android - Individual line spacing for each line

Question

Is it possible to define individual line spacings for each text line of a TextView?

Example:

TextView tv = new TextView(context);
tv.setText("line1
line2
line3");

The method setLineSpacing(float add, float mult) defines the line spacings for all text lines of the TextView. I would like to define another line spacing between line1 and line2 and a different line spacing between line2 and line3.

Any ideas how to do this ?

Does a spannable provide a solution ?

Answer 1

Yes, you can do it by utilizing the LineHeightSpan interface. Here's a quick and dirty sample code on how to do this:

public class MyActivity extends Activity {

    private static class MySpan implements LineHeightSpan {
        private final int height;

        MySpan(int height) {
            this.height = height;
        }

        @Override
        public void chooseHeight(CharSequence text, int start, int end, int spanstartv, int v,
                FontMetricsInt fm) {
            fm.bottom += height;
            fm.descent += height;
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        final TextView tv = new TextView(this);
        setContentView(tv);

        tv.setText("Lines:
", BufferType.EDITABLE);
        appendLine(tv.getEditableText(), "Line 1 = 40
", 40);
        appendLine(tv.getEditableText(), "Line 2 = 30
", 30);
        appendLine(tv.getEditableText(), "Line 3 = 20
", 20);
        appendLine(tv.getEditableText(), "Line 4 = 10
", 10);
    }

    private void appendLine(Editable text, String string, int height) {
        final int start = text.length();
        text.append(string);
        final int end = text.length();
        text.setSpan(new MySpan(height), start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

}