如何通过 onclick 侦听器从 Xamarin Android Activity 打开 Xamarin Forms 页面

Question

我正在向我的应用程序添加一个辅助功能，当用户按住主页按钮时，一个 android 活动将打开，用户可以单击该卡片，然后打开相关的 xamarin 表单页面，例如当数学点击卡片 MathPage xamarin 表单页面打开这里是我的 android 布局代码：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_tools_home_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingTop="10dp"
        android:id="@+id/whole"
        tools:context="${relativePackage}.${activityClass}"
        tools:layout_editor_absoluteY="0dp"
        tools:layout_editor_absoluteX="0dp">
        <LinearLayout
            android:layout_width="wrap_content"
            android:id="@+id/scroll"
            android:layout_height="wrap_content">
            <android.support.v7.widget.CardView
                android:id="@+id/one"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:cardBackgroundColor="@color/cardsbg"
                app:cardElevation="3dp"
                android:clickable="false"
                tools:layout_conversion_absoluteX="16dp"
                tools:layout_conversion_absoluteY="8dp"
                tools:layout_conversion_absoluteWidth="379dp"
                tools:layout_conversion_absoluteHeight="540dp">
                <RelativeLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content">
                    <android.support.v7.widget.CardView
                        android:id="@+id/webcard"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:layout_marginBottom="4dp"
                        android:layout_marginRight="8dp"
                        android:layout_marginLeft="8dp"
                        android:layout_marginTop="8dp"
                        android:foreground="?android:attr/selectableItemBackground"
                        app:cardBackgroundColor="@color/card_background"
                        app:cardElevation="3dp"
                        android:clickable="true"
                        android:onClick="web">
                        <RelativeLayout
                            android:layout_width="match_parent"
                            android:layout_height="match_parent">
                            <ImageView
                                android:id="@+id/webicon"
                                android:layout_width="68dp"
                                android:layout_height="68dp"
                                android:layout_centerVertical="true"
                                android:padding="5dp"
                                android:src="@drawable/web" />
                            <TextView
                                android:id="@+id/web"
                                android:layout_width="wrap_content"
                                android:layout_height="wrap_content"
                                android:layout_centerVertical="true"
                                android:layout_toRightOf="@id/webicon"
                                android:text="Internet"
                                android:paddingLeft="8dp"
                                android:textColor="@color/cardText"
                                android:textSize="20sp" />
                        </RelativeLayout>
                    </android.support.v7.widget.CardView>
                    <android.support.v7.widget.CardView
                        android:id="@+id/mailcard"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:foreground="?android:attr/selectableItemBackground"
                        android:layout_marginBottom="4dp"
                        android:layout_marginRight="8dp"
                        android:layout_marginLeft="8dp"
                        android:layout_marginTop="4dp"
                        android:layout_below="@+id/webcard"
                        app:cardBackgroundColor="@color/card_background"
                        app:cardElevation="3dp"
                        android:clickable="true"
                        android:onClick="email">
                        <RelativeLayout
                            android:layout_width="match_parent"
                            android:layout_height="match_parent">
                            <ImageView
                                android:id="@+id/emailicon"
                                android:layout_width="68dp"
                                android:layout_height="68dp"
                                android:layout_centerVertical="true"
                                android:padding="5dp"
                                android:src="@drawable/email" />
                            <TextView
                                android:id="@+id/email"
                                android:layout_width="wrap_content"
                                android:layout_height="wrap_content"
                                android:paddingLeft="8dp"
                                android:layout_centerVertical="true"
                                android:layout_toRightOf="@id/emailicon"
                                android:text="Email"
                                android:textColor="@color/cardText"
                                android:textSize="20sp" />
                        </RelativeLayout>
                    </android.support.v7.widget.CardView>
                    <android.support.v7.widget.CardView
                        android:id="@+id/mathcard"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:foreground="?android:attr/selectableItemBackground"
                        android:layout_marginBottom="4dp"
                        android:layout_marginRight="8dp"
                        android:layout_marginLeft="8dp"
                        android:layout_marginTop="4dp"
                        android:layout_below="@+id/mailcard"
                        app:cardBackgroundColor="@color/card_background"
                        app:cardElevation="3dp"
                        android:clickable="true"
                        android:onClick="math">
                        <RelativeLayout
                            android:layout_width="match_parent"
                            android:layout_height="match_parent">
                            <ImageView
                                android:id="@+id/musicicon"
                                android:layout_width="68dp"
                                android:layout_height="68dp"
                                android:layout_centerVertical="true"
                                android:padding="5dp"
                                android:src="@drawable/math" />
                            <TextView
                                android:id="@+id/music"
                                android:layout_width="wrap_content"
                                android:layout_height="wrap_content"
                                android:layout_centerVertical="true"
                                android:layout_toRightOf="@id/musicicon"
                                android:text="Math"
                                android:paddingLeft="8dp"
                                android:textColor="@color/cardText"
                                android:textSize="20sp" />
                        </RelativeLayout>
                    </android.support.v7.widget.CardView>
                    <android.support.v7.widget.CardView
                        android:id="@+id/scicard"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:foreground="?android:attr/selectableItemBackground"
                        android:layout_marginBottom="8dp"
                        android:layout_marginRight="8dp"
                        android:layout_marginLeft="8dp"
                        android:layout_marginTop="4dp"
                        android:layout_below="@+id/mathcard"
                        app:cardBackgroundColor="@color/card_background"
                        app:cardElevation="3dp"
                        android:clickable="true"
                        android:onClick="science">
                        <RelativeLayout
                            android:layout_width="match_parent"
                            android:layout_height="match_parent">
                            <ImageView
                                android:id="@+id/playicon"
                                android:layout_width="68dp"
                                android:layout_height="68dp"
                                android:layout_centerVertical="true"
                                android:padding="8dp"
                                android:src="@drawable/sci" />
                            <TextView
                                android:id="@+id/play"
                                android:layout_width="match_parent"
                                android:layout_height="wrap_content"
                                android:layout_centerVertical="true"
                                android:paddingLeft="8dp"
                                android:layout_toRightOf="@+id/playicon"
                                android:text="Science"
                                android:textColor="@color/cardText"
                                android:textSize="20sp" />
                        </RelativeLayout>
                    </android.support.v7.widget.CardView>
                    <android.support.v7.widget.CardView
                        android:id="@+id/englishcard"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:foreground="?android:attr/selectableItemBackground"
                        android:layout_marginBottom="8dp"
                        android:layout_marginRight="8dp"
                        android:layout_marginLeft="8dp"
                        android:layout_marginTop="4dp"
                        android:layout_below="@+id/scicard"
                        app:cardBackgroundColor="@color/card_background"
                        app:cardElevation="3dp"
                        android:clickable="true"
                        android:onClick="english">
                        <RelativeLayout
                            android:layout_width="match_parent"
                            android:layout_height="match_parent">
                            <ImageView
                                android:id="@+id/playicon"
                                android:layout_width="68dp"
                                android:layout_height="68dp"
                                android:layout_centerVertical="true"
                                android:padding="8dp"
                                android:src="@drawable/handwrittin" />
                            <TextView
                                android:id="@+id/play"
                                android:layout_width="match_parent"
                                android:layout_height="wrap_content"
                                android:layout_centerVertical="true"
                                android:paddingLeft="8dp"
                                android:layout_toRightOf="@+id/playicon"
                                android:text="Handwriting"
                                android:textColor="@color/cardText"
                                android:textSize="20sp" />
                        </RelativeLayout>
                    </android.support.v7.widget.CardView>
                    <android.support.v7.widget.CardView
                        android:id="@+id/flashcard"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:foreground="?android:attr/selectableItemBackground"
                        android:layout_marginBottom="8dp"
                        android:layout_marginRight="8dp"
                        android:layout_marginLeft="8dp"
                        android:layout_marginTop="4dp"
                        android:layout_below="@+id/englishcard"
                        app:cardBackgroundColor="@color/card_background"
                        app:cardElevation="3dp"
                        android:clickable="true"
                        android:onClick="flashcard">
                        <RelativeLayout
                            android:layout_width="match_parent"
                            android:layout_height="match_parent">
                            <ImageView
                                android:id="@+id/playicon"
                                android:layout_width="68dp"
                                android:layout_height="68dp"
                                android:layout_centerVertical="true"
                                android:padding="8dp"
                                android:src="@drawable/flashcards" />
                            <TextView
                                android:id="@+id/play"
                                android:layout_width="match_parent"
                                android:layout_height="wrap_content"
                                android:layout_centerVertical="true"
                                android:paddingLeft="8dp"
                                android:layout_toRightOf="@+id/playicon"
                                android:text="Flashcards"
                                android:textColor="@color/cardText"
                                android:textSize="20sp" />
                        </RelativeLayout>
                    </android.support.v7.widget.CardView>
                    <RelativeLayout
                        android:id="@+id/bttom"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:layout_below="@id/flashcard"
                        android:paddingTop="8dp"
                        android:layout_marginBottom="8dp">
                        <Button
                            android:id="@+id/button_2"
                            android:onClick="cam"
                            android:foreground="?android:attr/selectableItemBackground"
                            android:layout_alignParentLeft="true"
                            android:layout_marginLeft="50dp"
                            android:layout_width="50dp"
                            android:layout_height="50dp"
                            android:background="@drawable/settings" />
                        <Button
                            android:id="@+id/button_1"
                            android:onClick="settings"
                            android:foreground="?android:attr/selectableItemBackground"
                            android:layout_alignParentRight="true"
                            android:layout_marginRight="50dp"
                            android:layout_width="50dp"
                            android:layout_height="50dp"
                            android:background="@drawable/settings" />
                    </RelativeLayout>
                </RelativeLayout>
            </android.support.v7.widget.CardView>
        </LinearLayout>
        <Button
            android:layout_width="72dp"
            android:layout_height="72dp"
            android:id="@+id/button_4"
            android:onClick="now"
            android:layout_marginTop="-42dp"
            android:layout_below="@+id/scroll"
            android:foreground="?android:attr/selectableItemBackground"
            android:clipToPadding="false"
            android:layout_centerHorizontal="true"
            android:background="@drawable/books" />
    </RelativeLayout>
</RelativeLayout>

这是我的代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using Android.App;
using Android.Content;
using Android.Content.PM;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Xamarin.Forms.Platform.Android;

namespace AppName.Droid
{
[Activity(LaunchMode = LaunchMode.SingleInstance, Theme = "@style/Theme.Transparent")]
    [IntentFilter(new[] { Intent.ActionAssist }, Categories = new[] { Intent.CategoryDefault })]    
    public class ToolBelt : FormsApplicationActivity
    {

        Button mathbutton;

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.ToolBelt);

        }


        //Code That Opens The Math  Part!

        [Java.Interop.Export("math")] // The value found in android:onClick attribute.
        public void btnOneClick4(View v) // Does not need to match value in above attribute.
        {

            //code to open the MathPage Forms Page Goes here
        }

        //Code That Opens The Internet  App!

        [Java.Interop.Export("web")] // The value found in android:onClick attribute.
        public void btnOneClick8(View v) // Does not need to match value in above attribute.
        {
            var uri = Android.Net.Uri.Parse("http://www.google.com");
            var intent = new Intent(Intent.ActionView, uri);
            StartActivity(intent);
        }



        //Code That Opens The Gmail App!

        [Java.Interop.Export("email")] // The value found in android:onClick attribute.
        public void btnOneClick3(View v) // Does not need to match value in above attribute.
        {
            var intent = PackageManager.GetLaunchIntentForPackage("com.google.android.gm");
            StartActivity(intent);
        }
    }
}

Answer 1

这是一个简单的例子……

基于非表单的页面选择Activity：

用户点击一个按钮，我们创建一个Intent 来打开基于主表单的Activity 并添加一个字符串Extra 以及该用户选择的“页面”。

[Activity(Label = "PageSelectionActivity", Theme = "@style/MyTheme",  Name = "com.sushhangover.openpage.PageSelectionActivity")]
public class PageSelectionActivity : AppCompatActivity
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);
        SetContentView(Resource.Layout.PageSelection);
        Button button = FindViewById<Button>(Resource.Id.myButton);
        button.Click += delegate 
        {
            var intent = new Intent(ApplicationContext, typeof(MainActivity));
            intent.PutExtra("page", "StackOverflowPage");
            StartActivity(intent);          
        };
    }
}

修改您的MainActivity 以获取Extra（如果有）并将其传递给App .actor：

[Activity(Label = "OpenPage.Droid", Icon = "@drawable/icon", Theme = "@style/MyTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        TabLayoutResource = Resource.Layout.Tabbar;
        ToolbarResource = Resource.Layout.Toolbar;

        base.OnCreate(savedInstanceState);

        global::Xamarin.Forms.Forms.Init(this, savedInstanceState);

        var page = Intent.GetStringExtra("page");
        LoadApplication(new App(page));
    }
}

修改 App 默认 .actor 以接受参数并对其进行操作：

public class App : Application
{
    public App(string pageName = "SomeDefaultMainApplicationEntryPage")
    {
        switch (pageName)
        {
            case "StackOverflowPage":
                MainPage = new NavigationPage(new StackOverflowPage);
                break;
            default:
                MainPage = new NavigationPage(new SomeDefaultMainApplicationEntryPage);
                break;
        }
    }
}

测试

您可以使用adb打开页面选择Activity来启动它：

adb shell am start -n com.sushhangover.openpage/.PageSelectionActivity

注意：您需要处理Xamarin.Form 页面生命周期，因为它可能会变得混乱，这取决于您的ToolBelt Activity 是否在用户已经打开您的应用程序的情况下打开并且它正在进行一些活动，您通过重新启动应用程序来破坏他们的工作....