安卓入门-UI Components 之Menu (菜单)

安卓入门

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UI Components 之Menu (菜单)

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1.UI Components 是什么？
1)UI 对象（负责呈现view）
2)它不是view.它通过view呈现数据，实现与用户交互。



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2.Menu 是什么？
1)Android 中的一种菜单对象类型。
2)Android 中的一种呈现view的对象。


3.Menu 对象应用类型？


1)选项菜单（Option Menu）
2)上下文菜单(Context Menu)
3)弹出式菜单(PopuMenu)
4)子菜单(SubMenu 每种菜单都有子菜单)


4.选项菜单构建及应用？
1)构建选项菜单(重写activity中的onCreateOptionMenu)
2)处理选项菜单监听(重写activity中的onOptionItemSelected)

5.上下文菜单的创建及应用（基于view的长按事件）
0)在view上注册上下文菜单(registerForContextMenu)
1)构建上下文菜单(重写activity中的onCreateContextMenu)
2)处理上下文菜单监听(重写activity中的onContextItemSelected)


案例:listview 长按时弹出上下文菜单(删除，分享)

public class MainActivity extends Activity {private List<String> data=new ArrayList<String>();public MainActivity() {data.add("A");data.add("B");data.add("C");}ArrayAdapter<String> adapter;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);    ListView lsv=(ListView) findViewById(R.id.lsvId);    adapter=new ArrayAdapter<String>(this,         android.R.layout.simple_list_item_1,        data);    lsv.setAdapter(adapter);        //注册上下文菜单    registerForContextMenu(lsv);}/**长按listview的item时会执行此方法*/@Overridepublic void onCreateContextMenu(ContextMenu menu, View v,ContextMenuInfo menuInfo) {//getMenuInflater().inflate(menuRes, menu)//基于java方式创建菜单项menu.add(0, 101,//itemId201,//orderId (序号)"删除"//title);menu.add(0, 102,//itemId202,//orderId"分享"//title);}/**当我们点击上下文菜单中的选项时自动执行此方法*/@Overridepublic boolean onContextItemSelected(MenuItem item) {ContextMenuInfo c=item.getMenuInfo();Log.i("TAG", "c="+c);AdapterContextMenuInfo acm=(AdapterContextMenuInfo)c;//获得长按的位置int pos=acm.position;if(item.getItemId()==101){//删除数据 data.remove(pos); //刷新listview adapter.notifyDataSetChanged();}else if(item.getItemId()==102){ //分享的action: ACTION_SEND Intent target=new Intent(Intent.ACTION_SEND); //设置税局类型 target.setType("text/*"); //设置要分享的数据 target.putExtra(Intent.EXTRA_TEXT, data.get(pos)); //创建分享目标 Intent intent= Intent.createChooser(target, "请选择"); //启动activity startActivity(intent);}return true;}}

6.弹出式菜单(基于view的点击事件):了解


1)创建菜单(PopuMenu)及菜单项
2)显示菜单(show)
3)添加监听(setOnMenuItemClickListener)

public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}public void onClick(final View v){//构建菜单对象PopupMenu pm=new PopupMenu(this, v);//初始化菜单中的itempm.getMenuInflater().inflate(R.menu.pop,pm.getMenu());//pm.getMenu().add(groupId, itemId, order, title)//添加监听pm.setOnMenuItemClickListener(new OnMenuItemClickListener() {@Overridepublic boolean onMenuItemClick(MenuItem item) {((Button)v).setText(item.getTitle());return false;}});//显示菜单pm.show(); }}

8.子菜单(菜单项中还可以添加菜单)


案例：选项菜单中添加子菜单(xml,java)

public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}private Menu menu;@Overridepublic boolean onCreateOptionsMenu(Menu menu) {this.menu=menu;// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);//通过java方式添加子菜单SubMenu sm=menu.addSubMenu(0,1000,101, "item02");MenuItem item=menu.findItem(1000);item.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);    //添加菜单项sm.add(0, 2000, 200, "item0002");return true;}public void onClick(View v){menu.setGroupVisible(R.id.group01, true);}}

menu-xml文件如下：

<?xml version="1.0"?>-<menu xmlns:android="http://schemas.android.com/apk/res/android">-<group android:visible="false" android:id="@+id/group01">-<item android:title="item01" android:id="@+id/item01" android:showAsAction="ifRoom" android:orderInCategory="100">-<menu><item android:title="item001" android:id="@+id/item001" android:showAsAction="never" android:orderInCategory="300"/><item android:title="item002" android:id="@+id/item002" android:showAsAction="never" android:orderInCategory="301"/></menu></item></group></menu>

7.菜单的分组（可以同时显示或隐藏多个菜单项）


1)创建(xml:group)
2)调用menu对象的相关方法操作分组(例如显示或隐藏setGroupVisible)


9.侧滑菜单(菜单扩展)
1)DrawerLayout 布局（根元素必须是drawerlayout）
2)DrawerLayout 对象 (findViewByid)
a)初始化listview对象(侧滑item对象)
b)初始化framelayout对象

3)DrawerLayout 添加监听对象

public class MainActivity extends Activity implements OnItemClickListener {private List<Item> list=new ArrayList<Item>();public MainActivity() {list.add(new Item(android.R.drawable.ic_menu_save,"我的收藏"));list.add(new Item(android.R.drawable.ic_menu_camera,"我的设置"));list.add(new Item(android.R.drawable.ic_menu_delete,"退出"));}private DrawerLayout drawerLayout;private TextView contentTv;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);setDrawerLayout();setDrawerListView();setContent();}private void setContent() {contentTv=(TextView) findViewById(R.id.textId);}private void setDrawerListView() {ListView lsv=(ListView) findViewById(R.id.lsvId);    lsv.setAdapter(new ArrayAdapter<Item>(this,    android.R.layout.simple_list_item_1,list){    @Override    public View getView(int position, View convertView, ViewGroup parent) {    TextView v=(TextView)View.inflate(getContext(),  android.R.layout.simple_list_item_1, null);    Item item=getItem(position);    //获得图片资源的drawable对象    Drawable left=getResources()    .getDrawable(item.getLogo());    //设定对象的边界    left.setBounds(0, 0,50, 50);    //将left对象绘制到v的左边    v.setCompoundDrawables(left,    null, null, null);        v.setText(item.getName());    return v;    }    });    lsv.setOnItemClickListener(this);}private ActionBarDrawerToggle drawerToggle;private void setDrawerLayout() { getActionBar().setDisplayHomeAsUpEnabled(true);//显示图标drawerLayout=(DrawerLayout) findViewById(R.id.drawerLayoutId);    drawerToggle=new ActionBarDrawerToggle(this,    drawerLayout,    R.drawable.top_menu_on, R.string.open_drawer,R.string.close_drawer){    @Override    public void onDrawerOpened(View drawerView) {    super.onDrawerOpened(drawerView);    setTitle("Open");    }    @Override    public void onDrawerClosed(View drawerView) {    super.onDrawerClosed(drawerView);    setTitle("Close");    }    };drawerLayout.setDrawerListener(drawerToggle);}/**选项菜单创建之前执行，在此方法中同步drawerLayout状态*/@Overrideprotected void onPostCreate(Bundle savedInstanceState) {super.onPostCreate(savedInstanceState);drawerToggle.syncState();}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {//打开或收起drawerlayout对象if(drawerToggle.onOptionsItemSelected(item)){return true;}return true;}@Overridepublic void onItemClick(AdapterView<?> parent, View view, int position,long id) {Item item=(Item)parent.getItemAtPosition(position);contentTv.setText(item.getName());drawerLayout.closeDrawer(parent);}class Item{private int logo;private String name;public Item(int logo,String name) {this.logo=logo;this.name=name;}public int getLogo() {return logo;}public String getName() {return name;}}}

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