This is only happens on one machine, others seems to be better.
With SwiftUI, no code completion is shown after '#'. Anything like #State, #Published, #Binding, will not complete at all.
If I remove import SwiftUI, completion will start working, but will stop once the import statement returns.
If I only have import Combine, then all the SwiftUI is working, but not the Combine (#State will complete, #Published will not).
I tried (while restarting the Mac after each time), toggle code completion, cleared all DerivedData, re-downloading Xcode. Not sure what else can be done.
(While it only happens on one machine, M1 mac, other people had some other things like completion after #S but none after #St).
Related
I am playing around with SwiftUI and looks pretty interesting however I am facing very annoying performance issues.
When I create a new SwiftUI file or make a large change in a SwiftUI view, XCode would start recompiling everything. It would re-compile pods(I am using Firebase) even if they are not included in the view.
This behaviour is quite painful because it takes a few minutes for the process to finish and more often than not it will result with an XCode error and I will have to click "try again" before I have anything in the Canvas or on the device.
Is there anything I can do to improve performance when developing with SwiftUI?
This is what happens when I create a brand new SwiftUI file
A workaround for this issue is to create another app target that doesn't refer to any pods. This way, you can have fast compile and preview of the pure SwiftUI files as the pods and other files won't be compiled when you switch target.
I receive this error whenever I try to preview a freshly created swiftui view.
messageRepliedWithError("Connecting to launched interactive agent 9297", Optional(Error Domain=com.apple.dt.ultraviolet.service Code=17 "connectToPreviewHost: Failed to connect to 9297: Error Domain=com.apple.dt.ProcessAttachUtilities Code=3 "Target process 9297 exited prematurely, likely crashed" UserInfo={NSLocalizedDescription=Target process 9297 exited prematurely, likely crashed}" UserInfo={NSLocalizedDescription=connectToPreviewHost: Failed to connect to 9297: Error Domain=com.apple.dt.ProcessAttachUtilities Code=3 "Target process 9297 exited prematurely, likely crashed" UserInfo={NSLocalizedDescription=Target process 9297 exited prematurely, likely crashed}}))
I have no idea how to fix this so I can see previews again. I am on the latest Catalina 10.15.1
I found the Preview Canvas to be extremely buggy as well. Or maybe swiftUI code has a lot of undesired side effects.
In many occasions I found that Clean Build Folder, then kill Xcode, start Xcode, do a full Build may (sometimes) fix the problems. Until I make a tiny change somewhere... Then the whole circus starst again.
In practice this is very time consuming and basically unworkable. I found it more efficient to not use the preview canvas at all and just run the code. It is quicker, more reliable and in the end saves lots of time and frustration.
At the same time I think it is a bit of a shame on Apple. Most frustrating of all (for me at least) is that documentation is virtually non existing. It is all trial and error. Mostly error.
In short: my experience is that it is better not to use swiftUI Previews for anything beyond the very basic (yet).
I had the same problem with mine, I went through a couple of steps, so I will mention everything I did hopefully it helps someone.
But it's worth mentioning that I think the error was caused by Xcode trying to connect to the preview which failed all the time, because I was using an iPhone 8 preview.
Also I was able to use iPhone 8 preview after a while again. This looks like a buggy Xcode.
Steps.
1. Clean build folder and your derived data.
2. Close XCode Completely.
**Key Step. Open Xcode again and change your preview to iPhone XS or iPhone 11.
See the image below.
I had same issue. It was very confusing. I am using FirebaseFirestore pod in my podfile and when I remove FirebaseApp.configure() from AppDelegate didFinishLaunchingWithOptions function preview works.
I have done this 10 times just to make sure that this is an issue, and it was issue for me. So probably any code from Firbase added in that function was problem for me.
So, by checking logs I came across this error:
Crashed Thread: 3 Dispatch queue: com.google.GDTCORFlatFileStorage
Also googling I came across those bugs:
https://github.com/firebase/firebase-ios-sdk/issues/5707
https://github.com/firebase/firebase-ios-sdk/issues/5708
Turning off the thread sanitizer worked for me (I was just playing around with settings against another project that worked), so there's one more thing to try...
First of all, I'm quite new at Python, Stackoverflow and programming in general so please forgive any formal errors I might have made as I'm still trying to grasp many of the required conceptual programming protocols.
Here's the issue:
I'm trying to work around a specific, seemingly simple problem I've been having when using Tkinter: Whenever I'm fiddling with some code that confuses me, it generally takes many attempts until I finally find a working solution. So I write some code, run it, get an error, make some changes, run it again, get another error, change it again... and so on until a working result is achieved.
When the code finally works, I unfortunately also get additional Tkinter main windows popping up for every failed run I've executed. So if I've made, say, 20 changes before I eventually achieve working code, 20 additional Tkinter windows pop up. Annoying...
Now, I was thinking that maybe handling the exceptions with try/except might avoid this, but I'm unsure how to accomplish this properly.
I've been looking for a solution but can't seem to find a post that addresses this issue. I'm actually not really sure how to formulate the problem correctly... Anybody has some advice concerning this?
The following shows a simple but failed attempt of how I'm trying to circumvent this. The code works as is, but if you make a little typo in the code, run it a couple of times, then undo the typo and run the code again, you'll get multiple Tkinter windows which is what I'm trying to avoid.
Any help is, of course, appreciated...
(btw, I'm using Python 2.7.13.)
import Tkinter as tk
class App(tk.Frame):
def __init__(self, parent):
tk.Frame.__init__(self)
self.root = parent
self.canvas = tk.Canvas(self)
self.canvas.pack(expand=1,fill='both')
self.bindings()
def click(self,e):
print 'clicked'
def bindings(self):
self.root.bind('<1>',self.click)
def main():
root = tk.Tk()
app = App(root)
app.pack()
root.mainloop()
if __name__ == '__main__':
try:
main()
except:
print 'Run failed...'
Alright, great. The issue has indeed nothing to do with Tkinter or Python but with the IDE itself. Thank you Ethan for pointing that out.
PyScripter has several modes or engines. I've been running scripts with its internal engine which is faster but does not reinitialize with every run. I believe this causes the problem. The remote engine, on the other hand, does reinitialize with every run. This avoids the failed run popups.
A more in-depth explanation from the PyScripter manual below:
Python Engines:
Internal
It is faster than the other options however if there are problems with
the scripts you are running or debugging they could affect the
reliability of PyScripter and could cause crashes. Another limitation
of this engine is that it cannot run or debug GUI scripts nor it can
be reinitialized.
Remote
This the default engine of PyScripter and is the recommended engine
for most Python development tasks. It runs in a child process and
communicates with PyScripter using rpyc. It can be used to run and
debug any kind of script. However if you run or debug GUI scripts you
may have to reinitialize the engine after each run.
Remote Tk
This remote Python engine is specifically created to run and debug
Tkinter applications including pylab using the Tkagg backend. It also
supports running pylab in interactive mode. The engine activates a
Tkinter mainloop and replaces the mainloop with a dummy function so
that the Tkinter scripts you are running or debugging do not block the
engine. You may even develop and test Tkinter widgets using the
interactive console.
Remote Wx
This remote Python engine is specifically created to run and debug
wxPython applications including pylab using the WX and WXAgg backends.
It also supports running pylab in interactive mode. The engine
activates a wx MainLoop and replaces the MainLoop with a dummy
function so that the wxPython scripts you are running or debugging do
not block the engine. You may even develop and test wxPython Frames
and Apps using the interactive console. Please note that this engine
prevents the redirection of wxPython output since that would prevent
the communication with Pyscripter.
When using the Tk and Wx remote engines you can of course run or debug
any other non-GUI Python script. However bear in mind that these
engines may be slightly slower than the standard remote engine since
they also contain a GUI main loop. Also note that these two engines
override the sys.exit function with a dummy procedure.
I have created a GUI on Python 2.7.11 that consists of a main page along with page 1 and page 2 that are linked through buttons on main page. Converted main page to a python exe file using PyInstaller and there were no errors in the conversion. main page.exe appeared in the dist folder but on clicking it, a DOS screen flashed and the main page did not open nor persist on the screen.
Being a beginner, I am not sure about how to proceed further. Please help.
If you've got a line like root.mainloop() at the end (with root standing for your main Tk window) to make sure the event loop runs, then you'll need to debug your code. Try running a small segment of the code at a time to see if all goes well, and see where it is that all doesn't go well; then examine the offending part closely to find the error, maybe running some lines of code in the interpreter from the command line to see what (if any) error messages you get.
On the other hand, if you don't have a line like root.mainloop() at the end, that could produce the error you saw. Being a Python beginner myself, and having learned to program in Tcl where the Tk event loop runs automatically, I've seen that error a few times myself. :o(
There were multiple issues associated with converting the Python Script that links modules through button clicks. Keeping in mind these factors, it would be best to convert it to exe using Cx_Freeze. It is more user-friendly and was highly effective for the GUI when compared to PyInstaller and Py2Exe.
I'm using xcode in C++. I'm trying to debug my project, but at random intervals, it seems to ignore my breakpoints. There are three things that it does:
1) Sometimes, when I run, it automatically switches to "de-activate break points" mode. (the relevant button goes light and says "Activate")
2) Sometimes when I run, ALL of my breakpoints go "can't find" mode, with the yellow insides. I need to click twice on them to get them back dark blue (once to light blue = inactive, once to dark blue = active)
3) Sometimes, when I run, my breakpoint is dark blue, the button says "deactivate" and it still just ignores my breakpoint, running straight past it.
This makes it very difficult to debug my program...
I should add that I'm using XCode 3.1 beta on OSX 10.5.6, in case that matters.
thanks.
Try unchecking the Load symbols lazy in the Debugging panel in Preferences
alt text http://img.skitch.com/20090209-gj947qk7dxdyms1wij4q5em2f2.jpg
Had the same problem but only restarting the iPhone Simulator seemed to fix it.
I faced the same issue right now.
I tried all the options : enabling the GCC, active, base targets and restarting and closing xcode, nothing solved.
I finally restarted the simulator and things have started working.
I have more or less the same set of issues, and this suggestion of loading symbols lazily unfortunately does not resolve it for me. Moreover, I am not developing for the iphone, just a regular application.
To be specific, sometimes I can't disable or enable breakpoints on the fly - sometimes my code doesn't stop in breakpoints which I later prove are being executed (with print statements) and nothing I can do will make it stop there - I see that very annoying debug symbol with an orange center, even though I only have one project active.
Quitting and restarting XCode occasionally has an effect - and annoyingly, there have been a very small number of cases where quitting and restarting or rebuilding from clean fixed hard-to-diagnose compilation/linking errors. Unfortunately, I just tried all of these with no effect.
(Unrelated, my keyboard shortcuts are also unreliable. My shortcut of F2 for continue worked for weeks for me, stopped working for a long time, was working this morning and now doesn't work at exactly the same breakpoint it worked before - yet my F1, step over, key has been completely reliable...)
I'm a little disappointed to have to do so much debugging with print statements!