Android Tutorial

  You can also view this on my youtube channel How to Open Android Emulator from Commad Line 1.Open Command line 2.Change working directory to android sdk directory    cd  appdata/local/android/sdk/emulator 3.List all available Android virtual devices     emulator -list-avds 4. All your avds will be shown choose the avd_name you want to open    emulator -avd avd_name   5.Your Android virtual device will open up How to install APk file to emulator Drag the APK to Android emulator it will install automatically

ViewBinding is a feature that allow you to write code more easily.  First we will s ee an App without ViewBinding then we will enable ViewBinding in the App .Screenshot of our app is , it is asimple application when we  click the Button score Will Increase You can also see this tutorial in my youtube channel you can download source code of this project from GitHub https://github.com/arunkfedex/DemoNavGraphTest Layout file is activity_main.xml <?xml version="1.0" encoding="utf-8"?> <androidx.constraintlayout.widget.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/text1...

  Navigation is the way user navigate between different fragments and activities . New navigation component helps us  visualize all the navigation in our application in a single navigation graph . Navigation graph is xml resource which contains all navigation related information in one centralized location. This include all individual content area(fragments) which are called destinations  and paths user can take in the applicatio known as actions. Navigation graph of our sample application is screenshots of our sample application implementing android navigation  Full source code of the sample application can be downloaded from the following github link https://github.com/arunkfedex/demoNavigation In this application we use navigation component to implement overflow menu and Navigation drawer. We also use Safe Args for sending data between fragments. 1.First we need to add following dependenc...

We can write kotlin programs in text editor and run the programs using command line. We need kotlin complier for this . we can download KOTLIN COMPILER FROM HERE  .  1. Download kotlin-compiler -1.3.72.z.ip 2. Unzip Kotlin compiler to program files in c drive           3. Copy the path of bin (C:\Program Files\kotlin\bin) and add it your to PATH in System variable.    If you do not know how to add path in system variable , you can use the following link Adding PATH in System variable 4. Now open notepad and write your kotlin program fun main(args: Array<String>) { println("Hello World") } 5. save the program as helloworld.kt , i have saved it to my Documents 6. Open cmd  7. I have saved my helloworld.kt file in Documents folder , so i am changing my directory to Documents  (you have to change it to your directory where the file is saved)                 cd documents 8. Compile...

when user navigates in an application android maintains back stack of destinations . This allows android to go back to previous destination when user clicks back button . some  times we  need to implement our own back button behavior  for best user experience . For example  if we are in a timer based quiz  application . when the user clicks on the back button if we go back to the previous destination without stopping  the counter , it will crash  the application . So first we need to know whether the  user  pressed the back button accidentally or not by  using a dialogue box . If the user want to go back to previous destination  we need to stop the counter and  then go back to the previous destination. We can control the back button hahavior byusing OnBackPressedDispatcher  . This controls how back button events are dispatched to one or more onBackPressedCallback objects . callbacks are added using addCallback methods. e...

If you are using navigation UI in your application , if you want to hide your app bar (top bar of your app showing navigation icon)  or back navigation arrow in a particular fragment you can do like this in your Mainactivity class MainActivity : AppCompatActivity() { class MainActivity : AppCompatActivity() { private lateinit var drawerlayout : DrawerLayout private lateinit var navView : NavigationView override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) drawerlayout = findViewById(R.id.drawer_layout) navView = findViewById(R.id.nav_view) val navController : NavController = this.findNavController(R.id.navhost) NavigationUI.setupActionBarWithNavController(this,navController,drawerlayout) NavigationUI.setupWithNavController(navView,navController) navController.addOnDestinationChangedListener { _, destination, _ -> if(d...

This is a simple Application demonstrating the use of android navigation component . Screenshots of the apps are The Navigation components consist of Navigation graph , navHost and NavController Navigation graph is an XML file which contains all the information about destinations(destinations are different fragments) and  paths user can take in the app.  Navigation graph of our app is you can download the full source code of this app from my Github https://github.com/arunkfedex/QuizzDemoNavigation Working video of the Application