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      1 /*
      2  * Copyright (C) 2013 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.example.android.apis.app;
     18 
     19 import android.app.Activity;
     20 import android.content.Context;
     21 import android.os.Bundle;
     22 import android.os.CancellationSignal;
     23 import android.os.ParcelFileDescriptor;
     24 import android.print.PageRange;
     25 import android.print.PrintAttributes;
     26 import android.print.PrintDocumentAdapter;
     27 import android.print.PrintManager;
     28 import android.view.Menu;
     29 import android.view.MenuItem;
     30 import android.webkit.WebView;
     31 import android.webkit.WebViewClient;
     32 
     33 import com.example.android.apis.R;
     34 
     35 /**
     36  * This class demonstrates how to implement HTML content printing
     37  * from a {@link WebView} which is not shown on the screen.
     38  * <p>
     39  * This activity shows a text prompt and when the user chooses the
     40  * print option from the overflow menu an HTML page with content that
     41  * is not on the screen is printed via an off-screen {@link WebView}.
     42  * </p>
     43  *
     44  * @see PrintManager
     45  * @see WebView
     46  */
     47 public class PrintHtmlOffScreen extends Activity {
     48 
     49     private WebView mWebView;
     50 
     51     @Override
     52     protected void onCreate(Bundle savedInstanceState) {
     53         super.onCreate(savedInstanceState);
     54         setContentView(R.layout.print_html_off_screen);
     55     }
     56 
     57     @Override
     58     public boolean onCreateOptionsMenu(Menu menu) {
     59         super.onCreateOptionsMenu(menu);
     60         getMenuInflater().inflate(R.menu.print_custom_content, menu);
     61         return true;
     62     }
     63 
     64     @Override
     65     public boolean onOptionsItemSelected(MenuItem item) {
     66         if (item.getItemId() == R.id.menu_print) {
     67             print();
     68             return true;
     69         }
     70         return super.onOptionsItemSelected(item);
     71     }
     72 
     73     private void print() {
     74         // Create a WebView and hold on to it as the printing will start when
     75         // load completes and we do not want the WbeView to be garbage collected.
     76         mWebView = new WebView(this);
     77 
     78         // Important: Only after the page is loaded we will do the print.
     79         mWebView.setWebViewClient(new WebViewClient() {
     80             @Override
     81             public void onPageFinished(WebView view, String url) {
     82               doPrint();
     83             }
     84         });
     85 
     86         // Load an HTML page.
     87         mWebView.loadUrl("file:///android_res/raw/motogp_stats.html");
     88     }
     89 
     90     private void doPrint() {
     91         // Get the print manager.
     92         PrintManager printManager = (PrintManager) getSystemService(
     93                 Context.PRINT_SERVICE);
     94 
     95         // Create a wrapper PrintDocumentAdapter to clean up when done.
     96         PrintDocumentAdapter adapter = new PrintDocumentAdapter() {
     97             private final PrintDocumentAdapter mWrappedInstance =
     98                     mWebView.createPrintDocumentAdapter();
     99 
    100             @Override
    101             public void onStart() {
    102                 mWrappedInstance.onStart();
    103             }
    104 
    105             @Override
    106             public void onLayout(PrintAttributes oldAttributes, PrintAttributes newAttributes,
    107                     CancellationSignal cancellationSignal, LayoutResultCallback callback,
    108                     Bundle extras) {
    109                 mWrappedInstance.onLayout(oldAttributes, newAttributes, cancellationSignal,
    110                         callback, extras);
    111             }
    112 
    113             @Override
    114             public void onWrite(PageRange[] pages, ParcelFileDescriptor destination,
    115                     CancellationSignal cancellationSignal, WriteResultCallback callback) {
    116                 mWrappedInstance.onWrite(pages, destination, cancellationSignal, callback);
    117             }
    118 
    119             @Override
    120             public void onFinish() {
    121                 mWrappedInstance.onFinish();
    122                 // Intercept the finish call to know when printing is done
    123                 // and destroy the WebView as it is expensive to keep around.
    124                 mWebView.destroy();
    125                 mWebView = null;
    126             }
    127         };
    128 
    129         // Pass in the ViewView's document adapter.
    130         printManager.print("MotoGP stats", adapter, null);
    131     }
    132 }
    133