Kotlin Activity Change

R.layout.kotlin_activity_change

Kotlin is a language and used for avoid null pointer exception

kotlin has defaultly uses lambadas for concise event handling code

Kotlin is a safer and more concise code for writing

Kotlin is a modern and it reduces the number of lines code in mobile application development

Here we can see the how the activity

		

MainActivity[MainActivity.kt]

import android.support.v7.app.AppCompatActivity import android.os.Bundle import android.view.View import android.widget.Button import android.widget.Toast import com.androidfeeders.kotlinsampleapplication.R.id.bottonToast import kotlinx.android.synthetic.main.activity_main.* class MainActivity : AppCompatActivity(), View.OnClickListener { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) //First Button Onclick Listener bottonToast.setOnClickListener(this) //Second Button Onclick Listener val btn_Second_click_me = findViewById(R.id.onCreateToast) as Button btn_Second_click_me.setOnClickListener{ Toast.makeText(this,"My Sample kotlin Programme",Toast.LENGTH_SHORT).show(); } } override fun onClick(p0: View?) { Toast.makeText(this,"My Sample Kotlin Programme",Toast.LENGTH_SHORT).show(); } }

Layout Resource[activity_main.xml]

		
		<?xml version="1.0" encoding="utf-8"?>
		<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
			xmlns:app="http://schemas.android.com/apk/res-auto"
			xmlns:tools="http://schemas.android.com/tools"
			android:layout_width="match_parent"
			android:layout_height="match_parent"
			tools:context=".MainActivity">
		
			<TextView
				android:id="@+id/textView"
				android:layout_width="wrap_content"
				android:layout_height="wrap_content"
				android:background="@color/colorPrimaryDark"
				android:fontFamily="cursive"
				android:text="@string/app_name"
				android:textAlignment="center"
				android:textColor="@android:color/white"
				android:textSize="30sp"
				android:textStyle="bold"
				app:layout_constraintBottom_toBottomOf="parent"
				app:layout_constraintLeft_toLeftOf="parent"
				app:layout_constraintRight_toRightOf="parent"
				app:layout_constraintTop_toTopOf="parent"
				/>
		
			<Button
				android:id="@+id/bottonToast"
				android:layout_width="wrap_content"
				android:layout_height="wrap_content"
				android:text="Invoke Toast"
				android:layout_marginLeft="10dp"
				app:layout_constraintLeft_toLeftOf="parent"
				app:layout_constraintBottom_toBottomOf="parent"
				android:layout_marginBottom="10dp"
				android:layout_marginTop="10dp"
				app:layout_constraintTop_toTopOf="@+id/textView" />
		
			<Button
				android:id="@+id/onCreateToast"
				android:layout_width="wrap_content"
				android:layout_height="wrap_content"
				android:text="Invoke Toast"
				app:layout_constraintBottom_toBottomOf="parent"
				android:layout_marginBottom="10dp"
				android:layout_marginTop="10dp"
				app:layout_constraintTop_toTopOf="@+id/textView"
				app:layout_constraintLeft_toRightOf="@+id/bottonToast"
				android:layout_marginLeft="80dp" />
		
		</android.support.constraint.ConstraintLayout>
		

Gradle Scripts~build.gradle[Module:app]

		apply plugin: 'com.android.application'
		
		apply plugin: 'kotlin-android'
		
		apply plugin: 'kotlin-android-extensions'
		
		android {
			compileSdkVersion 28
			defaultConfig {
				applicationId "com.androidfeeders.kotlinsampleapplication"
				minSdkVersion 15
				targetSdkVersion 28
				versionCode 1
				versionName "1.0"
				testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
			}
			buildTypes {
				release {
					minifyEnabled false
					proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
				}
			}
		}
		
		dependencies {
			implementation fileTree(dir: 'libs', include: ['*.jar'])
			implementation"org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
			implementation 'com.android.support:appcompat-v7:28.0.0-alpha3'
			implementation 'com.android.support.constraint:constraint-layout:1.1.2'
			testImplementation 'junit:junit:4.12'
			androidTestImplementation 'com.android.support.test:runner:1.0.2'
			androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
		}
		
		
		

Gradle Scripts~build.gradle[Project:KotlinSampleApplication]

// Top-level build file where you can add configuration options common to all sub-projects/modules. buildscript { ext.kotlin_version = '1.2.41' repositories { google() jcenter() } dependencies { classpath 'com.android.tools.build:gradle:3.1.1' classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version" // NOTE: Do not place your application dependencies here; they belong // in the individual module build.gradle files } } allprojects { repositories { google() jcenter() } } task clean(type: Delete) { delete rootProject.buildDir }

Resource[strings.xml]

		<resources>
			<string name="app_name">Welcome To Kotlin</string>
		</resources>
		

manifests

		<?xml version="1.0" encoding="utf-8"?>
		<manifest xmlns:android="http://schemas.android.com/apk/res/android"
			package="com.androidfeeders.kotlinsampleapplication">
		
			<application
				android:allowBackup="true"
				android:icon="@mipmap/ic_launcher"
				android:label="@string/app_name"
				android:roundIcon="@mipmap/ic_launcher_round"
				android:supportsRtl="true"
				android:theme="@style/AppTheme">
				<activity android:name=".MainActivity">
					<intent-filter>
						<action android:name="android.intent.action.MAIN" />
		
						<category android:name="android.intent.category.LAUNCHER" />
					</intent-filter>
				</activity>
			</application>
		
		</manifest>
		

Ramasamy

I started to learn android and Kotlin and iOS and Hybrid application and i cant code IOS very well. But i love more interesting to code and finding new developer minds who are join to me You're welcome to keep on using my website.Instead, you can join our FB page for developer comments and post there: https://www.facebook.com/ramasamy.m.779 Best wishes :) Ramasamy(Software Developer)

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Kotlin and React native example too

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3 Comments

Ramasamy

5 min ago

Kotlin and React native example too

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Ramasamy

5 min ago

Kotlin and React native example too

Reply

Ramasamy

5 min ago

Kotlin and React native example too

Reply

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