3倍屏字体大小设置

package com.example.two;

import com.example.two.utils.UiUtils;

import android.app.Activity;
import android.os.Bundle;
import android.util.TypedValue;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends Activity {

    private TextView main_tv1;
    private TextView main_tv2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        main_tv1 = (TextView) findViewById(R.id.main_tv1);
        main_tv2 = (TextView) findViewById(R.id.main_tv2);
    }

    public void setFontSize(View v){

        main_tv1.setText("中国");
        main_tv1.setTextSize(UiUtils.dip2px(this, 28));
//      
//      main_tv2.setText("中国");
//      main_tv2.setTextSize(84, TypedValue.COMPLEX_UNIT_SP);
    }

    public void setFontSize2(View v){

        main_tv2.setText("中国");
        main_tv2.setTextSize(TypedValue.COMPLEX_UNIT_SP,28*3);
//      main_tv2.setTextSize(unit, size);
    }
}

布局：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
  >

    <Button 
        android:text="设置"
        android:layout_centerInParent="true"
        android:onClick="setFontSize"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/main_btn1"


        />
    <TextView
        android:id="@+id/main_tv1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <Button
        android:id="@+id/btn2"
        android:layout_alignBaseline="@id/main_btn1"
        android:layout_toRightOf="@id/main_btn1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="setFontSize2"
        android:text="设置2" />

    <TextView
        android:layout_toRightOf="@id/main_tv1"
        android:id="@+id/main_tv2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

</RelativeLayout>