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copied!<ol> <li><p>The 427kb is the download size of the PNG images. PNGs are compressed. When you open them up in memory they actually expand, so that each pixel in the image, could contain up to 4 bytes (ARGB) values (depending on the format) and also other PNG metadata.</p></li> <li><p>Saving the thumbnails with double the size (dimensions), will not necessarily yield a file size with double size. It could be larger or smaller, depending on the image and how good the image compressor is.</p></li> <li><p>Adding images directly to the list field won't make any difference. You still will have them loaded in memory. What you need to do is have some sort of manageable in memory cache of say 20 images maximum. Your code needs to be clever enough to detect where in the list field the user is at any moment, and display images for that view. </p></li> </ol> <p>So, let's say each list field object (or row) has a tag associated with the respective image (e.g. filename). Once the user has finished scrolling up/down, you can then load the images for that view. If the first row displayed in the list field is row 20 and you can display 8 items, you will need to grab images 20 - 28 and load them in to the in-memory cache if they are not already there (so check the cache first). Then call invalidate() on the list field to ensure it repaints.</p> <p>Threading:</p> <p>a) You won't need a thread to detect where the user is at any point. You should be able to use the moveFocus methods or navigation methods and figure out where the user is.</p> <p>b) For loading images you need a queuing mechanism. Task queues are quite simple to implement, once you get your head around the threading/locking mechanism. Each task in the queue will load the image in it's own thread.You will want to set a limit of how many tasks (threads) are active in the queue at once. I would go for 3-5 maximum (this is from experience on BB platforms). For queue implementations I would suggest by reading up about task/job queues, and producer/consumer problems.</p> <p>The above mechanism is used a lot. This is why when you scroll down a contacts list for example, you might see a slight delay before the image of the contact is loaded and rendered next to the contact name.</p>

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