display the selected image fullscreen

app/src/main/AndroidManifest.xml

@@ -24,5 +24,10 @@
         <activity
             android:name=".PhotosActivity"
             android:screenOrientation="portrait"/>
+
+        <activity
+            android:name=".PhotoActivity"
+            android:screenOrientation="portrait"
+            android:theme="@style/Theme.AppCompat.Light.NoActionBar"/>
     </application>
 </manifest>

app/src/main/java/gallery/simplemobiletools/com/Constants.java

@@ -2,4 +2,5 @@ package gallery.simplemobiletools.com;
 
 public class Constants {
     public static final String DIRECTORY = "directory";
+    public static final String PHOTO = "photo";
 }

app/src/main/java/gallery/simplemobiletools/com/MyPagerAdapter.java

@@ -0,0 +1,48 @@
+package gallery.simplemobiletools.com;
+
+import android.content.Context;
+import android.support.v4.view.PagerAdapter;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ImageView;
+
+import com.bumptech.glide.Glide;
+
+import java.util.List;
+
+public class MyPagerAdapter extends PagerAdapter {
+    private final Context context;
+    private final List<String> paths;
+    private final LayoutInflater inflater;
+
+    public MyPagerAdapter(Context context, List<String> paths) {
+        this.context = context;
+        this.paths = paths;
+        this.inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
+    }
+
+    @Override
+    public int getCount() {
+        return paths.size();
+    }
+
+    @Override
+    public boolean isViewFromObject(View view, Object object) {
+        return view == object;
+    }
+
+    @Override
+    public Object instantiateItem(ViewGroup container, int position) {
+        final View view = inflater.inflate(R.layout.pager_item, container, false);
+        final ImageView imageView = (ImageView) view.findViewById(R.id.photo);
+        Glide.with(context).load(paths.get(position)).fitCenter().crossFade().into(imageView);
+        container.addView(view);
+        return view;
+    }
+
+    @Override
+    public void destroyItem(ViewGroup container, int position, Object object) {
+        container.removeView((View) object);
+    }
+}

app/src/main/java/gallery/simplemobiletools/com/PhotoActivity.java

@@ -0,0 +1,55 @@
+package gallery.simplemobiletools.com;
+
+import android.database.Cursor;
+import android.net.Uri;
+import android.os.Bundle;
+import android.provider.MediaStore;
+import android.support.v4.view.ViewPager;
+import android.support.v7.app.AppCompatActivity;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+
+public class PhotoActivity extends AppCompatActivity {
+    private int pos;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_photo);
+
+        pos = 0;
+        final ViewPager pager = (ViewPager) findViewById(R.id.view_pager);
+        final MyPagerAdapter adapter = new MyPagerAdapter(this, getPhotos());
+        pager.setAdapter(adapter);
+        pager.setCurrentItem(pos);
+    }
+
+    private List<String> getPhotos() {
+        final List<String> photos = new ArrayList<>();
+        final String path = getIntent().getStringExtra(Constants.PHOTO);
+        final String fileDir = new File(path).getParent().toLowerCase();
+        final Uri uri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
+        final String where = MediaStore.Images.Media.DATA + " like ? ";
+        final String[] args = new String[]{fileDir + "%"};
+        final String[] columns = {MediaStore.Images.Media.DATA};
+        final Cursor cursor = getContentResolver().query(uri, columns, where, args, null);
+
+        int i = 0;
+        if (cursor != null && cursor.moveToFirst()) {
+            final int pathIndex = cursor.getColumnIndex(MediaStore.Images.Media.DATA);
+            do {
+                final String curPath = cursor.getString(pathIndex);
+                photos.add(curPath);
+
+                if (curPath.equals(path))
+                    pos = i;
+
+                i++;
+            } while (cursor.moveToNext());
+            cursor.close();
+        }
+        return photos;
+    }
+}

app/src/main/java/gallery/simplemobiletools/com/PhotosActivity.java

@@ -1,5 +1,6 @@
 package gallery.simplemobiletools.com;
 
+import android.content.Intent;
 import android.database.Cursor;
 import android.net.Uri;
 import android.os.Bundle;
@@ -13,12 +14,14 @@ import java.util.ArrayList;
 import java.util.List;
 
 public class PhotosActivity extends AppCompatActivity implements AdapterView.OnItemClickListener {
+    private List<String> photos;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_photos);
 
+        photos = new ArrayList<>();
         final GridView gridView = (GridView) findViewById(R.id.photos_grid);
         final PhotosAdapter adapter = new PhotosAdapter(this, getPhotos());
         gridView.setAdapter(adapter);
@@ -26,7 +29,6 @@ public class PhotosActivity extends AppCompatActivity implements AdapterView.OnI
     }
 
     private List<String> getPhotos() {
-        final List<String> photos = new ArrayList<>();
         final String path = getIntent().getStringExtra(Constants.DIRECTORY);
         final Uri uri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
         final String where = MediaStore.Images.Media.DATA + " like ? ";
@@ -46,6 +48,8 @@ public class PhotosActivity extends AppCompatActivity implements AdapterView.OnI
 
     @Override
     public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
-
+        final Intent intent = new Intent(this, PhotoActivity.class);
+        intent.putExtra(Constants.PHOTO, photos.get(position));
+        startActivity(intent);
     }
 }

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

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:background="@android:color/black">
+
+    <android.support.v4.view.ViewPager
+        android:id="@+id/view_pager"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"/>
+
+</LinearLayout>

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

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<ImageView
+    android:id="@+id/photo"
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"/>

app/src/main/res/values/styles.xml

@@ -1,8 +1,6 @@
 <resources>
 
-    <!-- Base application theme. -->
     <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
-        <!-- Customize your theme here. -->
         <item name="colorPrimary">@color/colorPrimary</item>
         <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
         <item name="colorAccent">@color/colorAccent</item>