How to allow user to locate a pdf file on android device, that is to be printed via google cloud print service embedded in an application?

Question

I am making an android application, through which User can choose an existing pdf file on his device and after verification, send it to be printed via Google cloud. Printer is connected to my own Gmail Id and only I have right to send a print job. So after user is verified print job is sent through my mail Id.

I am a beginner and your advice is appreciated. Thanks in advance :)

Answer 1

//It´s very easy don´t forget add to manifest permissions.
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Environment;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
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.content.Context;
import android.print.PrintDocumentInfo;
import android.print.pdf.PrintedPdfDocument;
import android.graphics.pdf.PdfDocument;
import android.graphics.pdf.PdfDocument.PageInfo;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.print.PrintManager;
import android.view.View;

public class MainActivity extends AppCompatActivity {
//Your file path
String Ruta= Environment.getExternalStorageDirectory().getPath()+"/MiPdf1.pdf";
File file=new File(Ruta);

public void printDocument(View view)
{
    PrintManager printManager = (PrintManager) this
            .getSystemService(Context.PRINT_SERVICE);

    String jobName = this.getString(R.string.app_name) +
            " Document";

    printManager.print(jobName, new
                    MyPrintDocumentAdapter(this),
            null);
}

public class MyPrintDocumentAdapter extends PrintDocumentAdapter
{
    Context context;
    private int pageHeight;
    private int pageWidth;
    public PdfDocument myPdfDocument;
    public int totalpages = 4;

    private boolean pageInRange(PageRange[] pageRanges, int page)
    {
        for (int i = 0; i<pageRanges.length; i++)
        {
            if ((page >= pageRanges[i].getStart()) &&
                    (page <= pageRanges[i].getEnd()))
                return true;
        }
        return false;
    }

    public MyPrintDocumentAdapter(Context context)
    {
        this.context = context;
    }

    @Override
    public void onWrite(PageRange[] pages, ParcelFileDescriptor destination, CancellationSignal cancellationSignal, WriteResultCallback callback){
        InputStream input = null;
        OutputStream output = null;

        try {

            input = new FileInputStream(file);
            output = new FileOutputStream(destination.getFileDescriptor());

            byte[] buf = new byte[1024];
            int bytesRead;

            while ((bytesRead = input.read(buf)) > 0) {
                output.write(buf, 0, bytesRead);
            }

            callback.onWriteFinished(new PageRange[]{PageRange.ALL_PAGES});

        } catch (FileNotFoundException ee){
            //Catch exception
        } catch (Exception e) {
            //Catch exception
        } finally {
            try {
                input.close();
                output.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    @Override
    public void onLayout(PrintAttributes oldAttributes, PrintAttributes newAttributes, CancellationSignal cancellationSignal, LayoutResultCallback callback, Bundle extras){

        if (cancellationSignal.isCanceled()) {
            callback.onLayoutCancelled();
            return;
        }

        //int pages = computePageCount(newAttributes);

        PrintDocumentInfo pdi = new PrintDocumentInfo.Builder("Name of file").setContentType(PrintDocumentInfo.CONTENT_TYPE_DOCUMENT).build();

        callback.onLayoutFinished(pdi, true);
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //If android version is 6.0
    if (!(ContextCompat.checkSelfPermission(this.getApplicationContext(), "android.permission.READ_EXTERNAL_STORAGE") == 0)) {
        ActivityCompat.requestPermissions(this, new String[]{ "android.permission.READ_EXTERNAL_STORAGE"}, 1);
    }
}
}