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Sometimes, we need read an image in assets directory to display in android, at this situation, we may need read data of image into a byte array so that we can use it in other place of our program. To read data of an image into a byte data is very simple, we can do like this:

Step 1: Put an image into assets directory in Android project

Before we start to coding, we should place an image into assets directory in android project, it may like this:

Step 2: Read data of image into a byte array

After we have place an image into assets directory, we can read its data into a byte array, this sample code realize read data of an image  in assets directory into a byte array, then display it on imageview.

Smaple code like this:

public void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 ImageView imageView = (ImageView) this.findViewById(R.id.image_id);
 //read an image in assets
 byte[] data = readImageFromAssets("logo.png");
 Bitmap bitmap = null;
 try {
 bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
 } catch(Exception e) {
 if(null != bitmap) {
 bitmap.recycle();
 bitmap = null;
 }
 }
 if(bitmap != null) {
 Drawable drawable =new BitmapDrawable(bitmap);
 imageView.setBackgroundDrawable(drawable);
 }
 }
 /** read a image into byte array from assets */
 private byte[] readImageFromAssets(String imageName) {
 InputStream is = null;
 ByteArrayOutputStream out = null;
 try {
 is = getBaseContext().getAssets().open(imageName);
 out = new ByteArrayOutputStream(1024);
 byte[] temp = new byte[1024];
 int size = 0;
 while ((size = is.read(temp)) != -1) {
 out.write(temp, 0, size);
 }
 byte[] content = out.toByteArray();

 if(is != null) {
 is.close();
 }
 if(out != null) {
 out.close();
 }
 return content;
 } catch (IOException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 } finally {

 }
 return null;

 }