Question

我在标题中怎么说，我需要在我的应用程序上实现系统打印，我添加此类并实现此代码，但是我不明白为什么当我点击代表“打印”的“ Stampa”时，纸张会出来但没有印任何东西。我该如何解决？（我使用Printooth库）我也尝试使用互联网上的不同代码，我发现每个人都遇到同样的问题代码：

package com.example.testaapplication0209;



import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Button;
import android.widget.Toast;

import com.mazenrashed.printooth.Printooth;
import com.mazenrashed.printooth.data.printable.Printable;
import com.mazenrashed.printooth.data.printable.RawPrintable;
import com.mazenrashed.printooth.data.printable.TextPrintable;
import com.mazenrashed.printooth.data.printer.DefaultPrinter;
import com.mazenrashed.printooth.ui.ScanningActivity;
import com.mazenrashed.printooth.utilities.Printing;
import com.mazenrashed.printooth.utilities.PrintingCallback;

import java.util.ArrayList;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

public class PrintActivity extends AppCompatActivity implements PrintingCallback {

    Printing printing;
    Button btn_unpair_pair, btn_print;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_print);
        Printooth.INSTANCE.init(this);
        printing = Printooth.INSTANCE.printer();

        initViews();
    }

    private void initViews() {
        btn_print = findViewById(R.id.btn_print);
        btn_unpair_pair = findViewById(R.id.btn_pair_unpair);

        if (printing != null)
            printing.setPrintingCallback(this);


        btn_print.setOnClickListener(view -> {
            if (!Printooth.INSTANCE.hasPairedPrinter())
                startActivityForResult(new Intent(PrintActivity.this, ScanningActivity.class), ScanningActivity.SCANNING_FOR_PRINTER);
            else
                printText();
        });

        changePairAndUnpair();

    }

    private void printText() {
        ArrayList<Printable> printables = new ArrayList<>();
        printables.add(new RawPrintable.Builder(new byte[]{27, 100, 4}).build());

        //Add Text
        printables.add(new TextPrintable.Builder().setText("Hello World: Jagadeesh")
                .setCharacterCode(DefaultPrinter.Companion.getCHARCODE_PC1252())
                .setNewLinesAfter(1)
                .build());

        //Custom Text
        printables.add(new TextPrintable.Builder()
                .setText("Hello World")
                .setLineSpacing(DefaultPrinter.Companion.getLINE_SPACING_60())
                .setAlignment(DefaultPrinter.Companion.getALIGNMENT_CENTER())
                .setEmphasizedMode(DefaultPrinter.Companion.getEMPHASIZED_MODE_BOLD())
                .setUnderlined(DefaultPrinter.Companion.getUNDERLINED_MODE_ON())
                .setNewLinesAfter(1)
                .build());

        printing.print(printables);
    }


    private void changePairAndUnpair() {
        if (Printooth.INSTANCE.hasPairedPrinter())
            btn_unpair_pair.setText(new StringBuilder("Unpair ").append(Printooth.INSTANCE
                    .getPairedPrinter().getName()).toString());
        else
            btn_unpair_pair.setText("Pair with Printer");
    }


    @Override
    public void connectingWithPrinter() {
        Toast.makeText(this, "Connecting to Printer", Toast.LENGTH_SHORT).show();
    }

    @Override
    public void connectionFailed(String s) {
        Toast.makeText(this, "Failed: " + s, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onError(String s) {
        Toast.makeText(this, "Error: " + s, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onMessage(String s) {
        Toast.makeText(this, "Message: " + s, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void printingOrderSentSuccessfully() {
        Toast.makeText(this, "Order sent to printer", Toast.LENGTH_SHORT).show();
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == ScanningActivity.SCANNING_FOR_PRINTER && resultCode == Activity.RESULT_OK)
            initPrinting();
        changePairAndUnpair();
    }

    private void initPrinting() {
        if (!Printooth.INSTANCE.hasPairedPrinter())
            printing = Printooth.INSTANCE.printer();
        if (printing != null)
            printing.setPrintingCallback(this);
    }
}

Answer 1

更改代码的这一行：

printing.print(printables);

对此：

Printooth.INSTANCE.printer().print(printables);

Android打印机，纸张出来但不打印

1 个答案: