getting null pointer exception cause an image online goes away btwn checking and loading

Programming Questions

giorgiomo..

getting null pointer exception cause an image online goes away btwn checking and loading

in Programming Questions • 1 year ago

I am loading images from the net, many many many of them, from instagram, and checking to make sure the URL is valid before loading the image, but once in a great while, in between checking for null and loading the image, the image is removed from the URL. quite a doozy. I had a workaround but it seems to invoke a memory leak in PImage, therefore crashing the app after 20 minutes or so.

any thoughts on how to avoid this bug? anyone even understand what I'm talking about?

if (loadImage(photo_urls[x]) != null) {
image(loadImage(photo_urls[x]), ((x)*width/5), 0, width/5, height);
}

Replies(4)

PhiLho

Re: getting null pointer exception cause an image online goes away btwn checking and loading

1 year ago

It doesn't make sense to load the image twice, even more from the Web (it might be the cause of null images, if some sites protects against such abuse).
Try:

PImage img = loadImage(photo_urls[x]);
if (img != null) {
image(img, x*width/5, 0, width/5, height);
}

giorgiomo..

Re: getting null pointer exception cause an image online goes away btwn checking and loading

1 year ago

cool thanks. I ended up finding out about the try/catch function which seems to be recommended vs checking for null. not sure why, but this code is a bit slicker than all the null checking I've been using. and more importantly, it works great!

try {
image(loadImage(photo_urls[x]), ((x)*width/5), 0, width/5, height);
}
catch(Exception e) {
}

PhiLho

Re: getting null pointer exception cause an image online goes away btwn checking and loading

1 year ago

" the try/catch function which seems to be recommended vs checking for null"
Technically, try/catch isn't a function, but a functionality, a language construct.

And I don't know where you saw this recommended over null check, but I wouldn't recommend this site...

My method is better (simpler, faster, no stack trace in the console) than try/catch.

giorgiomo..

Re: getting null pointer exception cause an image online goes away btwn checking and loading

1 year ago

you've lost me at "no stack trace in the console", care to explain?

also is there a reference for speed on these type of things, or is it best just to setup a timer within some code and test is myself?

thx

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