package com.example.dropdownmenu;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import android.os.Bundle;import android.app.Activity;import android.graphics.drawable.ColorDrawable;import android.view.Menu;import android.view.MotionEvent;import android.view.View;import android.view.ViewGroup.LayoutParams;import android.widget.AdapterView;import android.widget.ListView;import android.widget.PopupWindow;import android.widget.RelativeLayout;import android.widget.SimpleAdapter;import android.widget.TextView;public class MainActivity extends Activity {// 工具栏private RelativeLayout rlTopBar;// 左中右三个控件（工具栏里）private TextView tvLeft;private TextView tvRight;private TextView tvMiddle;// 左中右三个弹出窗口private PopupWindow popLeft;private PopupWindow popRight;private PopupWindow popMiddle;// 左中右三个layoutprivate View layoutLeft;private View layoutRight;private View layoutMiddle;// 左中右三个ListView控件（弹出窗口里）private ListView menulistLeft;private ListView menulistRight;private ListView menulistMiddle;// 菜单数据项private List<Map<String, String>> listLeft;private List<Map<String, String>> listRight;private List<Map<String, String>> listMiddle;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);initParam();}private void initParam() {rlTopBar = (RelativeLayout) this.findViewById(R.id.rl_topbar);tvLeft = (TextView) this.findViewById(R.id.tv_left);tvLeft.setOnClickListener(myListener);// 初始化数据项listLeft = new ArrayList<Map<String, String>>();for (int i = 1; i < 10; i++) {HashMap<String, String> mapTemp = new HashMap<String, String>();mapTemp.put("item", "left " + i);listLeft.add(mapTemp);}tvRight = (TextView) this.findViewById(R.id.tv_right);tvRight.setOnClickListener(myListener);// 初始化数据项listRight = new ArrayList<Map<String, String>>();for (int i = 1; i < 10; i++) {HashMap<String, String> mapTemp = new HashMap<String, String>();mapTemp.put("item", "right " + i);listRight.add(mapTemp);}tvMiddle = (TextView) this.findViewById(R.id.tv_middle);tvMiddle.setOnClickListener(myListener);// 初始化数据项listMiddle = new ArrayList<Map<String, String>>();for (int i = 1; i < 10; i++) {HashMap<String, String> mapTemp = new HashMap<String, String>();mapTemp.put("item", "mid " + i);listMiddle.add(mapTemp);}}private View.OnClickListener myListener = new View.OnClickListener() {@Overridepublic void onClick(View v) {switch (v.getId()) {case R.id.tv_left:if (popLeft != null && popLeft.isShowing()) {popLeft.dismiss();} else {layoutLeft = getLayoutInflater().inflate(R.layout.pop_menulist, null);menulistLeft = (ListView) layoutLeft.findViewById(R.id.menulist);SimpleAdapter listAdapter = new SimpleAdapter(MainActivity.this, listLeft, R.layout.pop_menuitem,new String[] { "item" },new int[] { R.id.menuitem });menulistLeft.setAdapter(listAdapter);// 点击listview中item的处理menulistLeft.setOnItemClickListener(new AdapterView.OnItemClickListener() {@Overridepublic void onItemClick(AdapterView<?> arg0,View arg1, int arg2, long arg3) {// 改变顶部对应TextView值String strItem = listLeft.get(arg2).get("item");tvLeft.setText(strItem);// 隐藏弹出窗口if (popLeft != null && popLeft.isShowing()) {popLeft.dismiss();}}});// 创建弹出窗口// 窗口内容为layoutLeft，里面包含一个ListView// 窗口宽度跟tvLeft一样popLeft = new PopupWindow(layoutLeft, tvLeft.getWidth(),LayoutParams.WRAP_CONTENT);ColorDrawable cd = new ColorDrawable(-0000);popLeft.setBackgroundDrawable(cd);popLeft.setAnimationStyle(R.style.PopupAnimation);popLeft.update();popLeft.setInputMethodMode(PopupWindow.INPUT_METHOD_NEEDED);popLeft.setTouchable(true); // 设置popupwindow可点击popLeft.setOutsideTouchable(true); // 设置popupwindow外部可点击popLeft.setFocusable(true); // 获取焦点// 设置popupwindow的位置（相对tvLeft的位置）int topBarHeight = rlTopBar.getBottom();popLeft.showAsDropDown(tvLeft, 0,(topBarHeight – tvLeft.getHeight()) / 2);popLeft.setTouchInterceptor(new View.OnTouchListener() {@Overridepublic boolean onTouch(View v, MotionEvent event) {// 如果点击了popupwindow的外部，popupwindow也会消失if (event.getAction() == MotionEvent.ACTION_OUTSIDE) {popLeft.dismiss();return true;}return false;}});}break;case R.id.tv_right:if (popRight != null && popRight.isShowing()) {popRight.dismiss();} else {layoutRight = getLayoutInflater().inflate(R.layout.pop_menulist, null);menulistRight = (ListView) layoutRight.findViewById(R.id.menulist);SimpleAdapter listAdapter = new SimpleAdapter(MainActivity.this, listRight, R.layout.pop_menuitem,new String[] { "item" },new int[] { R.id.menuitem });menulistRight.setAdapter(listAdapter);// 点击listview中item的处理menulistRight.setOnItemClickListener(new AdapterView.OnItemClickListener() {@Overridepublic void onItemClick(AdapterView<?> arg0,View arg1, int arg2, long arg3) {String strItem = listRight.get(arg2).get("item");tvRight.setText(strItem);if (popRight != null && popRight.isShowing()) {popRight.dismiss();}}});popRight = new PopupWindow(layoutRight, tvRight.getWidth(),LayoutParams.WRAP_CONTENT);ColorDrawable cd = new ColorDrawable(-0000);popRight.setBackgroundDrawable(cd);popRight.setAnimationStyle(R.style.PopupAnimation);popRight.update();popRight.setInputMethodMode(PopupWindow.INPUT_METHOD_NEEDED);popRight.setTouchable(true); // 设置popupwindow可点击popRight.setOutsideTouchable(true); // 设置popupwindow外部可点击popRight.setFocusable(true); // 获取焦点// 设置popupwindow的位置int topBarHeight = rlTopBar.getBottom();popRight.showAsDropDown(tvRight, 0,(topBarHeight – tvRight.getHeight()) / 2);popRight.setTouchInterceptor(new View.OnTouchListener() {@Overridepublic boolean onTouch(View v, MotionEvent event) {// 如果点击了popupwindow的外部，popupwindow也会消失if (event.getAction() == MotionEvent.ACTION_OUTSIDE) {popRight.dismiss();return true;}return false;}});}break;case R.id.tv_middle:if (popMiddle != null && popMiddle.isShowing()) {popMiddle.dismiss();} else {layoutMiddle = getLayoutInflater().inflate(R.layout.pop_menulist, null);menulistMiddle = (ListView) layoutMiddle.findViewById(R.id.menulist);SimpleAdapter listAdapter = new SimpleAdapter(MainActivity.this, listMiddle, R.layout.pop_menuitem,new String[] { "item" },new int[] { R.id.menuitem });menulistMiddle.setAdapter(listAdapter);// 点击listview中item的处理menulistMiddle.setOnItemClickListener(new AdapterView.OnItemClickListener() {@Overridepublic void onItemClick(AdapterView<?> arg0,View arg1, int arg2, long arg3) {String strItem = listMiddle.get(arg2).get("item");tvMiddle.setText(strItem);if (popMiddle != null && popMiddle.isShowing()) {popMiddle.dismiss();}}});popMiddle = new PopupWindow(layoutMiddle, tvMiddle.getWidth(),LayoutParams.WRAP_CONTENT);ColorDrawable cd = new ColorDrawable(-0000);popMiddle.setBackgroundDrawable(cd);popMiddle.setAnimationStyle(R.style.PopupAnimation);popMiddle.update();popMiddle.setInputMethodMode(PopupWindow.INPUT_METHOD_NEEDED);popMiddle.setTouchable(true); // 设置popupwindow可点击popMiddle.setOutsideTouchable(true); // 设置popupwindow外部可点击popMiddle.setFocusable(true); // 获取焦点// 设置popupwindow的位置int topBarHeight = rlTopBar.getBottom();popMiddle.showAsDropDown(tvMiddle, 0,(topBarHeight – tvMiddle.getHeight()) / 2);popMiddle.setTouchInterceptor(new View.OnTouchListener() {@Overridepublic boolean onTouch(View v, MotionEvent event) {// 如果点击了popupwindow的外部，popupwindow也会消失if (event.getAction() == MotionEvent.ACTION_OUTSIDE) {popMiddle.dismiss();return true;}return false;}});}break;default:break;}}};@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.activity_main, menu);return true;}}以上代码有详细的注释，，这里就不做过多解释啦！原理比较简单，点击工具栏上的TextView会弹出PopupWindow，里面包含ListView，显示所有菜单项。
谁的指间滑过了千年时光；谁在反反复复中追问可曾遗忘；
