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I want to list PDF files from Downloads folder, but I am getting error of null point while getting files. I am providing my code below. For displaying pdf file I am using com.github.barteksc:android-pdf-viewer:1.4.0' library. 

package com.tutorials.hp.gridviewpdf;

import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.GridView;

import java.io.File;
import java.util.ArrayList;


public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        final GridView gv= (GridView) findViewById(R.id.gv);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                gv.setAdapter(new CustomAdapter(MainActivity.this,getPDFs()));

            }
        });
    }

    private ArrayList<PDFDoc> getPDFs()

    {
        ArrayList<PDFDoc> pdfDocs=new ArrayList<>();
        //TARGET FOLDER
        File downloadsFolder= Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
        PDFDoc pdfDoc;

        if(downloadsFolder.exists())
        {
            //GET ALL FILES IN DOWNLOAD FOLDER
            File[] files=downloadsFolder.listFiles();

            //LOOP THRU THOSE FILES GETTING NAME AND URI
            for (int i=0;i<files.length;i++)
            {
                File file=files[i];

                if(file.getPath().endsWith("pdf"))
                {
                    pdfDoc=new PDFDoc();
                    pdfDoc.setName(file.getName());
                    pdfDoc.setPath(file.getAbsolutePath());

                    pdfDocs.add(pdfDoc);
                }

            }
        }

        return pdfDocs;
    }


}

Here is my logcat

enter image description here

Amit Mhaske
  • 471
  • 5
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  • If your target SDK is 23 or higher, you must request each dangerous permission it needs while the app is running. In this case, you will need to request user's permission for reading the SD card. Read [this](https://developer.android.com/training/permissions/requesting.html) – Shashank Kadne May 15 '17 at 13:30
  • `files` is null. Check for null before use. And if null dont use. – greenapps May 15 '17 at 18:00

0 Answers0