Android的自定义Menu使用PopupWindow实现

Android的对话框有两种：PopupWindow和AlertDialog。它们的不同点在于：1）AlertDialog的位置固定，而PopupWindow的位置可以随意2）AlertDialog是非阻塞线程的，而PopupWindow是阻塞线程的3）PopupWindow的位置按照有无偏移分，可以分为偏移和无偏移两种；按照参照物的不同，可以分为相对于某个控件和相对于父控件。具体如下：showAsDropDown(View anchor)：相对某个控件的位置（正左下方），无偏移showAsDropDown(View anchor, int xoff, int yoff)：相对某个控件的位置，有偏移showAtLocation(View parent, int gravity, int x, int y)：相对于父控件的位置（例如正中央Gravity.CENTER，下方Gravity.BOTTOM等），可以设置偏移或无偏移。先上几张效果图吧：首先，在layout下增加两个布局文件，第一个为menu.xml：

<?xml version="1.0" encoding="UTF-8"?><LinearLayoutandroid:id="@+id/menu"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="match_parent"android:background="#1b2936"xmlns:android="http://schemas.android.com/apk/res/android"><GridViewandroid:gravity="center"android:id="@+id/menuGridChange"android:background="#1b2936"android:layout_alignParentBottom="true"android:paddingLeft="20dp"android:paddingRight="20dp"android:paddingTop="400dp"android:layout_width="match_parent"android:layout_height="match_parent"android:horizontalSpacing="10.0dip"android:verticalSpacing="60.0dip"android:columnWidth="60.0dip"android:numColumns="3"/></LinearLayout>

然后是main.xml：

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical"android:layout_width="fill_parent"android:layout_height="fill_parent"android:background="#ffff"><Buttonandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:id="@+id/btn"android:layout_gravity="center"android:text="Menu按钮"/></LinearLayout>

最后是MenuText.java的完整代码：

public class MenuTest extends Activity implements OnItemClickListener {private PopupWindow pw;private LayoutInflater inflater ;private Button btn;private LinearLayout linearLayout;private int[] resArray = new int[]{R.drawable.more_membership,R.drawable.more_trip, R.drawable.more_share, R.drawable.more_return};private String[] title = new String[]{"会员信息", "寻找之旅", "分享"};@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);btn = (Button) findViewById(R.id.btn);View view = LayoutInflater.from(this).inflate(R.layout.menu, null);linearLayout = (LinearLayout) view.findViewById(R.id.menu);linearLayout.getBackground().setAlpha(200);//设置透明度，0为完全透明，255为完全不透明inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);view = inflater.inflate(R.layout.menu, null);GridView grid1 = (GridView) view.findViewById(R.id.menuGridChange);grid1.setOnItemClickListener(this);grid1.setFocusableInTouchMode(true);grid1.setAdapter(new ImageAdapter(this));/*第一个参数弹出显示view  后两个是窗口大小*/pw = new PopupWindow(view, LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);/*设置点击menu以外其他地方以及返回键退出*/pw.setFocusable(true);/*设置背景显示*/pw.setBackgroundDrawable(new ColorDrawable());/*设置再次按菜单键时退出*/grid1.setOnKeyListener(new OnKeyListener() {public boolean onKey(View v, int keyCode, KeyEvent event) {if ((keyCode == KeyEvent.KEYCODE_MENU) && (pw.isShowing())) {pw.dismiss();return true;}return false;}});btn.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {pw.showAtLocation(findViewById(R.id.btn), Gravity.CENTER, 0, 100);}});}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {menu.add("menu");// 必须创建一项return super.onCreateOptionsMenu(menu);}/*** 拦截MENU*/@Overridepublic boolean onMenuOpened(int featureId, Menu menu) {if (pw != null) {if (!pw.isShowing()) {/*最重要的一步：弹出显示   在指定的位置(parent)  最后两个参数 是相对于 x / y 轴的坐标*/pw.showAtLocation(findViewById(R.id.btn), Gravity.CENTER, 0, 100);} else {pw.dismiss();}}return false;// 返回为true 则显示系统menu}public class ImageAdapter extends BaseAdapter {private Context context;public ImageAdapter(Context context) {this.context = context;}@Overridepublic int getCount() {return resArray.length + 1;}@Overridepublic Object getItem(int position) {return resArray[position];}@Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View convertView, ViewGroup arg2) {if (position < 3) {LinearLayout linear = new LinearLayout(context);linear.setOrientation(LinearLayout.VERTICAL);//装进一张图片ImageView iv = new ImageView(context);iv.setImageBitmap(((BitmapDrawable) context.getResources().getDrawable(resArray[position])).getBitmap());LinearLayout.LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);lp.gravity = Gravity.CENTER;linear.addView(iv, lp);//显示文字TextView tv = new TextView(context);tv.setText(title[position]);linear.addView(tv, lp);return linear;} else if (position == 4) {ImageView iv = new ImageView(context);iv.setImageBitmap(((BitmapDrawable) context.getResources().getDrawable(resArray[3])).getBitmap());return iv;} else {TextView textView = new TextView(context);return textView;}}}@Overridepublic void onItemClick(AdapterView<?> parent, View view, int position,long id) {switch (position) {case 0:Toast.makeText(this, "会员信息", Toast.LENGTH_LONG).show();break;case 1:Toast.makeText(this, "寻找之旅", Toast.LENGTH_LONG).show();break;case 2:Toast.makeText(this, "分享", Toast.LENGTH_LONG).show();break;case 4:pw.dismiss();break;}}}