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Super-simple example of C# observer/observable with delegates
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The observer pattern is usually implemented with events.
Here's an example:
using System;
class Observable
{
public event EventHandler SomethingHappened;
public void DoSomething() =>
SomethingHappened?.Invoke(this, EventArgs.Empt...
source command not found in sh shell
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/bin/sh is usually some other shell trying to mimic The Shell. Many distributions use /bin/bash for sh, it supports source. On Ubuntu, though, /bin/dash is used which does not support source. Most shells use . instead of source. If you can...
How do I change the android actionbar title and icon
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This is very simple to accomplish
If you want to change it in code, call:
setTitle("My new title");
getActionBar().setIcon(R.drawable.my_icon);
And set the values to whatever you please.
Or, in the Android manifest XML file:
<activity android:name=".MyActivity"
android:icon="@d...
How to avoid null checking in Java?
...ts they are participating in and defensively overcheck for nulls. Additionally, when writing their own code, they tend to rely on returning nulls to indicate something thus requiring the caller to check for nulls.
To put this another way, there are two instances where null checking comes up:
Whe...
Learning Python from Ruby; Differences and Similarities
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[x*x for x in values if x > 15]
to get a new list of the squares of all values greater than 15. In Ruby, you'd have to write the following:
values.select {|v| v > 15}.map {|v| v * v}
The Ruby code doesn't feel as compact. It's also not as efficient since it first converts the values a...
Determining if a number is either a multiple of ten or within a particular set of ranges
...rite out the pseudo code, but I'm not entirely sure how to write them logically.
13 Answers
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Python requests - print entire http request (raw)?
...ests.post(...) (or requests.get or requests.put, etc) methods, you can actually get the PreparedResponse through response.request. It can save the work of manually manipulating requests.Request and requests.Session, if you don't need to access the raw http data before you receive a response.
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What is recursion and when should I use it?
...sion.
To see why, walk through the steps that the above languages use to call a function:
space is carved out on the stack for the function's arguments and local variables
the function's arguments are copied into this new space
control jumps to the function
the function's code runs
the function's...
Java Keytool error after importing certificate , “keytool error: java.io.FileNotFoundException & Acc
...mmand prompt in administrator mode. If not, you can also go to start -> all programs -> accessories -> right click command prompt and click 'run as administrator'.
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Nested fragments disappear during transition animation
...is, but based on @Jayd16's answer, I think I've found a pretty solid catch-all solution that still allows for custom transition animations on child fragments, and doesn't require doing a bitmap cache of the layout.
Have a BaseFragment class that extends Fragment, and make all of your fragments exte...