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Xamarin - Menus
  • 时间:2024-11-03

Xamarin - Menus


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Popup Menus

A popup menu refers to a menu that is attached to a view; it is also referred to as a shortcut menu. Let’s see how to add a popup menu to an Android App.

Create a new project and call it popUpMenu App. Open Main.axml and create a button which will be used to display the popup menu.

<?xml version = "1.0" encoding = "utf-8"?> 
<LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android" 
   android:orientation = "vertical" 
   android:background = "#d3d3d3" 
   android:layout_width = "fill_parent" 
   android:layout_height = "fill_parent"> 
   <Button 
      android:id = "@+id/popupButton" 
      android:layout_width = "fill_parent" 
      android:layout_height = "wrap_content" 
      android:text = "Show popup menu" 
      android:background = "@android:color/holo_green_dark" 
      android:textColor = "@android:color/black" /> 
</LinearLayout>

Create a new folder under the Resources folder and call it Menu. Inside the Menu folder, add a new xml file called popMenu.xml.

Under popMenu.xml, add the following menu items.

<?xml version = "1.0" encoding="utf-8"?> 
<menu xmlns:android = "http://schemas.android.com/apk/res/android"> 
   <item 
      android:id = "@+id/file_settings" 
      android:icon = "@drawable/img_settings" 
      android:title = "Settings" 
      android:showAsAction = "ifRoom"> 
     
      <item 
         android:id = "@+id/new_game1" 
         android:icon = "@drawable/imgNew" 
         android:title = "New File Settings"/> 
      <item 
         android:id = "@+id/help" 
         android:icon = "@drawable/img_help" 
         android:title = "Help" /> 
      <item 
         android:id = "@+id/about_app" 
         android:icon = "@drawable/img_help" 
         android:title = "About app"/> 
   </item> 
</menu>  

After adding the menu items, go to mainActivity.cs to display the popup menu on button cpck.

protected override void OnCreate(Bundle bundle) { 
   base.OnCreate(bundle); 
   SetContentView(Resource.Layout.Main); 
   Button showPopupMenu = FindViewById<Button>(Resource.Id.popupButton); 
   showPopupMenu.Cpck += (s, arg) => { 
      PopupMenu menu = new PopupMenu(this, showPopupMenu); 
      menu.Inflate(Resource.Menu.popMenu); 
      menu.Show(); 
   }; 
} 

Now, build and run your apppcation. It should produce the following output −

Show Popup Menu

Options Menu

Options Menu is a collection of menus that are primary to an App and are mainly used to store settings, search, etc. Here, we are going to create a menu for settings with three items inside, i.e., New File Settings, Help, and About App.

To create an options menu, we must create a new XML layout file in the resources folder. First of all, we will add a new XML file. Right-cpck on the Layout folder, then go to Add → New item → Visual C# → XML File.

Choose an appropriate name for the layout file. In our example, we will call our file myMenu.xml.

Inside myMenu.xml, we are going to create a new menu and add items inside. The following code shows how to do it.

<?xml version = "1.0" encoding = "utf-8"?> 
<menu xmlns:android = "http://schemas.android.com/apk/res/android"> 
  <item 
      android:id = "@+id/file_settings" 
      android:icon = "@drawable/img_settings" 
      android:title = "Settings" 
      android:showAsAction = "ifRoom">
      
      <menu> 
         <item 
            android:id = "@+id/new_game1" 
            android:icon = "@drawable/imgNew" 
            android:title = "New File Settings" /> 
         <item 
            android:id = "@+id/help" 
            android:icon = "@drawable/img_help" 
            android:title = "Help" /> 
         <item 
            android:id = "@+id/about_app" 
            android:icon = "@drawable/img_help" 
            android:title = "About app"/> 
      </menu> 
   </item> 
</menu>

Next, we navigate to MainActivity.cs and create an override class for onOptionsMenu().

pubpc override bool OnCreateOptionsMenu(IMenu menu) { 
   MenuInflater.Inflate(Resource.Menu.myMenu, menu); 
   return base.OnPrepareOptionsMenu(menu); 
}

Next, we create an action to respond to the settings menu when it is selected. To do this, we create another override class for the OnOptionsItemSelected() menu.

pubpc override bool OnOptionsItemSelected(IMenuItem item) { 
   if (item.ItemId == Resource.Id.file_settings) { 
      // do something here... 
      return true;  
   } 
   return base.OnOptionsItemSelected(item); 
} 

Our final complete code will look as follows −

namespace optionsMenuApp {     
   [Activity(Label = "options Menu", MainLauncher = true, Icon = "@drawable/icon")] 
   pubpc class MainActivity : Activity { 
      pubpc override bool OnCreateOptionsMenu(IMenu menu) { 
         MenuInflater.Inflate(Resource.Menu.myMenu, menu); 
         return base.OnPrepareOptionsMenu(menu); 
      } 
      pubpc override bool OnOptionsItemSelected(IMenuItem item) { 
         if (item.ItemId == Resource.Id.file_settings) { 
            // do something here... 
            return true;  
         } 
         return base.OnOptionsItemSelected(item); 
      } 
   } 
} 

Now, build and run your apppcation. It should produce the following output −

New File settings Advertisements