Friday, February 14, 2020

android kotlin ktx - Background foreground color span

MainActivity.kt

package com.example.jetpack

import android.graphics.Color
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.text.style.*
import androidx.core.text.set
import androidx.core.text.toSpannable
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {


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

        val text = ("Lorem Ipsum is simply dummy text of the printing and" +
                " typesetting industry. Lorem Ipsum has been the industry's" +
                " standard dummy text ever since the 1500s, when an unknown" +
                " printer took a galley of type and scrambled it" +
                " to make a type specimen book.").toSpannable()


        // Set text background color span
        text[100..text.length] = BackgroundColorSpan(Color.YELLOW)

        // Set text color span
        text[25..125] = ForegroundColorSpan(Color.RED)

        textView.text = text
    }
}
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/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="8dp"
        android:padding="15dp"
        android:text=""
        android:textAppearance="@style/TextAppearance.AppCompat.Large"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
build.gradle dependencies[add]

// android ktx
implementation 'androidx.core:core-ktx:1.2.0'
build.gradle [add]

android {
    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_1_8.toString()
    }
}
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