Tutorial by Examples: le

From lists def lst = ['foo', 'bar', 'baz'] // for each entry return a list containing [key, value] lst.collectEntries { [it, it.toUpperCase()] } // [foo: FOO, bar: BAR, baz: BAZ] // another option, return a map containing the single entry lst.collectEntries { [(it): it.toUpperCase()] } // [...

Apply the transformation to non-collection entries, delving into nested collections too and preserving the whole structure. def lst = ['foo', 'bar', ['inner_foo', 'inner_bar']] lst.collectNested { it.toUpperCase() } // [FOO, BAR, [INNER_FOO, INNER_BAR]]

This is an example on how to use React Native's BackAndroid along with the Navigator. componentWillMount registers an event listener to handle the taps on the back button. It checks if there is another view in the history stack, and if there is one, it goes back -otherwise it keeps the default beha...

Here's a simple example that uses XSLT to convert data in an XML file into a table in an HTML file. You can use it to experiment with simple XSLT transforms. Prerequisite: Install a Java Runtime Environment and add the location of the JRE to your PATH variable. (On Windows, most installers will add...

class ImageExample extends Component { render() { return ( <View> <Image style={{width: 30, height: 30}} source={{uri: 'http://facebook.github.io/react/img/logo_og.png'}} /> </View> ); } }

While catching the Throwable, Exception, Error and RuntimeException exceptions is bad, throwing them is even worse. The basic problem is that when your application needs to handle exceptions, the presence of the top level exceptions make it hard to discriminate between different error conditions. ...

Controls how the image should be resized or moved to match the size of ImageView. XML attribute: android:scaleType="..." i will illustrate different scale types with a square ImageView which has a black background and we want to display a rectangular drawable in white background in Im...

SELECT * INTO NewTable FROM OldTable Creates a new table with structure of old table and inserts all rows into the new table. Some Restrictions You cannot specify a table variable or table-valued parameter as the new table. You cannot use SELECT…INTO to create a partitioned table, even whe...

The following example can be used to find the total row count for a specific table in a database if table_name is replaced by the the table you wish to query: SELECT COUNT(*) AS [TotalRowCount] FROM table_name; It is also possible to get the row count for all tables by joining back to the table'...

First of all, ensure that you've enabled the 'Virtualization' in your BIOS setup. Start the Android SDK Manager, select Extras and then select Intel Hardware Accelerated Execution Manager and wait until your download completes. If it still doesn't work, open your SDK folder and run /extras/intel/Ha...

This is relevant for apps that implement a BootListener. Test your app by killing your app and then test with: adb shell am broadcast -a android.intent.action.BOOT_COMPLETED -c android.intent.category.HOME -n your.app/your.app.BootListener (replace your.package/your.app.BootListener with proper ...

/** * Created by Nick Cardoso on 03/08/16. * This is not a complete parcelable implementation, it only highlights the easiest * way to read and write your Enum values to your parcel */ public class Foo implements Parcelable { private final MyEnum myEnumVariable; private final M...

If a java library contains interfaces that should be implemented by the user (e.g. click listeners like View.IOnClickListener or callbacks), the implementing class has to inherit -- directly or indirectly -- from Java.Lang.Object or Java.Lang.Throwable. This is a common error, because the packaging ...

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...

You can default to the normal Mongo format by defining your collections with the idGeneration field. MyCollection = new Meteor.Collection('mycollection', {idGeneration : 'MONGO'});

Geospatial collections generally involve storing GeoJSON in the Mongo database, streaming that data to the client, accessing the browser's window.navigator.geolocation, loading up a Map API, converting GeoJSON to LatLngs, and plotting on the map. Preferably all in realtime. Here are a list of reso...