Merge pull request by skarempudi which fixes SDK 23 permission problems in sample app

Merge pull request by skarempudi for showing info on phones without file manager
Add feature from 1.x - canvas is set to drawable from View#getBackground()
Add info about new repo to README

Author: barteksc

README.md

@@ -2,6 +2,9 @@
 
 # Android PdfViewer
 
+AndroidPdfViewer 1.x is available on [AndroidPdfViewerV1](https://github.com/barteksc/AndroidPdfViewerV1)
+repo, where can be developed independently.
+
 Library for displaying PDF documents on Android, with `animations`, `gestures`, `zoom` and `double tap` support.
 It is based on [PdfiumAndroid](https://github.com/barteksc/PdfiumAndroid) for decoding PDF files. Works on API 11 and higher.
 Licensed under Apache License 2.0.

android-pdf-viewer/src/main/java/com/github/barteksc/pdfviewer/PDFView.java

@@ -24,11 +24,11 @@
 import android.graphics.PointF;
 import android.graphics.Rect;
 import android.graphics.RectF;
+import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.os.AsyncTask;
 import android.util.AttributeSet;
 import android.util.Log;
-import android.view.View;
 import android.widget.RelativeLayout;
 
 import com.github.barteksc.pdfviewer.exception.FileNotFoundException;
@@ -529,7 +529,13 @@ protected void onDraw(Canvas canvas) {
         // abstraction of the screen position when rendering the parts.
 
         // Draws background
-        canvas.drawColor(Color.WHITE);
+
+        Drawable bg = getBackground();
+        if (bg == null) {
+            canvas.drawColor(Color.WHITE);
+        } else {
+            bg.draw(canvas);
+        }
 
         if (recycled) {
             return;

sample/src/main/java/com/github/barteksc/sample/PDFViewActivity.java

@@ -21,6 +21,7 @@
 import android.database.Cursor;
 import android.net.Uri;
 import android.provider.OpenableColumns;
+import android.support.annotation.NonNull;
 import android.support.v4.app.ActivityCompat;
 import android.support.v4.content.ContextCompat;
 import android.support.v7.app.AppCompatActivity;
@@ -31,7 +32,6 @@
 import com.github.barteksc.pdfviewer.listener.OnLoadCompleteListener;
 import com.github.barteksc.pdfviewer.listener.OnPageChangeListener;
 import com.github.barteksc.pdfviewer.scroll.DefaultScrollHandle;
-import com.github.barteksc.pdfviewer.scroll.ScrollHandle;
 import com.shockwave.pdfium.PdfDocument;
 
 import org.androidannotations.annotations.AfterViews;
@@ -43,6 +43,7 @@
 import org.androidannotations.annotations.ViewById;
 
 import java.util.List;
+
 @EActivity(R.layout.activity_main)
 @OptionsMenu(R.menu.options)
 public class PDFViewActivity extends AppCompatActivity implements OnPageChangeListener, OnLoadCompleteListener {
@@ -89,8 +90,7 @@ void launchPicker() {
         intent.setType("application/pdf");
         try {
             startActivityForResult(intent, REQUEST_CODE);
-        }
-        catch (ActivityNotFoundException e) {
+        } catch (ActivityNotFoundException e) {
             //alert user that file manager not working
             Toast.makeText(this, R.string.toast_pick_file_error, Toast.LENGTH_SHORT).show();
         }
@@ -193,13 +193,14 @@ public void printBookmarksTree(List<PdfDocument.Bookmark> tree, String sep) {
 
     /**
      * Listener for response to user permission request
-     * @param requestCode Check that permission request code matches
-     * @param permissions Permissions that requested
+     *
+     * @param requestCode  Check that permission request code matches
+     * @param permissions  Permissions that requested
      * @param grantResults Whether permissions granted
      */
     @Override
-    public void onRequestPermissionsResult(int requestCode, String permissions[],
-                                           int[] grantResults) {
+    public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[],
+                                           @NonNull int[] grantResults) {
         if (requestCode == PERMISSION_CODE) {
             if (grantResults.length > 0
                     && grantResults[0] == PackageManager.PERMISSION_GRANTED) {