Make a certain part of a android-textview align to the right

Here is a solution that works with Spannable, with the cavate that if the right and left are too wide, they will overlap on the same line. Since to do the Left/Right trick with a spannable requires a line feed between Left and Right, my fix is to add a spannable that reduces the line height to zero (i.e. overlapped lines) for the one linefeed and then restore normal line height after that.

    String fullText = leftText + "\n " + rightText;     // only works if  linefeed between them! "\n ";

    int fullTextLength = fullText.length();
    int leftEnd = leftText.length();
    int rightTextLength = rightText.length();

    final SpannableString s = new SpannableString(fullText);
    AlignmentSpan alignmentSpan = new AlignmentSpan.Standard(Layout.Alignment.ALIGN_OPPOSITE);
    s.setSpan(alignmentSpan, leftEnd, fullTextLength, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    s.setSpan(new SetLineOverlap(true), 1, fullTextLength-2, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    s.setSpan(new SetLineOverlap(false), fullTextLength-1, fullTextLength, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

And we have the small routine to handle the overlapping lines:

    private static class SetLineOverlap implements LineHeightSpan {
    private int originalBottom = 15;        // init value ignored
    private int originalDescent = 13;       // init value ignored
    private Boolean overlap;                // saved state
    private Boolean overlapSaved = false;   // ensure saved values only happen once

    SetLineOverlap(Boolean overlap) {
        this.overlap = overlap;
    }

    @Override
    public void chooseHeight(CharSequence text, int start, int end, int spanstartv, int v,
                             Paint.FontMetricsInt fm) {
        if (overlap) {
            if (!overlapSaved) {
                originalBottom = fm.bottom;
                originalDescent = fm.descent;
                overlapSaved = true;
            }
            fm.bottom += fm.top;
            fm.descent += fm.top;
        } else {
            // restore saved values
            fm.bottom = originalBottom;
            fm.descent = originalDescent;
            overlapSaved = false;
        }
    }
}

TextView resultTextView = new TextView(this);
final String resultText = LeftText + "  " + RightText;
final SpannableString styledResultText = new SpannableString(resultText);
styledResultText.setSpan(new AlignmentSpan.Standard(Alignment.ALIGN_OPPOSITE)
    , LeftText.length() + 2
    , LeftText.length() + 2 + RightText.length()
    , Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
resultTextView.setText(styledResultText);

Alignment.ALIGN_OPPOSITE is the equivalent for right side.

Alignment.ALIGN_NORMAL is the equivalent for left side.