~楓花雪岳~: [X.Form] Dependency Service

星期六, 7月 01, 2017

[X.Form] Dependency Service

Xamarin.Form 是整合 UI，要使用各平台裝置功能還是必須去呼叫原生 API，基本上只要需求不是太特別，應該都可以在 nuget 或 Xamarin Plugin 網站內找到相關套件使用，這篇是利用官方範例 - Checking Device Orientation 來練習使用 Dependency Service

Dependency Service 簡單說就是在 Xamarin Shared Code 上定義 interface，各平台實在該 interface 後，可以在 Shared Code 內呼叫使用

該圖取至官方文章

利用 IDeviceOrientation interface 來統一呼叫各平台偵測裝置方向功能

IDeviceOrientation

namespace DependencyServiceSample
{
    public enum DeviceOrientations
    {
        Undefined,
        Landscape,
        Portrait
    }

    public interface IDeviceOrientation
    {
        DeviceOrientations GetOrientation();
    }
}

Android

using DependencyServiceSample.Droid;

[assembly: Xamarin.Forms.Dependency(typeof(DeviceOrientationImplementation))]
namespace DependencyServiceSample.Droid
{
    public class DeviceOrientationImplementation : IDeviceOrientation
    {
        public DeviceOrientations GetOrientation()
        {
            IWindowManager windowManager = Android.App.Application.Context.GetSystemService(Context.WindowService).JavaCast<IWindowmanager>();

            var rotation = windowManager.DefaultDisplay.Rotation;
            bool isLandscape = rotation == SurfaceOrientation.Rotation90 || rotation == SurfaceOrientation.Rotation270;
            return isLandscape ? DeviceOrientations.Landscape : DeviceOrientations.Portrait;
        }
    }
}

iOS

using UIKit;
using DependencyServiceSample.iOS; 

[assembly: Xamarin.Forms.Dependency(typeof(DeviceOrientationImplementation))]
namespace DependencyServiceSample.iOS
{
    public class DeviceOrientationImplementation : IDeviceOrientation
    {
        public DeviceOrientations GetOrientation()
        {
            var currentOrientation = UIApplication.SharedApplication.StatusBarOrientation;
            bool isPortrait = currentOrientation == UIInterfaceOrientation.Portrait || currentOrientation == UIInterfaceOrientation.PortraitUpsideDown;
            return isPortrait ? DeviceOrientations.Portrait : DeviceOrientations.Landscape;
        }
    }
}

MainPage.xaml，就放一個 Button 佔滿整個畫面

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:DependencyServiceSample"
             x:Class="DependencyServiceSample.MainPage">

 <Button x:Name="btnOrientations" Text="顯示裝置方向" Clicked="BtnOrientations_Clicked"></Button>

</ContentPage>

MainPage.xaml.cs，點擊 Button 會顯示裝置方向

namespace DependencyServiceSample
{
    public partial class MainPage : ContentPage
    {
        public MainPage()
        {
            InitializeComponent();
        }

        private void BtnOrientations_Clicked(object sender, EventArgs e)
        {
            var orientation = DependencyService.Get<IDeviceorientation>().GetOrientation();
            switch (orientation)
            {
                case DeviceOrientations.Undefined:
                    DisplayAlert("訊息", "未定義", "OK");
                    break;
                case DeviceOrientations.Landscape:
                    DisplayAlert("訊息", "橫向", "OK");
                    break;
                case DeviceOrientations.Portrait:
                    DisplayAlert("訊息", "直向", "OK");
                    break;
            }
        }
    }
}

測試結果

~楓花雪岳~

星期六, 7月 01, 2017

[X.Form] Dependency Service

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