Question

我有三个活动A，B和C。我使用StartForResult（）将值从A传递到B，然后再次使用相同的startforResult（）将值从B传递给C。该值在活动B中已更新，我知道更新值是通过再次单击该按钮或再次打开该应用程序。但是，我需要显示的是从C传递值后的电导率B。如何解决此问题？会很大的帮助。因为我的代码是：

活动A

 public void okClick()
        {

            Intent updatevalue = new Intent(this, typeof(HoldingRegister));
            updatevalue.PutExtra("passclickedvalue", clickedvalue);
            updatevalue.PutExtra("PassParameters", textBox1.Text);
            SetResult(Result.Ok, updatevalue);
            Finish();
        }

活动B

protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
        {
            base.OnActivityResult(requestCode, resultCode, data);
            if (resultCode == Result.Ok)
            {
                int ValuedClicked = data.GetIntExtra("passclickedvalue", 0);
                string enterdata = data.GetStringExtra("PassParameters");
                PassUpdatedValues(enterdata, ValuedClicked);


            }
        }
        public void PassUpdatedValues(string datas, int ValuedClicked)
        {
            double val = Convert.ToDouble(datas);
            bool res = double.TryParse(datas, out val);

           if (ValuedClicked == 2)
            {
                if (res == true && val > -1 && val < 2)
                {
                    lblDensityCorrectionHR.Text = datas;
                    Intent HRvalue = new Intent(this, typeof(ToolBarMainActivity));
                    HRvalue.PutExtra("passclickedvalue", ValuedClicked);
                    HRvalue.PutExtra("PassParameters", datas);
                    SetResult(Result.Ok, HRvalue);
                    Finish();
               }
            }
         }

活动c

protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
        {
            base.OnActivityResult(requestCode, resultCode, data);
            if (resultCode == Result.Ok)
            {
                ValuedClicked = data.GetIntExtra("passclickedvalue", 0);
                enterdata = data.GetStringExtra("PassParameters");
                if (ValuedClicked == 2)
                {
                    Density(enterdata);
                }
}

 public void Density(string datas)
            {
                int addr = 0x13;
                int cmdNo = 03;
                ParamWrite(addr, true);
                               ListGlobalFrame.Clear();
                if (RsTransmitRec(cmdMake(cmdNo, CMD_RD), modestate) == true)                  {
                    if (DivRecData(GetRecData, cmdNo) == true)  //Response separation
                    {
                        Intent ReturnHRvalue = new Intent(this, typeof(HoldingRegister));
                        ReturnHRvalue.PutExtra("passclickedvalue", ValuedClicked);
                        ReturnHRvalue.PutExtra("PassParameters", RecDt.confDCorretion.ToString());
                        StartActivityForResult(ReturnHRvalue, 0);
                                                                   }
                    else
                    {
                        MsgLogDispSet("Invalid Response Data。", Android.Graphics.Color.Red);
                    }
                }
            }

Answer 1

问题原因： 您使用StartForResult（）方法的方式不正确

分辨率： 通过单击活动B上的按钮打开活动C时，如果要在从活动C中重试时获得结果，则需要使用StartForResult（）方法。同时，您需要在Acitivity C中使用SetResult（）并在Activity B中实现OnActivityResult（）接口。

我不太确定您的逻辑，因此我编写了一个简单的演示来描述StartForResult的用法：

演示：

ActivityA：

public class ActivityA : Activity
{
    Button button1;
    EditText textBox1;

    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);
        SetContentView(Resource.Layout.layout1);
        button1 = FindViewById<Button>(Resource.Id.button1);
        textBox1 = FindViewById<EditText>(Resource.Id.editText1);

        button1.Click += delegate {

            //Call Your Method When User Clicks The Button
            Intent updatevalue = new Intent(this, typeof(ActivityB));
            updatevalue.PutExtra("PassParameters", textBox1.Text);
            StartActivity(updatevalue);
        };

    }

}

ActivityB：

    public class ActivityB : Activity
{
    EditText edittext2;
    Button button2;
    string valueFromA;
    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);
        SetContentView(Resource.Layout.layout2);
        valueFromA = Intent.Extras.GetString("PassParameters");
        edittext2 = FindViewById<EditText>(Resource.Id.editText2);
        edittext2.Text = valueFromA;
        button2 = FindViewById<Button>(Resource.Id.button2);
        button2.Click += delegate {

            //Call Your Method When User Clicks The Button
            Intent updatevalue = new Intent(this, typeof(ActivityC));
            updatevalue.PutExtra("PassParameters", edittext2.Text);
            StartActivityForResult(updatevalue, 0);

        };
    }

    protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
    {
        base.OnActivityResult(requestCode, resultCode, data);
        if (resultCode == Result.Ok)
        {
            string dataFromC = data.GetStringExtra("PassParameters");
            edittext2.Text = dataFromC;

        }
    }
}

ActivityC：

    public class ActivityC : Activity
{
    EditText edittext3;
    Button button3;
    string valueFromB;
    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);
        SetContentView(Resource.Layout.layout3);
        valueFromB = Intent.Extras.GetString("PassParameters");
        edittext3 = FindViewById<EditText>(Resource.Id.editText3);
        edittext3.Text = valueFromB;
        button3 = FindViewById<Button>(Resource.Id.button3);
        button3.Click += delegate {

            Intent HRvalue = new Intent(this, typeof(ActivityB));
            HRvalue.PutExtra("PassParameters", edittext3.Text);
            SetResult(Result.Ok, HRvalue);
            Finish();
        };

    }

}

如何在Xamarin中启动更新的活动

1 个答案: