Conversion from Arraylist<Byte> to byte array in android

Question

I have a arraylist of Bytes and i am converting them into a byte array.I have used the following method.However it gives me the following error: E/AndroidRuntime(5228): java.lang.NoClassDefFoundError: com.google.common.primitives.Bytes

ArrayList<Byte> byteArrayList_song=new ArrayList<Byte>();
byte[] bytes_song_byte;

 for(int i=0;i<int_arraylist.size();i++)
 {
            bytes_song_byte=Bytes.toArray(byteArrayList_song);                
 }

Alex DiCarlo · Accepted Answer · 2013-01-14 07:37:47Z

2

Looks like Google Guava is not on your class path, also you should remove the for loop from the above code, as that is what the Guava function does for you.

ArrayList<Byte> byteArrayList_song = new ArrayList<Byte>();
byte[] bytes_song_byte = Bytes.toArray(byteArrayList_song);

answered Jan 14, 2013 at 7:37

Alex DiCarlo

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1 Comment

Joyson Over a year ago

Thanks dicarlo2 But i have add the library as a external jar file into my project.Bulid Path->Configure Build Path->Add External Jars.Do i need to make any more changes?

Evgeniy Dorofeev · Accepted Answer · 2013-01-14 07:48:09Z

1

You can do this conversion without external libs

    byte[] bytes_song_byte = new byte[byteArrayList_song.size()];
    for (int i = 0; i < byteArrayList_song.size(); i++) {
        bytes_song_byte[i] = byteArrayList_song.get(i);
    }

note that if byteArrayList_song has any null elements this code will throw a NullPointerException

answered Jan 14, 2013 at 7:48

Evgeniy Dorofeev

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4 Comments

Alex DiCarlo Over a year ago

Indeed you could but, the purpose of all of Guava's convenience functions like Bytes.toArray is exactly that, for convenience. No reason to type the above when it can be wrapped up in a function for you.

Alex DiCarlo Over a year ago

With that said, would I include an entire external library just to use a couple of toArray functions? Probably not, I'd just write them myself.

Joyson Over a year ago

I tried the above code but when i try print the size of the bytes_song_byte it gives me null

Evgeniy Dorofeev Over a year ago

You probably mean 0. Your ArrayList is probably empty, add some values: byteArrayList_song.add(true); byteArrayList_song.add(false);

Priya · Accepted Answer · 2013-01-14 07:39:04Z

-1

Try the following

      ArrayList<Byte> byteArrayList_song=new ArrayList<Byte>();
        byte[] bytes_song_byte;
        bytes_song_byte=byteArrayList_song.toArray(new Byte[byteArrayList_song.size()]);

answered Jan 14, 2013 at 7:39

Priya

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