Tutorial by Examples: ev

for numbers, a zero value evaluates to false, non zero to true int i = 0 ... if (i) print "some ${i}" else print "nothing" will print "nothing"

a string (including GStrings) evaluates to true if not null and not empty, false if null or empty def s = '' ... if (s) println 's is not empty' else println 's is empty' will print: 's is empty'

Collections and Maps evaluates to true if not null and not empty and false if null or empty /* an empty map example*/ def userInfo = [:] if (!userInfo) userInfo << ['user': 'Groot', 'species' : 'unknown' ] will add user: 'Groot' , species : 'unknown' as default userInfo since the u...

a null object reference evaluates to false, a non null reference to true, but for for strings, collections, iterators and enumerations it also takes into account the size. def m = null if (!m) println "empty" else println "${m}" will print "empty" de...

Sometimes it may be useful to have a specific asBoolean definition in your own program for some kind of objects. /** an oversimplified robot controller */ class RunController { def complexCondition int position = 0 def asBoolean() { return complexCondition(this...

Of course, the best way to detect mobile is for the hardware to notify you directly. Cordova PhoneGap exposes a 'deviceready' event, that you can add an event listener to. document.addEventListener('deviceready', function(){ Session.set('deviceready', true); }, false);

It is possible to query an object about its instance variables using instance_variables, instance_variable_defined?, and instance_variable_get, and modify them using instance_variable_set and remove_instance_variable: class Foo attr_reader :bar def initialize @bar = 42 end end f = F...

pie view - (void)drawRect:(CGRect)rect { NSArray *data = @[@30, @15, @5, @17, @3, @10, @20]; // 1. context CGContextRef cxtRef = UIGraphicsGetCurrentContext(); CGPoint center = CGPointMake(150, 150); CGFloat radius = 150; __block CGFloat startAngle = 0; ...

adb devices Is your phone displaying? If not, enable developer mode on your phone, and connect it by USB. adb reverse tcp:8081 tcp:8081 : In order to link correctly your phone and that React-Native recognize him during build. (NOTE:Android Version 5 or above.) react-native run-andr...

%storemagic stores variables and macros on IPython's database. To automatically restore stored variables at startup add this to ipython_config.py: c.StoreMagic.autorestore = True Example: In [1]: l = ['hello',10,'world'] In [2]: %store l In [3]: exit (IPython session is closed and started...

EventNetworks returned by compile must be actuated before reactimated events have an effect. main = do (inputHandler, inputFire) <- newAddHandler eventNetwork <- compile $ do inputEvent <- fromAddHandler inputHandler let inputEventReaction = fmap putStrLn inp...

Copy and Paste following class in your package: public class MLRoundedImageView extends ImageView { public MLRoundedImageView(Context context) { super(context); } public MLRoundedImageView(Context context, AttributeSet attrs) { super(context, attrs); } ...

Set up some constants for the server and authentication information. Assuming LDAPv3, but it's easy enough to change that. // Authentication, and the name of the server. private const string LDAPUser = "cn=example:app:mygroup:accts,ou=Applications,dc=example,dc=com"; private readonly ch...

It is convenient to set custom conditional preprocessing at project level when some actions need to be skipped lets say for tests. Go to Solution Explorer -> Click Right Mouse on project you want to set variable to -> Properties -> Build -> In General find field Conditional compilation ...

SELECT SERVERPROPERTY('ProductVersion') AS ProductVersion, SERVERPROPERTY('ProductLevel') AS ProductLevel, SERVERPROPERTY('Edition') AS Edition, SERVERPROPERTY('EngineEdition') AS EngineEdition;

SELECT DATEDIFF(DAY, login_time, getdate()) UpDays FROM master..sysprocesses WHERE spid = 1

If you want to set some alias name to installed node version, do: nvm alias <name> <version> Similary to unalias, do: nvm unalias <name> A proper usecase would be, if you want to set some other version than stable version as default alias. default aliased versions are loade...

First, make sure your app can be backed up in AndroidManifest.xml, i.e. android:allowBackup is not false. Backup command: adb -s <device_id> backup -noapk <sample.package.id> Create a tar with dd command: dd if=backup.ab bs=1 skip=24 | python -c "import zlib,sys;sys.stdout.wri...

When we attach the !important keyword to a mixin call, the Less compiler will automatically add the !important to all properties that are present within the mixin. For example, consider the below mixin: .set-default-props() { margin: 4px; padding: 4px; border: 1px solid black; font-wei...

This script demonstrates how to receive complicated GUI events from different controls in the same event callback function. We'll be using two ListView controls for that. Now every time an action is detected on one of those ListView controls, we want a precise description of what happened and have ...