~楓花雪岳~: [X.Andriod] Activity 回傳參數

星期四, 6月 30, 2016

[X.Andriod] Activity 回傳參數

這篇 [X.Andriod] Activity 傳遞參數是紀錄從 Activity 丟參數到另一個 Activity 去，本篇記錄要從 Activity 呼叫 Activity 後，讓使用者進行操作並回傳操作結果

layout1.axml：兩個 Button，都是呼叫 Activity2

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:minWidth="25px"
    android:minHeight="25px">
    <Button
        android:text="MS 產品"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/btnMS" />
    <Button
        android:text="非 MS 產品"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/btnNonMS" />
</LinearLayout>

layout2.axml：CheckBox 讓使用者勾選並確認回傳

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/cbLayout">
    <CheckBox
        android:text="SQL Server 2016"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/checkBox1"
        android:textSize="20dp" />
    <CheckBox
        android:text="Windows Server 2016"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/checkBox2"
        android:textSize="20dp" />
    <CheckBox
        android:text="ASP.NET Core"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/checkBox3"
        android:textSize="20dp" />
    <CheckBox
        android:text="Xamarin"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/checkBox4"
        android:textSize="20dp" />
    <CheckBox
        android:text="Hyper-V"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/checkBox5"
        android:textSize="20dp" />
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="39.0dp"
        android:id="@+id/linearLayout1">
        <Button
            android:text="確定"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:id="@+id/btnOK" />
        <Button
            android:text="取消"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:id="@+id/btnCancel" />
    </LinearLayout>
</LinearLayout>

Activity1.cs

namespace ActivityBack
{
    [Activity(Label = "Activity1", MainLauncher = true)]
    public class Activity1 : Activity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            SetContentView(Resource.Layout.layout1);

            FindViewById<Button>(Resource.Id.btnMS).Click += (sender, e) =>
            {
                // StartActivityForResult 第二參數是故意塞 btnMS id 進去
               // 只要是大於零的整數都是 OK 的
                this.StartActivityForResult(
                  typeof(Activity2),
                  Resource.Id.btnMS);
            };

            FindViewById<Button>(Resource.Id.btnNonMS).Click += (sender, e) =>
            {
                // 故意也呼叫 Activity2，要在 OnActivityResult 內判斷是由哪個 Button 觸發的
                this.StartActivityForResult(
                  typeof(Activity2),
                  Resource.Id.btnNonMS);
            };
        }

        protected override void OnActivityResult(
            int requestCode,
            [GeneratedEnum] Result resultCode,
            Intent data)
        {
            if (resultCode != Result.Ok) return;

            // 不是由 btnMS 進入 Activity 並回傳點選結果，就要擋下來
            if (requestCode != Resource.Id.btnMS)
            {
                string message = $"邏輯異常喔，requestCode 為 { Resource.Id.btnNonMS}";
                Toast.MakeText(this, message, ToastLength.Short).Show();
                return;
            }

            StringBuilder sb = new StringBuilder();
            // 第一參數：requestCode 即為 StartActivityForResult 第二參數，可以透過該參數來判斷當初的來源是誰
            sb.AppendLine($"requestCode：{requestCode}");
            // 第三參數 data：從 Activity2 回傳的 Intent
            sb.AppendLine(data.GetStringExtra("RetValue") ?? "沒有相關資料");
            Toast.MakeText(this, sb.ToString(), ToastLength.Long).Show();
        }
    }
}

Activity2.cs

namespace ActivityBack
{
    [Activity(Label = "Activity2")]
    public class Activity2 : Activity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            SetContentView(Resource.Layout.layout2);

            FindViewById<Button>(Resource.Id.btnOK).Click += (sender, e) =>
            {
                Intent i = new Intent();
                i.PutExtra("RetValue", CheckBoxState());
                SetResult(Result.Ok, i);
                this.Finish();
            };

            FindViewById<Button>(Resource.Id.btnCancel).Click += (sender, e) =>
            {
                SetResult(Result.Canceled);
                this.Finish();
            };
        }

        private string CheckBoxState()
        {
            LinearLayout layout = FindViewById<LinearLayout>(Resource.Id.cbLayout);
            int ctls = layout.ChildCount;
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < ctls; i++)
            {
                View v = layout.GetChildAt(i);
                if ((v is CheckBox) == false) continue;
                CheckBox cb = v as CheckBox;
                sb.AppendLine((cb.Checked == true ? "已勾選" : "未勾選") + "：" + cb.Text);
            }
            return sb.ToString();
        }
    }
}

Resource.Designer.cs 內的 btnMS ID 和 btnNonMS ID，ID 資料型別為 int 喔