Make the K9Activity GestureDetector more generic so that it can be used by both MessageList and MessageView.

Make the mTopView a ToggleScrollView.  The only consumer is currently the MessageView, which uses a ToggleScrollView anyway.  This should make it easier to reuse the anti-scrolling features in ToggleScrollView for ListView later on.

src/com/fsck/k9/activity/K9Activity.java

@@ -14,15 +14,15 @@ import android.view.View;
 import android.view.animation.AccelerateInterpolator;
 import android.view.animation.Animation;
 import android.view.animation.TranslateAnimation;
-import android.widget.ScrollView;
 import com.fsck.k9.K9;
 import com.fsck.k9.helper.DateFormatter;
+import com.fsck.k9.view.ToggleScrollView;
 
 
 public class K9Activity extends Activity {
     private GestureDetector gestureDetector;
 
-    protected ScrollView mTopView;
+    protected ToggleScrollView mTopView;
 
     @Override
     public void onCreate(Bundle icicle) {
@@ -86,12 +86,26 @@ public class K9Activity extends Activity {
     public java.text.DateFormat getDateFormat() {
         return mDateFormat;
     }
-    protected void onNext() {
 
-    }
+    /**
-    protected void onPrevious() {
+     * Called when a swipe from right to left is handled by {@link MyGestureDetector}.  See
+     * {@link android.view.GestureDetector.OnGestureListener#onFling(android.view.MotionEvent, android.view.MotionEvent, float, float)}
+     * for more information on the {@link MotionEvent}s being passed.
+     * @param e1 First down motion event that started the fling.
+     * @param e2 The move motion event that triggered the current onFling.
+     */
+    protected void onSwipeRightToLeft(final MotionEvent e1, final MotionEvent e2) {
     }
 
+    /**
+     * Called when a swipe from left to right is handled by {@link MyGestureDetector}.  See
+     * {@link android.view.GestureDetector.OnGestureListener#onFling(android.view.MotionEvent, android.view.MotionEvent, float, float)}
+     * for more information on the {@link MotionEvent}s being passed.
+     * @param e1 First down motion event that started the fling.
+     * @param e2 The move motion event that triggered the current onFling.
+     */
+    protected void onSwipeLeftToRight(final MotionEvent e1, final MotionEvent e2) {
+    }
 
     protected Animation inFromRightAnimation() {
         return slideAnimation(0.0f, +1.0f);
@@ -150,9 +164,9 @@ public class K9Activity extends Activity {
                         return false;
                     // right to left swipe
                     if (e1.getX() - e2.getX() > min_distance && Math.abs(velocityX) > min_velocity) {
-                        onNext();
+                        onSwipeRightToLeft(e1, e2);
                     } else if (e2.getX() - e1.getX() > min_distance && Math.abs(velocityX) > min_velocity) {
-                        onPrevious();
+                        onSwipeLeftToRight(e1, e2);
                     }
                 } catch (Exception e) {
                     // nothing

src/com/fsck/k9/activity/MessageList.java

@@ -1660,22 +1660,25 @@ public class MessageList
         }
     }
 
-    class MyGestureDetector extends SimpleOnGestureListener {
     @Override
-        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
+    protected void onSwipeRightToLeft(final MotionEvent e1, final MotionEvent e2) {
-            if (e2 == null || e1 == null)
+        // Handle right-to-left as an un-select
-                return true;
+        handleSwipe(e1, false);
+    }
 
-            float deltaX = e2.getX() - e1.getX(),
+    @Override
-                  deltaY = e2.getY() - e1.getY();
+    protected void onSwipeLeftToRight(final MotionEvent e1, final MotionEvent e2) {
-
+        // Handle left-to-right as a select.
-            boolean movedAcross = (Math.abs(deltaX) > Math.abs(deltaY * 4));
+        handleSwipe(e1, true);
-            boolean steadyHand = (Math.abs(deltaX / deltaY) > 2);
+    }
-
-            if (movedAcross && steadyHand) {
-                boolean selected = (deltaX > 0);
-                int position = mListView.pointToPosition((int)e1.getX(), (int)e1.getY());
 
+    /**
+     * Handle a select or unselect swipe event
+     * @param downMotion Event that started the swipe
+     * @param selected true if this was an attempt to select (i.e. left to right).
+     */
+    private void handleSwipe(final MotionEvent downMotion, final boolean selected) {
+        int position = mListView.pointToPosition((int) downMotion.getX(), (int) downMotion.getY());
         if (position != AdapterView.INVALID_POSITION) {
             MessageInfoHolder msgInfoHolder = (MessageInfoHolder) mAdapter.getItem(position);
 
@@ -1688,10 +1691,6 @@ public class MessageList
         }
     }
 
-            return false;
-        }
-    }
-
     @Override
     public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
         super.onCreateContextMenu(menu, v, menuInfo);

src/com/fsck/k9/activity/MessageView.java

@@ -82,7 +82,6 @@ public class MessageView extends K9Activity implements OnClickListener {
     private View mArchive;
     private View mMove;
     private View mSpam;
-    private ToggleScrollView mToggleScrollView;
     private Account mAccount;
     private MessageReference mMessageReference;
     private ArrayList<MessageReference> mMessageReferences;
@@ -132,14 +131,14 @@ public class MessageView extends K9Activity implements OnClickListener {
     public boolean dispatchTouchEvent(MotionEvent ev) {
         if (ev.getAction() == MotionEvent.ACTION_UP) {
             // Text selection is finished. Allow scrolling again.
-            mToggleScrollView.setScrolling(true);
+            mTopView.setScrolling(true);
         } else if (K9.zoomControlsEnabled()) {
             // If we have system zoom controls enabled, disable scrolling so the screen isn't wiggling around while
             // trying to zoom.
             if (ev.getAction() == MotionEvent.ACTION_POINTER_2_DOWN) {
-                mToggleScrollView.setScrolling(false);
+                mTopView.setScrolling(false);
             } else if (ev.getAction() == MotionEvent.ACTION_POINTER_2_UP) {
-                mToggleScrollView.setScrolling(true);
+                mTopView.setScrolling(true);
             }
         }
         return super.dispatchTouchEvent(ev);
@@ -187,7 +186,7 @@ public class MessageView extends K9Activity implements OnClickListener {
              * Selecting text started via shift key. Disable scrolling as
              * this causes problems when selecting text.
              */
-            mToggleScrollView.setScrolling(false);
+            mTopView.setScrolling(false);
             break;
         }
         case KeyEvent.KEYCODE_DEL: {
@@ -379,7 +378,7 @@ public class MessageView extends K9Activity implements OnClickListener {
         requestWindowFeature(Window.FEATURE_NO_TITLE);
         setContentView(R.layout.message_view);
 
-        mTopView = mToggleScrollView = (ToggleScrollView) findViewById(R.id.top_view);
+        mTopView = (ToggleScrollView) findViewById(R.id.top_view);
         mMessageView = (SingleMessageView) findViewById(R.id.message_view);
 
         //set a callback for the attachment view. With this callback the attachmentview
@@ -871,7 +870,22 @@ public class MessageView extends K9Activity implements OnClickListener {
         }
     }
 
+    /**
+     * Handle a right-to-left swipe as "move to next message."
+     */
     @Override
+    protected void onSwipeRightToLeft(MotionEvent e1, MotionEvent e2) {
+        onNext();
+    }
+
+    /**
+     * Handle a left-to-right swipe as "move to previous message."
+     */
+    @Override
+    protected void onSwipeLeftToRight(MotionEvent e1, MotionEvent e2) {
+        onPrevious();
+    }
+
     protected void onNext() {
         if (mNextMessage == null) {
             Toast.makeText(this, getString(R.string.end_of_folder), Toast.LENGTH_SHORT).show();
@@ -886,7 +900,6 @@ public class MessageView extends K9Activity implements OnClickListener {
         mNext.requestFocus();
     }
 
-    @Override
     protected void onPrevious() {
         if (mPreviousMessage == null) {
             Toast.makeText(this, getString(R.string.end_of_folder), Toast.LENGTH_SHORT).show();
@@ -1019,7 +1032,7 @@ public class MessageView extends K9Activity implements OnClickListener {
             });
             break;
         case R.id.select_text:
-            mToggleScrollView.setScrolling(false);
+            mTopView.setScrolling(false);
             mMessageView.beginSelectingText();
             break;
         default:

src/com/fsck/k9/activity/setup/AccountSetupBasics.java

@@ -240,7 +240,6 @@ public class AccountSetupBasics extends K9Activity
         }
     }
 
-    @Override
     protected void onNext() {
         String email = mEmailView.getText().toString();
         String[] emailParts = splitEmail(email);

src/com/fsck/k9/activity/setup/AccountSetupIncoming.java

@@ -385,7 +385,6 @@ public class AccountSetupIncoming extends K9Activity implements OnClickListener
         }
     }
 
-    @Override
     protected void onNext() {
         try {
             int securityType = (Integer)((SpinnerOption)mSecurityTypeView.getSelectedItem()).value;

src/com/fsck/k9/activity/setup/AccountSetupNames.java

@@ -79,7 +79,6 @@ public class AccountSetupNames extends K9Activity implements OnClickListener {
         Utility.setCompoundDrawablesAlpha(mDoneButton, mDoneButton.isEnabled() ? 255 : 128);
     }
 
-    @Override
     protected void onNext() {
         if (Utility.requiredFieldValid(mDescription)) {
             mAccount.setDescription(mDescription.getText().toString());

src/com/fsck/k9/activity/setup/AccountSetupOutgoing.java

@@ -285,7 +285,6 @@ public class AccountSetupOutgoing extends K9Activity implements OnClickListener,
         }
     }
 
-    @Override
     protected void onNext() {
         int securityType = (Integer)((SpinnerOption)mSecurityTypeView.getSelectedItem()).value;
         URI uri;