Android开发中PopupWindow用法实例分析

private TextView tv_appmanager_title;private ListView lv_app_manager;private LinearLayout ll_appmanager_loading;private AppManagerProvider provider;private List<AppManagerInfo> infos ;private AppManagerAdapter adapter;private PopupWindow localPopupWindow;private Handler handler = new Handler(){  public void handleMessage(android.os.Message msg) {    switch (msg.what) {    case Constants.MSG_APP_MANAGER:      ll_appmanager_loading.setVisibility(View.INVISIBLE);      adapter = new AppManagerAdapter(infos, AppManagerActivity.this);      lv_app_manager.setAdapter(adapter);      break;    }  };};@Overrideprotected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.appmanager);  lv_app_manager = (ListView) this.findViewById(R.id.lv_app_manager);  ll_appmanager_loading = (LinearLayout) this.findViewById(R.id.ll_appmanager_loading);  ll_appmanager_loading.setVisibility(View.VISIBLE);  new Thread(){    public void run() {      provider = new AppManagerProvider(AppManagerActivity.this);      infos = provider.getAppManagerInfo();      Message msg = new Message();      msg.what = Constants.MSG_APP_MANAGER;      handler.sendMessage(msg);    };  }.start();  lv_app_manager.setOnItemClickListener(new OnItemClickListener() {    @Override    public void onItemClick(AdapterView<?> parent, View view,        int position, long id) {      if(null != localPopupWindow){        localPopupWindow.dismiss();        localPopupWindow = null;      }      int [] location = new int[2];      view.getLocationInWindow(location);      int x = location[0] + 60;      int y = location[1];      TextView tv = new TextView(AppManagerActivity.this);      AppManagerInfo info = (AppManagerInfo) lv_app_manager.getItemAtPosition(position);      tv.setText(info.getPackName());      tv.setTextSize(20);      tv.setTextColor(Color.RED);      localPopupWindow = new PopupWindow(tv, LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);      Drawable background = new ColorDrawable(Color.GRAY);      localPopupWindow.setBackgroundDrawable(background);      localPopupWindow.showAtLocation(tv, 51, x, y);    }  });  lv_app_manager.setOnScrollListener(new OnScrollListener() {    @Override    public void onScrollStateChanged(AbsListView view, int scrollState) {      if(null != localPopupWindow){        localPopupWindow.dismiss();        localPopupWindow = null;      }    }    @Override    public void onScroll(AbsListView view, int firstVisibleItem,        int visibleItemCount, int totalItemCount) {      if(null != localPopupWindow){        localPopupWindow.dismiss();        localPopupWindow = null;      }    }  });}