Develop Reference

ListView with Image Adapter Locking the UI Thread

I have a listview that load images with a adapter. Every time that I scroll the screen, the listview calls the getView to refresh the listview, then the getView loads a image, doing that in my ui thread, locking my screen for a moment.
What I did was to load the images in a AsyncTask class. But the problem is that it take a little bit, and when you scroll you see the wrong image, after a while it louds the right image. I didn't want to have that problem, showing the wrong image for a moment.
I search and saw that there is no way to stop that listview automatic refresh.
What should I do to resolve that problem? Any tutorial would be helpful.

What should I do to resolve that problem?
Set the ImageView to show a placeholder image in getView(), while you fork the task to load the real image. Or, as others have suggested, use any number of libraries for managing all of that for you (and I echo the Picasso recommendation).

Android Gallery View and adapter getView gets called many time

I have a Gallery, which has an adapter connects to it. In the getView method, i have a custom layout, so that I can i have image and caption displayed together
The image is downloaded from an URL, which is done asynchously, and working as expected.
Currently i make each item to fill the screen, so i only have one item display at a time, basically i want to make it like a slide show.
let me be clear, currently i have an activity, and it only has one View, which is a Gallery.
problem occurs when I am swiping, the image bounces and stays at the same image. i need to swipe many times, hard, and long swipe, then i can get to next image.
i put a debug message in my custom adapter in the getView(), it seems getView is getting called many times (4 times), and position being passed is either the current position or the previous one, which explains why i am stuck at the same screen.
if i remove the remote downloading image part, or just use a static image form the phone, i don't have any more issues, in fact, the getView only gets called once, with correct position.
i am very frustrated, not sure what the problem is, could it be because i am downloading image asynchously, which will cause the image to update which causes getView to get called again to redraw itself?
i am not sure..
please help

Unfortunately this is a bug with gallery. Listviews will scroll nicely regardless of data being updated asynchronously. However, the gallery is just not coded up to par with the listview
When the gallery tries to update a visible view (due to your image loading callback) this view will "snap" back to the focused position. If you are changing the view in any way when it is scrolling it will snap. This is likely why you have to scroll hard to get away from the current view. It is trying to perform a callback on your view and only scrolling fast will prevent the callback from occurring before you move away from that view.
I've reported this bug a while ago here:
Android Issues
There are a few workarounds posted in there you can try if you are set on using a Gallery.
Unfortunately it hasn't gained attention from the Android developers.
It seems the issue is caused with views being set to "wrap_content" and the gallery having to remeasure/redraw its views
I have since migrated away from using the gallery and instead use a ViewPager. It is much easier to manage and you don't have to worry about this problem. This has been a known problem with the Gallery since the gallery was first introduced. I have no idea if this was fixed in any of the newer Android versions (3.x/4.x). As of 2.3.7 it is not fixed.

At first you should note: Any AdapterView (Gallery, ListView etc) doesn't guarantee that each time getView() method is called it will pass the same View instance parameter. It only guarantees that each view will have the same type (see Adapter.getIntemViewType() method docs)
So, when you start image downloading you should only specify position of the element. Then after the image has been downloaded you should bind specified ImageView with downloaded image in Adapter.getView() method call.
Take a look to the ImageDownloader from the Android samples here
The other approach is to use WeakHashMap in order to contain map of adapter views to its positions. I can provide you with code samples if you need.

How to create horizontal listview which is fix the count of item when display

I want to create a horizontal listview which contain many item, one item will contain a image. When user slide listview => the count of item will be fix when it display, example display only 3 or 4 image. How can I do that? Many thanks.
Edit:
I use this
to create a HorizontalList view, everything is ok but I don;t know how to make the Next and Previous button work! Any idea?

Instead of a horizontal ListView (which, as far as I know, isn't offered by the Android SDK) you can use a HorizontalScrollView. You can add the items like to any other kind of layout class.

It looks like what you are looking for is a Paginated Gallery. I have written one here.
Its still only a couple of days old but hopefully the included Activity code will get you off the ground.

Actions on gallery view android

i have two gallery views in my single UI screen or you may say activity, i want to have listener in such a way that on scroll of one gallery view the other should also scroll , i tried giving listener to one gallery and calling the other one gallery view into that ., but its working for me , pls can any one help me..
thanks in advance
Datta

You could try to find the position of one of the galleries with Gallery.setOnItemSelectedListener() and then update the other gallery with Gallery.setSelection().

I believe the Gallery view is missing a lot of functionality (or is broken) as compared to ListView or GridView. In this particular instance, you need a "setOnCenteredItemChangedListener" or something like that. However, the documentation does not show anything close to this.
One option would be to implement your own Gallery class using HorizontalScrollView.
Another (hacky) option would be to rely on your Gallery adapter to push the current position being fetched (which may NOT be the one displayed in the middle) and use that to guess the currently selected position.

You have to override the scroll event of your first gallery and inside this method you should call the onScroll event of your second gallery like this,
gallery_two.onScroll(MotionEvent e1,MotionEvent e2,x,y);

OnClickListener and OnTouchListener

I have an 2 adapters extending BaseAdapater. The first Adapter (let's call it imageAdapter) loads an image base on an ID, the second adapter (pageAdapter) builds grids of images from the first adapter. I set the second adapter to a gallery. The idea is that I can sort have pages in an album where there are multiple pictures on each album.
Now I want to the imageViews to fire off clicks, so I set an onClickListener for each of the imageViews from the imageAdapter. The problem is that after I set the onClickListener, I cannot scroll the gallery by touch/fling/scrolling on the images anymore. I think it's an issue of parent/children event pass through thing.. but I am not sure how to fix it exactly. Please help.

This is a wild guess based on an experience with ListView (where one clickListener worked but the parent onClickListener did not), but setting the onClickListener on the imageViews might have made it so they have taken away the focus, and now your other touch events are not registering.
try setting myImageView.setFocusable(false)
I am assuming that everything worked as expected before you added the onClickListener to the ImageViews.

I solved this problem by subclassing Gallery and overriding onDown() and onSingleTapUp(). I have to also implement a pointToChildId() method to translate motion events to item ids. =) it was a lot more work than I initially planned for, but it works now and I am quite happy with the solution.