Button in fragment gives null pointer for no reason
What is a NullPointerException, and how do I fix it?
Last seen not updating when using Android app This isn't directly related to the app, but probably more on the APIs it's using. The last seen on the profile page doesn't seem to reflect that I'm actively using the Android app, or taking actions. I was able to vote on items and the last seen property on the profile page said I was last seen 50 minutes ago, when I was using a computer.  I'm assuming it won't count as a visit for the Enthusiast and Fantic badges either. I don't want someone angrily posting on Meta swearing they used the app for a day, yet they lost the consecutive days and has to prove it by showing they voted for something (we're probably far from this situation since it's alpha...) How to model non-negative zero-inflated continuous data? I'm currently trying to apply a linear model (family = gaussian) to an indicator of biodiversity that cannot take values lower than zero, is zero-inflated and is continuous. Values range from 0 to a little over 0.25. As a consequence, there is quite an obvious pattern in the residuals of the model that I haven't managed to get rid of:   Does anyone have any ideas on how to solve this? How does PK know better than Jaggu? In , PK knows about Jaggu's boyfriend that he didn't cheat/left her in Belgium. But PK only read the mind of Jaggu. PK didn't know about Tapasvi's lies. How does he know that Sarfaraz still loves Jaggu in the ending? I want to convert .mov to .mp4! I saved the video from iMovie but it is in .mov format! How do I convert it to .mp4?  I'm using a MacBook and I want to share it to my phone, but my phone can't open .mov format video. Author information column wise I am using authblk package and I want to achieve following output using this package. I don't understand, because if 'don't' is 'do not' then wouldn't the sentence without conjunctions be 'do not you dare' which I'm pretty sure isn't grammatically correct. Like, when we say the term it means something else, certainly not 'do not you dare' anyway. Any ideas on why? I am so glad English is my first language. Post for clarifications on the updated pronouns FAQ Cannot install R-forge package using install.packages Is there a single word or very short phrase to describe the act of contemptuously referring to someone by using a diminutive "nickname", with which that person is not normally associated?  For example, referring to Henry Wadsworth Longfellow as Hank Longfellow? Or William Penn as Billy Penn? I want to get the following:    I tried the following  \[    a(i,k) \leftarrow     \min\Big\{0, r(k,k) + \sum_{i^{'} | i^{'}\notin \{i,k\}}\max\{0, r(i{'},k)\}\Big\} \]   and got    How can I make the part under the summation extend to left and right without making a space between plus and max as in the first figure? Var[A+B+C] = Var [A] + Var [B] + Var [C] I know that this relationship is correct when A,B and C are pairwise independent. However, I'm finding it difficult to calculate it.  Let's say that: Var [A] = Var [B] = Var [C] = 0.25. How can I prove that Var[A+B+C] = 0.75?  I started to work with the formula: Var[A+B+C] =E[(A+B+C)^2]−(E[A+B+C])^2 but I got stuck.  Thanks! Let's say I have 1m of 2,5mm² copper wire, insulated with H07V-K. The wire carries 40A and environment temperature is 25°C. The wire is suspended in free air. How hot will the wire get? And how can I calculate it for other values?  The use case is a 12V-230V AC converter I want to hook up to my car and determine the minimum wire thickness required. Because it's only used from time to time and not buried in a wall I suspect I can use thinner wires. This is a temporary thing and doesn't need to be up to code. "See somebody do" and "see somebody doing" I know what you're thinking: "of course it has, for example, it can be used to tell you how many times you can go around a circle". But that isn't really true, now is it? You'd be dead or the world would go under long before an infinite amount of loops had been reached.  Are there any practical applications for the concept of infinity? Is it a useful concept in maths at all?  I know that Donald E. Knuth has argued that for all practical purposes, a very, very large number has the same effect as infinity, in his book "Things a Computer Scientist Rarely Talks About" (can't remember the exact quote, nor find it online, unfortunately).  Examples are appreciated. How to evaluate the integral $$\int_{25\pi / 4}^{53\pi / 4}\frac{1}{(1+2^{\sin x})(1+2^{\cos x})}dx\ ?$$ Hidden fields though inheritance Using ArcPy to convert .txt to shapefile with coordinate system? I tried to define my coordinate system on creating the shapefile but when I zoom to layer I don't see my features and ArcGIS crashes. I know it's not in the coordinate system I defined for it but it shows the coordinate under properties but doesn't reflect when I zoom to layer. Here is my python code:  import arcpy  newfcName ="newfc.shp"   outpath = r"C:/FLOOD/IKEJA AND KOSOFE"  # Declaration arcpy.env.overwriteOutput=True  arcpy.env.workspace= outpath  # Create new Shapefile and add FIELDS newfc = arcpy.CreateFeatureclass_management(outpath, newfcName, "Point") # get the coordinate system by describing a feature class dsc = arcpy.Describe("newfc.shp" )  coord_sys = dsc.spatialReference  try:        # run the tool    arcpy.DefineProjection_management(newfcName , coord_sys)     # print messages when the tool runs successfully    print(arcpy.GetMessages(0))  except arcpy.ExecuteError:    print(arcpy.GetMessages(2))  except Exception as ex:    print(ex.args[0])  arcpy.AddField_management(newfc, "X", "STRING", field_length = 50) arcpy.AddField_management(newfc, "Y", "STRING", field_length = 50) arcpy.AddField_management(newfc, "Z", "STRING", field_length = 50) arcpy.AddField_management(newfc, "I", "FLOAT", field_length = 50)  # Reference Cursors cursor=arcpy.da.InsertCursor(newfc, ["X", "Y", "Z", "I"])  # Read File  a = open("C:/FLOOD/IKEJA AND KOSOFE/DEM/532722.txt","r")  inputF = a.readlines()  for line in inputF:     xCoordinate, yCoordinate, zValue, iValue = line.split(" ")      newRow = (str(xCoordinate), str(yCoordinate), str(zValue), float(iValue))      cursor.insertRow(newRow)  a.close() Would the One Ring have stayed hidden if Bilbo hadn't turned up? I've been studying the Huddleston and Pullum book for four months now. So far only one thing confuses me: the identity of gerund. Is it a noun or a verb?        His constant smoking upset me.  smoking seems  noun because of adjective constant.   Him/His constantly smoking upset me. smoking seems to be verb because of adverb constantly.   Him/His smoking cigars upset me. smoking seems to be a verb because of object cigars.      "His smoking upset me." So is this smoking gerund a noun or verb? Because there is no differentiation, is it both verb and noun? Maybe it's new word category?  Also his seems to be both  sometimes a subject and at other times a possessive determiner. Is that correct? How symbol lookup actually works