为什么数据不能传递到第二个活动

Question

根据教程中的示例使用XamarinStudio和下面的代码。这里是问题。

null

---Activity 1  

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

    public class FirstActivity : Activity

    {

        int count = 1;



        protected override void OnCreate (Bundle bundle)

        {

            base.OnCreate (bundle);



            //Use UI created in Main.axml

            SetContentView (Resource.Layout.Main);



            var showSecond = FindViewById (Resource.Id.showSecond);

            showSecond.Click += (sender, e) => {

                var second = new Intent(this, typeof(SecondActivity));

                second.PutExtra("FirstData", "Data from FirstActivity");

                StartActivity (typeof(SecondActivity));

            };

        }

    }


---Activity 2

    [Activity (Label = "SecondActivity")]           

    public class SecondActivity : Activity

    {

        protected override void OnCreate (Bundle bundle)

        {

            base.OnCreate (bundle);


            // Create your application here


            SetContentView (Resource.Layout.Second);

            var label = FindViewById (Resource.Id.screen2Label);

            label.Text = Intent.GetStringExtra("FirstData") ?? "Data not available";

        }

    }

谢谢

Answer 1

好吧，当我自己重新制作这个项目时，我发现了这个问题。问题就出在这段代码中：

var second = new Intent(this, typeof(SecondActivity));
second.PutExtra("FirstData", "Data from FirstActivity");
StartActivity (typeof(SecondActivity));

发生的事情是，你用正确的数据做出了意图。但是您在没有这些数据的情况下开始了一个新的活动。要修复它，请将代码改为：

var second = new Intent(this, typeof(SecondActivity));
second.PutExtra("FirstData", "Data from FirstActivity");
StartActivity(second);`