android TextView 设置字体大小

package com.example.yanlei.yl4;

import android.graphics.Color;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.Spannable;
import android.text.style.AbsoluteSizeSpan;
import android.text.style.BackgroundColorSpan;
import android.text.style.StyleSpan;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    TextView edit;
    Button sendBu;

    @Override

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        edit = (TextView) findViewById(R.id.textView);
        sendBu = (Button) findViewById(R.id.button);
        sendBu.setOnClickListener(new ButtonClickListener());
    }

    private class ButtonClickListener implements View.OnClickListener {

        public void onClick(View v) {
            //System.exit(0);
            edit.setText("闫磊我爱你");
            edit.setTextColor(Color.BLUE);

            edit.setText("这是我的第一个TextView，嘿嘿", TextView.BufferType.EDITABLE);
/**
 * 要设置文本的背景色，
 * 必须将文本设置成BufferType.SPANNABLE,BufferType.EDITABLE
 */
            Spannable sp = (Spannable) edit.getText();
//设置红色背景
            sp.setSpan(new BackgroundColorSpan(Color.RED), 3, 8,
                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

            sp.setSpan(new StyleSpan(android.graphics.Typeface.BOLD_ITALIC),
                    0, 7, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);   //设置斜体
            sp.setSpan(new AbsoluteSizeSpan(80), 0, 2, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE); //设置字体大小
            edit.setText(sp);

            //edit.setHeight(60);
            //android.os.Process.killProcess(android.os.Process.myPid());
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}