Attempt to invoke virtual method 'long android.database.sqlite.SQLiteDatabase.insert
What is a NullPointerException, and how do I fix it?
Contour graphing algorithm I am not sure if this belongs on Mathematics Stack Exchange, but it is somewhat relevant here.       The Problem If you've installed any graphing/plotting apps on your smartphone, you will notice that the app will only take the equation in form of a single variable for 2D (e.g  $y=f(x)$) or in 2 variables for a 3D plot (e.g $z=f(x,y)$). This is problematic as many equations are tough to reduce to the form of $y=f(x)$ or $z=f(x,y)$. The plotters like this because this is the only way they can plot it in form of lines connecting multiple points. These plotters compute the $y$ value at fixed intervals of $x$ and join the point to the previous one. The brute force approach to counter this is to check if the function satisfies it at each point on the image. The problem is that this not only takes more time, but gives discontinuous graph for the function as the image cannot have infinite resolution.         The Question The only way to fix this is to identify which point comes after the next in the plot and join them together by a line. That is where I am stuck. How do you identify which point is sequentially the next one for a given function? Keep in mind that for a human, this might be very easy to do. But, for a computer, this requires a general algorithm. Any ideas? Resource for Blender addons? Check if an image is loaded (no errors) with jQuery I'm still new to ZFS. I've been using Nexenta but I'm thinking of switching to OpenIndiana or Solaris 11 Express. Right now, I'm at a point of considering virtualizing the ZFS server as a guest within either ESXi, Hyper-V or XenServer (I haven't decided which one yet - I'm leaning towards ESXi for VMDirectPath and FreeBSD support).   The primary reason being that it seems like I have enough resources to go around that I could easily have 1-3 other VMs running concurrently. Mostly Windows Server. Maybe a Linux/BSD VM as well. I'd like the virtualized ZFS server to host all the data for the other VMs so their data could be kept on a physically separate disks from the ZFS disks (mount as iscsi or nfs).  The server currently has an AMD Phenom II with 6 total cores (2 unlocked), 16GB RAM (maxed out) and an LSI SAS 1068E HBA with (7) 1TB SATA II disks attached (planning on RAIDZ2 with hot spare). I also have (4) 32GB SATA II SSDs attached to the motherboard. I'm hoping to mirror two of the SSDs to a boot mirror (for the virtual host), and leave the other two SSDs for ZIL and L2ARC (for the ZFS VM guest). I'm willing to add two more disks to store the VM guests and allocate all seven of the current disks as ZFS storage. Note: The motherboard does not have IOMMU support as the 880G doesn't support it, but I do have an 890FX board which does have IOMMU if it makes a huge difference.  My questions are:  1) Is it wise to do this? I don't see any obviously downside (which makes me wonder why no one else has mentioned it). I feel like I could be making a huge oversight and I'd hate to commit to this, move over all my data only to go fubar from some minute detail I missed.  2) ZFS virtual guest performance? I'm willing to take a small performance hit but I'd think if the VM guest has full disk access to the disks that at the very least, disk I/O performance will be negligible (in comparison to running ZFS non-virtualized). Can anyone speak to this from experience hosting a ZFS server as a VM guest? What are the key principles that effective designs share? You have arrived on this page because you are clearly curious about underlying fundamentals that you can incorporate into your thought process when designing.  According to many that came before us, there are key principles that can be considered when creating an effective design. In the following answers, you will find useful theories from a variety of respected sources.  Use this question as a reference for navigating the variety of topics:  Gestalt Principles  &nbsp;&nbsp;  &nbsp;&nbsp;  &nbsp;&nbsp;  &nbsp;&nbsp;  Other Fundamentals and Useful Information  &nbsp;&nbsp;  &nbsp;&nbsp;  &nbsp;&nbsp;  &nbsp;&nbsp;  If you know of a topic that hasn't been covered here, please add an answer with references to respected resources and it will be added to the list.  Of course direct quotes and paraphrasing from respected resources are a must, but should be limited to a small paragraph per topic at most and referenced back to their source as thoroughly as possible.  A  has been posted before, but not to create a collection of snippets that are enlightening for graphic designers of any and all skill levels. Can I use film that's 20+ years old? What is better performance wise with i7 2600k: 1x4GB or 2x2GB RAM? Is it better to use 2x 2GB or 1x 4GB RAM with a i7 2600k Sandy Bridge performance-wise for:   Applications? Games? Both? Incubated but not hatched egg I got the message "oh" and it showed my egg. Before I could do anything the server went down. When I got back on my egg was gone. Is there anything I can do to retrieve my incubated but not hatched egg? The  currently says  In the context of Stack Exchange sites, any copying and pasting of any amount of text or code that wasn't written by you is plagiarism if you try, explicitly or implicitly, to pass it off as your own work. (italics mine)  There is also a concept of . Should this also be addressed in the FAQs? In other words, is it OK to copy (large parts of) your own answer  without proper attribution? Changing user preferences via console? The machine that I'm currently using is an extremely slow netbook. Whenever I go to change user preferences in Blender, it stalls out. What I need to do is activate the "emulate 3 button mouse" checkbox. Is there a way to do this via console/script? When signing in with Google (OAuth), it shows a list of accounts it already knows about. How can I remove some accounts from this list?    I know I can nuke all of them by deleting all cookies, but I'd prefer to remove one account that I don't want there, rather than all of them.  There used to be an ability to edit this list in the older version of this screen, but in 2018 redesign Google has removed [×] buttons next to the accounts. How to download a file over HTTP? I have a small utility that I use to download an MP3 file from a website on a schedule and then builds/updates a podcast XML file which I've added to iTunes.  The text processing that creates/updates the XML file is written in Python. However, I use wget inside a Windows .bat file to download the actual MP3 file. I would prefer to have the entire utility written in Python.  I struggled to find a way to actually download the file in Python, thus why I resorted to using wget.  So, how do I download the file using Python? Does the  tag position in HTML affects performance of the webpage? Persistent Dummy Output Android CalendarView for Showing Events This issue happens only on UEFI systems with enabled Secure Boot.  When I try to install DKMS modules like VirtualBox, Nvidia, or Broadcom drivers, they do not install and I get Required key not available when I try to modprobe them.  VirtualBox complains that vboxdrv is not loaded.  Broadcom wl driver is shown in lspci -k as a kernel module but is not in use. sudo modprobe wl throws Required key not available.  Also this issue may happen when I install some kernel modules from git sources.  This issue may appear after a kernel update as disabled wireless adapter, black screen after a reboot, etc.   How can I fix it? How can we evaluate this series  $$\sum_{n=1}^\infty \frac{n^a}{b^n}?$$  Here $a$ and $b$ are positive integers. If $b=1$ then series will be diverging, in other cases, it will be converging, but how to find this sum?  Isn't there a simple solution which doesn't involve Stirling numbers? Is there a universal way to turn Windows 7 Aero desktop, all windows, etc into grayscale? I had an option to do this in Intel video drivers on my old laptop, now I have NVIDIA and don't know how to replicate this effect.   There might be a shader or filter that would cause Aero to render stuff into grayscale, but I was unable to find anything. Or must it be explicitly supported by video driver as a bonus? My friend wants to consolidate his various retirement account accumulated over the past 20-30 years to make it easier to manage/track his retirement savings. He doesn't recall immediately all the accounts he currently has (one of the reasons to rollover), but we've determined he has at least the following types of accounts: 401(a), 401(k), 403(b), 457(b), and "something from the city". He's trying to track down all the relevant paperwork for all of the accounts, but we'd like to know what kind of limits he might have to watch out for.   Are there any restrictions on the types of the accounts that can be rolled over? Is there a limit to the number of accounts that can be rolled into a single IRA (whether all at once or over the lifetime of the IRA)? Is there a limit to the number of times accounts can be rolled over (can/should he do 1 or 2 at a time as he gets the paperwork in order, or wait until he has everything sorted out)? Is this a yearly limit or lifetime? Is there a dollar limit on the amount that can be rolled over? Is there a limit to the age of accounts that can be rolled over?   As far as we know, all of the accounts are pre-tax/non-Roth accounts, and that Roth vs. traditional accounts should be rolled over to separate (Roth vs. traditional) IRAs. How can I stop sending my hostname via DHCP? Ubuntu sends my computer's configured hostname to any DHCP server it tries to use. How do I stop it from sending a hostname?