Channels

Go’s concurrency model is based on “Do not communicate by sharing memory; instead, share memory by communicating”, and channels is the way of achieving this. Channels are used for inter Go Routine communication. Unlike other programming language where objects/memory is shared between two or more thread by acquiring lock, in Go channels are used to pass the objects to Go Routine thereby ensuring only one Go Routine have access to it.

Go Routine

One of the most talked feature of Go is its support for Concurrency and Go Routine and Channel are the two most important instrument provided by Go for concurrency. In today’s blog we will try and understand what Go Routine is and how to use it. But we before start, let us try and understand what Concurrency is? Concurrency The most common answer is doing things in parallel and in case of programming, executing the piece of code in parallel.

Interface and Composition

In today’s post we are going to look at how Go supports interface and composition. Interface and composition form the base of any language and Go is no different. Interface Interface is defined as group of methods without the actual method implementation. It is the responsibility of implementer of the interface to provide the actual implementation. Thus Interface can be considered as a contract/protocol which needs to be fulfilled by implementer.

Functions and Pointers

Functions Go, does not have keywords like private, public, protected and final etc and Go does not have concept of inheritance so it is very important to understand how functions can be used to do things that we ideally do when we use any other language. Keyword func, is used for defining function. We have already seen the function main which is starting point of every application. func main() { fmt.

Struct, Map, Array and Slice

Struct Go is not a traditional OO language and hence does not have concept of class. Instead structures are used for holding values. If you are familiar with Java or .Net (may be true for some other OO languages too), you can co-relate struct to beans. type Person struct { FirstName string LastName string Age int } Here, we have defined Person of type struct, to hold values for properties/fields related to person like first name, last name and age.

Control Flows

The best part of programming in Go is that there are not multiple ways of doing standard things and that makes reading code and understanding it easier. But at the same time as we saw in previous post Go follows different conventions which needs to be understood. for Loop The for loop construct, is the only way for looping. Unlike other languages Go does not have familiar constructs like while, do-while etc.

Basics: Types, Variables and Constants

In today’s post we will learn basics of Go language like supported Types, how to declare and initialize variables and constants. Just like any other language, Go has its own way of declaring and initializing variables and constants. Data Types Boolean: Used for true and false. Use bool to declare variable of type Boolean. Numeric: Go supports unsigned, signed integer, float, complex, byte and rune Numeric Types Description Unsigned integers uint8 0-255 uint16 0-65535 uint32 0-4294967295 uint64 0-18446744073709551615 Signed integers int8 -128-127 int16 -32768-32767 int32 -2147483648-2147483647 int64 -9223372036854775808-9223372036854775807 Floating Numbers float32 32 bit float64 64 bit Floating Number with imaginary part complex64 32 bit complex128 64 bit byte Alias to uint8 rune Alias to int32 In addition to above, Go also has uint and int (32 or 64 bit depending on underlying OS) and uintptr (unsigned integer to store uninterrupted bits of pointer value)

Introduction to GoLang

GoLang is an open source language developed and backed by internet giant Google. GoLang is famously known as Go and that is how we are going to refer to in future. In 2007, Robert Griesemer, Rob Pike and Ken Thompson at Google started with experiment to develop a language that will have minimal of features, but will cater most of the use cases. Beside this their idea was to overcome some of the hurdles in development, build and deployment of code written in C (and also of any other languages).

Change Preference Summary

In Today’s post we are going to look at How to Change Summary of Edit Text Preference. But before moving ahead, if you want to know more about Preferences click here. First create a preference screen with only one preference EditTextPreference as show below in xml. Let us call this xml as setttings.xml <?xml version="1.0" encoding="utf-8"?> <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" > <EditTextPreference android:dialogTitle="Enter Name" android:key="name" android:summary="Enter Your Name" android:title="Edit Text Preference" /> </PreferenceScreen> As shown above we are creating EditTextPreference with key “name”.

Introduction to Android SQLite Database

Android provide various options for data persistence like Preferences, File and Database etc. This post we will introduce you to one of the option i.e. Android SQLite Database. Let us take an example of Student database. i.e. student_database (DATABASE_NAME). We will create table tb_student (DATABASE_TABLE), with 3 columns i.e. _id (KEY_ROWID), name (KEY_NAME) and grade (KEY_GRADE). Columns _id is primary key and autoincrement, while name and garde are text .