popupMenu-----弹出菜单

 import android.os.Bundle;
 import android.app.Activity;
 import android.graphics.Color;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
 import android.widget.PopupMenu;
 import android.widget.PopupMenu.OnMenuItemClickListener;
 import android.widget.TextView;

 public class MainActivity extends Activity {

     private TextView textView;
     private float fontSize =15;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         textView = (TextView) findViewById(R.id.textView);
     }
     //弹出菜单是3.0开始出现的，所以api最低为11
     public void btnClick(View v)
     {
         //第二个参数是弹出菜单显示的参考位置,通常在参考视图的下边显示
         //创建一个弹出菜单对象
         PopupMenu  pop = new PopupMenu(this, v);

         //给菜单添加菜单项
         getMenuInflater().inflate(R.menu.main, pop.getMenu());

         //给菜单项添加事件监听
         pop.setOnMenuItemClickListener(new OnMenuItemClickListener() {

             @Override
             public boolean onMenuItemClick(MenuItem item) {
                 switch(item.getItemId())
                 {
                     case R.id.action_add:
                         fontSize+=5;
                         textView.setTextSize(fontSize);
                         break;
                     case R.id.action_sub:
                         fontSize-=5;
                         textView.setTextSize(fontSize);
                         break;
                     case R.id.action_background:
                         int red = (int)(Math.random()*256);
                         int green = (int)(Math.random()*256);
                         int blue = (int)(Math.random()*256);
                         textView.setBackgroundColor(Color.rgb(red, green, blue));
                         break;
                 }
                 return false;
             }
         });

         //显示菜单
         pop.show();
     }

 }

MainActivity

 <menu xmlns:android="http://schemas.android.com/apk/res/android" >

      <item
         android:id="@+id/action_add"
         android:orderInCategory="100"
         android:showAsAction="never"
         android:title="放大字体"/>
     <item
         android:id="@+id/action_sub"
         android:orderInCategory="100"
         android:showAsAction="never"
         android:title="缩小字体"/>
     <item
         android:id="@+id/action_background"
         android:orderInCategory="100"
         android:showAsAction="never"
         android:title="改变背景颜色"/>

 </menu>

menu_main