Convert Arraylist

Question

I m trying to get/convert the value of Arraylist in byte[] below is my code

final ArrayList<Object> imglists = new ArrayList<Object>();

this is my arraylist of Objects in this arraylist m storing the values of images in form of bytes

for (int i=0; i<mPlaylistVideos.size();i++) {
    holder.mThumbnailImage.buildDrawingCache();
    Bitmap bitmap= holder.mThumbnailImage.getDrawingCache();
    ByteArrayOutputStream bs = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.JPEG, 50, bs);
    byte[] rough = bs.toByteArray();
    imglists.add(i,rough);
}

I m trying to get the specific value from arraylist and store that in byte[] this is what I was trying to do

byte[] value=imglists.get(2);

I could not find any complete answer to convert Arraylist of Object into byte[] I know Arraylist doesn't support primitive datatype (i-e byte)

A java object is a serializable. you can convert object to String and after that convert it to byte[]. — AmmY, Sep 24 '16 at 15:39
@DeendayalGarg nop i dont want arraylist of byte arraylist dosn't support byte[] . i just want to get the Arraylist — hatib abrar, Sep 24 '16 at 15:40
@AmmY converting into string is fine but when i convert it back into byte[] values doesn't match — hatib abrar, Sep 24 '16 at 15:40
@AmmY Arraylist doesn't support byte[] its primitive data type — hatib abrar, Sep 24 '16 at 15:41
I think this will help you. http://stackoverflow.com/a/5837739/2362301 — AmmY, Sep 24 '16 at 15:43

Nicolas Filotto · Accepted Answer · 2016-09-24T15:56:03.223

4

What you are looking for is a List of byte[], something like that:

List<byte[]> imglists = new ArrayList<>();

Then you can simply add your byte array to your List using the add(E) method as next:

imglists.add(bs.toByteArray());

You will then be able to access to a given byte array from its index in the List using the method get(int) as you try to achieve:

// Get the 3th element of my list
byte[] value = imglists.get(2);

edited Sep 24 '16 at 15:56

answered Sep 24 '16 at 15:54

Nicolas Filotto

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let me try this – hatib abrar Sep 24 '16 at 15:56
Thanks Bro this is what i was looking for Thanks Again – hatib abrar Sep 24 '16 at 16:11

score 0 · Answer 2 · answered Sep 24 '16 at 16:23

You want to convert ArrayList to byte[] ? or Object to byte[]?

I wrote in this way, just simply convert the element in ArrayList into byte[] ,it works!

    List<Object> objects = new ArrayList<Object>();

    objects.add("HelloWorld".getBytes());

    byte[] bytes = (byte[]) objects.get(0);

    System.out.println(new String(bytes));  // HelloWorld

2 Answers2