Keep screen ON on other activities.

app/src/main/java/fr/chteufleur/mytrackingdog/FilePicker.java

@@ -19,8 +19,6 @@ import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
 
-import fr.chteufleur.mytrackingdog.R;
-
 public class FilePicker extends ListActivity {
 
     public final static String EXTRA_FILE_PATH = "file_path";
@@ -40,15 +38,17 @@ public class FilePicker extends ListActivity {
 
         LayoutInflater inflator = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
 
+        if (inflator != null) {
             View emptyView = inflator.inflate(R.layout.empty_view, null);
             ((ViewGroup) getListView().getParent()).addView(emptyView);
             getListView().setEmptyView(emptyView);
+        }
 
         // Set initial directory
         Directory = new File(DEFAULT_INITIAL_DIRECTORY);
 
         // Initialize the ArrayList
-        Files = new ArrayList<File>();
+        Files = new ArrayList<>();
 
         // Set the ListAdapter
         Adapter = new FilePickerListAdapter(this, Files);
@@ -123,7 +123,7 @@ public class FilePicker extends ListActivity {
     private class FilePickerListAdapter extends ArrayAdapter<File> {
         private List<File> mObjects;
 
-        public FilePickerListAdapter(Context context, List<File> objects) {
+        private FilePickerListAdapter(Context context, List<File> objects) {
             super(context, R.layout.list_item, android.R.id.text1, objects);
             mObjects = objects;
         }
@@ -133,15 +133,17 @@ public class FilePicker extends ListActivity {
             View row = null;
 
             if (convertView == null) {
-                LayoutInflater inflater = (LayoutInflater)
-                        getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
+                LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
+                if (inflater != null) {
                     row = inflater.inflate(R.layout.list_item, parent, false);
+                }
             } else {
                 row = convertView;
             }
 
             File object = mObjects.get(position);
 
+            if (row != null) {
                 ImageView imageView = row.findViewById(R.id.file_picker_image);
                 TextView textView = row.findViewById(R.id.file_picker_text);
                 textView.setSingleLine(true);
@@ -152,6 +154,7 @@ public class FilePicker extends ListActivity {
                 } else {
                     imageView.setImageResource(R.drawable.ic_folder);
                 }
+            }
 
             return row;
         }
@@ -184,7 +187,7 @@ public class FilePicker extends ListActivity {
 
         private String[] Extensions;
 
-        public ExtensionFilenameFilter(String[] extensions) {
+        private ExtensionFilenameFilter(String[] extensions) {
             super();
             Extensions = extensions;
         }
@@ -197,8 +200,8 @@ public class FilePicker extends ListActivity {
             }
 
             if (Extensions != null && Extensions.length > 0) {
-                for (int i = 0; i < Extensions.length; i++) {
-                    if (filename.endsWith(Extensions[i])) {
+                for (String ext: Extensions) {
+                    if (filename.endsWith(ext)) {
                         // The filename ends with the extension
                         return true;
                     }

app/src/main/java/fr/chteufleur/mytrackingdog/QRCodeGeneratorActivity.java

@@ -5,6 +5,8 @@ import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.os.Bundle;
 import android.util.Log;
+import android.view.View;
+import android.view.WindowManager;
 import android.widget.ImageView;
 
 import com.google.zxing.BarcodeFormat;
@@ -26,6 +28,9 @@ public class QRCodeGeneratorActivity extends Activity {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.qr_code_generator);
 
+        // Keep screen ON
+        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
+
         imageView = findViewById(R.id.qr_code_image);
         while (generating) {
             try {
@@ -36,6 +41,12 @@ public class QRCodeGeneratorActivity extends Activity {
         if (image != null) {
             imageView.setImageBitmap(image);
         }
+        imageView.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                onBackPressed();
+            }
+        });
     }
 
     public static void textToImageEncode(String value, Resources resources) throws WriterException {

app/src/main/java/fr/chteufleur/mytrackingdog/QRCodeReaderActivity.java

@@ -7,6 +7,7 @@ import android.content.pm.PackageManager;
 import android.os.Build;
 import android.os.Bundle;
 import android.support.annotation.RequiresApi;
+import android.view.WindowManager;
 
 import com.google.zxing.Result;
 
@@ -37,6 +38,10 @@ public class QRCodeReaderActivity extends Activity implements ZXingScannerView.R
             checkPermissions();
         }
         setContentView(R.layout.qr_code_reader);
+
+        // Keep screen ON
+        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
+
         mScannerView = new ZXingScannerView(this);
         setContentView(mScannerView);
     }

app/src/main/res/layout/qr_code_generator.xml

@@ -8,8 +8,8 @@
 
     <ImageView
         android:id="@+id/qr_code_image"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
         android:layout_marginTop="20dp" />
 
 </LinearLayout>