I'm working in Android Studio 3.0.1. I created a EditText in which I write a text now I want when user long press that text it get copied in clipboard.  I used a method here (which is not working)   ClipboardManager mClipboard = (ClipboardManager) getSystemService(CLIPBOARD_SERVICE);         mEditText.setText(mClipboard.getText());  It says Method Invocation 'get text' may produce 'java.lang.NullpoinyerException' I need help what should i do ?
What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?
I understand that multivariate regression models contain more than 1 dependent variable, but what is the difference between running a multivariate regression with dependent a and b to a set of independent variables, rather than running two regression models, one for a and one for b against the same set of independent variables? Are the XBLA and PC versions of Minecraft compatible? When should I use a List vs a LinkedList How do I appropriately examine the dimensionality of binary data? I have 72 binary variables and, at a theoretical level, I am trying to identify groups of variables that seem to vary together. In practice, I am struggling with how to analyze this data properly. I am using R and the psych package. Here is what I have tried and what the outcomes were:  Estimated a tetrachoric correlation matrix (ran without problem) Estimated MSA (relatively strong values, ran without problem) Ran parallel analysis to identify how many factors to extract (ran without problem) EFA using fa() to estimate factors (non-positive definite matrix and strangely high RMSEA) Tried different factor counts, smoothing/unsmoothing, estimation methods, rotations methods, and removing variables (problems persisted) Tried to focus instead on eBIC (always returned as NULL in output) EFA using (inappropriately) Pearson correlations (RMSEA behaved)  From looking at other questions and answers on here, I am now aware that tetrachoric matrices can be problematic like this. However, I don't know what to do with that information. Accept the problems as a limitation and move forward? Conduct a different type of analysis? I considered IRT as is recommended, but am unaware of an exploratory way to conduct IRT analyses. I understand that most of my options are imperfect. My goal is to find an analysis that is at least arguably appropriate for binary variables and that will inform the ways in which I group these variables in my theorizing. Given this, my questions are:  Can I trust EFA on a tetrachoric matrix despite problematic output? Can I somehow recover the lost eBIC value and use that? Is exploratory IRT possible/desirable? Are there other analyses, in R, that can be used to examine the dimensionality of binary data?  I appreciate all feedback! I love learning about data analysis and hearing about how I can improve. When reading about  on the OALD, I saw the following note:     The difference between someone and anyone is the same as the difference between  and . Look at the notes there.   The note that I read for some is the following:     In negative sentences and questions any is usually used instead of some:           I don't want any more vegetables.     Is there any wine left?           However, some is used in questions that expect a positive reply:           Would you like some milk in your coffee?     Didn't you borrow some books of mine?      Does that apply to someone too? Should I use someone in a question when I am expecting a positive answer?      Does someone know the answer? Why don't gksu/gksudo or launching a graphical application with sudo work with Wayland? I have an equation like this:     \begin{align}       P(A \cup B) = \sum_{\omega \in A \cup B} P(\omega) = \sum_{\omega \in A} P(\omega) + \sum_{\omega \in B} P(\omega)       = P(A) + P(B)     \end{align}   For some reason, LaTeX is automatically labeling the equation. How do I turn that off? Secondly how do I write something in LaTeX on this site. I tried enclosing in '$' but it doesn't work. Initializing Manipulator value within DialogInput (version 10.1 only) Specifying a no-indent for a list I have the following:  This is just normal text...  \begin{enumerate} \item First Item ?\\\\ This is the text of the first item \item Second Item ?\\\\ This is the text of the second item \end{enumerate}   Which renders the following:  This is just normal text...  1. First Item ?     This is the text of the first item  2. Second Item ?      This is the text of the second item   I want to specify that the text of the items has no indentation.  Basically, I want it to be rendered like such:  This is just normal text...  1. First Item ?  This is the text of the first item  2. Second Item ?   This is the text of the second item   How can I specify this form of no indentation? Limit points of the set $\{\frac {\varphi(n) }n : n\in \mathbb{N}\}$ Why do my LED lights stay on, even when the switch is off? Is it possible to recover an email that has been clicked "delete forever" in the trash folder? Is it possible to recover an email that has been clicked on "delete forever" in the trash folder? I have accidentally clicked delete forever for an email but now I need to recover it. Profitable strategy in coin tossing? There is a coin with a probability $p$ of heads, and $1-p$ of tails. Tosses are independent of each other. When you bet an amount of money $x$, you receive $2x$ if it lands heads, and you lose what you bet if it lands tails.  We are going to use the following strategy:  You start betting an initial amount $x_0$. Every time you lose, you bet twice what you bet in the previous throw. You keep doing this, until you win, at which point you retire, or start again, betting $x_0$.  The interesting case of course is when $p &lt; 0.5$.  The question is: How profitable is this strategy? Intuitively I feel that eventually I can always win an arbitrarily large amount of money. But that can't be entirely right ("the house always wins!"). So what am I missing here? What's the expected win in each run?  Also, does this sort of strategy have a name in the literature?  P.S.: Found this later, Why does no physical energy-momentum tensor exist for the gravitational field? Add a new repository to software sources Error when updating texlive 2015 When I want to update packages of texlive 2015 I get this error? what is the problem?  tlmgr update --list  The locale codeset (cp720) isn't one that perl can decode, stopped at   C:\texlive \2015\tlpkg\tlperl\lib/Encode/Locale.pm line 123. Compilation  failed in require at C:\texlive\2015\tlpkg\tlperl\lib/LWP/UserAgent. pm  line 1001. How to choose the default gcc and g++ version? Why is gravity such a unique force? My knowledge on this particular field of physics is very sketchy, but I frequently hear of a theoretical "graviton", the quantum of the gravitational field.  So I guess most physicists' assumption is that gravity can be described by a QFT?  But I find this weird, because gravity seems so incredibly different from the other forces (yes, I know "weirdness" isn't any sort of scientific deduction principle).  For relative strengths:   Strong force: $10^{38}$ Electromagnetic force: $10^{36}$ Weak force: $10^{25}$ Gravity: $1$   Not only does gravity have a vastly weaker magnitude, it also has a very strange interaction with everything else.  Consider the Standard Model interactions:    No particle (or field) interacts directly with all other fields.  Heck, gluons only barely interact with the rest of them.  So why is it then that anything that has energy (e.g. everything that exists) also has a gravitational interaction?  Gravity seems unique in that all particles interact through it.  Then there's the whole issue of affecting spacetime.  As far as I'm aware, properties such as charge, spin, color, etc. don't affect spacetime (only the energy related to these properties). Good math books for physicists In his first lesson (transcripted in "Tips on Physics"), Feynman talks about math for physicists in a very cool and practical way. And at the end of the section he talks something like "so the first thing to do is to learn to learn derivative, integral and algebra" (I don't know how much precise I'm being because I've read it in Portuguese). I would to know if there is some book that deals with math as Feynman did it in this lesson (respecting formalities, but teaching how to use the practical rules)? Also, someone have any recommendations for algebra book (college level)? A subspace $X$ is closed iff $X =( X^\perp)^\perp$ Let $X$ be a subspace of a Hilbert space $H$.  prove:  $X$ is closed iff $X =( X^\perp)^\perp$   I do not know how to proceed. any hints would be appreciated.  thanks.  $X^\perp = ${ $y \in H$:$\langle x,y\rangle = 0 \forall x \in  X\}$.