Here's a nice way to do it with a Kotlin extension.
Note that we need to wait for the view to layout before we can measure and append the suffix.
In TextViewExtensions.kt
fun TextView.setEllipsizedSuffix(maxLines: Int, suffix: String) {
addOnLayoutChangeListener(object: View.OnLayoutChangeListener {
override fun onLayoutChange(v: View?, left: Int, top: Int, right: Int, bottom: Int, oldLeft: Int, oldTop: Int, oldRight: Int, oldBottom: Int) {
val allText = text.toString()
var newText = allText
val tvWidth = width
val textSize = textSize
if(!TextUtil.textHasEllipsized(newText, tvWidth, textSize, maxLines)) return
while (TextUtil.textHasEllipsized(newText, tvWidth, textSize, maxLines)) {
newText = newText.substring(0, newText.length - 1).trim()
}
//now replace the last few chars with the suffix if we can
val endIndex = newText.length - suffix.length - 1 //minus 1 just to make sure we have enough room
if(endIndex > 0) {
newText = "${newText.substring(0, endIndex).trim()}$suffix"
}
text = newText
removeOnLayoutChangeListener(this)
}
})
}
In TextUtil.kt
fun textHasEllipsized(text: String, tvWidth: Int, textSize: Float, maxLines: Int): Boolean {
val paint = Paint()
paint.textSize = textSize
val size = paint.measureText(text).toInt()
return size > tvWidth * maxLines
}
Then actually using it like this
myTextView.setEllipsizedSuffix(2, "...See more")
Note: if your text comes from a server and may have new line characters, then you can use this method to determine if the text has ellipsized.
fun textHasEllipsized(text: String, tvWidth: Int, textSize: Float, maxLines: Int): Boolean {
val paint = Paint()
paint.textSize = textSize
val size = paint.measureText(text).toInt()
val newLineChars = StringUtils.countMatches(text, "\n")
return size > tvWidth * maxLines || newLineChars >= maxLines
}
StringUtils
is from implementation 'org.apache.commons:commons-lang3:3.4'
l.getEllipsisStart()
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