No error on code but application crash when perform function. Logcat show FATAL EXCEPTION on (MainActivity.java:623)
What is a NullPointerException, and how do I fix it?
Make the enter key send message on iPad From the man page on git-merge, there are a number of merge strategies you can use.     resolve -  This can only resolve two heads (i.e. the current branch and another branch you pulled from) using 3-way merge algorithm. It tries to carefully detect criss-cross merge ambiguities and is considered generally safe and fast. recursive -  This can only resolve two heads using 3-way merge algorithm. When there are more than one common ancestors that can be used for 3-way merge, it creates a merged tree of the common ancestors and uses that as the reference tree for the 3-way merge. This has been reported to result in fewer merge conflicts without causing mis-merges by tests done on actual merge commits taken from Linux 2.6 kernel development history. Additionally this can detect and handle merges involving renames. This is the default merge strategy when pulling or merging one branch. octopus -  This resolves more than two-head case, but refuses to do complex merge that needs manual resolution. It is primarily meant to be used for bundling topic branch heads together. This is the default merge strategy when pulling or merging more than one branches. ours -  This resolves any number of heads, but the result of the merge is always the current branch head. It is meant to be used to supersede old development history of side branches. subtree -  This is a modified recursive strategy. When merging trees A and B, if B corresponds to a subtree of A, B is first adjusted to match the tree structure of A, instead of reading the trees at the same level. This adjustment is also done to the common ancestor tree.   When should I specify something different than the default?  What scenarios are each best for? Windows 7 low and critical battery levels cannot be set lower than 10% root owned program with setuid bit on Ping is a a program owned by root with the user id bit set.  $ ls -l `which ping` -rwsr-xr-x 1 root root 35752 Nov  4  2011 /bin/ping   As I understand it, if a user runs the ping process, then the effective user id will change from the real user id (i.e. the user id of the person who launched the process) to the user id root. However when I try this and look at the output of ps to see if the ping process is running as the root user, I still get the real user id showing.  ps -e -o user,ruser,euser,cmd,args | grep ping sashan   sashan   sashan   ping -i 10 -c 1000 www.goog ping -i 10 -c 1000 www.google.com How to store date/time and timestamps in UTC time zone with JPA and Hibernate Unless I missed something key during Descent 1/2, how is it that the Borg are once again a collective? Calculate the product of distances for a line perpendicular to hyperbola Let us have a hyperbola $\frac{x^2}{a^2} - \frac{y^2}{b^2} = 1$ and assume the normal at P meets the transverse (horizontal) axis $AA'$ in $G$ and the conjugate (vertical) axis $BB'$ in $g$. Assume CF be perpendicular to the normal from the center.   Find $\frac{PF \cdot PG}{CB^2}$ Find $PF \cdot Pg$   How can I solve the question in least amount of steps?  My attempt:  I first formed the equation of the normal and then I found out the points where it cuts the conjugate and transverse axis. After finding these points I used distance formula to find the distance required and convert it in the form that the question asked. But its a long method and took lot of steps How to share the "Look Back" video from Facebook? On Facebook, there is a  looking back on your Facebook history. Apparently, some people have shared this video with their friends, however I and someone else cannot figure out how to do so. This URL is not unique, it's a global URL which shows the video of who's logged in. People say there's supposed to be a "share" link, but there are no links whatsoever. And, I can't share the URL because it would show them their own videos.  How do I share this video with friends on Facebook?  without using a screen recorder to capture it When do we still need the table and figure environments when we don't want the enclosed objects to float? The LaTeX Wikibook :     Please understand: you do not have to use floating tables. It only   looks more professional. If you want to place your tables where they   lie in your source code, do not use table at all! This is a very   common misunderstanding among newcomers.   LaTeX works with an intricate , but I often prefer immediate placement with the H placement specifier (enabled by the float package).  My understanding is that captions and table/figure numbering require the table/figure environments. Is this really so, or are there ways around that? What other reasons are there for using table/figure if we know that we don't want a particular object to float? Weird artifacts in my UV mapped texture Any ideas what's causing those chunks of geometric artifacts?  Argh. Why does the Sun's (or other stars') nuclear reaction not use up all its "fuel" immediately? The temperature and pressure everywhere inside the Sun reach the critical point to start nuclear reactions - there is no reason for it to take such a long time to complete the reaction process.  Just like a nuclear bomb will complete all the reaction within $10^{-6}$seconds.  Why does most of the hydrogen of the Sun still not react even though it reaches the critical point, and why take stars billions of years to run out of fuel? How to put a framed box around text + math environment How to handle WndProc messages in WPF? In Windows Forms, I'd just override WndProc, and start handling messages as they came in.  Can someone show me an example of how to achieve the same thing in WPF? Quotient ring of Gaussian integers $\mathbb{Z}[i]/(a+bi)$ when $a$ and $b$ are NOT coprime The isomorphism $\mathbb{Z}[i]/(a+bi) \cong \Bbb Z/(a^2+b^2)\Bbb Z$ is , when the integers $a$ and $b$ are coprime. But what happens when they are not coprime, say $(a,b)=d&gt;1$?      — For instance if $p$ is prime (which is not coprime with $0$) then $$\mathbb{Z}[i]/(p) \cong \mathbb{F}_p[X]/(X^2+1) \cong \begin{cases} \mathbb{F}_{p^2} &amp;\text{if } p \equiv 3 \pmod 4\\ \mathbb{F}_{p} \times \mathbb{F}_{p} &amp;\text{if } p \equiv 1 \pmod 4 \end{cases}$$ (because $-1$ is a square mod $p$ iff $(-1)^{(p-1)/2}=1$).  — More generally, if $n=p_1^{r_1} \cdots p_m^{r_m} \in \Bbb N$, then  each pair of integers $p_j^{r_j}$ are coprime, so that by CRT we get $$\mathbb{Z}[i]/(n) \cong \mathbb{Z}[i]/(p_1^{r_1}) \times \cdots \times \mathbb{Z}[i]/(p_m^{r_m})$$  I was not sure how to find the structure of $\mathbb{Z}[i]/(p^{r}) \cong (\Bbb Z/p^r \Bbb Z)[X] \,/\, (X^2+1)$ when $p$ is prime and $r&gt;1$.  — Even more generally, in order to determine the structure of $\mathbb{Z}[i]/(a+bi)$ with $a+bi=d(x+iy)$ and $(x,y)=1$, we could try to use the CRT, provided that $d$ is coprime with $x+iy$ in $\Bbb Z[i]$. But this is not always true: for $d=13$ and $x+iy=2+3i$, we can't find Gauss integers $u$ and $v$ such that $du + (x+iy)v=1$, because this would mean that $(2+3i)[(2-3i)u+v]=1$, i.e. $2+3i$ is a unit in $\Bbb Z[i]$ which is not because its norm is $13 \neq ±1$.  — I was not able to go further. I recall that my general question is to known what $\mathbb{Z}[i]/(a+bi)$ is isomorphic to, when $a$ and $b$ are integers which are not coprime (for instance $a=p^r,b=0$ or $d=(a,b) = a^2+b^2&gt;1$).  Thank you for your help! Guests see the Protected notice , somewhat displaced:    Logged in, all is fine:    It actually belongs there, at the bottom, but then it has some design glitches, or it needs to be placed at the top.  Verified on Firefox and Chrome stable. How to install Tor? I tried to install Tor on my new version of Ubuntu, but it seems that Tor is not available in the repositories.  How else can I install and use Tor? What is the recommended CIDR when creating VPC on AWS? I have been creating AWS VPCs and I am wondering if there is a recommended CIDR value when creating VPCs. What are the factors that I must consider when choosing a CIDR and does the CIDR value affect the performance of the network? Vacuum sealing vs. water displacement method when doing longer sous vide cooking Modernist Cuisine recommends that for longer sous vide cooking (times greater than 36 hours) that bags are vacuum sealed rather than just using the water displacement method to remove the air from a ziploc bag.  What is the reason for this? Will I be losing something essential if I just use a regular ziploc bag without vacuum sealing? I want to be able to tell if the mains voltage is on or off with an Arduino.   How could I do this safely with minimal components (or components from Radio Shack)? Figuring out algorithm/formula for item scaling in WoW