How to merge some spannable objects?

Question

I divide a spannable object into 3 parts, do different operations, and then I need to merge them.

Spannable str = editText.getText();
Spannable selectionSpannable = new SpannableStringBuilder(str, selectionStart, selectionEnd);
Spannable endOfModifiedSpannable = new SpannableStringBuilder(str, selectionEnd, editText.getText().length());
Spannable beginningOfModifiedSpannable = new SpannableStringBuilder(str, 0, selectionStart);            

How can I do it? I haven't found the required method or constructor to do it.

Answer 1

You could use this:

TextUtils.concat(span1, span2);

http://developer.android.com/reference/android/text/TextUtils.html#concat(java.lang.CharSequence...)

Answer 2

Thanks, it works. I have noticed that I can merge even 3 spannable object:

(Spanned) TextUtils.concat(foo, bar, baz)

Answer 3

I know this is old. But after modifying kotlin stdlib a bit I've got this code:

fun <T> Iterable<T>.joinToSpannedString(separator: CharSequence = ", ", prefix: CharSequence = "", postfix: CharSequence = "", limit: Int = -1, truncated: CharSequence = "...", transform: ((T) -> CharSequence)? = null): SpannedString {
    return joinTo(SpannableStringBuilder(), separator, prefix, postfix, limit, truncated, transform)
            .let { SpannedString(it) }
}

Hope it might help somebody.

Answer 4

As marwinXXII said in a comment, using TextUtils.concat does work but can cause loss of styles in some cases when you have multiple instances of the same span in a single CharSequence.

A workaround could be to write the CharSequence to a Parcel and then read it back. Example Kotlin extension code to do this below:

fun CharSequence.cloneWithSpans(): CharSequence {
    val parcel = Parcel.obtain()
    TextUtils.writeToParcel(this, parcel, 0)
    parcel.setDataPosition(0)
    val out = TextUtils.CHAR_SEQUENCE_CREATOR.createFromParcel(parcel)
    parcel.recycle()
    return out
}

Example usage of this code:

TextUtils.concat(*yourListOfText.map { it.cloneWithSpans() }.toTypedArray())

Now you can concatenate tons of CharSequences without worrying about losing any of the styles and formatting you have on them!

Note that this will work for most styles, it doesn't work all the time but should be enough to cover all the basic styles.