How to create Custom Span

main

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:background="#fff" >

    <TextView
        android:id="@+id/TextView2"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

MainActivity

import android.app.Activity;
import android.content.Context;
import android.graphics.Typeface;
import android.os.Bundle;
import android.text.Spannable;
import android.text.SpannableStringBuilder;
import android.text.method.LinkMovementMethod;
import android.text.style.ClickableSpan;
import android.text.style.StyleSpan;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
	
	Context mContext;
	TextView txt_sample;
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		mContext = this;

	    txt_sample = (TextView) findViewById(R.id.TextView2);
		
		
		SpannableStringBuilder stringBuilder = new SpannableStringBuilder("Here's a smiley ");
		String stringToAppend = "2";
		stringBuilder.append(stringToAppend);
		
		stringBuilder.setSpan(new RoundedBackgroundSpan(), 16, 16 + stringToAppend.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
		stringBuilder.append(" Testing other words");
		stringBuilder.setSpan(new ClickableSpan() {

			@Override
			public void onClick(View widget) {
				Toast.makeText(widget.getContext(), "RoundedBackGroundSpan is clicked",
						Toast.LENGTH_SHORT).show();

			}
		}, 16, 16 +stringToAppend.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

		txt_sample.setText(stringBuilder);
		txt_sample.setMovementMethod(LinkMovementMethod.getInstance());
		txt_sample.setClickable(true);
	    //Linkify.addLinks(txt_sample, Linkify.ALL);

	}
}

RoundedBackgroundSpan

import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.text.style.ReplacementSpan;

public class RoundedBackgroundSpan extends ReplacementSpan {

	
	@Override
	public  void draw(Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom, Paint paint)
    {
		RectF rect = new RectF(x, top, x + measureText(paint, text, start, end), bottom);
        paint.setColor(Color.BLUE);
        canvas.drawRoundRect(rect, 100f, 30f, paint);
        paint.setColor(Color.WHITE);
        canvas.drawText(text, start, end, x, y, paint);
    }
	@Override
    public  int getSize(Paint paint, CharSequence text, int start, int end, Paint.FontMetricsInt fm)
    {
        return Math.round(measureText(paint, text, start, end));
    }

    private float measureText(Paint paint, CharSequence text, int start, int end)
    {
        return paint.measureText(text, start, end);
    }

}