Question

为什么text2.Text =“message”在我的代码中不起作用？我想在函数中以这种方式工作，参见代码。我在Visual Stduio中开发了Mono for android in C＃

源代码：

using System;
using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;

namespace ChatClient_Android
{
[Activity(Label = "ChatClient_Android", MainLauncher = true, Icon = "@drawable/icon")]
public class MainChat : Activity
{
    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);

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

        // Get our button from the layout resource,
        // and attach an event to it
        EditText text2 = FindViewById<EditText>(Resource.Id.text2);
     }

   private void  recieved()
   {
    text2.Text = "mesage";   // The text2 does not existe in this context 

    }
 }

}

Answer 1

声明

EditText text2不是全局的，而是声明方法。将EditText text2;放在课堂上。

应该是这样的：

public class MainChat : Activity
{
    EditText text2; // <----- HERE
    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);
        SetContentView(Resource.Layout.Main);
        text2 = FindViewById<EditText>(Resource.Id.text2);
     }

   private void  recieved()
   {
    text2.Text = "mesage";   

    }
 }

Answer 2

text2在OnCreate内定义，因此received对此一无所知。

您需要将text2定义为类字段，如下所示：

public class MainChat : Activity
{
    private EditText text2;
    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);

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

        // Get our button from the layout resource,
        // and attach an event to it
         text2 = FindViewById<EditText>(Resource.Id.text2);
     }

   private void  recieved()
   {
    text2.Text = "mesage";   // The text2 does not existe in this context 

    }
 }

为什么text2.Text =“message”在我的代码中不起作用？

2 个答案: