SpannableStringBuilder to create String with multiple fonts/text sizes etc Example?

Question

I need to create a String placed in a TextView that will display a string like this:

First Part Not Bold BOLD rest not bold

Answer 1

If you are using Kotlin you can do the following using the android-ktx library

val s = SpannableStringBuilder()
        .append("First Part Not Bold ")
        .bold { append("BOLD") } 
        .append("Rest not bold")

The bold is an extension function on SpannableStringBuilder. You can see the documentation here for a list of operations you can use.

Another example:

val s = SpannableStringBuilder()
            .color(green, { append("Green text ") })
            .append("Normal text ")
            .scale(0.5, { append("Text at half size " })
            .backgroundColor(green, { append("Background green") })

Where green is a resolved RGB color.

It is even possible to nest spans so you end up with an embedded DSL:

bold { underline { italic { append("Bold and underlined") } } }

You will need the following in your app module level build.gradle for it to work:

repositories {
    google()
}

dependencies {
    implementation "androidx.core:core-ktx:1.2.0"
}