MethodHandle.invoke and MethodHandle.invokeExact are only supported starting with Android O (--min-api 26)

Question

I am developing an application in android in which i want to print the Image on reciept using thermal printer.

To achive this task i have added the escpos-coffee package in my application.

To print image it is using import java.imageio.BufferedImage, to read image it is using ImageIO.read(file) method both classes are located in rt.jar library which i have externally added in the project.

But when i try to build it, it thorws error :

Error: MethodHandle.invoke and MethodHandle.invokeExact are only supported starting with Android O (--min-api 26)

Before that my sdk version versions were changed, then changed the min sdk to 5.1 and (target & compile skd version to 7.0) then it started throwing.

Any help in detail will be appreciated.

Thank you.

Answer 1

you need to use SNAPSHOT version com.github.anastaciocintra:escpos-coffee:4.0.0-SNAPSHOT

(SNAPSHOT yet...)

and, after that, implement CoffeImage interface: (CoffeeImageAndroidImpl.java)

import android.graphics.Bitmap;

import com.github.anastaciocintra.escpos.image.CoffeeImage;

public class CoffeeImageAndroidImpl implements CoffeeImage {
    private Bitmap bitmap;

    public CoffeeImageAndroidImpl(Bitmap bitmap) {
        this.bitmap = bitmap;
    }


    @Override
    public int getWidth() {
        return bitmap.getWidth();
    }

    @Override
    public int getHeight() {
        return bitmap.getHeight();
    }

    @Override
    public CoffeeImage getSubimage(int x, int y, int w, int h) {
        return new CoffeeImageAndroidImpl(bitmap.createBitmap(this.bitmap,x,y,w,h));
    }

    @Override
    public int getRGB(int x, int y) {
        return bitmap.getPixel(x, y);
    }
}

and ... print with image like this:

...

            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inScaled = false;

            Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.dog, options);
            RasterBitImageWrapper imageWrapper = new RasterBitImageWrapper();
            escpos.writeLF("BitonalOrderedDither()");
            // using ordered dither for dithering algorithm with default values
            Bitonal algorithm = new BitonalOrderedDither();
            EscPosImage escposImage = new EscPosImage(new CoffeeImageAndroidImpl(bitmap), algorithm);
            escpos.write(imageWrapper, escposImage);
            escpos.feed(5).cut(EscPos.CutMode.FULL);



...

read more and get github sample on: https://github.com/anastaciocintra/escpos-coffee/issues/9#issuecomment-541343942