[Xamarin] 透過StartActivityForResult傳值回來(转贴)

2022-12-28 23:13:30

上一篇文章(開啟另外一個Activity 並且帶資料)，提到了開啟一個新的Activity ，我們將值透過intent 帶到下個Activity

但是，如果我們開啟的Actrivity其實是有一個任務的，他必須要回傳值回來，讓父親可以知道一些訊息可以帶回來，我們該如何做

這次案例首先主畫面為.

點下按鈕後，就會開啟 LayoutAskQuestion.axml

然後就會回到主要的畫面，並且Toast剛剛選擇的結果.

內容我就寫在code 註解裡..

主畫面 Main.axml :

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

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

    android:orientation="vertical"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent">

    <Button

        android:id="@+id/btnAskQuestion"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="詢問問題" />

</LinearLayout>

Activity1.cs:

using Android.App;

using Android.Content;

using Android.Widget;

using Android.OS;

namespace TestStartActivityForResult

    [Activity(Label = "TestStartActivityForResult", MainLauncher = true, Icon = "@drawable/icon")]

    public class Activity1 : Activity

        protected override void OnCreate(Bundle bundle)

            base.OnCreate(bundle);

            SetContentView(Resource.Layout.Main);

            var btnAskQuestion = FindViewById<Button>(Resource.Id.btnAskQuestion);

            //詢問的按鈕按下後

            btnAskQuestion.Click += delegate

                //因為期許他將回傳值，所以使用StartActivityForResult 叫起

                //第二參數為 requestcode 這邊主要是設定讓 OnActivityResult 可以判斷當初發出的動機

                StartActivityForResult(typeof(ActivityAskQuestion), 1);

};

        /// <summary>

        /// 當有 AcrivityForReult Activity 被呼叫且結束後

        /// </summary>

        /// <param name="requestCode"></param>

        /// <param name="resultCode"></param>

        /// <param name="data"></param>

        protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)

            base.OnActivityResult(requestCode, resultCode, data);

            //如果當初的發的requestCode =1

            if (requestCode == 1 && resultCode == Result.Ok)

                Toast.MakeText(this, "選取結果(OnActivityResult):" + data.GetStringExtra("hero"), ToastLength.Short).Show();

被呼叫端 LayoutAskQuestion.axml :

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

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

    android:orientation="vertical"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent">

    <Button

        android:id="@+id/btnBlackWidow"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="黑寡婦" />

    <Button

        android:id="@+id/btnIronMan"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="鋼鐵人" />

</LinearLayout>

ActivityAskQuestion.cs:

using Android.App;

using Android.Content;

using Android.OS;

using Android.Widget;

namespace TestStartActivityForResult

    [Activity(Label = "Son Activity")]

    public class ActivityAskQuestion : Activity

        protected override void OnCreate(Bundle bundle)

            base.OnCreate(bundle);

            SetContentView(Resource.Layout.LayoutAskQuestion);

            var btnBlackWidow = FindViewById<Button>(Resource.Id.btnBlackWidow);

            btnBlackWidow.Click += delegate

                //開啟一個新的intent

                var intent = new Intent(this, typeof(Activity1));

                //放入一個key 為hero 值為 黑寡婦

                intent.PutExtra("hero", "黑寡婦");

                //狀態設為OK

                SetResult(Result.Ok, intent);

                //呼叫後將關閉此視窗

                Finish();

};

            var btnIronMan = FindViewById<Button>(Resource.Id.btnIronMan);

            btnIronMan.Click += delegate

                var intent = new Intent(this, typeof(Activity1));

                intent.PutExtra("hero", "鋼鐵人");

                SetResult(Result.Ok, intent);

                Finish();

};

呼叫結果..

码农公寓