Android TextSwitcher is a user interface widget that contains a number of textView and displays one at a time. Textswitcher is a subclass of View Switcher which is used to animate one text and display the next one. Generally, we use TextSwitcher in two ways manually in XML layout and programmatically in Kotlin file. We should define an XML component, to use TextSwitcher in our android application.
< TextSwitcher android:id = "@+id/imgSw"
android:layout_width = "match_parent"
android:layout_height = "250dp" >
</ ImageSwitcher >
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First, we create a new project by following the below steps:
- Click on File, then New => New Project.
- After that include the Kotlin support and click on next.
- Select the minimum SDK as per convenience and click the next button.
- Then select the Empty activity => next => finish.
Different attributes of the TextSwitcher widget
XML attributes | Description |
---|---|
android:id | Used to specify the id of the view. |
android:onClick | Used to specify the action when this view is clicked. |
android:background | Used to set the background of the view. |
android:padding | Used to set the padding of the view. |
android:visibility | Used to set the visibility of the view. |
android:inAnimation | Used to define the animation to use when the view is shown. |
android:outAnimation | Used to define the animation to use when the view is hidden. |
android:animateFirstView | Used to define whether to animate the current view when the view animation is first displayed. |
Modify activity_main.xml file
In this file, we use the TextSwitcher, and Buttons and also set their attributes.
<? xml version = "1.0" encoding = "utf-8" ?>
< androidx.constraintlayout.widget.ConstraintLayout
android:layout_width = "match_parent"
android:layout_height = "match_parent"
android:orientation = "vertical" >
< TextSwitcher
android:id = "@+id/textSwitcher"
android:layout_width = "match_parent"
android:layout_height = "wrap_content"
android:layout_marginLeft = "32dp"
android:layout_marginTop = "32dp"
android:layout_marginRight = "32dp"
app:layout_constraintLeft_toLeftOf = "parent"
app:layout_constraintRight_toRightOf = "parent"
app:layout_constraintTop_toTopOf = "parent" />
< Button
android:id = "@+id/prev"
android:layout_width = "wrap_content"
android:layout_height = "wrap_content"
android:layout_marginStart = "32dp"
android:layout_marginTop = "128dp"
android:text = "@string/prev"
app:layout_constraintRight_toLeftOf = "@id/next"
app:layout_constraintStart_toStartOf = "parent"
app:layout_constraintTop_toBottomOf = "@+id/textSwitcher" />
< Button
android:id = "@+id/next"
android:layout_width = "wrap_content"
android:layout_height = "wrap_content"
android:layout_marginEnd = "32dp"
android:text = "@string/next"
app:layout_constraintEnd_toEndOf = "parent"
app:layout_constraintHorizontal_bias = "1.0"
app:layout_constraintStart_toEndOf = "@+id/prev"
app:layout_constraintTop_toBottomOf = "@id/textSwitcher"
app:layout_constraintTop_toTopOf = "@+id/prev" />
</ androidx.constraintlayout.widget.ConstraintLayout >
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Update strings.xml file
Here, we update the name of the application using the string tag.
< resources >
< string name = "app_name" >TextSwitcherInKotlin</ string >
< string name = "next" >Next</ string >
< string name = "prev" >Prev</ string >
</ resources >
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Access TextSwitcher in MainActivity.kt file
First, we declare an array languages which contains the list of languages used for the textView.
private val textList = arrayOf("Java","Python","Kotlin","Scala","C++")
then, we access the TextSwitcher from the XML layout and set attributes like text color, text Size.
val textSwitcher = findViewById<TextSwitcher>(R.id.textSwitcher)
package com.geeksforgeeks.myfirstkotlinapp
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.Gravity
import android.view.animation.AnimationUtils
import android.widget.Button
import android.widget.TextSwitcher
import android.widget.TextView
import android.graphics.Color
class MainActivity : AppCompatActivity() {
private val languages = arrayOf( "Java" , "Python" , "Kotlin" , "Scala" , "C++" )
private var index = 0
override fun onCreate(savedInstanceState: Bundle?) {
super .onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// accessing the TextSwitcher from XML layout
val textSwitcher = findViewById<TextSwitcher>(R.id.textSwitcher)
textSwitcher.setFactory {
val textView = TextView( this @MainActivity )
textView.gravity = Gravity.TOP or Gravity.CENTER_HORIZONTAL
textView.textSize = 32f
textView.setTextColor(Color.BLUE)
textView
}
textSwitcher.setText(languages[index])
val textIn = AnimationUtils.loadAnimation(
this , android.R.anim.slide_in_left)
textSwitcher.inAnimation = textIn
val textOut = AnimationUtils.loadAnimation(
this , android.R.anim.slide_out_right)
textSwitcher.outAnimation = textOut
// previous button functionality
val prev = findViewById<Button>(R.id.prev)
prev.setOnClickListener {
index = if (index - 1 >= 0 ) index - 1 else 4
textSwitcher.setText(languages[index])
}
// next button functionality
val button = findViewById<Button>(R.id.next)
button.setOnClickListener {
index = if (index + 1 < languages.size) index + 1 else 0
textSwitcher.setText(languages[index])
}
}
} |
AndroidManifest.xml file
<? xml version = "1.0" encoding = "utf-8" ?>
package = "com.geeksforgeeks.myfirstkotlinapp" >
< 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 >
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Run as Emulator:
Click the next button then we obtain the other text in the TextView.