我正在设计用于从Android到无线本地打印机打印的android应用程序。应用程序正在运行但在logcat中显示错误，“打印机无法解析或支持”。我使用的打印机是Brother QL-710W，具有无线连接。 这背后的原因是什么。
代码如下。
主要活动
import android.os.Bundle;
import android.print.PrintDocumentAdapter;
import android.print.PrintManager;
import android.print.PrinterInfo;
import android.support.v4.print.PrintHelper;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.view.Menu;
import android.view.View;
public class MainActivity extends Activity
{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public void onClick(View v)
{
if(v.getId()==R.id.button1)
{
CustomDocumentAdaptor adaptor=new CustomDocumentAdaptor(getApplicationContext(), BitmapFactory.decodeResource(getResources(), R.drawable.dmg), "Mandar", "Kuch bhi");
PrintPdf("test.pdf", adaptor);
}
}
private void PrintPdf(String jobName, PrintDocumentAdapter adaptor)
{
if(PrintHelper.systemSupportsPrint())
{
PrintManager manager=(PrintManager)getSystemService(Context.PRINT_SERVICE);
manager.print(jobName, adaptor, null);
}
}
用于pdf打印的CustomDocumentAdaptor如下
import java.io.FileOutputStream;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.pdf.PdfDocument;
import android.os.Bundle;
import android.os.CancellationSignal;
import android.os.ParcelFileDescriptor;
import android.print.PageRange;
import android.print.PrintAttributes;
import android.print.PrintDocumentAdapter;
import android.print.PrintDocumentInfo;
import android.print.pdf.PrintedPdfDocument;
public class CustomDocumentAdaptor extends PrintDocumentAdapter
{
private Paint paint=new Paint();
private Context myContext;
private Bitmap myBitmap;
private String myName,message;
PrintedPdfDocument pdfDocument;
public CustomDocumentAdaptor(Context context,Bitmap bitmap,String Name,String msg)
{
myContext=context;
myBitmap=bitmap;
myName=Name;
message=msg;
}
@Override
public void onLayout(PrintAttributes arg0, PrintAttributes arg1, CancellationSignal arg2, LayoutResultCallback arg3, Bundle arg4)
{
pdfDocument=new PrintedPdfDocument(myContext, arg1);
if(arg2.isCanceled())
{
arg3.onLayoutCancelled();
return;
}
int pages=1;
PrintDocumentInfo info=new PrintDocumentInfo.Builder("test.pdf")
.setContentType(PrintDocumentInfo.CONTENT_TYPE_DOCUMENT)
.setPageCount(pages).build();
arg3.onLayoutFinished(info, true);
}
@Override
public void onWrite(PageRange[] arg0, ParcelFileDescriptor arg1,
CancellationSignal arg2, WriteResultCallback arg3)
{
if(pdfDocument==null)
{
return;
}
PdfDocument.Page page=pdfDocument.startPage(0);
if(arg2.isCanceled())
{
arg3.onWriteCancelled();
pdfDocument.close();
pdfDocument=null;
return;
}
onDraw(page.getCanvas());
pdfDocument.finishPage(page);
try
{
pdfDocument.writeTo(new FileOutputStream(arg1.getFileDescriptor()));
}
catch(Exception e)
{
}
finally
{
pdfDocument.close();
pdfDocument=null;
}
arg3.onWriteFinished(arg0);
}
public void onDraw(Canvas canvas)
{
paint.setTextSize(14);
paint.setColor(Color.BLACK);
canvas.drawText(myName, 25, 25, paint);
canvas.drawBitmap(myBitmap,35,55 , paint);
}
}
logcat如下
01-17 16:18:23.159: D/PRINT_LIB(20142): Response from /192.168.1.1:161
01-17 16:18:23.159: E/SnmpDiscovery(20142): Error while reading SNMP response.
01-17 16:18:23.159: E/SnmpDiscovery(20142): java.net.ProtocolException: SNMP error: 2
01-17 16:18:23.159: E/SnmpDiscovery(20142): at com.hp.mobileprint.discoveryservice.parsers.DeviceStatus.<init>(DeviceStatus.java:117)
01-17 16:18:23.159: E/SnmpDiscovery(20142): at com.hp.mobileprint.discoveryservice.SnmpDiscovery.parseResponse(SnmpDiscovery.java:78)
01-17 16:18:23.159: E/SnmpDiscovery(20142): at com.hp.mobileprint.discoveryservice.MultiProtocolDiscovery.parseResponse(MultiProtocolDiscovery.java:91)
01-17 16:18:23.159: E/SnmpDiscovery(20142): at com.hp.mobileprint.printservice.tasks.LocalPrinterDiscoveryTask.processIncomingPacket(LocalPrinterDiscoveryTask.java:177)
01-17 16:18:23.159: E/SnmpDiscovery(20142): at com.hp.mobileprint.printservice.tasks.LocalPrinterDiscoveryTask.receiveResponsePackets(LocalPrinterDiscoveryTask.java:136)
01-17 16:18:23.159: E/SnmpDiscovery(20142): at com.hp.mobileprint.printservice.tasks.LocalPrinterDiscoveryTask.doInBackground(LocalPrinterDiscoveryTask.java:77)
01-17 16:18:23.159: E/SnmpDiscovery(20142): at com.hp.mobileprint.printservice.tasks.LocalPrinterDiscoveryTask.doInBackground(LocalPrinterDiscoveryTask.java:51)
01-17 16:18:23.159: E/SnmpDiscovery(20142): at android.os.AsyncTask$2.call(AsyncTask.java:288)
01-17 16:18:23.159: E/SnmpDiscovery(20142): at java.util.concurrent.FutureTask.run(FutureTask.java:237)
01-17 16:18:23.159: E/SnmpDiscovery(20142): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
01-17 16:18:23.159: E/SnmpDiscovery(20142): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
01-17 16:18:23.159: E/SnmpDiscovery(20142): at java.lang.Thread.run(Thread.java:841)
01-17 16:18:23.159: W/PRINT_LIB(20142): Printer could not be parsed or is not supported.
01-17 16:18:23.159: D/PRINT_LIB(20142): Response from /192.168.1.1:161
01-17 16:18:23.169: E/SnmpDiscovery(20142): Error while reading SNMP response.
01-17 16:18:23.169: E/SnmpDiscovery(20142): java.net.ProtocolException: SNMP error: 2
01-17 16:18:23.169: E/SnmpDiscovery(20142): at com.hp.mobileprint.discoveryservice.parsers.DeviceStatus.<init>(DeviceStatus.java:117)
01-17 16:18:23.169: E/SnmpDiscovery(20142): at com.hp.mobileprint.discoveryservice.SnmpDiscovery.parseResponse(SnmpDiscovery.java:78)
01-17 16:18:23.169: E/SnmpDiscovery(20142): at com.hp.mobileprint.discoveryservice.MultiProtocolDiscovery.parseResponse(MultiProtocolDiscovery.java:91)
01-17 16:18:23.169: E/SnmpDiscovery(20142): at com.hp.mobileprint.printservice.tasks.LocalPrinterDiscoveryTask.processIncomingPacket(LocalPrinterDiscoveryTask.java:177)
01-17 16:18:23.169: E/SnmpDiscovery(20142): at com.hp.mobileprint.printservice.tasks.LocalPrinterDiscoveryTask.receiveResponsePackets(LocalPrinterDiscoveryTask.java:136)
01-17 16:18:23.169: E/SnmpDiscovery(20142): at com.hp.mobileprint.printservice.tasks.LocalPrinterDiscoveryTask.doInBackground(LocalPrinterDiscoveryTask.java:77)
01-17 16:18:23.169: E/SnmpDiscovery(20142): at com.hp.mobileprint.printservice.tasks.LocalPrinterDiscoveryTask.doInBackground(LocalPrinterDiscoveryTask.java:51)
01-17 16:18:23.169: E/SnmpDiscovery(20142): at android.os.AsyncTask$2.call(AsyncTask.java:288)
01-17 16:18:23.169: E/SnmpDiscovery(20142): at java.util.concurrent.FutureTask.run(FutureTask.java:237)
01-17 16:18:23.169: E/SnmpDiscovery(20142): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
01-17 16:18:23.169: E/SnmpDiscovery(20142): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
01-17 16:18:23.169: E/SnmpDiscovery(20142): at java.lang.Thread.run(Thread.java:841)
01-17 16:18:23.169: W/PRINT_LIB(20142): Printer could not be parsed or is not supported.
01-17 16:18:23.169: D/PRINT_LIB(20142): Response from /192.168.1.35:5353
01-17 16:18:23.169: D/BonjourParser(20142): Found PDL service without support for HP PCL: Brother QL-710W._pdl-datastream._tcp.local