digitechhive

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>