แชร์ผ่าน


Xamarin.Android PopUp Menu

The PopupMenu (also called a shortcut menu) is a menu that is anchored to a particular view. In the following example, a single Activity contains a button. When the user taps the button, a three-item popup menu is displayed:

Example of an app with a button and three-item pop-up menu

Creating a Popup Menu

The first step is to create a menu resource file for the menu and place it in Resources/menu. For example, the following XML is the code for the three-item menu displayed in the previous screenshot, Resources/menu/popup_menu.xml:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@+id/item1"
          android:title="item 1" />
    <item android:id="@+id/item1"
          android:title="item 2" />
    <item android:id="@+id/item1"
          android:title="item 3" />
</menu>

Next, create an instance of PopupMenu and anchor it to its view. When you create an instance of PopupMenu, you pass its constructor a reference to the Context as well as the view to which the menu will be attached. As a result, the popup menu is anchored to this view during its construction.

In the following example, the PopupMenu is created in the click event handler for the button (which is named showPopupMenu). This button is also the view to which the PopupMenu is anchored, as shown in the following code example:

showPopupMenu.Click += (s, arg) => {
    PopupMenu menu = new PopupMenu (this, showPopupMenu);
};

Finally, the popup menu must be inflated with the menu resource that was created earlier. In the following example, the call to the menu's Inflate method is added and its Show method is called to display it:

showPopupMenu.Click += (s, arg) => {
    PopupMenu menu = new PopupMenu (this, showPopupMenu);
    menu.Inflate (Resource.Menu.popup_menu);
    menu.Show ();
};

Handling Menu Events

When the user selects a menu item, the MenuItemClick click event will be raised and the menu will be dismissed. Tapping anywhere outside the menu will simply dismiss it. In either case, when the menu is dismissed, its DismissEvent will be raised. The following code adds event handlers for both the MenuItemClick and DismissEvent events:

showPopupMenu.Click += (s, arg) => {
    PopupMenu menu = new PopupMenu (this, showPopupMenu);
    menu.Inflate (Resource.Menu.popup_menu);

    menu.MenuItemClick += (s1, arg1) => {
        Console.WriteLine ("{0} selected", arg1.Item.TitleFormatted);
    };

    menu.DismissEvent += (s2, arg2) => {
        Console.WriteLine ("menu dismissed");
    };
    menu.Show ();
};