In Android, it is simple to protect a PDF document or file. In this Android tip, I am going to show you how to protect the PDF document using iTextG library. The iTextG library allows you to protect the PDF document by two passwords: user password and owner password. The user password protects the PDF document from being opened. It prompts to enter the user password when you open the protected PDF document in a PDF Viewer application. The owner password sets the permissions to the PDF document. For example, only copying and printing are allowed on the PDF document.


<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"   
   tools:context="com.example.examples.MainActivity" 
   android:orientation="vertical"
   >
   
   
	<EditText 
	  android:id="@+id/txtuserpwd"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:hint="Enter user password"
		 android:inputType="textPassword"
		 />
   <EditText 
	  android:id="@+id/txtownerpwd"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:hint="Enter owner password"
      android:inputType="textPassword"
	   />
   <Button
      android:id="@+id/btprotected"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:text="Protect"
      android:onClick="protect" 
      />
   <TextView
      android:id="@+id/txtstatus"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
    />

</LinearLayout>

public class MainActivity extends Activity{

   private String filepath="";
   private TextView txtStatus;
   private EditText txtUserPwd;
   private EditText txtOwnerPwd;
   protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      txtStatus=(TextView)findViewById(R.id.txtstatus);
      txtUserPwd=(EditText)findViewById(R.id.txtuserpwd);
      txtOwnerPwd=(EditText)findViewById(R.id.txtownerpwd);
      Intent intent=getIntent();
      if(intent!=null){
      String action=intent.getAction();
      String type=intent.getType();
      if((Intent.ACTION_PICK.equals(action) || Intent.ACTION_VIEW.equals(action)) && type.endsWith("pdf")){
      	//get the file path from the intent object
      	filepath=intent.getData().getPath();
      	
      	}
      }
   
   }
   
   public void protect(View view){
   	BackTask bt=new BackTask();
   	if(!filepath.equals(""))
   		bt.execute(filepath);
   	else
   		txtStatus.setText("No PDF file is selected.");
   }
   
   class BackTask extends AsyncTask<String,Void,Void>{
   	
   	protected void onPreExecute(){
    		super.onPreExecute();
    		txtStatus.setText("Processing...");
    		
   	}
   	protected Void doInBackground(String...params){
   		// User password
   		byte[] USER =txtUserPwd.getText().toString().getBytes();
   		// Owner password
      	byte[] OWNER =txtOwnerPwd.getText().toString().getBytes();
      	try {
      		// Read the PDF document into PdfReader object
				PdfReader reader = new PdfReader(params[0]);
				
				File f=new File(params[0]);
				// Create PdfStamper object to modify the existing PDF document
				PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(f.getParent()+"/protected_"+f.getName()));
				// Protect pdf file
				// Copying and printing are allowed
				stamper.setEncryption(USER, OWNER, PdfWriter.ALLOW_COPY | PdfWriter.ALLOW_PRINTING, PdfWriter.ENCRYPTION_AES_128);
				stamper.close();
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
    
   		return null;
   	}
   	protected void onPostExecute(Void result){
   		txtStatus.setText("The Pdf file is protected.");
    	}	  
   }

<intent-filter>
        		<action android:name="android.intent.action.VIEW" />
        		<action android:name="android.intent.action.PICK" />
        		<category android:name="android.intent.category.DEFAULT" />
                        <data android:scheme="file" />
        		<data android:mimeType="application/pdf" />
        		<data android:pathPattern=".*\\.pdf" />
        		<data android:host="*" />
     </intent-filter> 
 

Posted by: Dara | post date: 01-26-2015 | Subject: Android Apps Development