
//Get root directory of storage directory, pass in the name of the Folder if they are being stored farther down, i.e getExternalFilesDir("FolderName/FolderName2")
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state)) {
// We can read and write the media
File dir = getExternalFilesDir(null);
Bitmap bmap = null;
try {
InputStream is = new FileInputStream(new File(dir,"image.jpg"));
bmap = BitmapFactory.decodeStream(is);
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
if (bmap!=null) {
ImageView view = new ImageView(this);
view.setImageBitmap(bmap);
}
}

How to get access to raw resources that I put in res folder?

In J2ME, I've do this like that:
getClass().getResourceAsStream("/raw_resources.dat");
But in android, I always get null on this, why?

For raw files, you should consider creating a raw folder inside res directory and then call getResources().openRawResource(resourceName) from your activity.

InputStream raw = context.getAssets().open("filename.ext");
Reader is = new BufferedReader(new InputStreamReader(raw, "UTF8"));

In some situations we have to get image from drawable or raw folder using image name instead if generated id
// Image View Object
mIv = (ImageView) findViewById(R.id.xidIma);
// create context Object for to Fetch image from resourse
Context mContext=getApplicationContext();
// getResources().getIdentifier("image_name","res_folder_name", package_name);
// find out below example
int i = mContext.getResources().getIdentifier("ic_launcher","raw", mContext.getPackageName());
// now we will get contsant id for that image
mIv.setBackgroundResource(i);

Android access to raw resources
An advance approach is using Kotlin Extension function
fun Context.getRawInput(#RawRes resourceId: Int): InputStream {
return resources.openRawResource(resourceId)
}
One more interesting thing is extension function use that is defined in Closeable scope
For example you can work with input stream in elegant way without handling Exceptions and memory managing
fun Context.readRaw(#RawRes resourceId: Int): String {
return resources.openRawResource(resourceId).bufferedReader(Charsets.UTF_8).use { it.readText() }
}

TextView txtvw = (TextView)findViewById(R.id.TextView01);
txtvw.setText(readTxt());
private String readTxt()
{
InputStream raw = getResources().openRawResource(R.raw.hello);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
int i;
try
{
i = raw.read();
while (i != -1)
{
byteArrayOutputStream.write(i);
i = raw.read();
}
raw.close();
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
return byteArrayOutputStream.toString();
}
TextView01:: txtview in linearlayout
hello:: .txt file in res/raw folder (u can access ny othr folder as wel)
Ist 2 lines are 2 written in onCreate() method
rest is to be written in class extending Activity!!

getClass().getResourcesAsStream() works fine on Android. Just make sure the file you are trying to open is correctly embedded in your APK (open the APK as ZIP).
Normally on Android you put such files in the assets directory. So if you put the raw_resources.dat in the assets subdirectory of your project, it will end up in the assets directory in the APK and you can use:
getClass().getResourcesAsStream("/assets/raw_resources.dat");
It is also possible to customize the build process so that the file doesn't land in the assets directory in the APK.

InputStream in = getResources().openRawResource(resourceName);
This will work correctly. Before that you have to create the xml file / text file in raw resource. Then it will be accessible.
Edit Some times com.andriod.R will be imported if there is any error in layout file or image names. So You have to import package correctly, then only the raw file will be accessible.

This worked for for me: getResources().openRawResource(R.raw.certificate)