Android baseadapter getview not called dating

ListView content background changed when I scroll down and up. (Android forum at Coderanch)

android baseadapter getview not called dating

Jul 9, If they are stored locally, a native Android implementation will result in stuttering. In fact, our Android book has an exercise where you write one in an app called View getView(int position, View convertView, ViewGroup parent) { if If a request is invalid or out of date, it skips over to the next request. Date · DriverManager · DriverPropertyInfo · SQLPermission · Time · Timestamp .. For example, this can be used if the client does not want a particular view to be public abstract View getView (int position, View convertView, ViewGroup parent) This method will only be called when the adapter is set on the AdapterView. Oct 3, The ListView is a widget used extensively in Android applications to display data method is invoked is drastically reduced, existing views do not have to be public View getView (int position, View convertView, ViewGroup parent) .. one prior to the app's official launch date and another on the same day.

The onProgressUpdate method receives progress updates from doInBackground method, which is published via publishProgress method, and this method can use this progress update to update event thread The onPostExecute method handles results returned by doInBackground method. If an async task not using any types, then it can be marked as Void type.

android baseadapter getview not called dating

An running async task can be cancelled by calling cancel method. The generic types used by AsyncTask are Params, the type of the parameters sent to the task upon execution Progress, the type of the progress units published during the background computation.

Result, the type of the result of the background computation. Let us take a glance at how to use it practically for downloading image asynchronously from web. Once download is over, it displays the bitmap on the image view.

Creating custom ListView Now that we understand the basics of AsyncTask, let us proceed with creating the custom list view in android.

android baseadapter getview not called dating

The focus of this tutorial is tried to image download. We will complete this activity in Section 3. Create list row layout Now let us focus on the layout for list view row item.

ViewHolder considered harmful — Xebia Blog

Creating custom list adapter Adapter is acts as a bridge between data source and adapter views such as ListView, GridView. It has some nice properties, too: There are a few drawbacks to this implementation, though. One is that I have a lot of integration with the lifecycle of my fragment: I could solve some of these problems by centralizing my image downloader in a singleton, but then my implementation would need to be able to handle multiple client fragments simultaneously, making it more complicated.

Okay, enough boring setup. Pulling it into your project is as straightforward as these things get. Square claims easy integration into your code, too, stating that Picasso allows for hassle-free image loading in your application—often in one line of code! That one line of code looks like this: This code is almost exactly what my code in PhotoGallery ended up looking like.

android baseadapter getview not called dating

All the code onCreateonDestroyView and onDestroy ended up going away, and my adapter implementation turned into this: I broke my implementation out into more than one line for clarity, but other than that it is the same.

I also had to disable a default behavior. Out of the box, Picasso displays a slick fade-in animation when your image loads. This is actually nice to see in Android—we rarely get any free visual spiff. I turned it off with a call to noFade. Particularly nifty is that the transformations are performed prior to caching, which would be a big win in some scenarios.

android baseadapter getview not called dating

Pros and cons of Picasso So what do I get with those five lines? An automatically created singleton image downloader which you can do without if you like Memory and disk caching of uncompress imagery, post-processing Request cancellation Multiple downloads at one time A couple of things jumped out at me as being handy for embedding Picasso into existing apps: It plays nicely with existing code.

No custom ImageView subclass is necessary. In PhotoGallery, no changes needed to be made to my adapter code, apart from ripping out the old image code and plugging in the new. And how can Picasso be extended?

Solving the Android image loading problem: Volley vs. Picasso

You can make your own custom image transformations. These plug right in alongside the existing transformations. You can plug in your own image loader. Finally, one thing I found to be a hassle with Picasso: So why is it difficult? This means that it has to know how big the image is at the time you request it. Unfortunately, you will not know how big the image needs to be at the time you usually build the request: A more general solution: This implementation has a smaller footprint in my controller code, and also has the advantage that the request gets cleaned up in onDestroy if the user navigates away for some reason.

This is exciting because traditionally, networking in Android has been hairy.

Your ViewHolders are Dumb. Make ’em Not Dumb.

In practice, something like our AsyncTask implementation is common. We explain how it all works in our book, but I have often wished for something simpler. So how do we integrate image loading? The very first step is actually to integrate this library into our app.

android baseadapter getview not called dating

Volley lives in AOSP, but it is not for the time being exposed as a library through, for example, the support library.