布局文件中添加menu

menu_main.xml

<?xml version="1.0" encoding="utf-8"?>

<menu xmlns:android="http://schemas.android.com/apk/res/android"

      xmlns:support="http://schemas.android.com/apk/res-auto"

    >

    <item

        android:id="@+id/menu_setting"

        android:icon="@mipmap/ic_action_settings"

        android:title="@string/menu_setting"

        support:showAsAction="never"/>

    <item

        android:id="@+id/menu_refresh"

        android:icon="@mipmap/ic_action_refresh"

        android:title="@string/menu_refresh"

        support:showAsAction="always"/>

</menu>

Activity中添加menu

values/ids.xml

<resources>

    <item name="menu_location" type="id"/>

</resources>

@Override

public boolean onCreateOptionsMenu(Menu menu) {

    getMenuInflater().inflate(R.menu.menu_main,menu);

    MenuItem location=menu.add(0,R.id.menu_location,0,"Location");

    location.setIcon(R.mipmap.ic_action_location);

    MenuItemCompat.setShowAsAction(location,MenuItemCompat.SHOW_AS_ACTION_IF_ROOM);

    return true;

}

@Override

public boolean onOptionsItemSelected(MenuItem item) {

    switch (item.getItemId()){

        case R.id.menu_setting:

            return true;

        case R.id.menu_location:

            return true;

        case R.id.menu_refresh:

            return true;

    }

    return super.onOptionsItemSelected(item);

}

用法

运行时更改菜单项

mButtonForbidRefresh.setOnClickListener(new View.OnClickListener() {

           private int i=0;

           @Override

           public void onClick(View view) {

               i++;

               if(i%2==1)

                   mButtonForbidRefresh.setActivated(true);

               else

                   mButtonForbidRefresh.setActivated(false);

               invalidateOptionsMenu();

           }

       });

@Override

    public boolean onPrepareOptionsMenu(Menu menu) {

        menu.clear();

        getMenuInflater().inflate(R.menu.menu_main, menu);

        MenuItem item=menu.findItem(R.id.menu_refresh);

        if(mButtonForbidRefresh.isActivated()){

           item.setEnabled(false);

        }

        MenuItem location = menu.add(0, R.id.menu_location, Menu.CATEGORY_SECONDARY, "Location");

        location.setIcon(R.mipmap.ic_action_location);

        MenuItemCompat.setShowAsAction(location, MenuItemCompat.SHOW_AS_ACTION_IF_ROOM);

        return super.onPrepareOptionsMenu(menu);

    }

menu.findItem(int id)

menu.getItem(int index)

onPrepareOptionsMenu(Menu menu)和onCreateOptionsMenu(Menu menu)区别

onCreateOptionsMenu(Menu menu)只在最初的时候会调用每次点击menu都会调用一次onPrepareOptionsMenu(Menu menu).使用invalidateOptionsMenu()会直接调用onPrepareOptionsMenu(Menu menu);