Question

I am quite new to android. I want to save image to internal memory and later retrieve the image from internal memory and load it to image view. I have successfully stored the image in internal memory using the following code :

void saveImage() {
    String fileName="image.jpg";
    //File file=new File(fileName);
    try 
    {

       FileOutputStream fOut=openFileOutput(fileName, MODE_PRIVATE);
       bmImg.compress(Bitmap.CompressFormat.JPEG, 100, fOut);

    }
    catch (Exception e) 
    {
       e.printStackTrace();
    }
}

using this code image is saved. But when i try to retrieve the image it gives me error. The code used to retrieve the image is :

FileInputStream fin = null;

        ImageView img=new ImageView(this);
        try {
            fin = openFileInput("image.jpg");
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        byte[] bytes = null;
        try {
            fin.read(bytes);
        } catch (Exception e) {
            e.printStackTrace();
        }
        Bitmap bmp=BitmapFactory.decodeByteArray(bytes,0,bytes.length);
        img.setImageBitmap(bmp);

But i get a Null pointer exception.

I checked the file is there in internal memory at path :

/data/data/com.test/files/image.jpg

What am i doing wrong please help me out with this. I have gone through a lot of stack questions.

Answer 1

it is because your bytes array is null, instantiate it, and assign size.

 byte[] bytes = null;  // you should initialize it with some bytes size like new byte[100]
    try {
        fin.read(bytes);
    } catch (Exception e) {
        e.printStackTrace();
    }

Edit 1: I am not sure but you can do something like

byte[] bytes = new byte[fin.available()]

Edit 2 : here is a better solution, as you are reading Image,

FileInputStream fin = null;

    ImageView img=new ImageView(this);
    try {
        fin = openFileInput("image.jpg");
        if(fin !=null && fin.available() > 0) {
            Bitmap bmp=BitmapFactory.decodeStream(fin) 
            img.setImageBitmap(bmp);
         } else {
            //input stream has not much data to convert into  Bitmap
          }
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

Helped by – Jason Robinson