如何从Android平板电脑通过WiFi打印机打印简单文本

Question

正在开发一个需要打印选项的Android应用程序。我用下面的代码的WiFi打印机要做到这一点，但它给Networkonmainthread exception

try { 
    Socket sock = new Socket("192.168.199.245", 9100); // ip and port of printer 
    PrintWriter oStream = new PrintWriter(sock.getOutputStream()); 
    oStream.println("\t\t Text to The Printer"); 
    oStream.println("\n\n\n"); 
    oStream.close(); 
    sock.close(); 
} catch (UnknownHostException e) { 
    e.printStackTrace(); 
} catch (IOException e) { 
    e.printStackTrace(); 
} 

有没有人知道如何做到这一点？我需要在无线网络打印机打印一个示例代码.....感谢

Answer 1

我的代码工作： WifiPrint.java

公共类WifiPrint延伸活动{TextView的打印机名称， gate_way，printer_port; int port = 9100; WifiManager wifi = null; android.net.DhcpInfo d;字符串gateway_ip =“”;

@Override保护无效的onCreate（Bundle savedInstanceState）{ super.onCreate（savedInstanceState）; setContentView（R.layout.activity_wifi_print）; wifi =（WifiManager） getSystemService（Context.WIFI_SERVICE）; printer_name =（TextView） findViewById（R.id.textView1）; gate_way =（TextView） findViewById（R.id.textView2）; printer_port =（TextView） findViewById（R.id.textView3）; /* de.lohndirekt.print.IppPrintService svc = new IppPrintService（printerURI）; InputStream stream = new BufferedInputStream（new FileInputStream（“image.epl”））; DocFlavor flavor = DocFlavor.INPUT_STREAM.AUTOSENSE; Doc myDoc = new SimpleDoc（stream，flavor，null）; DocPrintJob job = svc.createPrintJob（）; job.print（myDoc，NULL）; */

}

@覆盖公共布尔onCreateOptionsMenu（菜单菜单）{// 充气菜单;这会将项目添加到操作栏（如果存在）。 getMenuInflater（）。inflate（R.menu.wifi_print，menu）;返回true; }

公共无效wifisettings（视图v）{startActivityForResult（新 意图（ android.provider.Settings.ACTION_WIFI_SETTINGS），0）; }

公共无效connectSocket（视图v）{
/*乌里文件路径= Uri.parse（ “android.resource：//” + getPackageName（）+ “/” + R.raw.pdfsample）; Toast.makeText（this，filepath.getPath（），Toast.LENGTH_LONG）.show（）; */ClientThread clientThread = new ClientThread（“”）;线程clientstartThread = new 线程（clientThread）; clientstartThread.start（）; }

公共字符串intToIp（int i）以{返回（第（i &为0xFF）+ “” +（（I >> 8） &为0xFF）+ “” +（（I >> 16）& 0xFF的） +“。”+（（i >> 24）& 0xFF））; }

@覆盖保护无效onActivityResult（INT requestCode，整数 resultCode为，意图数据）{// TODO自动生成方法存根

super.onActivityResult(requestCode, resultCode, data);  if 

（requestCode == 0）{WifiInfo wifiinfo = wifi.getConnectionInfo （）; d = wifi。getDhcpInfo（）;

 printer_name.setText("Name:" + wifiinfo.getSSID());    gateway_ip = 

intToIp（d.gateway）; gate_way.setText（“Printer Ip：”+ gateway_ip）; printer_port.setText（“Port：”+ port）;

} } 

公共文件createFileFromInputStream（InputStream的的inputStream）{

try{ 
    File f = new File("/sdcard/testpdf.pdf"); 
    OutputStream outputStream = new FileOutputStream(f); 
    byte buffer[] = new byte[1024]; 
    int length = 0; 

    while((length=inputStream.read(buffer)) > 0) { 
     outputStream.write(buffer,0,length); 
    } 

    outputStream.close(); 
    inputStream.close(); 

    return f; 
}catch (IOException e) { 
     //Logging exception 
} 

return null;  } 

类ClientThread实现Runnable {字符串文件路径= “”; BufferedInputStream bis = null; FileInputStream fis;

Socket socket; 

    public ClientThread(String filename) {   filepath = filename;  } 

    @Override  public void run() {    // TODO Auto-generated method 

存根尝试{
的InputStream在= getResources（）openRawResource（R.raw.pdfsample）。 createFileFromInputStream（in）; File pdfFile = new File（“/ sdcard/testpdf.pdf”）; byte [] mybytearray = new byte [（int）pdfFile.length（）]; socket = new Socket（gateway_ip，port）; runOnUiThread（新的Runnable（）{
@Override 公共无效的run（）{// TODO自动生成方法存根 如果（socket.isConnected（））{ Toast.makeText（WifiPrint.this， “插座连接“， Toast.LENGTH_LONG）.show（）;
}
} }）;
fis = new FileInputStream（pdfFile）; bis = new BufferedInputStream（fis）; bis.read（mybytearray，0，mybytearray.length）; OutputStream os = socket.getOutputStream（）; os.write（mybytearray，0，mybytearray.length）; os.flush（）;

  if (bis != null) { 
       bis.close(); 
       os.close(); 
       socket.close(); 
       fis.close(); 

      } 
       } catch (final UnknownHostException e) { 
      // TODO Auto-generated catch block 
      runOnUiThread(new Runnable() { 

       @Override 
       public void run() { 
        // TODO Auto-generated method stub 
        Toast.makeText(WifiPrint.this, 
          "UnHost Exceptions" + e.getMessage(), 
          Toast.LENGTH_LONG).show(); 

       } 
      });    } catch (final IOException e) { 
      // TODO Auto-generated catch block 
      runOnUiThread(new Runnable() { 

       @Override 
       public void run() { 
        // TODO Auto-generated method stub 
        Toast.makeText(WifiPrint.this, 
          "Io Exceptions" + e.getMessage(), 
          Toast.LENGTH_LONG).show(); 

       } 
      });    } finally { 
      try { 
       if (bis != null) { 
        bis.close(); 
        socket.close(); 
        fis.close(); 
       } 
      } catch (final IOException e) { 
       // TODO Auto-generated catch block 
       runOnUiThread(new Runnable() { 
        @Override 
        public void run() { 
         // TODO Auto-generated method stub 
         Toast.makeText(
           WifiPrint.this, 
           "Io Exeption in Closing Socket" 
             + e.getMessage(), Toast.LENGTH_LONG) 
           .show(); 
        } 
       }); 
      }   }  } 

}

}

而且清单文件添加某些permssions：

<uses-feature android:name="android.hardware.wifi" />