Flutter-printer/android/src/main/java/edesarrollos/printer/PrinterPlugin.java

package edesarrollos.printer;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.os.Handler;
import android.os.Looper;

import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
import io.flutter.plugin.common.MethodChannel.Result;
import io.flutter.plugin.common.PluginRegistry.Registrar;

import com.qs.helper.printer.Device;
import com.qs.helper.printer.bt.*;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.nio.Buffer;
import java.nio.IntBuffer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * PrinterPlugin
 */
public class PrinterPlugin implements MethodCallHandler {
  private BtService BlueService;
  private static final int EstadoConectado = 3;

  private PrinterPlugin(Activity activity) {
    Handler controlador = new Handler(Looper.getMainLooper());
    Handler controladorSecundario = new Handler(Looper.getMainLooper());
    BlueService = new BtService(activity, controlador, controladorSecundario);
  }

  /**
   * Plugin registration.
   */
  public static void registerWith(Registrar registrar) {
    final MethodChannel channel = new MethodChannel(registrar.messenger(), "printer");
    channel.setMethodCallHandler(new PrinterPlugin(registrar.activity()));
  }

  @Override
  public void onMethodCall(MethodCall call, Result result) {
    switch (call.method) {
      case "getPlatformVersion":
        result.success("Android " + android.os.Build.VERSION.RELEASE);
        break;
      case "getDeviceList":
        Map<String, String> map = new HashMap<>();
        for (Device d : BlueService.getDeviceList()) {
          map.put(d.deviceAddress, d.deviceName);
        }
        result.success(map);
        break;
      case "isConnected":
        result.success(BlueService.getState() == EstadoConectado);
        break;
      case "connect":
        int intentos = 5;
        String mac = call.argument("mac");
        if (mac == null || mac.trim().length() == 0) {
          result.success(false);
          break;
        }
        do {
          if (intentos == 0) {
            result.success(false);
            break;
          }
          if (BlueService.getState() == EstadoConectado) {
            result.success(true);
            break;
          }
          for (Device dispositivo : BlueService.getDeviceList()) {
            if (dispositivo.deviceAddress.equals(mac)) {
              if (BlueService.getState() != EstadoConectado) {
                intentos--;
                BlueService.connect(dispositivo.deviceAddress);
              } else {
                result.success(true);
              }
              break;
            }
          }
          try {
            Thread.sleep(1000);
          } catch (Exception e) {
            System.out.print("No se puede detener el hilo");
            result.success(false);
            break;
          }
          if (BlueService.getState() == EstadoConectado) {
            result.success(true);
            break;
          }
        } while (BlueService.getState() != 3);
        break;
      case "printText":
        String texto = call.argument("text");
        if (texto == null || texto.trim().length() == 0) {
          result.success(false);
          break;
        }
        BlueService.printText(texto);
        result.success(true);
        break;
      case "printBitmap":
        byte[] mapa = call.argument("map");
        if (mapa == null) {
          result.success(false);
          break;
        }
        Bitmap bitmap = BitmapFactory.decodeByteArray(mapa, 0, mapa.length);

        // change transparent bitmap background to white
        Bitmap newBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig());
        Canvas canvas = new Canvas(newBitmap);
        canvas.drawColor(Color.WHITE);
        canvas.drawBitmap(bitmap, 0, 0, null);

        //crop bounding white color
        newBitmap = ImageUtils.cropBitmapToBoundingBox(newBitmap, Color.WHITE);

        // get inputStream from bitmap
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        newBitmap.compress(Bitmap.CompressFormat.PNG, 0 /*ignored for PNG*/, bos);
        byte[] bitmapdata = bos.toByteArray();
        ByteArrayInputStream bs = new ByteArrayInputStream(bitmapdata);

        BlueService.printImage(BitmapFactory.decodeStream(bs));
        result.success(true);
        break;
      case "printBitmap2":
        byte[] mapa2 = call.argument("map");
        if (mapa2 == null) {
          result.success(false);
          break;
        }
        Bitmap bitmap2 = BitmapFactory.decodeByteArray(mapa2, 0, mapa2.length);
        BlueService.printImage2(bitmap2);
        result.success(true);
        break;
      case "disconnect":
        result.success(BlueService.disconnect());
        break;
      default:
        result.notImplemented();
        break;
    }
  }

  private int[] convertIntegers(List<Integer> integers) {
    int[] ret = new int[integers.size()];
    Iterator<Integer> iterator = integers.iterator();
    for (int i = 0; i < ret.length; i++) {
      ret[i] = iterator.next().intValue();
    }
    return ret;
  }
}