public class MyActivity extends Activity{     private PopupWindow menu;     private LayoutInflater inflater;     private View layout;     @Override     public void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.main);         //实例化PopupWindow创建菜单         initMenu();     }     //判断按键 菜单的显示与隐藏     @Override     public boolean onKeyDown(int keyCode, KeyEvent event) {         if(!menu.isShowing()&&keyCode == KeyEvent.KEYCODE_MENU){            show();         }else{             menu.dismiss();         }         if(keyCode == KeyEvent.KEYCODE_BACK&&menu.isShowing()){             menu.dismiss();         }         return true;     }     //实例化PopupWindow创建菜单     private void initMenu(){             //获取LayoutInflater实例             inflater  = (LayoutInflater) this.getSystemService(LAYOUT_INFLATER_SERVICE);             //获取弹出菜单的布局             layout = inflater.inflate(R.layout.menu,null);             //设置popupWindow的布局             menu = new PopupWindow(layout, WindowManager.LayoutParams.WRAP_CONTENT,WindowManager.LayoutParams.WRAP_CONTENT);     }     //显示菜单     private void show(){            //设置位置             menu.showAtLocation(this.findViewById(R.id.main), Gravity.BOTTOM|Gravity.CENTER_HORIZONTAL,0,0); //设置在屏幕中的显示位置     } }

<?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="horizontal"         >     <ImageView         android:id="@+id/icon_1"         android:background="@drawable/icon_1"         android:layout_width="40dp"         android:layout_height="40dp"/>     <ImageView         android:id="@+id/icon_2"         android:background="@drawable/icon_2"         android:layout_width="40dp"         android:layout_height="40dp"/>     <ImageView         android:id="@+id/icon_3"         android:background="@drawable/icon3"         android:layout_width="40dp"         android:layout_height="40dp"/>     <ImageView         android:id="@+id/icon_4"         android:background="@drawable/icon4"         android:layout_width="40dp"         android:layout_height="40dp"/> </LinearLayout>