*** PopupWindow

*显示类型：

下拉式

mWindow.showDropDown(anchor,xoff,yoff,gravity);

浮动式

mWindow.showAtlocation(ContentView,Gravity,BOOTTOM,0,0)

案例效果:点击菜单按钮时若PopuWindow未显示则让它从底部显示出来，若已显示则让它消失，点击返回键时若PopupWindow正在显 示则让它消失；点击收藏和分享选项时Toast显示，点击退出选项时若PopupWindow正在显示则让它消失并结束活动

content_layout.xml文件中创建Popup显示时的选项：

MainActivity.java中：

public class MainActivity extends Activity implements OnClickListener{    private View contentView;    private PopupWindow mWindow;    private ImageView iv1,iv2,iv3;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);                initPopuWindow();        initView();    }    private void initView() {        iv1 = (ImageView) contentView.findViewById(R.id.iv1);        iv2 = (ImageView) contentView.findViewById(R.id.iv2);        iv3 = (ImageView) contentView.findViewById(R.id.iv3);                iv1.setOnClickListener(this);        iv2.setOnClickListener(this);        iv3.setOnClickListener(this);       }    private void initPopuWindow() {        //将xml布局文件转换成我们需要的内容分视图        contentView = getLayoutInflater().inflate(R.layout.content_layout, null);        //第一个参数contentView参数：是内容视图        mWindow = new PopupWindow(contentView, LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);        //设置触摸PopupWindow外面的区域时是否可以使得这个PopupWindow消失        mWindow.setOutsideTouchable(true);        //设置背景        //mWindow.setBackgroundDrawable(background);        //设置PopupWindow是否触摸时会有响应        //mWindow.setTouchable(true);            }    //重写专门处理某个按键的方法    @Override    public boolean onKeyDown(int keyCode, KeyEvent event) {        switch (keyCode) {        case KeyEvent.KEYCODE_MENU://监听menu键            if(mWindow.isShowing()){//isShowing():判断PoupWindow是否正在显示                mWindow.dismiss();//dismiss()：让popupWindow消失的方法            }else{                //显示PoupWindow--->在某个位置显示                mWindow.showAtLocation(contentView, Gravity.BOTTOM, 0, 0);                //作为下拉视图显示                //mWindow.showAsDropDown(anchor, xoff, yoff);            }            break;        case KeyEvent.KEYCODE_BACK://监听返回键            if(mWindow.isShowing()){                mWindow.dismiss();            }            break;        }        return super.onKeyDown(keyCode, event);    }        @Override    public void onClick(View v) {        switch (v.getId()) {        case R.id.iv1:            finish();            if(mWindow.isShowing()){                mWindow.dismiss();            }            break;        case R.id.iv2:            Toast.makeText(this, "收藏", Toast.LENGTH_SHORT).show();            break;        case R.id.iv3:            Toast.makeText(this, "分享", Toast.LENGTH_SHORT).show();            break;        }       }    @Override    protected void onDestroy() { //PopupWindow不用时将它的对象给回收掉        super.onDestroy();        if(mWindow!=null){            mWindow.dismiss();            mWindow = null;        }    }}