| java.lang.Object | ||||
| ↳ | android.content.Context | |||
| ↳ | android.content.ContextWrapper | |||
| ↳ | android.app.Service | |||
| ↳ | android.printservice.PrintService | |||
This is the base class for implementing print services. A print service knows how to discover and interact one or more printers via one or more protocols.
       A print service is responsible for discovering printers, adding discovered printers,
 removing added printers, and updating added printers. When the system is interested
 in printers managed by your service it will call
       
        
         onCreatePrinterDiscoverySession()
        
       
       from which you must return a new
       
        
         PrinterDiscoverySession
        
       
       instance. The returned session encapsulates the interaction
 between the system and your service during printer discovery. For description of this
 interaction refer to the documentation for
       
        
         PrinterDiscoverySession
        
       
       .
      
For every printer discovery session all printers have to be added since system does not retain printers across sessions. Hence, each printer known to this print service should be added only once during a discovery session. Only an already added printer can be removed or updated. Removed printers can be added again.
       When a new print job targeted to a printer managed by this print service is is queued,
 i.e. ready for processing by the print service, you will receive a call to
       
        
         onPrintJobQueued(PrintJob)
        
       
       . The print service may handle the print job immediately
 or schedule that for an appropriate time in the future. The list of all active print
 jobs for this service is obtained by calling
       
        
         getActivePrintJobs()
        
       
       . Active
 print jobs are ones that are queued or started.
      
       A print service is responsible for setting a print job's state as appropriate
 while processing it. Initially, a print job is queued, i.e.
       
        
         PrintJob.isQueued()
        
       
       returns true, which means that the document to be printed is
 spooled by the system and the print service can begin processing it. You can obtain
 the printed document by calling
       
        
         PrintJob.getDocument()
        
       
       whose data is accessed via
       
        
         PrintDocument.getData()
        
       
       .
 After the print service starts printing the data it should set the print job's
 state to started by calling
       
        
         start()
        
       
       after which
       
        
         PrintJob.isStarted()
        
       
       would return true. Upon successful
 completion, the print job should be marked as completed by calling
       
        
         PrintJob.complete()
        
       
       after which
       
        
         PrintJob.isCompleted()
        
       
       would return true. In case of a failure, the print job should
 be marked as failed by calling
       
        
         PrintJob.fail(
 String)
        
       
       after which
       
        
         PrintJob.isFailed()
        
       
       would
 return true.
      
       If a print job is queued or started and the user requests to cancel it, the print
 service will receive a call to
       
        
         onRequestCancelPrintJob(PrintJob)
        
       
       which
 requests from the service to do best effort in canceling the job. In case the job
 is successfully canceled, its state has to be marked as cancelled by calling
       
        
         PrintJob.cancel()
        
       
       after which
       
        
         PrintJob.isCacnelled()
        
       
       would return true.
      
       The lifecycle of a print service is managed exclusively by the system and follows
 the established service lifecycle. Additionally, starting or stopping a print service
 is triggered exclusively by an explicit user action through enabling or disabling it
 in the device settings. After the system binds to a print service, it calls
       
        
         onConnected()
        
       
       . This method can be overriden by clients to perform post binding setup.
 Also after the system unbinds from a print service, it calls
       
        
         onDisconnected()
        
       
       .
 This method can be overriden by clients to perform post unbinding cleanup. Your should
 not do any work after the system disconnected from your print service since the
 service can be killed at any time to reclaim memory. The system will not disconnect
 from a print service if there are active print jobs for the printers managed by it.
      
       A print service is declared as any other service in an AndroidManifest.xml but it must
 also specify that it handles the
       
        
         Intent
        
       
       with action
       
        
         android.printservice.PrintService
        
       
       . Failure to declare this intent
 will cause the system to ignore the print service. Additionally, a print service must
 request the
       
        
         android.permission.BIND_PRINT_SERVICE
        
       
       permission to ensure that only the system can
 bind to it. Failure to declare this intent will cause the system to ignore the print
 service. Following is an example declaration:
      
       <service android:name=".MyPrintService"
         android:permission="android.permission.BIND_PRINT_SERVICE">
     <intent-filter>
         <action android:name="android.printservice.PrintService" />
     </intent-filter>
     . . .
 </service>
      
      A print service can be configured by specifying an optional settings activity which exposes service specific settings, an optional add printers activity which is used for manual addition of printers, vendor name ,etc. It is a responsibility of the system to launch the settings and add printers activities when appropriate.
       A print service is configured by providing a
       
        
         meta-data
        
       
       entry in the manifest when declaring the service. A service declaration with a meta-data
 tag is presented below:
       
        <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>
       
      
      
       For more details for how to configure your print service via the meta-data refer to
       
        
         SERVICE_META_DATA
        
       
       and
       
        <
       
       
        
         print-service
        
       
       >
       .
      
Note: All callbacks in this class are executed on the main application thread. You should also invoke any method of this class on the main application thread.
| Constants | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| String | EXTRA_PRINT_JOB_INFO | 
         If you declared an optional activity with advanced print options via the
         
          
           advancedPrintOptionsActivity
          
         
         attribute, this extra is used to pass in the currently constructed
         
          
           PrintJobInfo
          
         
         to your activity allowing you to modify it.
         | 
       |||||||||
| String | SERVICE_INTERFACE | 
         The
         
          
           Intent
          
         
         action that must be declared as handled by a service
 in its manifest for the system to recognize it as a print service.
         | 
       |||||||||
| String | SERVICE_META_DATA | 
         Name under which a
         
          
           PrintService
          
         
         component publishes additional information
 about itself.
         | 
       |||||||||
| 
         
          [Expand]
         
          
          Inherited Constants
          
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         From class
         
          android.app.Service
         
         
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         From class
         
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         From interface
         
          android.content.ComponentCallbacks2
         
         
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| Public Constructors | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 
          | 
        
          | 
       ||||||||||
| Public Methods | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 
          | 
        
          
          Generates a global printer id given the printer's locally unique one.
          
         | 
       ||||||||||
| 
          | 
        
          
          Gets the active print jobs for the printers managed by this service.
          
         | 
       ||||||||||
| 
          | 
        
          
          Return the communication channel to the service.
          
         | 
       ||||||||||
| Protected Methods | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 
          | 
        
          
          Set the base context for this ContextWrapper.
          
         | 
       ||||||||||
| 
          | 
        
          
          The system has connected to this service.
          
         | 
       ||||||||||
| 
          | 
        
          
          Callback asking you to create a new
           
        
           
            PrinterDiscoverySession
           
          
          .
          | 
       ||||||||||
| 
          | 
        
          
          The system has disconnected from this service.
          
         | 
       ||||||||||
| 
          | 
        
          
          Called when there is a queued print job for one of the printers
 managed by this print service.
          
         | 
       ||||||||||
| 
          | 
        
          
          Called when cancellation of a print job is requested.
          
         | 
       ||||||||||
| 
         
          [Expand]
         
          
          Inherited Methods
          
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         From class
         
          android.app.Service
         
         
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         From class
         
          android.content.ContextWrapper
         
         
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         From class
         
          android.content.Context
         
         
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         From class
         
          java.lang.Object
         
         
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         From interface
         
          android.content.ComponentCallbacks
         
         
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         From interface
         
          android.content.ComponentCallbacks2
         
         
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         If you declared an optional activity with advanced print options via the
         
          
           advancedPrintOptionsActivity
          
         
         attribute, this extra is used to pass in the currently constructed
         
          
           PrintJobInfo
          
         
         to your activity allowing you to modify it. After you are
 done, you must return the modified
         
          
           PrintJobInfo
          
         
         via the same extra.
        
         You cannot modify the passed in
         
          
           PrintJobInfo
          
         
         directly, rather you
 should build another one using the
         
          
           PrintJobInfo.Builder
          
         
         class. You
 can specify any standard properties and add advanced, printer specific,
 ones via
         
          
           PrintJobInfo.Builder#putAdvancedOption(String, String)
          
         
         and
         
          
           PrintJobInfo.Builder#putAdvancedOption(String, int)
          
         
         . The advanced options
 are not interpreted by the system, they will not be visible to applications,
 and can only be accessed by your print service via
         
          
           PrintJob.getAdvancedStringOption(String)
          
         
         and
         
          
           PrintJob.getAdvancedIntOption(String)
          
         
         .
        
         If the advanced print options activity offers changes to the standard print
 options, you can get the current
         
          
           PrinterInfo
          
         
         using the
 "android.intent.extra.print.EXTRA_PRINTER_INFO" extra which will allow you to
 present the user with UI options supported by the current printer. For example,
 if the current printer does not support a give media size, you should not
 offer it in the advanced print options dialog.
        
         The
         
          
           Intent
          
         
         action that must be declared as handled by a service
 in its manifest for the system to recognize it as a print service.
        
         Name under which a
         
          
           PrintService
          
         
         component publishes additional information
 about itself. This meta-data must reference a XML resource containing a
         
          <
         
         
          
           print-service
          
         
         >
         tag. This is
 a sample XML file configuring a print service:
         
          <print-service
     android:vendor="SomeVendor"
     android:settingsActivity="foo.bar.MySettingsActivity"
     andorid:addPrintersActivity="foo.bar.MyAddPrintersActivity."
     . . .
 />
         
        
        
         For detailed configuration options that can be specified via the meta-data
 refer to
         
          
           android.R.styleable.PrintService
          
         
         .
        
         If you declare a settings or add a printers activity, they have to be exported,
 by setting the
         
          
           exported
          
         
         activity attribute to
         
          true
         
         . Also in case you want only the system to be able to start any of these
 activities you can specify that they request the android.permission
 .START_PRINT_SERVICE_CONFIG_ACTIVITY permission by setting the
         
          
           permission
          
         
         activity attribute.
        
Generates a global printer id given the printer's locally unique one.
| localId | A locally unique id in the context of your print service. | 
|---|
Gets the active print jobs for the printers managed by this service. Active print jobs are ones that are not in a final state, i.e. whose state is queued or started.
         Return the communication channel to the service.  May return null if 
 clients can not bind to the service.  The returned
         
          
           IBinder
          
         
         is usually for a complex interface
 that has been
         
          described using
 aidl
         
         .
        
Note that unlike other application components, calls on to the IBinder interface returned here may not happen on the main thread of the process . More information about the main thread can be found in Processes and Threads .
| intent | 
           The Intent that was used to bind to this service,
 as given to
           
            
             Context.bindService
            
           
           .  Note that any extras that were included with
 the Intent at that point will
           
            not
           
           be seen here.
           | 
         
|---|
Set the base context for this ContextWrapper. All calls will then be delegated to the base context. Throws IllegalStateException if a base context has already been set.
| base | The new base context for this wrapper. | 
|---|
         Callback asking you to create a new
         
          
           PrinterDiscoverySession
          
         
         .
        
The system has disconnected from this service.
Called when there is a queued print job for one of the printers managed by this print service.
| printJob | The new queued print job. | 
|---|
         Called when cancellation of a print job is requested. The service
 should do best effort to fulfill the request. After the cancellation
 is performed, the print job should be marked as cancelled state by
 calling
         
          
           cancel()
          
         
         .
        
| printJob | The print job to cancel. | 
|---|