From the two lines below, in which line the actual download happens ?. and if possible please explain
InputStream input = new java.net.URL(imageURL).openStream();
bitmap = BitmapFactory.decodeStream(input);
This:
InputStream input = new java.net.URL(imageURL).openStream();
Creates a connection to the URL. The result is a stream, that can be used to get the content of the URL.
This:
bitmap = BitmapFactory.decodeStream(input);
Uses the above mentioned stream to read the URL's content and use it to create the bitmap, so this is where the "download" happens. Bear in mind, that this doesn't mean the image is actually saved on the internal memory or SD card. It's just there in memory.
Try this for getting and saving .
Also you can easly work with Universal Image lOader library or picasso
https://github.com/nostra13/Android-Universal-Image-Loader
http://square.github.io/picasso/
URL url = new URL("....your site .....");
InputStream input = null;
FileOutputStream output = null;
try {
String outputName = "thumbnail.jpg";
input = url.openConnection().getInputStream();
output = c.openFileOutput(outputName, Context.MODE_PRIVATE);
int read;
byte[] data = new byte[1024];
while ((read = input.read(data)) != -1)
output.write(data, 0, read);
return outputName;
} finally {
if (output != null)
output.close();
if (input != null)
input.close();
}
Related
I'm trying to convert this image url to file object :
https://graph.facebook.com/v4.0/10211842143528384/picture?height=200&width=200&migration_overrides=%7Boctober_2012%3Atrue%7D
this link came from the facebook response after i logged in.
i used this method to convert this image url to File object:
URL url = null;
try {
url = new URL(sharePreferences.getPreferencesProfilePicture());
} catch (MalformedURLException e) {
e.printStackTrace();
}
File f = new File(url.getFile());
Log.d("CHECKER",""+f.exists());
Log.d("CHECKER",""+f.length());
but when i check it's length, its just 0 and the file exist is false.
You have a file with length 0 because you are just creating it with the name of the result of url.getFile(), url.getFile() returns a string which corresponds to the fetched file name.So you end up with a file named picture:
https://graph.facebook.com/v4.0/10211842143528384/picture?height=200&width=200&migration_overrides=%7Boctober_2012%3Atrue%7 But what about the contents? you have to download them fron the internet as a stream and feed that stream into a file. There many ways of doing that with plain Java. A basic copy-paste from https://www.baeldung.com/java-download-file
try (BufferedInputStream in = new BufferedInputStream(new URL(FILE_URL).openStream());
FileOutputStream fileOutputStream new FileOutputStream(FILE_NAME)) {
byte dataBuffer[] = new byte[1024];
int bytesRead;
while ((bytesRead = in.read(dataBuffer, 0, 1024)) != -1) {
fileOutputStream.write(dataBuffer, 0, bytesRead);
}
} catch (IOException e) {
// handle exception
}
Since you are using android I would strongly encourage you to use fully featured Network libraries such as OkHttp3, Retrofit or Volley, but guessing your knowledge I think you will do better learning the basics on Java then jump to the mentioned libraries.
Remember, for android you need the INTERNET permission to access the internet, then if you download into a file on the external storage you would also need the EXTERNAL_STORAGE permission. Snippet for android:
try {
URLConnection conection = url.openConnection();
conection.connect();
int lenghtOfFile = conection.getContentLength();
// Read from the Network stream
InputStream input = new BufferedInputStream(url.openStream());
OutputStream output = new FileOutputStream(Environment
.getExternalStorageDirectory().toString()
+ "/downloaded.png");
byte data[] = new byte[1024];
while ((count = input.read(data)) != -1) {
total += count;
// Feed the bytes read from the input stream into our output stream
output.write(data, 0, count);
}
// Flushing the out stream.
output.flush();
// closing streams
output.close();
input.close();
} catch (Exception e) {
Log.e("Error: ", e.getMessage());
}
This snippet does networking stuff so you need to run it on a background thread. I hope my answer helps you, if not, let me know what else can I do for you.
I have a large size of the image file which is nearly 16MB size. I want to load this image in my imageView and zoom it after that add markers. I tried this with subsampling-scale-image-view. I am following the below link https://github.com/davemorrissey/subsampling-scale-image-view .
The important point is I am loading image from url. The above library not supporting that. So I just downloaded the image and save to SD card after that load from that local file. Technically which is working.
Issue:
Now the issue is it is taking too much of time for the first time downloading. Also even second time it takes nearly a minute.
My Idea:
Due to this issue, I try to load image byte by byte. Once the image is downloading 100bytes then show that in imageView next download the next part of the image from url. Is it possible to doing like that?
Currently I am loading image like the following code:
URL url = new URL(url_);
URLConnection conection = url.openConnection();
conection.connect();
// getting file length
int lenghtOfFile = conection.getContentLength();
// input stream to read file - with 8k buffer
InputStream input = new BufferedInputStream(url.openStream(), 8192);
// Output stream to write file
OutputStream output = new FileOutputStream(root+"/"+ fileName);
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
// writing data to file
output.write(data, 0, count);
}
// flushing output
output.flush();
// closing streams
output.close();
input.close();
runOnUiThread(new Runnable() {
#Override
public void run() {
image.setImage(ImageSource.uri(root+"/"+ fileName));
}
});
Can somebody help me to solve this riddle?
Note: If there are any possibilities other than this library pls add your suggestions.
Never tried this but you can check if this work.
Get the data from url in form of byte Array.
data = getImageStream(url); //should call in async Task..
Now convert byte array into bitmap and set in imageView.
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
image.setImageBitmap(bitmap)
Not writing into file.This will help with some performance improvement.
public byte[] getImageStream(String url){
ByteArrayOutputStream baos = new ByteArrayOutputStream();
InputStream is = null;
try {
is = url.openStream ();
byte[] byteChunk = new byte[4096]; // Or whatever size you want to read in at a time.
int n;
while ( (n = is.read(byteChunk)) > 0 ) {
baos.write(byteChunk, 0, n);
}
}
catch (IOException e) {
System.err.printf ("Failed while reading bytes from %s: %s", url.toExternalForm(), e.getMessage());
e.printStackTrace ();
// Perform any other exception handling that's appropriate.
}
finally {
if (is != null) { is.close(); }
}
return baos.toByteArray();
}
I have stored some image in the device private storage like:
InputStream inputStream = response.getEntity().getContent();
FileOutputStream fileOutputStream = openFileOutput("someImage.jpeg", cont.MODE_PRIVATE);
int read = 0;
byte[] buffer = new byte[32768];
while((read = inputStream.read(buffer)) > 0) {
fileOutputStream.write(buffer, 0, read);
}
fileOutputStream.close();
inputStream.close();
Then I want to read that image and store it as bitmap to show it to the user, I don't know what to do to accomplish this! I want to read the image again from the private storage, then convert it to bitmap.
any experience?
What you need here is BitmapFactory.decodeStream(String name).
First, get an inputstream:
InputStream input = openFileInput("someImage.jpeg");
Next, use that to get a bitmap:
Bitmap bmp = BitmapFactory.decodeStream(input);
Don't forget to close your inputstream afterwards!
I need to get image from the web and store it in the phone for later use.
I tryed this:
public Drawable grabImageFromUrl(String url) throws Exception
{
return Drawable.createFromStream((InputStream)new URL(url).getContent(), "src");
}
So this my function to grab image from Url, i just need a proccess to get the returned drawable and save.
How can i do that ?
see this complete example give here
http://android-example-code.blogspot.in/p/download-store-and-read-images-from.html
Based off here, you can actually download the image using a different method. Is it absolutely necessary that you store it as a drawable before saving it? Because I think you could save it first, and THEN open it, if need be.
URL url = new URL ("file://some/path/anImage.png");
InputStream input = url.openStream();
try {
//The sdcard directory e.g. '/sdcard' can be used directly, or
//more safely abstracted with getExternalStorageDirectory()
String storagePath = Environment.getExternalStorageDirectory();
OutputStream output = new FileOutputStream (storagePath + "/myImage.png");
try {
byte[] buffer = new byte[aReasonableSize];
int bytesRead = 0;
while ((bytesRead = input.read(buffer, 0, buffer.length)) >= 0) {
output.write(buffer, 0, bytesRead);
}
} finally {
output.close();
}
} finally {
input.close();
}
I've got the URL of a .png image, that needs to be downloaded and set as a source of an ImageView. I'm a beginner so far, so there are a few things I don't understand:
1) Where do I store the file?
2) How do I set it to the ImageView in java code?
3) How to correctly override the AsyncTask methods?
Thanks in advance, will highly appreciate any kind of help.
I'm not sure you can explicity build a png from a download. However, here is what I use to download images and display them into Imageviews :
First, you download the image :
protected static byte[] imageByter(Context ctx, String strurl) {
try {
URL url = new URL(urlContactIcon + strurl);
InputStream is = (InputStream) url.getContent();
byte[] buffer = new byte[8192];
int bytesRead;
ByteArrayOutputStream output = new ByteArrayOutputStream();
while ((bytesRead = is.read(buffer)) != -1) {
output.write(buffer, 0, bytesRead);
}
return output.toByteArray();
} catch (MalformedURLException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
And then, create a BitMap and associate it to the Imageview :
bytes = imagebyter(this, mUrl);
bm = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
yourImageview.setImageBitmap(bm);
And that's it.
EDIT
Actually, you can save the file by doing this :
File file = new File(fileName);
FileOutputStream fos = new FileOutputStream(file);
fos.write(imagebyter(this, mUrl));
fos.close();
You can explicity build a png from a download.
bm.compress(Bitmap.CompressFormat.PNG, 100, out);
100 is your compression (PNG's are generally lossless so 100%)
out is your FileOutputStream to the file you want to save the png to.