1 namespace Phoneword_Droid
 2 {
 3     public static class PhoneTranslator
 4     {
 5         public static string ToNumber(string raw)
 6         {
 7             if (string.IsNullOrWhiteSpace(raw))
 8                 return "";
 9             else
10                 raw = raw.ToUpperInvariant();
11 
12             var newNumber = new StringBuilder();
13             foreach (var c in raw)
14             {
15                 if (" -0123456789".Contains(c))
16                     newNumber.Append(c);
17                 else
18                 {
19                     var result = TranslateToNumber(c);
20                     if (result != null)
21                         newNumber.Append(result);
22                 }
23             }
24             return newNumber.ToString();
25         }
26 
27         public static int? TranslateToNumber(char c)
28         {
29             if ("ABC".Contains(c))
30                 return 2;
31             else if ("DEF".Contains(c))
32                 return 3;
33             else if ("GHI".Contains(c))
34                 return 4;
35             else if ("JKL".Contains(c))
36                 return 5;
37             else if ("MNO".Contains(c))
38                 return 6;
39             else if ("PQRS".Contains(c))
40                 return 7;
41             else if ("TUV".Contains(c))
42                 return 8;
43             else if ("WXYZ".Contains(c))
44                 return 9;
45             return null;
46         }
47     }
48 }

1             base.OnCreate(bundle);
2             SetContentView(Resource.Layout.Main);
3             EditText phoneNumberText = FindViewById<EditText>(Resource.Id.PhoneNumberText);
4             Button translateButton = FindViewById<Button>(Resource.Id.TranslateButton);
5             Button callButton = FindViewById<Button>(Resource.Id.CallButton);
6 
7             callButton.Enabled = false;

 1             string translatedNumber = string.Empty;
 2             translateButton.Click += (object sender, EventArgs e) =>
 3             {
 4                 translatedNumber = PhoneTranslator.ToNumber(phoneNumberText.Text);
 5                 if (String.IsNullOrWhiteSpace(translatedNumber))
 6                 {
 7                     callButton.Text = "Call";
 8                     callButton.Enabled = false;
 9                 }
10                 else
11                 {
12                     callButton.Text = "Call" + translatedNumber;
13                     callButton.Enabled = true;
14                 }
15             };

 1             callButton.Click += (s, e) =>
 2             {
 3                 //对话框
 4                 var callDialog = new AlertDialog.Builder(this);
 5 
 6                 //对话框内容
 7                 callDialog.SetMessage("Call" + translatedNumber + "?");
 8 
 9                 //拨打按钮
10                 callDialog.SetNeutralButton("Call", delegate
11                 {
12                     //使用意图拨打电话
13                     var callIntent = new Intent(Intent.ActionCall);
14 
15                     //将需要拨打的电话设置为意图的参数
16                     callIntent.SetData(Android.Net.Uri.Parse("tel:" + translatedNumber));
17                     
18                     StartActivity(callIntent);
19                 });
20 
21                 //取消按钮
22                 callDialog.SetNegativeButton("Cancel", delegate { });
23                 
24                 //显示对话框
25                 callDialog.Show();
26             };