1. Definition

Basic Views are the smallest UI components in Android that users can see or interact with.

Examples:

TextView → display text
EditText → input text
Button → clickable action
ImageView → display images

Simple meaning:

Views = Visible UI elements on the screen

2. Purpose

Basic Views are used to:

Show text information
Take user input
Display images
Perform actions when clicked

Example in a Login Screen:

Username → EditText
Password → EditText
Login → Button

3. Basic XML Syntax

Example Layout file:

<TextView
    android:id="@+id/textTitle"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Hello Android"/>

4. Using Views in Kotlin Code

In Kotlin (inside MainActivity.kt):

import android.os.Bundle
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val textView = findViewById<TextView>(R.id.textTitle)
        textView.text = "Welcome to Kotlin"
    }
}

Explanation:

findViewById() → connects Kotlin code with XML view
textView.text → changes text

5. Common Properties

These properties are used in XML.

1. layout_width

match_parent
wrap_content

Example:

android:layout_width="match_parent"

2. layout_height

android:layout_height="wrap_content"

3. text

android:text="Hello"

4. textSize

android:textSize="20sp"

5. background

android:background="#FF0000"

6. padding

android:padding="10dp"

6. Important Methods (Kotlin)

setText()

textView.text = "Hello User"

setOnClickListener()

For button click.

val button = findViewById<Button>(R.id.btnSubmit)

button.setOnClickListener {
    println("Button Clicked")
}

setVisibility()

textView.visibility = View.GONE

Options:

View.VISIBLE
View.INVISIBLE
View.GONE

setEnabled()

button.isEnabled = false

7. Real-Time Examples

Example 1: Login Screen

XML Layout

<EditText
    android:id="@+id/etUsername"
    android:hint="Username"/>

<Button
    android:id="@+id/btnLogin"
    android:text="Login"/>

Kotlin Code

val username = findViewById<EditText>(R.id.etUsername)
val button = findViewById<Button>(R.id.btnLogin)

button.setOnClickListener {
    val name = username.text.toString()
    println("Hello $name")
}

Example 2: Change Text on Button Click

XML

<TextView
    android:id="@+id/txtMessage"
    android:text="Welcome"/>

<Button
    android:id="@+id/btnChange"
    android:text="Change Text"/>

Kotlin

val text = findViewById<TextView>(R.id.txtMessage)
val button = findViewById<Button>(R.id.btnChange)

button.setOnClickListener {
    text.text = "Text Changed!"
}

Example 3: Display Image

XML

<ImageView
    android:id="@+id/imgLogo"
    android:src="@drawable/logo"
    android:layout_width="100dp"
    android:layout_height="100dp"/>