2020. 2. 13. 20:54ㆍ카테고리 없음
IntroductionTo use Python as a graphical interface for an Arduino powered robot, programmatically read the USB with the library. However, waiting for input from pySerial's Serial object is blocking, which means that it will prevent your GUI from being responsive. The process cannot update buttons or react to input because it is busy waiting for the serial to say something.The first key is to use the root.after(milliseconds) method to run a non-blocking version of read in the tkinter main loop.
Keep in mind that when TkInter gets to the root.mainloop method, it is running its own while loop. It needs the things in there to run every now and then in order to make the interface respond to interactions. If you are running your own infinite loop anywhere in the code, the GUI will freeze up.
Alternatively, you could write your own infinite loop, and call root.update yourself occasionally. Both methods achieve basically the same goal of updating the GUI.However, the real issue is making sure that reading from serial is non-blocking.
Normally, the Serial.read and Serial.readline will hold up the whole program until it has enough information to give. For example, a Serial.readline won't print anything until there is a whole line to return, which in some cases might be never! Even using the after and update methods will still not allow the UI to be updated in this case, since the function never ends. This problem can be avoided with the timeout=0 option when enitializing the Serial object, which will cause it to return nothing unless something is already waiting in the Serial object's buffer.
On Oct 1, 4:12 pm, Thomas Guettler wrote:Please explain what you want to do.I'm primarily looking for alternatives to MVC frameworks for webdevelopment, particularly SAAS. I've looked around, and somewhitepapers suggest that event-based frameworks often perform betterthan MVC. Since I'm looking at SAAS, having a 'view' is prettypointless since I'll either be using Thrift, returning simple HTTPheaders, or returning some sort of JSON/YAML/XML content (possiblybased on accept headers).' View' doesn't imply (x)html - any valid HTTP response is ok.
The wholepoint of decoupling controler from view (in web MVC) is to allow thesame controler to return different views. Lie Ryan In fact, MVC and event-driven is two entirely different concept. You can have both, or none.
It is, in the end, your choice which one to use or whether you want to use both or none. Event-driven programming is a concept that your programs are entirely composed of function definition and binding that function definition to events. The rest is handled by a mainloop, which calls the appropriate functions when it receives something. MVC is a separation of concern. In MVC code you want that there is.
On Oct 1, 4:12 pm, Thomas Guettler wrote:Please explain what you want to do.I'm primarily looking for alternatives to MVC frameworks for webdevelopment, particularly SAAS. I've looked around, and somewhitepapers suggest that event-based frameworks often perform betterthan MVC. Since I'm looking at SAAS, having a 'view' is prettypointless since I'll either be using Thrift, returning simple HTTPheaders, or returning some sort of JSON/YAML/XML content (possiblybased on accept headers).' View' doesn't imply (x)html - any valid HTTP response is ok. The wholepoint of decoupling controler from view (in web MVC) is to allow thesame controler to return different views.In fact, MVC and event-driven is two entirely different concept.
You canhave both, or none. It is, in the end, your choice which one to use orwhether you want to use both or none.Event-driven programming is a concept that your programs are entirelycomposed of function definition and binding that function definition toevents. The rest is handled by a mainloop, which calls the appropriatefunctions when it receives something.MVC is a separation of concern. In MVC code you want that there is aclear boundary between code that handles Model, View, and Controller, soit'd be easier to manage the code. On Oct 1, 6:53?pm, Lie Ryan wrote:In fact, MVC and event-driven is two entirely different concept. You canhave both, or none. It is, in the end, your choice which one to use orwhether you want to use both or none.Event-driven programming is a concept that your programs are entirelycomposed of function definition and binding that function definition toevents.
Event Driven Program Python
Python Event Driven
The rest is handled by a mainloop, which calls the appropriatefunctions when it receives something.MVC is a separation of concern. In MVC code you want that there is aclear boundary between code that handles Model, View, and Controller, soit'd be easier to manage the code.So are there any other patterns that can be used in stead of MVC? James Mills There is an alternative to the MVC architecture, and that is to have a set of Resources that are used by any User Interface, be on the Web, Desktop or Console, as long as it understands HTTP (but it doesn't have to restrict itself to the HTTP transport). Normally the applications I build don't use your typical MVC model or any MVC framework (as mentioned earlier, I've used pymills). I take the CRUX/RESTful approach and build a set of resources for my application and SaaS. Then I build a User. On Thu, Oct 2, 2008 at 2:09 AM, Bruno Desthuilliers wrote:'view' doesn't imply (x)html - any valid HTTP response is ok.
The wholepoint of decoupling controler from view (in web MVC) is to allow the samecontroler to return different views.There is an alternative to the MVC architecture, and that is to have aset of Resources that are used by any User Interface, be on the Web,Desktop or Console, as long as it understands HTTP (but it doesn'thave to restrict itself to the HTTP transport).Normally the applications I build don't use your typical MVC modelor any MVC framework (as mentioned earlier, I've used pymills). I takethe CRUX/RESTful approach and build a set of resources for myapplication and SaaS. Then I build a User Interface (normally I use ExtJS)j.cheersJames. On Wed, Oct 1, 2008 at 6:55 PM, Phillip B Oldham wrote:I've noticed that. I'm thinking more for a web environment (instead ofMVC) or as a HTTP server.
I know Twisted has TwistedWeb, but I'mlooking for alternatives.Again with pymills, here's an alternative:I have built 2 commercial web applications using mypymills library and it's web server components (seesimple example above).NB: I do not plan to write yet another framework:) but instead a setof re-usable and flexible components.cheersJames. On Oct 2, 1:28?am, 'James Mills' wrote:Phillip, I have been developing a rather uniqueevent-driven and component architecture libraryfor quite some time that is (not twisted).
Actuallyit's nothing like twisted, but based on 2 coreconcepts:?. Everything is a Component?. Everything is an EventIt's currently called pymills.eventLet me know if you're interested, I probablyplan to re-package and re-branch this library(the event library) at some point.I'd be very interested in seeing this.
Component-based programming issomething which interests me also. On Oct 2, 1:28 am, 'James Mills' wrote:Phillip, I have been developing a rather uniqueevent-driven and component architecture libraryfor quite some time that is (not twisted). Actuallyit's nothing like twisted, but based on 2 coreconcepts:. Everything is a Component. Everything is an EventIt's currently called pymills.eventLet me know if you're interested, I probablyplan to re-package and re-branch this library(the event library) at some point.I'd be very interested in seeing this. Component-based programming issomething which interests me also.Phillip, you can normally clone my library usingMercurial by doing:$ hg cloneIf my VPS is still down, email me and I'll send youa tar.bz2 (or something).It may also interest you to know that I've portedmy library to py3k and so far all tests are working:)Thanks,cheersJames.