Create a file from drawable

Question

I have a large number of resources in my drawable folder.All are having big size more than 500KB. I have to load all these 25 images all at once in a srollView. As usual I ran out of memory. Is there any way to reduce the size of the image programmatically.

I got this function but it's parameter is a File and I don't know how to create a File from a drawable.

private Bitmap decodeFile(File f){
    Bitmap b = null;
    try {
        //Decode image size
        BitmapFactory.Options o = new BitmapFactory.Options();
        o.inJustDecodeBounds = true;

        FileInputStream fis = new FileInputStream(f);
        BitmapFactory.decodeStream(fis, null, o);
        fis.close();

        int scale = 1;
        if (o.outHeight > IMAGE_MAX_SIZE || o.outWidth > IMAGE_MAX_SIZE) {
            scale = Math.pow(2, (int) Math.round(Math.log(IMAGE_MAX_SIZE / (double) Math.max(o.outHeight, o.outWidth)) / Math.log(0.5)));
        }

        //Decode with inSampleSize
        BitmapFactory.Options o2 = new BitmapFactory.Options();
        o2.inSampleSize = scale;
        fis = new FileInputStream(f);
        b = BitmapFactory.decodeStream(fis, null, o2);
        fis.close();
    } catch (FileNotFoundException e) {
    }
    return b;
}

I have to go thorugh this screen cyclically many times after a number of traversal the system is showing Low memory and it is removing the other views in the back from the stack , but I actually need it. Please help me.

Answer 1

You can open an InputStream from your drawable resource using following code:

InputStream is = getResources().openRawResource(id);

here id is the identifier of your drawable resource. for eg: R.drawable.abc

Now using this input stream you can create a file. If you also need help on how create a file using this input stream then tell me.

Update: to write data in a file:

try
    {
    File f=new File("your file name");
    InputStream inputStream = getResources().openRawResource(id);
    OutputStream out=new FileOutputStream(f);
    byte buf[]=new byte[1024];
    int len;
    while((len=inputStream.read(buf))>0)
    out.write(buf,0,len);
    out.close();
    inputStream.close();
    }
    catch (IOException e){}
    }

Answer 2

I like shortcuts so I prefer using this.

For creatting file from drawable see this.

Put this in your build.gradle

compile 'id.zelory:compressor:1.0.4'

And wherever you want to compress the image put

 Bitmap compressedImageFile = Compressor.getDefault(context).compressToBitmap(your_file);

README.md provides much more information. Sorry for bringing the answer after 6 years.

Answer 3

bro there are two methods

1. Easiest one Use some 3rd party library
2. Or use Bitmap class to scale drawable down

just use Bitmap.createScaledBitmap method to compress drawables

steps :

// Step 1 Load drawable and convert it to bitmap

Bitmap b = BitmapFactory.decodeResource( context , resId )

// Step 2 reScale your Bitmap

Bitmap nBitmap = b.createScaledBitmap( getResources() , newHieght , newWidth , true );  

// Step 3 Create a drawable from bitmap

BitmapDrawable drawable = new BitmapDrawable(nBitmap);

I highly recommend you to use 3rd part library because this method is very expensive

like https://github.com/Tourenathan-G5organisation/SiliCompressor

Answer 4

I took cue from @mudit's answer and created the drawable from Input Stream. And later loaded the drawable to the ImageView in the Adapter.

InputStream inputStream = mContext.getResources().openRawResource(R.drawable.your_id);

Bitmap b = BitmapFactory.decodeStream(inputStream);
b.setDensity(Bitmap.DENSITY_NONE);
Drawable d = new BitmapDrawable(b);
mImageView.setImageDrawable(d);

Here is the detailed version of solution