In Android, to style our text we use Spans.
Spans are markup objects that can be applied to parts of the text.

It requires us to deal with the indexes of the text that we want to style.

val string = SpannableString("Text with a foreground color span")
string.setSpan(ForegroundColorSpan(Color.RED), 12, 28, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)

But what if the text is dynamic and the styling of the text is also dynamic.
Now, dealing with indexes and styling becomes really difficult for us.

This is where SpannableStringParser helps us.
You can specify which text to style and how to style them inside the string itself, and use the spannify() extension function to style it.

val string = "Text with a { `foreground color` < text-color:#FF0000 /> } span".spannify()

This string can also come from a back-end server and if we wish to change the style of the text in future, the string can be easily changed from back-end and no front-end change will be required.

SpannableStringParser internally uses Spannable, which is more performant than Html.

1. Text having a property

"Hello { `SpannableStringParser` < text-color:#0000FF /> }"

2. Text having multiple properties

"Hello { `SpannableStringParser` < text-color:#0000FF ; text-decoration:underline /> }"

3. Text having multiple properties with multiple values

"Hello { `SpannableStringParser` < text-color:#0000FF ; text-decoration:underline|strike-through /> }"

Usage

• Syntax for "text" having a property

  text_view.text = "{ `text` < property:value /> }".spannify()
  

• Syntax for "text" having multiple properties

  text_view.text = "{ `text` < property:value ; property:value /> }".spannify()
  

• Syntax for "text" having multiple properties with multiple values

  text_view.text = "{ `text` < property:value ; property:value|value /> }".spannify()
  

• You can even add custom properties using the spanner method.

  spanner { property, value ->
    when (property) {
        "..." -> {
            if (value == "...")
                return@spanner Custom1Span()
        }
        "..." -> {
            if (value == "...")
                return@spanner Custom2Span()
        }
    }
    return@spanner null
  }
  

• If you don't want these properties and values coming from a back-end server, you can use the property method.

  "text"
    .property("property", "value")
    .property("property", "value", "value")
    .spannify()
  

  Note: Make sure to call the spannify method at the end.

---

If you are using Node.js for your back-end, you can use SpannableStringFormatter to efficiently and correctly format your strings.

Supported Properties

text-color

• The text-color property specifies the color of text.

"Hello { `World` < text-color:#FF00FF /> }"

"Hello { `World` < text-color:#44FF00FF /> }"

---

background-color

• The background-color property specifies the background color of text.

"Hello { `World` < background-color:#FF00FF /> }"

"Hello { `World` < background-color:#44FF00FF /> }"

---

line-background-color

• The line-background-color property specifies the background color of lines.

"Hello { `World` < line-background-color:#FF00FF /> }"

"Hello { `World` < line-background-color:#44FF00FF /> }"

---

text-size

• The text-size property sets the size of text.

"Hello { `World` < text-size:24dp /> }"

"Hello { `World` < text-size:2.4em /> }"

"Hello { `World` < text-size:24px /> }"

---

text-decoration

• The text-decoration property sets the kind of text decoration to use (like underline, strike-through).

"Hello { `World` < text-decoration:underline /> }"

"Hello { `World` < text-decoration:strike-through /> }"

---

subscript

• The subscript property defines subscript text.

"Hello { `World` < subscript:true /> }"

---

superscript

• The superscript property defines superscript text.

"Hello { `World` < superscript:true /> }"

---

text-style

• The text-style property specifies the style of text.

"Hello { `World` < text-style:normal /> }"

"Hello { `World` < text-style:bold /> }"

"Hello { `World` < text-style:italic /> }"

---

font-family

• The font-family property specifies the font of text.

"Hello { `World` < font-family:monospace /> }"

"Hello { `World` < font-family:serif /> }"

"Hello { `World` < font-family:sans-serif /> }"

---

text-alignment

• The text-alignment property specifies the alignment of text.

"{ `Hello World` < text-alignment:normal /> }"

"{ `Hello World` < text-alignment:opposite /> }"

"{ `Hello World` < text-alignment:center /> }"

---

line-height

• The line-height property specifies the height of line.

val lorem_ipsum = "lorem ipsum ..."
"{ `${lorem_ipsum}` < line-height:120px /> }"

---

url

• The url property specifies the url for text, clicking on which will open the url.

"Click { `here` < url:`https://www.google.com` /> } for more information"

Note: You have to set LinkMovementMethod on the TextView for supporting url clicks.

text_view.movementMethod = LinkMovementMethod.getInstance()

---

more-properties-coming-soon

You can add your custom properties using the spanner method.
But! If you want any property to be added in SpannableStringParser, feel free to open issues/pull requests.

Download

Add JitPack repository to your root build.gradle file

allprojects {
    repositories {
        maven { url 'https://jitpack.io' }
    }
}

Add the dependency to your app build.gradle file

dependencies {
    implementation 'com.github.hitanshu-dhawan:SpannableStringParser:1.2.1'
}

Licence

Copyright (c) 2019 Hitanshu Dhawan

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.