Android — ScrollView inside a Gallery

问题

So, the goal is to have a scroll view behaving correctly inside a gallery. I'm using an example posted by atraudes which you can see below:

public class GalleryFriendlyScrollView extends ScrollView{
    private static int NONE = -1;
    private static int DOSCROLLVIEW = 0;
    private static int DOGALLERY = 1;

    private float lastx = 0;
    private float lasty = 0;
    private float firstx = 0;
    private float firsty = 0;
    private float lastRawx = 0;
    private float lastRawy = 0;
    private int gestureRecipient = NONE;
    private boolean donewithclick = true;
    private Gallery parent = null;
    private boolean firstclick = true;

    public GalleryFriendlyScrollView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        boolean retthis = true;
        //Indicating a fresh click
        if(donewithclick){
            firstx = ev.getX();
            firsty = ev.getY();
            lastx = firstx;
            lasty = firsty;
            lastRawx = ev.getRawX();
            lastRawy = ev.getRawY();
            donewithclick = false;
            firstclick = true;
        }
        //We don't know where these gesture events are supposed to go to. 
        //We have movement on the x and/or why axes, so we can determine where they should go now.
        if((gestureRecipient == NONE) && (lastx != ev.getX() || lasty != ev.getY())){
            //Determine whether there's more movement vertically or horizontally
            float xdiff = ev.getX() - lastx;
            float ydiff = ev.getY() - lasty;
            if(xdiff < 0)xdiff = xdiff * -1;
            if(ydiff < 0)ydiff = ydiff * -1;
            if((xdiff) > (ydiff)){
                gestureRecipient = DOGALLERY;
            } else {
                gestureRecipient = DOSCROLLVIEW;
            }
        }
        if(gestureRecipient == DOGALLERY){
            if(!firstclick){
                //After you drag the screen left or right a bit, the baseline for where it calculates
                //x and y from changes, so we need to adjust the offset to our original baseline
                float offsetx = (((ev.getX() - lastx) - (ev.getRawX() - lastRawx)) * -1);
                float offsety = (((ev.getY() - lasty) - (ev.getRawY() - lastRawy)) * -1);
                ev.offsetLocation(offsetx, offsety);
            }
            retthis = getGallery().onTouchEvent(ev);
            Log.i("TAG", "gallery");
            firstclick = false;
        } else if(gestureRecipient == DOSCROLLVIEW){
            retthis = super.onTouchEvent(ev); //FIXME This isn't actually scrolling
            Log.i("TAG", "scroll");
        }
        if(ev.getAction() == MotionEvent.ACTION_UP){
            //User's finger has been lifted
            if(((firstx == ev.getX()) && (firsty == ev.getY()))){
                //Since there isn't any movement in either direction, it's a click
                getGallery().onSingleTapUp(ev);
                super.onTouchEvent(ev);
            }
            donewithclick = true;
            gestureRecipient = NONE;
            Log.i("TAG", "END");
        }
        //And record our coordinate data
        lastx = ev.getX();
        lasty = ev.getY();
        lastRawx = ev.getRawX();
        lastRawy = ev.getRawY();
        return retthis;
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        getGallery().onTouchEvent(ev);
        return super.onInterceptTouchEvent(ev);
    }

    private Gallery getGallery(){
        //Gets the gallery
        if(parent == null)
            parent = (Gallery) (this.getParent().getParent());
        return parent;
    }
}

This seems to be catching all the correct cases (horizontal, vertical and none) based on the log messages I've appended, but for some reason the scroll view isn't scrolling when super.onTouchEvent(ev) is being called in onTouchEvent(MotionEvent ev).

回答1:

See my answer to an identical question: Android: How do I place a ScrollView (with text in) into Gallery?

回答2:

Here's the answer I ended up crafting.

来源：https://stackoverflow.com/questions/5012545/android-scrollview-inside-a-gallery