Summery of widgets- AGN HUB

 In Kotlin, widgets typically refer to UI components used in Android development with the Android SDK. These components are part of the Android Views system and are used to build graphical user interfaces for Android apps. Below is a summary of commonly used widgets in Android development with Kotlin:

Common Android Widgets in Kotlin

1. TextView

  • Displays text to the user.

  • Often used for static or dynamic content.

val textView: TextView = findViewById(R.id.textView)

textView.text = "Hello, Kotlin!"

2. EditText

  • Input field where the user can enter text.

val editText: EditText = findViewById(R.id.editText)

val userInput = editText.text.toString()

3. Button

  • Interactive element that triggers actions when clicked.

val button: Button = findViewById(R.id.button)

button.setOnClickListener {

    Toast.makeText(this, "Button clicked!", Toast.LENGTH_SHORT).show()

}

4. ImageView

  • Used to display images.

val imageView: ImageView = findViewById(R.id.imageView)

imageView.setImageResource(R.drawable.image)

5. CheckBox

  • Toggle option that can be checked or unchecked.

val checkBox: CheckBox = findViewById(R.id.checkBox)

if (checkBox.isChecked) {

    Toast.makeText(this, "Checked!", Toast.LENGTH_SHORT).show()

}

6. RadioButton & RadioGroup

  • Single-selection radio buttons.

val radioGroup: RadioGroup = findViewById(R.id.radioGroup)

val selectedId = radioGroup.checkedRadioButtonId

val selectedRadioButton: RadioButton = findViewById(selectedId)

Toast.makeText(this, "Selected: ${selectedRadioButton.text}", Toast.LENGTH_SHORT).show()

7. Spinner

  • Drop-down menu for selecting an item from a list.

val spinner: Spinner = findViewById(R.id.spinner)

val adapter = ArrayAdapter(this, android.R.layout.simple_spinner_item, listOf("Option 1", "Option 2"))

spinner.adapter = adapter

8. Switch

  • Toggle between on and off states.

val switch: Switch = findViewById(R.id.switch)

switch.setOnCheckedChangeListener { _, isChecked ->

    Toast.makeText(this, "Switch is $isChecked", Toast.LENGTH_SHORT).show()

}

9. RecyclerView

  • Displays a list or grid of items efficiently.

  • Requires an adapter and layout manager.

val recyclerView: RecyclerView = findViewById(R.id.recyclerView)

recyclerView.layoutManager = LinearLayoutManager(this)

recyclerView.adapter = MyAdapter(myDataList)

10. ProgressBar

  • Shows loading progress.

val progressBar: ProgressBar = findViewById(R.id.progressBar)

progressBar.visibility = View.VISIBLE

Custom Widgets

You can create your custom widgets by extending existing ones or combining multiple widgets into a ViewGroup.

class CustomWidget(context: Context, attrs: AttributeSet) : LinearLayout(context, attrs) {

    init {

        LayoutInflater.from(context).inflate(R.layout.custom_widget, this, true)

    }

}

Jetpack Compose (Modern Alternative)

Jetpack Compose is the modern UI toolkit in Android development. Widgets are replaced by Composable functions in Compose.

@Composable

fun MyButton() {

    Button(onClick = { /* Do something */ }) {

        Text("Click Me")

    }

}

Would you like examples of a specific widget or guidance on using Jetpack Compose?

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