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java - Android 中的自定义 PrintService 未显示在打印机列表中

问题描述

我正在尝试为 Android 创建一个自定义 PrintService 插件，除了它没有显示在“所有打印机”下的打印机列表中，并且如果我单击“无法添加打印机”在我的打印服务下，我拥有一切手动添加打印机”。我下载了这个打印服务，它确实显示在打印机列表中，但我无法弄清楚他们的代码与我的代码有什么不同。

我的 PrintService 类：

public class MyPrintService extends PrintService {

PrinterInfo mThermalPrinter;

@Override
public void onCreate() {
    mThermalPrinter = new PrinterInfo.Builder(generatePrinterId("USB"),
            "USB Printer", PrinterInfo.STATUS_IDLE).build();
}

@Override
protected void onPrintJobQueued(PrintJob printJob) {
    Intent intent = new Intent(MyPrintService.this, MainActivity.class);
    intent.putExtra("data", printJob.getDocument().getData());
    printJob.start();
    startActivity(intent);
}

@Nullable
@Override
protected PrinterDiscoverySession onCreatePrinterDiscoverySession() {
    return new ThermalPrinterDiscoverySession(mThermalPrinter);
}

@Override
protected void onRequestCancelPrintJob(PrintJob printJob) {
    printJob.cancel();
}
}

class ThermalPrinterDiscoverySession extends PrinterDiscoverySession {

private PrinterInfo printerInfo;


ThermalPrinterDiscoverySession(PrinterInfo printerInfo) {
    PrinterCapabilitiesInfo capabilities =
            new PrinterCapabilitiesInfo.Builder(printerInfo.getId())
                    .addMediaSize(PrintAttributes.MediaSize.ISO_A5, true)
                    .addResolution(new PrintAttributes.Resolution("1234","Default",200,200), true)
                    .setColorModes(PrintAttributes.COLOR_MODE_MONOCHROME, PrintAttributes.COLOR_MODE_MONOCHROME)
                    .build();
    this.printerInfo = new PrinterInfo.Builder(printerInfo)
            .setCapabilities(capabilities)
            .build();
}

@Override
public void onStartPrinterDiscovery(List<PrinterId> priorityList) {
    List<PrinterInfo> printers = new ArrayList<PrinterInfo>();
    printers.add(printerInfo);
    addPrinters(printers);
}

@Override
public void onStopPrinterDiscovery() {

}

@Override
public void onValidatePrinters(List<PrinterId> printerIds) {

}

@Override
public void onStartPrinterStateTracking(PrinterId printerId) {

}

@Override
public void onStopPrinterStateTracking(PrinterId printerId) {

}

@Override
public void onDestroy() {

}
}

谢谢！

标签： javaandroidprinting

解决方案

原来这是 AndroidManifest.xml 的问题。

清单需要如下所示：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.dubtel.print_service">

    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        r
        <service
            android:name=".MyPrintService"
            android:permission="android.permission.BIND_PRINT_SERVICE">
            <intent-filter>
                <action android:name="android.printservice.PrintService" />
            </intent-filter>

            <meta-data
                android:name="android.printservice"
                android:resource="@xml/printservice" />
        </service>

        <activity
            android:name=".MainActivity"
            android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <!--
 ATTENTION: This was auto-generated to add Google Play services to your project for
     App Indexing.  See https://g.co/AppIndexing/AndroidStudio for more information.
        -->
        <meta-data
            android:name="com.google.android.gms.version"
            android:value="@integer/google_play_services_version" />

    </application>

</manifest>

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