Python Jumpstart by Building 10 Apps Transcripts
Chapter: App 6: LOLCat Factory
Lecture: Showing LOLCats on OS X
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So our cat app is basically working,
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the last thing we need to do is display the cats to the users.
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Now we were looking to them over here in PyCharm
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but obviously the users won't be running this in pyCharm
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and we do kind of say hey we downloaded your cats
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but let's show them to them. Now we have to keep in mind
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we are working in a terminal app
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so we kind of can't really show it like on a cool web page or in some kind of window,
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the best I think we can hope for is maybe showing
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the finder window or the explorer window
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and letting them browse with the operating system file browser.
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So the last thing we are going to do is write this display cats method, let's do that.
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And the only thing we are going to need to know is
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what folder do we have so let's go write this at the bottom,
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and we'll define this method we'll say pass just for a second,
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now let's think how do we open the finder window
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so it turns out that you can just type open and give it a folder name
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so you could like type open. in the terminal,
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in OS X that would launch the finder window in whatever window you are at.
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Now on Windows, that doesn't work, you have to say start.
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and that would then launch the Windows Explorer
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to that location as well and in Ubuntu
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neither of these work you actually do xdg-open
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and then the folder so something like . to open the current one.
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We can run these three programs
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and let's go ahead and write it just for OS X first
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since that's what I am on,
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and then I'll show you how to actually determine
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what platform we are on and choose the right commander run based on that.
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So the command we are going to use is open folder,
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something like this, we want to call this open process,
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we want to launch another process from our application
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and we do that with the sub process module,
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now like all of these modules we have to import them,
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PyCharm will do that for us thank you very much,
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and then it has a call() method,
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and call takes you can see there is a few options here,
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call takes an array strings,
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the first string is going to be the name of the program,
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the second one is going to be the argument
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that we are going to pass to open
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so we just say open, folder and that should do it,
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let's test it out and maybe put a little print statement here
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just to say displaying cats in OS window
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so let me come out of full screen
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so this doesn't look weird when it launches,
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boom, there are some cats check that out,
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let me make them a little bigger for you, oh yeah,
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those are good cats there has been a failure on the internet,
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of course there has right, so we can sort of flip through our cats like this,
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I kind of like the dune cat, he is a good one.
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So we've successfully displayed our cats to the user,
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granted we have pretty simple mechanism for that
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because we have a simple terminal app, but nonetheless, pretty cool,
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it shows you how to work with sub-processes, in an incredibly easy way.
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Now the last thing to do is to say well, if I run this on Windows,
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or I run this on Linux,
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this is not going to work so well,
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let's actually take it and run it on Linux and watch it crash
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and then we'll fix it over there.
