大约有 49,000 项符合查询结果（耗时：0.1085秒） [XML]
getActivity() returns null in Fragment function
... suggest adding an
onAttach(Activity activity)
method to your Fragment and putting a break point on it and seeing when it is called relative to your call to asd(). You'll see that it is called after the method where you make the call to asd() exits. The onAttach call is where the Fragment is att...
List passed by ref - help me explain this behaviour
...e value of the variable (i.e. the reference - think "pointer") is copied - and changes to the value of the parameter inside ChangeList aren't seen by TestMethod.
try:
private void ChangeList(ref List<int> myList) {...}
...
ChangeList(ref myList);
This then passes a reference to the local-v...
When to call activity context OR application context?
...plicationContext() when you know why you are using getApplicationContext() and only when you need to use getApplicationContext().
To be blunt, "some programmers" use getApplicationContext() (or getBaseContext(), to a lesser extent) because their Java experience is limited. They implement an inner c...
“Least Astonishment” and the Mutable Default Argument
...
Actually, this is not a design flaw, and it is not because of internals, or performance.
It comes simply from the fact that functions in Python are first-class objects, and not only a piece of code.
As soon as you get to think into this way, then it completely ...
List files ONLY in the current directory
...
Just use os.listdir and os.path.isfile instead of os.walk.
Example:
import os
files = [f for f in os.listdir('.') if os.path.isfile(f)]
for f in files:
# do something
But be careful while applying this to other directory, like
files ...
Running unittest with typical test directory structure
...
The best solution in my opinion is to use the unittest command line interface which will add the directory to the sys.path so you don't have to (done in the TestLoader class).
For example for a directory structure like this:
new_project
├── antigravity.py
└── test_antig...
How to implement an STL-style iterator and avoid common pitfalls?
I made a collection for which I want to provide an STL-style, random-access iterator. I was searching around for an example implementation of an iterator but I didn't find any. I know about the need for const overloads of [] and * operators. What are the requirements for an iterator to be "STL-s...
How to check if a particular service is running on Ubuntu
...ed Hat Linux you can see all running services by running the following command:
service --status-all
On the list the + indicates the service is running, - indicates service is not running, ? indicates the service state cannot be determined.
...
Use '=' or LIKE to compare strings in SQL?
...
LIKE and the equality operator have different purposes, they don't do the same thing:
= is much faster, whereas LIKE can interpret wildcards. Use = wherever you can and LIKE wherever you must.
SELECT * FROM user WHERE login LIKE ...
How are 3D games so efficient? [closed]
...ever understood. How can a great big PC game like GTA IV use 50% of my CPU and run at 60fps while a DX demo of a rotating Teapot @ 60fps uses a whopping 30% ?
...