Allow tapping on the edges of the chapter to change pages

app/src/main/java/eu/kanade/mangafeed/ui/activity/ReaderActivity.java

@@ -18,12 +18,13 @@ import eu.kanade.mangafeed.data.models.Page;
 import eu.kanade.mangafeed.presenter.ReaderPresenter;
 import eu.kanade.mangafeed.ui.activity.base.BaseRxActivity;
 import eu.kanade.mangafeed.ui.adapter.ReaderPageAdapter;
+import eu.kanade.mangafeed.widget.ReaderViewPager;
 import nucleus.factory.RequiresPresenter;
 
 @RequiresPresenter(ReaderPresenter.class)
 public class ReaderActivity extends BaseRxActivity<ReaderPresenter> {
 
-    @Bind(R.id.view_pager) ViewPager viewPager;
+    @Bind(R.id.view_pager) ReaderViewPager viewPager;
     @Bind(R.id.page_number) TextView pageNumber;
 
     private ReaderPageAdapter adapter;
@@ -43,6 +44,12 @@ public class ReaderActivity extends BaseRxActivity<ReaderPresenter> {
         setupViewPager();
     }
 
+    @Override
+    public void onDestroy() {
+        getPresenter().setCurrentPage(currentPage);
+        super.onDestroy();
+    }
+
     private void createAdapter() {
         adapter = new ReaderPageAdapter(getSupportFragmentManager());
         viewPager.setAdapter(adapter);
@@ -67,14 +74,24 @@ public class ReaderActivity extends BaseRxActivity<ReaderPresenter> {
 
             }
         });
+        viewPager.setOnChapterBoundariesOutListener(new ReaderViewPager.OnChapterBoundariesOutListener() {
+            @Override
+            public void onFirstPageOut() {
+                // TODO load previous chapter
+            }
+
+            @Override
+            public void onLastPageOut() {
+                // TODO load next chapter
+            }
+        });
     }
 
-    @Override
-    public void onDestroy() {
-        getPresenter().setCurrentPage(currentPage);
-        super.onDestroy();
+    public ReaderViewPager getViewPager() {
+        return viewPager;
     }
 
+
     public void onPageList(List<Page> pages) {
         adapter.setPages(pages);
         updatePageNumber();
@@ -104,4 +121,5 @@ public class ReaderActivity extends BaseRxActivity<ReaderPresenter> {
         }
 
     }
+
 }

app/src/main/java/eu/kanade/mangafeed/ui/fragment/ReaderPageFragment.java

@@ -12,12 +12,13 @@ import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView;
 
 import eu.kanade.mangafeed.R;
 import eu.kanade.mangafeed.data.models.Page;
+import eu.kanade.mangafeed.ui.activity.ReaderActivity;
 import eu.kanade.mangafeed.util.PageFileTarget;
 
 public class ReaderPageFragment extends Fragment {
     public static final String URL_ARGUMENT_KEY = "UrlArgumentKey";
 
-    private SubsamplingScaleImageView mPageImageView;
+    private SubsamplingScaleImageView imageView;
 
     private String mUrl;
 
@@ -53,19 +54,21 @@ public class ReaderPageFragment extends Fragment {
     private void loadImage() {
         Glide.with(getActivity())
                 .load(mUrl)
-                .downloadOnly(new PageFileTarget(mPageImageView));
+                .downloadOnly(new PageFileTarget(imageView));
     }
 
     @Override
     public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
-        mPageImageView = (SubsamplingScaleImageView)inflater.inflate(R.layout.fragment_page, container, false);
-        mPageImageView.setDoubleTapZoomStyle(SubsamplingScaleImageView.ZOOM_FOCUS_FIXED);
-        mPageImageView.setPanLimit(SubsamplingScaleImageView.PAN_LIMIT_INSIDE);
-        mPageImageView.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CENTER_INSIDE);
-        mPageImageView.setOnImageEventListener(new SubsamplingScaleImageView.OnImageEventListener() {
+        imageView = (SubsamplingScaleImageView)inflater.inflate(R.layout.fragment_page, container, false);
+        imageView.setDoubleTapZoomStyle(SubsamplingScaleImageView.ZOOM_FOCUS_FIXED);
+        imageView.setPanLimit(SubsamplingScaleImageView.PAN_LIMIT_INSIDE);
+        imageView.setMinimumScaleType(SubsamplingScaleImageView.SCALE_TYPE_CENTER_INSIDE);
+        imageView.setOnTouchListener((view, motionEvent) ->
+                ((ReaderActivity) getActivity()).getViewPager().onImageTouch(motionEvent));
+        imageView.setOnImageEventListener(new SubsamplingScaleImageView.OnImageEventListener() {
             @Override
             public void onReady() {
-                mPageImageView.setVisibility(View.VISIBLE);
+                imageView.setVisibility(View.VISIBLE);
             }
 
             @Override
@@ -85,7 +88,7 @@ public class ReaderPageFragment extends Fragment {
             }
         });
 
-        return mPageImageView;
+        return imageView;
     }
 
     @Override
@@ -93,4 +96,5 @@ public class ReaderPageFragment extends Fragment {
         super.onActivityCreated(savedInstanceState);
         loadImage();
     }
+
 }

app/src/main/java/eu/kanade/mangafeed/widget/ReaderViewPager.java

@@ -0,0 +1,135 @@
+package eu.kanade.mangafeed.widget;
+
+import android.content.Context;
+import android.support.v4.view.ViewPager;
+import android.util.AttributeSet;
+import android.view.GestureDetector;
+import android.view.MotionEvent;
+
+public class ReaderViewPager extends ViewPager {
+
+    private GestureDetector gestureDetector;
+
+    private OnChapterBoundariesOutListener mOnChapterBoundariesOutListener;
+    private OnChapterSingleTapListener mOnChapterSingleTapListener;
+
+    private static final float LEFT_REGION = 0.33f;
+    private static final float RIGHT_REGION = 0.66f;
+    private static final float SWIPE_TOLERANCE = 0.25f;
+    private float startDragX;
+
+    public ReaderViewPager(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        gestureDetector = new GestureDetector(getContext(), new ReaderViewGestureListener());
+    }
+
+    @Override
+    public boolean onInterceptTouchEvent(MotionEvent ev) {
+        try {
+            gestureDetector.onTouchEvent(ev);
+
+            if ((ev.getAction() & MotionEvent.ACTION_MASK) == MotionEvent.ACTION_DOWN) {
+                if (this.getCurrentItem() == 0 || this.getCurrentItem() == this.getAdapter().getCount() - 1) {
+                    startDragX = ev.getX();
+                }
+            }
+
+            return super.onInterceptTouchEvent(ev);
+        } catch (IllegalArgumentException e) {
+            // Do Nothing.
+        }
+
+        return false;
+    }
+
+    @Override
+    public boolean onTouchEvent(MotionEvent ev) {
+        try {
+            if (mOnChapterBoundariesOutListener != null) {
+                if (this.getCurrentItem() == 0) {
+                    if ((ev.getAction() & MotionEvent.ACTION_MASK) == MotionEvent.ACTION_UP) {
+                        float displacement = ev.getX() - startDragX;
+
+                        if (ev.getX() > startDragX && displacement > getWidth() * SWIPE_TOLERANCE) {
+                            mOnChapterBoundariesOutListener.onFirstPageOut();
+                            return true;
+                        }
+
+                        startDragX = 0;
+                    }
+                } else if (this.getCurrentItem() == this.getAdapter().getCount() - 1) {
+                    if ((ev.getAction() & MotionEvent.ACTION_MASK) == MotionEvent.ACTION_UP) {
+                        float displacement = startDragX - ev.getX();
+
+                        if (ev.getX() < startDragX && displacement > getWidth() * SWIPE_TOLERANCE) {
+                            mOnChapterBoundariesOutListener.onLastPageOut();
+                            return true;
+                        }
+
+                        startDragX = 0;
+                    }
+                }
+            }
+
+            return super.onTouchEvent(ev);
+        } catch (IllegalArgumentException e) {
+            // Do Nothing.
+        }
+
+        return false;
+    }
+
+    public boolean onImageTouch(MotionEvent event) {
+        return gestureDetector.onTouchEvent(event);
+    }
+
+    public interface OnChapterBoundariesOutListener {
+        public void onFirstPageOut();
+
+        public void onLastPageOut();
+    }
+
+    public interface OnChapterSingleTapListener {
+        public void onSingleTap();
+    }
+
+    public void setOnChapterBoundariesOutListener(OnChapterBoundariesOutListener onChapterBoundariesOutListener) {
+        mOnChapterBoundariesOutListener = onChapterBoundariesOutListener;
+    }
+
+    public void setOnChapterSingleTapListener(OnChapterSingleTapListener onChapterSingleTapListener) {
+        mOnChapterSingleTapListener = onChapterSingleTapListener;
+    }
+
+
+    private class ReaderViewGestureListener extends GestureDetector.SimpleOnGestureListener {
+
+        @Override
+        public boolean onSingleTapConfirmed(MotionEvent e) {
+            final int position = getCurrentItem();
+            final float positionX = e.getX();
+
+            if (positionX < getWidth() * LEFT_REGION) {
+                if (position != 0) {
+                    setCurrentItem(position - 1, true);
+                } else {
+                    if (mOnChapterBoundariesOutListener != null) {
+                        mOnChapterBoundariesOutListener.onFirstPageOut();
+                    }
+                }
+            } else if (positionX > getWidth() * RIGHT_REGION) {
+                if (position != getAdapter().getCount() - 1) {
+                    setCurrentItem(position + 1, true);
+                } else {
+                    if (mOnChapterBoundariesOutListener != null) {
+                        mOnChapterBoundariesOutListener.onLastPageOut();
+                    }
+                }
+            }
+
+            return true;
+        }
+
+    }
+
+}

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

@@ -3,11 +3,11 @@
     android:layout_width="match_parent"
     android:layout_height="match_parent">
 
-    <android.support.v4.view.ViewPager
+    <eu.kanade.mangafeed.widget.ReaderViewPager
         android:id="@+id/view_pager"
         android:layout_width="match_parent"
         android:layout_height="wrap_content">
-    </android.support.v4.view.ViewPager>
+    </eu.kanade.mangafeed.widget.ReaderViewPager>
 
     <TextView
         android:layout_width="wrap_content"