SimpleOnGestureListener code not working in Android 2.2
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I have some code that I wrote to implement a vertical swipe on a Gallery widget. It works great in Android 1.5 and 1.6 but does not work in Android 2.2 (I have yet to try it with 2.1).

public class SwipeUpDetector extends SimpleOnGestureListener
implements OnTouchListener
{
       private GestureDetector m_detector;

       public SwipeUpDetector()
       {
               m_detector = new GestureDetector(m_context, this);
       }

       @Override
       public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
       {
               if (Math.abs(e1.getX() - e2.getX()) < s_swipeMaxOffPath &&
                       e1.getY() - e2.getY() >= s_swipeMinDistance &&
                       Math.abs(velocityY) >= s_swipeMinVelocity)
               {
                       int pos = m_gallery.pointToPosition((int)e1.getX(), (int)e2.getY());
                       startAnimation(pos);

                       return true;
               }

               return false;
       }

       @Override
       public boolean onTouch(View v, MotionEvent event)
       {
               return m_detector == null ? false : m_detector.onTouchEvent(event);
       }
}

And to be able to get my gallery to detect the onFling I have the following:

   m_gallery.setOnTouchListener(new SwipeUpDetector());

In Android 1.5 and 1.6 this works great. In Android 2.2 onFling() is never called. In looking around on Google and StackOverflow I found one possible solution was to implement onDown() and return true.

However, I am also listening to single clicks and have a context menu listener set up on this gallery. When I implement onDown() and return true I do indeed get the swipe to work. But when I do this the context menu doesn't display on a long click and the single clicks don't work either... Clicking on items in the gallery cause the gallery to jump around and I don't get any feedback when I click on an item in the gallery. It just immediately makes that item the selected item and moves it to the center.

I looked at the API differences report between 1.6, 2.1, and 2.2 and didn't see anthing of significance that could have caused this to break...

What am I doing wrong?

EDIT:

It might also be helpful to know that the gallery is nested inside a couple layouts as follows (this isn't a complete layout... it is just intended to show the hierarchy of where this Gallery lives):

 <ScrollView>
      <LinearLayout>
           <RelativeLayout> <!-- This relative layout is a custom one that I subclassed -->
                <Gallery />
           </RelativeLayout>
      </LinearLayout>
 </ScrollView>

EDIT #2:

Here are the requested layouts... There are two of them, for reusability purposes. Here is the first one, which is the main activity's layout:

<?xml version="1.0" encoding="utf-8"?>
<ScrollView 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:myns="http://com.magouyaware/appswipe"
    android:id="@+id/main_layout_id"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_gravity="center_horizontal"
    android:scrollbarAlwaysDrawVerticalTrack="false"
>
    <LinearLayout 
        android:id="@+id/appdocks_layout_id"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_marginTop="10dp"
        android:layout_gravity="center"
        android:orientation="vertical"
        android:gravity="center"
        android:background="@null"
    >
        <com.magouyaware.appswipe.TitledGallery
            android:id="@+id/running_gallery_layout_id"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:visibility="gone"
            myns:gallery_title="@string/running_title"
        />

        <com.magouyaware.appswipe.TitledGallery
            android:id="@+id/recent_gallery_layout_id"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:visibility="gone"
            myns:gallery_title="@string/recent_title"
        />

        <com.magouyaware.appswipe.TitledGallery
            android:id="@+id/favs_gallery_layout_id"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:visibility="gone"
            myns:gallery_title="@string/favs_title"
        />

        <com.magouyaware.appswipe.TitledGallery
            android:id="@+id/service_gallery_layout_id"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:visibility="gone"
            myns:gallery_title="@string/service_title"
        />

        <com.magouyaware.appswipe.TitledGallery
            android:id="@+id/process_gallery_layout_id"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:visibility="gone"
            myns:gallery_title="@string/process_title"
        />

        <include 
            android:id="@+id/indeterminate_progress_layout_id" 
            layout="@layout/indeterminate_progress_layout" 
        />
    </LinearLayout>
</ScrollView>

And here is the layout file for com.magouyaware.appswipe.TitledGallery... This is nothing more than a RelativeLayout subclass for the purpose of controlling several views as a single item in the code and for reusability:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/titled_gallery_main_layout_id"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:gravity="center_vertical"
    android:layout_gravity="center_vertical"
    android:background="@null"
>
    <LinearLayout
        android:id="@+id/titled_gallery_expansion_layout_id"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:focusable="true"
        android:clickable="true"
        android:gravity="center_vertical"
    >
        <ImageView
            android:id="@+id/titled_gallery_expansion_image_id"
            android:layout_width="20dp"
            android:layout_height="20dp"
            android:duplicateParentState="true"
            android:clickable="false"
        />

        <TextView
            style="@style/TitleText"
            android:id="@+id/titled_gallery_title_id"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="left"
            android:paddingLeft="1sp"
            android:paddingRight="10sp"
            android:textColor="@drawable/titled_gallery_text_color_selector"
            android:duplicateParentState="true"
            android:clickable="false"
        />
    </LinearLayout>

    <Gallery
        android:id="@+id/titled_gallery_id"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/titled_gallery_expansion_layout_id"
        android:layout_alignWithParentIfMissing="true"
        android:spacing="5sp"
        android:clipChildren="false"
        android:clipToPadding="false"
        android:unselectedAlpha=".5"
        android:focusable="false"
    />

    <TextView 
        style="@style/SubTitleText"
        android:id="@+id/titled_gallery_current_text_id"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/titled_gallery_id"
        android:layout_alignWithParentIfMissing="true"
        android:gravity="center_horizontal"
    />
</RelativeLayout>
Polymorphous answered 3/3, 2011 at 22:4 Comment(1)
I should probably clarify that when I say I never get into the onFling() method that I mean I never get into that method for a vertical fling... I always get into that method if I fling left to right or vice versa.Polymorphous
C
1

I was able to receive single/double clicks and long click as well by implementing onSingleTapConfirmed, onDoubleTap and onLongPress in my implementation of SimpleOnGestureListener (while returning true from onDown).

Concerning why we should override onDown method. I think it is related to the issue #8233. It was reported one year ago against 2.1 version. Since only 10 people starred it so far I guess it would not be fixed in the near future.

UPDATE

It turned out that the issue was caused by the combination of ScrollView and Gallery and usage of OnTouchListener. Gallery itself implements OnGestureListener and encapsulates GestureDetector which is disabled when we set our OnTouchListener, resulting in a strange gallery behavior sometimes. On the other hand if we just subclass Gallery component and perform long-click/swipe detection in its onLongPress/onFling methods the parent ScrollView will intercept vertical move events preventing onFling call for such events. The solution is to override Gallery.dispatchTouchEvent and call requestDisallowInterceptTouchEvent(true) for gallery parent.

To summarize: if you want to detect swipes (long-, double-clicks etc.) for the Gallery (and possibly place it inside the ScrollView) use the custom component provided below instead of GestureDetector/OnTouchListener.

public class FlingGallery extends android.widget.Gallery implements OnDoubleTapListener {

  private static final int SWIPE_MIN_VELOCITY = 30;   // 30dp, set to the desired value

  private static final int SWIPE_MIN_DISTANCE = 50;   // 50dp, set to the desired value

  private static final int SWIPE_MAX_OFF_PATH = 40;   // 40dp, set to the desired value

  private final float mSwipeMinDistance;

  private final float mSwipeMaxOffPath;

  private final float mSwipeMinVelocity;

  public FlingGallery(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    float density = context.getResources().getDisplayMetrics().density;
    this.mSwipeMinDistance = density * SWIPE_MIN_DISTANCE;
    this.mSwipeMaxOffPath = density * SWIPE_MAX_OFF_PATH;
    this.mSwipeMinVelocity = density * SWIPE_MIN_VELOCITY;
  }

  public FlingGallery(Context context, AttributeSet attrs) {
    this(context, attrs, android.R.attr.galleryStyle);
  }

  public FlingGallery(Context context) {
    this(context, null);
  }

  @Override
  public boolean dispatchTouchEvent(MotionEvent ev) {
    final ViewParent parent;
    if (ev.getAction() == MotionEvent.ACTION_MOVE && (parent = getParent()) != null) {
      parent.requestDisallowInterceptTouchEvent(true);  // this will be passed up to the root view, i.e. ScrollView in our case
    }
    return super.dispatchTouchEvent(ev);
  }

  @Override
  public boolean onDoubleTap(MotionEvent e) {
  // Your double-tap handler...
    return true;
  }

  @Override
  public boolean onDoubleTapEvent(MotionEvent e) {
    return false;
  }

  @Override
  public boolean onSingleTapConfirmed(MotionEvent e) {
  // Your single-tap handler...
    return true;
  }    

  @Override
  public void onLongPress(MotionEvent event) {
  // Your long-press handler...
    super.onLongPress(event);
  }

  @Override
  public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
    if (e1 == null) {
      return super.onFling(e1, e2, velocityX, velocityY);
    }
    float dx = e2.getX() - e1.getX();
    float dy = e2.getY() - e1.getY();
    if (abs(dx) < mSwipeMaxOffPath && abs(velocityY) > mSwipeMinVelocity && abs(dy) > mSwipeMinDistance) {
      if (dy > 0) {
        // Your from-top-to-bottom handler...
      } else {
        // Your from-bottom-to-top handler...
      }
    } else if (abs(dy) < mSwipeMaxOffPath && abs(velocityX) > mSwipeMinVelocity && abs(dx) > mSwipeMinDistance) {
      if (dx > 0) {
        // Your from-left-to-right handler...
      } else {
        // Your from-right-to-left handler...
      }
    }
    return super.onFling(e1, e2, velocityX, velocityY);
  }
}
Confraternity answered 14/3, 2011 at 13:57 Comment(12)
Are you doing this on a Gallery view? I think my problem might be specific to using a Gallery view. When I return true from onDown() and try to implement those methods my Gallery jumps around like crazy and I don't get any visual feedback from my selector (i.e. background color changes based on the pressed/selected/focused states). Also I never get into the onLongPress, onDoubleTap, and onSingleTapConfirmed methods...Polymorphous
Looking at the bug it does seem like the exact problem I am facing... Unfortunately the workaround listed does not work in my casePolymorphous
Yes, I'm using it with Gallery view.Confraternity
I tried it on the layout you provided - and it worked (I even created custom RelativeLayout as you do). Just to clarify, my GestureListener does not implement OnTouchListener. Instead I'm attaching it to the Gallery like this: final GestureListener gst = new GestureListener(context, this); OnTouchListener touchListener = new View.OnTouchListener() { public boolean onTouch(View v, MotionEvent event) { return gst.onTouchEvent(event); } }; view.setOnTouchListener(touchListener);Confraternity
As an update, I was able to get all the methods to get hit, including the onFling() method. However, when I get to this point I lose all user-feedback from my custom selector (if it is focused it has a blue gradient background, if currently pressed it has a red gradient background and if selected has an orange gradient). Also... I as soon as I touch an item the current selection changes, without waiting for whether it is a single-tap, double-tap, long press, or swipe. I'll try changing it how you are doing it to see what happensPolymorphous
Maybe something is wrong with your layout. Can you please post layout details (including the attributes)? This can speed up issue identification.Confraternity
Sorry for the delay in answering... I'm editing my post above to contain your requested informationPolymorphous
I have tested the layout you provided and it works well - detecting taps (single/double) and vertical flings as well. Tested under Android 2.2 emulator.Confraternity
When you perform a long-press on the emulator, does the item pressed on immediately switch to the center? That is the behavior on my phone (T-Mobile MyTouch 3G 1.2 running Android 2.2.1)Polymorphous
I don't observe such behavior. I created a test project - you can compare it to yours, maybe it will help to resolve your issue. I will send you a mail. (And yeah, it's not an April 1st hoax ;-) ).Confraternity
Unfortunately the sample you sent me still has problems with long press... I sent an email explaining how to reproduce it.Polymorphous
Idolon has helped me figure out the cause of the problem and how to solve it. At least in my specific case, I needed to get rid of the ScrollView... As soon as I removed it everything started working again. In my case I was able to restructure my app so I didn't need it. I believe Idolon has come up with a way to make the ScrollView and Gallery view work together, so maybe he can post that solution here as well...Polymorphous
F
0

If you do not handle the down you will not get any event (scroll, fling, up) linked to this down event. So you must return true.

I tried to understand why but I failed yet. Maybe since SimpleOnGestureListener returns false by default, and some new 2.2 optimizations in the outer Layout feels you do not want the event. You are not a valid target anymore for the chain of events.

To get your longPress working, can't you implement the onLongPress event in your detector and call the code that makes your menu appear?

Florez answered 13/3, 2011 at 22:10 Comment(1)
As mentioned in my post, when I implement onDown() and try to process single clicks (including onLongPress) the Gallery view jumps around sporadically and gives all sorts of wild behavior...Polymorphous

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