Android中的Menu分为三种，分别为：OptionsMenu（选项菜单）、ContextMenu（上下文菜单）、SubMenu（子菜单）。
1、OptionsMenu
按Menu键就会显示，用于当前的Activity。
在Activity里面，一般通过以下函数来使用options menu：
Activity::onCreateOptionsMenu (Menu menu) 创建options menu，这个函数只会在menu第一次显示时调用。
Activity::onPrepareOptionsMenu (Menu menu) 更新改变options menu的内容，这个函数会在menu每次显示时调用。
Activity::onOptionsItemSelected (MenuItem item) 处理选中的菜单项。
//menu.add(groupId, itemId, order, title); 通过add()增加menuItem，每个menuItem有groupId，itemId，Order。这三个属性是相互独立，没有关联。
MenuItem redMenu = menu.add(MENU_GROUP_1, 0, 0, "Red");
MenuItem OrangedMenu = menu.add(MENU_GROUP_1, 1, 1, "Orange");
MenuItem YellowMenu = menu.add(MENU_GROUP_2, 2, 2, "Yellow");
MenuItem GreenMenu = menu.add(MENU_GROUP_2, 3, 3, "Green");
MenuItem BlueMenu = menu.add(MENU_GROUP_2, 4, 4, "Blue");
MenuItem CyangonMenu = menu.add(MENU_GROUP_3, 5, 5, "Cyangon");
MenuItem PurpleMenu = menu.add(MENU_GROUP_3, 6, 6, "Purple");
menu.setGroupCheckable(MENU_GROUP_2, true /*isCheckable*/, false);//第三个参数true为单选，false为多选
menu.setGroupEnabled(MENU_GROUP_2, true/*isEnabled*/);
menu.setGroupVisible(MENU_GROUP_2, true/*isVisible*/);
menu.setGroupCheckable(MENU_GROUP_3, true, true);
完整代码如下：
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast; public class MainActivity extends AppCompatActivity { private static int MENU_GROUP_1 = 1;
private static int MENU_GROUP_2 = 2;
private static int MENU_GROUP_3 = 3; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
} @Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuItem redMenu = menu.add(MENU_GROUP_1, 0, 0, "Red");
MenuItem OrangedMenu = menu.add(MENU_GROUP_1, 1, 1, "Orange");
MenuItem YellowMenu = menu.add(MENU_GROUP_2, 2, 2, "Yellow");
MenuItem GreenMenu = menu.add(MENU_GROUP_2, 3, 3, "Green");
MenuItem BlueMenu = menu.add(MENU_GROUP_2, 4, 4, "Blue");
MenuItem CyangonMenu = menu.add(MENU_GROUP_3, 5, 5, "Cyangon");
MenuItem PurpleMenu = menu.add(MENU_GROUP_3, 6, 6, "Purple"); menu.setGroupCheckable(MENU_GROUP_2, true /*isCheckable*/, false);//第三个参数true为单选，false为多选
menu.setGroupEnabled(MENU_GROUP_2, true/*isEnabled*/);
menu.setGroupVisible(MENU_GROUP_2, true/*isVisible*/);
menu.setGroupCheckable(MENU_GROUP_3, true, true); return super.onCreateOptionsMenu(menu);
} @Override
public boolean onOptionsItemSelected(MenuItem item) {
super.onOptionsItemSelected(item);
switch (item.getItemId()) {
case 0:
Toast.makeText(this, "Red", Toast.LENGTH_SHORT).show();
break;
case 1:
Toast.makeText(this, "Orange", Toast.LENGTH_SHORT).show();
break;
case 2:
if(item.isCheckable()){
item.setChecked(!item.isChecked());
}
break;
case 3:
if(item.isCheckable()){
item.setChecked(!item.isChecked());
}
break;
case 4:
if(item.isCheckable()){
item.setChecked(!item.isChecked());
}
break;
case 5:
if(item.isCheckable()){
item.setChecked(true);
}
break;
case 6:
if(item.isCheckable()){
item.setChecked(true);
}
break;
}
return true;
} }
MainActivity.java
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2、ContextMenu
要在相应的view上按几秒后才显示的，用于view，跟某个具体的view绑定在一起。这类型的菜单不支持icon和快捷键！
在Activity里面，一般通过以下函数来使用context menu：
Activity::registerForContextMenu(View view) 为某个view注册context menu，一般在Activity::onCreate里面调用。
Activity::onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) 创建context menu，和options menu不同，context meun每次显示时都会调用这个函数。
Activity::onContextItemSelected(MenuItem item) 处理选中的菜单项。
menu.setHeaderTitle("ContextMenu");
menu.add(GROUP_COLOR, 0, 0, "Red");
menu.add(GROUP_COLOR, 1, 1, "Green");
menu.add(GROUP_COLOR, 2, 2, "Blue");
菜单响应事件处理和OptionMenu类似。
public class MainActivity extends AppCompatActivity {
private TextView colorText;
private static int GROUP_COLOR = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
colorText = (TextView) findViewById(R.id.textView);
registerForContextMenu(colorText);
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
menu.setHeaderTitle("ContextMenu");
menu.add(GROUP_COLOR, 0, 0, "Red");
menu.add(GROUP_COLOR, 1, 1, "Green");
menu.add(GROUP_COLOR, 2, 2, "Blue");
}
@Override
public boolean onContextItemSelected(MenuItem item) {
super.onContextItemSelected(item);
switch (item.getItemId()) {
case 0:
colorText.setTextColor(Color.RED);
break;
case 1:
colorText.setTextColor(Color.GREEN);
break;
case 2:
colorText.setTextColor( Color.BLUE);
break;
}
return true;
}
}
3、SubMenu
SubMenu可以和OptionMenu、ContextMenu配合使用，但子菜单不能嵌套子菜单，这意味着在Android系统，菜单只有两层。同时子菜单不支持icon。
可以在onCreateOptionMenu或者onCreateContextMenu内定义SubMenu：
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo); menu.setHeaderTitle("ContextMenu");
menu.add(GROUP_COLOR, 0, 0, "Red");
menu.add(GROUP_COLOR, 1, 1, "Green");
menu.add(GROUP_COLOR, 2, 2, "Blue"); SubMenu subMenu = menu.addSubMenu(Menu.NONE, 10, 10, "Text Size");
subMenu.add(Menu.NONE, 11, 11, "Large");
subMenu.add(Menu.NONE, 12, 12, "Small");
}
完整代码：
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuItem;
import android.view.SubMenu;
import android.view.View;
import android.widget.TextView; public class MainActivity extends AppCompatActivity { private TextView colorText;
private static int GROUP_COLOR = 1; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); colorText = (TextView) findViewById(R.id.textView);
registerForContextMenu(colorText);
} @Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo); menu.setHeaderTitle("ContextMenu");
menu.add(GROUP_COLOR, 0, 0, "Red");
menu.add(GROUP_COLOR, 1, 1, "Green");
menu.add(GROUP_COLOR, 2, 2, "Blue"); SubMenu subMenu = menu.addSubMenu(Menu.NONE, 10, 10, "Text Size");
subMenu.add(Menu.NONE, 11, 11, "Large");
subMenu.add(Menu.NONE, 12, 12, "Small");
} @Override
public boolean onContextItemSelected(MenuItem item) {
super.onContextItemSelected(item); switch (item.getItemId()) {
case 0:
colorText.setTextColor(Color.RED);
break;
case 1:
colorText.setTextColor(Color.GREEN);
break;
case 2:
colorText.setTextColor( Color.BLUE);
break;
case 11:
colorText.setTextSize(30);
break;
case 12:
colorText.setTextSize(20);
break;
}
return true;
} }
MainActivity.java
4、XML定义菜单
首先在/res/menu新建一个menu_main.xml，在其中定义相关Menu
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
tools:context=".MainActivity">
<item android:id="@+id/subMenu"
android:title="SubMenu" >
<menu> <!--定义子菜单-->
<item android:id="@+id/subLarge"
android:title="Large"/>
<item android:id="@+id/subSmall"
android:title="Small"/>
</menu>
</item>
<!--定义菜单组1-->
<group android:id="@+id/group1"
android:checkableBehavior="single"
android:enabled="true">
<item android:id="@+id/redMenu"
android:title="Red"/>
<item android:id="@+id/blueMenu"
android:title="Blue"/>
</group>
<!--定义菜单组2-->
<group android:id="@+id/group2"
android:checkableBehavior="all"
android:enabled="true">
<item android:id="@+id/greenMenu"
android:title="Green"/>
<item android:id="@+id/purpleMenu"
android:title="Purple"/>
</group>
</menu>
（1）XML定义OptionsMenu
重载onCreateOptionsMenu即可：
@Override
public boolean onCreateOptionsMenu(Menu menu){
MenuInflater menuInflater = new MenuInflater(getApplication());
menuInflater.inflate(R.menu.menu_main, menu);
return super.onCreateOptionsMenu(menu);
}
完整代码为：
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.widget.TextView; public class MainActivity extends AppCompatActivity { private TextView colorText; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
} @Override
public boolean onCreateOptionsMenu(Menu menu){
MenuInflater menuInflater = new MenuInflater(getApplication());
menuInflater.inflate(R.menu.menu_main, menu);
return super.onCreateOptionsMenu(menu);
} }
MainActivity.java
（2）XML定义ContextMenu
首先为ContextMenu注册菜单项
colorText = (TextView)findViewById(R.id.textView);
registerForContextMenu(colorText);
然后重载onCreateContextMenu即可：
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo); getMenuInflater().inflate(R.menu.menu_main, menu);
}
完整代码为：
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.View;
import android.widget.TextView; public class MainActivity extends AppCompatActivity { private TextView colorText; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); colorText = (TextView)findViewById(R.id.textView);
registerForContextMenu(colorText);
} @Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo); getMenuInflater().inflate(R.menu.menu_main, menu);
} }
MainActivity.java